N IO Z - R A PP O R T 1989 - 8
im ithiuf vonr ?
t e m * L:
»nnses
8401 Brcdene - btlg.u,,,. iel. "c5y / eo 37
TRACE ELEMENT GEOCHEMISTRY OF SANDY
SEDIMENTS AND OVERLYING WATERS AT
THE DOGGERBANK, NORTH SEA
P.M. Saager, H.J.W. de Baar, H.T. Kloosterhuis, W. van Raaphorst
Nederlands Instituut voor Onderzoek der Zee
BEWON Publication no 5
©1989
This report is not to be cited without the consent of:
Netherlands Institute for Oceanic Sciences
P.O. Box 59, 1790 AB Den Burg
Texel, The Netherlands
ISSN 0923 - 3210
IniHhisit «m U n-^àerem »ja no*
M t ó s ?... ^ ^
f'ririsôs
S4Ö1 Brederne - Belgium -
* ...,„■
Ït-I. 0 5 ? / C0 37 f 5
TRACE ELEMENT GEOCHEMISTRY OF SANDY
SEDIMENTS AND OVERLYING WATERS AT
THE DOGGERBANK, NORTH SEA
P.M. Saager, H.J.W. de Baar, H.T. Kloosterhuis, W. van Raaphorst
This research was carried out under supervision of
H.J. Lindeboom and J.P. Boon
NETHERLANDS INSTITUTE FOR OCEANIC SCIENCES
Beleidsgericht Wetenschappelijk Onderzoek NIOZ, publication no 5
NIOZ - RAPPORT 1989 - 8
SUMMARY
T h e trac e e l e m e n t c o m p o s i t i o n o f the s e d im e n ts , the w a t e r c o lu m n
a n d s u s p e n d e d p a r t i c u l a t e m a t t e r in the a r e a n e a r the D o g g e r b a n k
does not yield e v id en c e for large scale an th ro p o g e n ic inputs. It is as
ye t not p o s s i b l e to d i s t i n g u i s h b e t w e e n n a tu r a l (i.e. b a c k g r o u n d )
c o n c e n t r a t i o n s a n d m a n - m a d e i n f l u e n c e . I n t e r s t i t i a l w a t e r t ra c e
e l e m e n t c o n c e n t r a t i o n s are hig h in c o m p a r i s o n wit h th e v e r y low
c o n c e n t r a t i o n s f o r M n, Fe ( a nd Si, P) f o u n d in t h e p o o r s a n d y
D o g g e r b a n k s e d im e n ts and are o f the s a m e o r d e r o f m a g n i t u d e as
th o s e f o u n d fo r e ast P a c if ic s e d i m e n t s c o n s i s t i n g m a i n l y o f fin e
c la y s ( S H A W , 1987 ). T h e la rg e c o n c e n t r a t i o n g r a d i e n t s n e a r the
s e d i m e n t w a t e r i n t e r f a c e m a y r e s u l t in s u b s t a n t i a l fl u x e s to the
ov e rly in g North Sea waters. M i x i n g o f the sh allow N or th Se a waters
w o u l d q u i c k l y e r o d e th e e l e v a t e d c o n c e n t r a t i o n s r e s u l t e d f r o m
th e s e f lu x e s a fe w m e te rs av. ay fr o m the sea flo o r. It is h o w e v e r
likely that very
n ear the s ea flo o r d is so lv e d trace e lem en t
c o n c e n t r a t i o n s in t h e w a t e r c o l u m n are m u c h h i g h e r t h a n in
o v e r l y i n g w a te r s .
1.
Introduction
Thi s project is part o f the B E W O N ( B e l e i d s g e r i c h t W e t e n s c h a p p e l i j k
O n d e r z o e k N I O Z ) re s ea rc h p r o g r a m m e w h i c h fo c us es on the e c o lo g y
a nd tra ce c h e m i c a l p o ll u ta n ts
in the N o r t h Sea. In
the s u m m e r of
1988 the W I N D O W e x p e d it io n
on boa rd R V T Y R O in v e s t i g a t e d the
D o g g e r b a n k (Fig. 1). O u r o b je c t iv e was a first s tu d y o f the trace
m e t a l d i a g e n e s i s in c o a r s e s a n d y s e d i m e n t s . A l m o s t all p r e v i o u s
s t u d i e s i n v e s t i g a t i n g t r a c e m e t a l d i a g e n e s i s h a v e d e a l t w i t h fin e
g r a i n e d s e d i m e n t s , w h i c h are
far e a s i e r to s a m p l e a n d to p r o c e s s
t h a n s a n d y s e d i m e n t s . D u r i n g th e p a s t
t e n y e a r s th e
N orth Sea
w a t e r c o l u m n ha s b e e n e x t e n s i v e l y s t u d i e d f o r its d i s s o l v e d a nd
s u s p e n d e d p a r t i c u l a t e tr a c e e l e m e n t c o m p o s i t i o n
( D U I N K E R and
N O L T I N G , 1978; 1982; BA LLS, 1985a; 1985b; K R E M L I N G and H Y D E S ,
1988).
T h e c o m b i n a t i o n o f s p e c ia ll y d e s i g n e d w a t e r t i g h t b o x c o r e s w it h a
novel p ore w a te r cen tr if u g e tube a ll o w e d us to s am pl e larg e v o l u m e
i n t e r s t i t i a l w a t e r f r o m c o a r s e s a n d y s e d i m e n t s . F u r t h e r m o r e th e
sedim ent
itself and
the
im m ediately
overlying
w aters
and
suspended particulate matter were sampled.
T h e w a t e r o v e r l y i n g the D o g g e r b a n k and the are a in the i m m e d i a t e
vic in ity is v e ry s h a l l o w and n o w h e r e stat ion s w e r e d e e p e r th a n 90
m e te rs . T h e s e d i m e n t s in this re g i o n c o n s i s t o f c o a r s e s a n d s with
v e r y lo w c o n c e n t r a t i o n s o f or g a n ic m a tt e r a nd h a v e lo w b i o lo g ic a l
a c ti v it y . B e c a u s e o f th e n e a r - b y p r e s e n c e o f h ig h l y i n d u s t r i a l i z e d
c o u n t r i e s e l e v a t e d c o n c e n t r a t i o n s o f s o m e t r a c e e l e m e n t s are
expected.
2. M a te ri a ls and m e th o d s
2.1 S e d im e nt s
North Sea sediments
w e r e c o l l e c t e d w i t h n e w s t a i n l e s s steel
b o x c o r e s (50 c m i.d.). H o w e v e r , the use o f steel b o x c o r e s m u s t be
a v o i d e d in f u t u r e s t u d i e s s i n c e t h e y p r o b a b l y a re a s i g n i f i c a n t
source of contam ination. U p o n recovery subsam ples w ere taken
w it h a c i d - w a s h e d acry lic tu b e s (50 m m i.d. ). T h e s e d i m e n t cores
w e r e cut into 0.5 or 1 c m slices a nd the s e d i m e n t s w e re d r ie d at
105 ° C f o r 24 h o u r s . In o r d e r to m i n i m i z e c o n t a m i n a t i o n the
s e d i m e n t s w e re not gro un d, e x c e p t s a m p l e s 67 a n d 75 w h ic h w ere
p r o v i d e d by V a n R a a p h o r s t a nd K l o o s t e r h u i s .
T h e s e s a m p l e s had
b e e n g r o u n d in an a gate mill. T h e acry lic liners ha d b e e n b e v e le d
severa l tim e s on b o a rd ship in case the y ha d brok en . T h e lu bri can t
u s e d for b e v e li n g is also a lik e ly so u rc e o f c o n t a m i n a t i o n . A m p l e
s u p p l y o f a cid w a s h e d a cr y li c lin e rs is r e c o m m e n d e d a n d b r o k e n
liners m u s t be re p la c e d by c lea n new liners.
S e d i m e n t t e x t u r e a n a l y s e s w e r e m a d e by L A S E R - s p e c t r o m e t r y at
the U n i v e r s i t y o f U tr e c h t. S e d i m e n t p o r o s i t y w a s d e t e r m i n e d by
w e ig h t loss o f the samp le after d ry in g at 105 ° C fo r sev e ra l hours.
T he organic carbon content and total nitrogen content were
d e t e r m i n e d by C H N - a n a l y z e r at th e L i m n o l o g i c a l I n s t i t u t e . T h e
a l u m i n u m c o n c e n t r a t i o n was d e t e r m i n e d a fte r tota l d i g e s t i o n o f the
s e d i m e n t a nd m e a s u r e d by f l a m e A A S ( P e r k in E l e m e r 4 0 3 a to m ic
absorption spectrophotom eter),
see b e lo w for to ta l d ig e s tio n
p r o c e d u r e . D a ta on s e d im e n t p o ro s it y , or g a n ic c a r b o n c o n te n t , total
n i t r o g e n c o n c e n t r a t i o n a nd a l u m i n u m c o n c e n t r a t i o n w e r e p r o v i d e d
by V a n R a a p h o r s t and K lo os te rh ui s.
F o r the d e t e r m i n a t i o n o f the total m e ta l c o n te n t a bo ut 0.5 g r a m of
hom ogenized
sedim ent
was
digested
using
a
m ixture
of
H F / H N O 3/HCI (5 ml HF, 1 ml A q u a R eg ia , ul tr ap u re qual ity ) in a
t e f l o n b o m b at 120 ° C f o r 6 h o u r s . A f t e r d i g e s t i o n 30 ml
s u p e r s a t u r a t e d u l t r a p u r e b or ic ac id w e r e a d d e d a n d the v o l u m e
w a s a d ju s t e d to 100 ml with d o u b le di s ti ll e d wa ter. Six p r o c e d u r a l
bl a n ks c o n s i s t i n g o f re a ge nt s only w ere tr e a te d a c c o rd in g ly .
M a n y e l a b o r a t e s c h e m e s ex ist to d e t e r m i n e the r e a c t i v e fr a c ti o n o f
the tr a c e m e ta l c o n t e n t in the s e d im e n t. T h e r e a c t i v e t ra c e m e ta l
frac tio n is the a m o u n t of trace metal that can go into s ol u tio n un d e r
c h a n g i n g p h y s i c o - c h e m i c a l c o n d i t i o n s in the s e d i m e n t p o r e w a te r s,
e.g. c h a n g i n g re d o x po te nti al or pH. In this stud y a one step acid le a c h w i t h 1 N HC1 w as u s e d to a s s e s s th e t o t a l a m o u n t o f
e x ch a n g e a b le metal, without attem pting or c laim in g any subtle
d i s t i n c t i o n b e t w e e n t h e v a r i o u s c h e m i c a l s o l i d p h a s e s in t h e
s e d i m e n t . It is t h o u g h t tha t m o s t o f the r e a c ti v e m e ta l f r a c ti o n is
p r e s e n t in
f e r r o m a n g a n e s e oxi de s and or g a n ic c o a ti n g s , w h ic h will
l a r g e l y d i s s o l v e by this m e t h o d (D E B A A R et al., 198 8) . It is
h o w e v e r i m p o r t a n t to r e m e m b e r t h a t t h e m e t a l c o n t e n t t h u s
d e t e r m i n e d is o p e r a t i o n a l l y d e f i n e d and not n e c e s s a r i l y r e l a t e d to
c e r t a i n in s it u c h e m i c a l p h a s e s in th e s e d i m e n t . T h e r e s i d u a l
f r ac tio n is t h o u g h t to be in c o rp o ra te d w ith in the c rys tal s tru c tu re of
s ili cat e la tti ces a nd is b e l i e v e d to be inert u n d e r l o w t e m p e r a t u r e
geochem ical conditions.
F o r the d e t e r m i n a t i o n of the a c i d - l e a c h a b l e f r a c t i o n 0.5 g r a m o f
h o m o g e n i z e d s e d im e n t was le ach ed in 50 ml ultra p ur e 1 N HC1 for
24 ho urs . T h r e e p r o c e d u r a l bla nk s c o n s is ti n g o f r e a g e n t s o n ly w e re
treated accordingly.
M n , Fe a nd T i w e r e m e a s u r e d by F l a m e A A S ( P e r k in E l m e r 403
a t o m i c a b s o r p t i o n s p e c t r o p h o t o m e t e r ) u s i n g the m e t h o d o f s t a n d a r d
a d d it io n . Cd, Co , Cu, Ni, Pb and Zn w e r e m e a s u r e d by G r a p h i t e
Furnace
AAS
(P erkin
Elm er
5000
atom ic
absorption
spectrophotom eter, H G A -500 heated graphite furnace and AS-40
a u t o s a m p l e r ) also u s i n g s ta n d a r d a ddit io n . P r e c i s i o n o f th e m e t h o d
is 10 p e rc en t. B l a n k c o n c e n tr a ti o n s w er e a lw ay s b e l o w the de te c ti o n
limit.
T h e a c i d - l e a c h e d s e d i m e n t w as not t r e a t e d by th e t o ta l d i g e s t i o n
p r o c e d u r e a f t e r w a r d s . T o j u s t i f y this d e c i s i o n a s e d i m e n t ( s a m p l e
98, 2 0 - 3 0 c m ) w as split into tw o parts in a s e p a r a te e x p e r i m e n t .
O n e part w as c o m p l e t e l y di ge st ed as d e sc ri b e d abo ve, the oth e r part
w as first le ac he d in 1 N HC1 and th e n d ig e st ed like the oth er half.
T h e result is s ho w n in table 1.
2 .2
In t e r s t i t i a l
water
F o r th e c o l l e c t i o n o f i n t e r s t i t i a l w a t e r s s e d i m e n t b o x c o r e s w e r e
s u b s a m p l e d u s i n g a c i d - w a s h e d a c r y l i c l i n e r s (5 c m i. d . ) . T h e
s e d i m e n t c o re s w e r e i m m e d i a t e l y t r a n s p o r t e d to a n i t r o g e n g lo v e box situated in a cold van and su bs a m pl e d in 0.5 or 1 c m slices at in
situ t e m p e r a t u r e u n d e r an inert a t m o s p h e r e .
T h e s e d i m e n t s w e re
c e n t r i f u g e d u n d e r n i t r o g e n at 1500 g f o r fiv e m i n u t e s ( M S E - 2 0 0
centrifuge).
T h e c e n t r i f u g e tu be s h a d b e e n s p e c ia ll y d e s i g n e d for
th e e x t r a c t i o n o f c o a r s e s a n d y
s e d i m e n t ( S A A G E R et al., 1989).
P r e c a u t i o n s w e r e t a k e n to a v o id t ra c e m e t a l c o n t a m i n a t i o n d u r i n g
s a m p l i n g a nd p r o c e s s in g . T h e fi lt ra te
was imm ediately discarded
into h o t - a c i d c l e a n e d p o l y e t h y l e n e b o tt le s a n d a c i d i f i e d to p H 2
w i t h t r i p l e q u a r t z d i s t i l l e d H N O 3 to p r e v e n t o x i d a t i o n o f r e d o x
s e n s it iv e e l e m e n ts , algal g r o w t h and a d s o r p t i o n o f t ra c e m e ta ls to
the wall of the vials.
For
the
analysis
of
trace
elem ents
the
sam ples
were
p r e c o n c e n t r a t e d with A P D C - D D D C so lvent e x tr a c ti o n ( D A N I E L S S O N ,
1979) m o d i f i e d a fte r G E R R I N G A (P ers. C o m m . ) as f o ll o w s . T e n
m ill il ite r o f the s am pl e was b u ff e re d to p H 4-4.5 w ith 0.1 m l o f a
m ix tu r e c o n ta i n in g a m m o n i u m ace ta te/a c e tic acid a nd
APDC/DDDC.
A fter vigo ro u s shaking the m e ta l-A P D C /D D D C - c o m p le x e s were
e x t r a c t e d into 10 ml of F R E O N and th e n b a c k e x t r a c t e d into 0.1 ml
trip le q u a rtz d is tille d c o n c e n tra te d H N O 3. Lastly 1 ml quartz
di s til le d H 2O was add ed to obtain a pre c o n ce n tr a ti o n o f a factor 10.
F e a nd M n w e re dir ec tly m e a s u r e d ei th e r by F l a m e A A S or direct
injection Graphite Furnace AAS using standard addition. The pre­
c o n c e n t r a t e d s a m p l e s a n a l y z e d fo r Cd, Co, Cu, Ni, Pb a nd Z n by
G r a p h i t e F u r n a c e A A S u s i n g s t a n d a r d a d d it io n . O v e r a l l p r o c e d u r a l
b l a n k s w e r e m a d e by e x t r a c t i n g r e a g e n t s o n ly a n d c o n c e n t r a t i o n s
w ere
corrected
for
blank
concentrations.
P recision
of the
m e a s u r e m e n ts is 3% for Fe and M n and 5% for the other elements.
F o r m e a s u r i n g in te rs tit ia l w a t e r n u t r i e n t p r o f il e s s e p a r a t e s e d i m e n t
s lic es w e r e s q u e e z e d w it h R e e b u r g h ty p e s q u e e z e r s ( R E E B U R G H ,
19 67 ). N u t r i e n t c o n c e n t r a t i o n s w e r e d e t e r m i n e d by a u t o a n a l y z e r
a cco rding to the m e th od of S T R I C K L A N D and P A R S O N S , 1968.
2.3
Suspended
Particulate
M atter
S u s pended particulate m atter was collected on acid -rin sed p r e ­
w e i g h e d 0.4 | i m N u c l e p o r e filter s m o u n t e d in an a c i d - c l e a n e d all
T e f l o n f i l t r a t i o n u n i t . In t h e s h o r e l a b o r a t o r y t h e f i l t e r s w e r e
w e i g h e d and th e n
l e a c h e d in a bou t 30 ml triple q u a r t z - d i s t i l l e d I N
HC1 fo r 24 ho urs . U n u s e d , p r e c l e a n e d filters w e r e also l e a c h e d to
a ss e ss b l a n k c o n c e n t r a t i o n s . T h e me ta l c o n c e n t r a t i o n w a s m e a s u r e d
by G r a p h i t e F u r n a c e A A S w it h s t a n d a r d a d d i t i o n . B l a n k s w e r e
a l w a y s b e l o w d e t e c t i o n limit.
2.4 D i s s o l v e d tr a c e e le m e n ts
S e a w a t e r s a m p l e s w e r e c o ll e c te d u s in g a C T D - R o s e t t e s a m p l e r with
p re -c le an e d , m o d i f i e d ( B R U L A N D et al., 1979) 12-litre G o F l o bottles
(G e ne r al O c ea nic s) . T h e rosette s a m p l e r w as first sent d o w n in orde r
to obta in real ti m e h y d ro g r a p h ic d a ta and to flush the G o F lo bottles.
U p o n r e c o v e r y , th e b ot tle s w h ic h w e r e s a m p l e d d u r i n g th e up c as t,
w ere h o o k e d onto the outside o f a clean air lab cont ai ner. T h e wa te r
was p r e s s u re fil ter ed t h ro u g h a c i d - w a s h e d 0.4 ji m N u c l e p o r e filters,
u s i n g in-line p r e - c l e a n e d all T e f l o n fil tra tio n units a n d st o re d in 1
li tr e h o t a c i d c l e a n e d p o l y e t h y l e n e b o t t l e s . T h e s a m p l e s w e r e
acidified to pH 2 with triple qua rtz distilled H N O 3.
Su r fa c e w a te r s a m p l e s w er e c o ll e c te d with a r u b b e r bo a t a b o u t 200
m e te rs u p w i n d fr o m the m a in vessel. S a m p le s w e re c o ll e c te d in hot
ac id c l e a n e d 1 litre p o l y e t h y l e n e bott le s a nd i m m e d i a t e l y a c id i fi e d
on bo a rd ship. T h e s a m p l e s w e re not filtered.
In th e s h o r e l a b o r a t o r y th e s a m p l e s w e r e p r e c o n c e n t r a t e d u s i n g
C h e l e x - 1 0 0 io n e x c h a n g e c h r o m a t o g r a p h y m o d i f i e d a ft e r D E B A A R
(1 98 3) . O n l y a c i d - w a s h e d T e f l o n la b w a r e w a s u s e d fo r the C h e l e x
c o l u m n s . Q u a r t z dis ti ll e d r e a g e n ts a nd u l t r a p u r e M i l l i - Q w a t e r w ere
u s e d a fte r b l a n k c o n c e n t r a t i o n s w e r e a s s e s s e d a nd f o u n d n e g li g ib le
or b e lo w
d e tec tio n limit. All h a ndlin g was p e r f o r m e d ins ide a class100 l a m i n a r fl o w b e n c h s it ua te d in a c le a n air la b o r a to r y . O v e ra l l
p r o c e d u r a l b la n k s w e r e a s s e s s e d by e x t r a c t i n g r e a g e n t s a c c o r d i n g
to the p ro c e d u re us ed for sea water.
T h e e x t r a c t s w e r e m e a s u r e d by G r a p h i t e F u r n a c e A A S a g a i n s t a
s ta n d a rd cal ib ra ti on cu rv e m a d e in 0.1 N H N 0 3 (Perkin E l m e r 5000
atomic absorption spectrometer, H G A -500 heated graphite furnace,
A S-40 autosam pler). Procedural blanks were mostly
low and
c o n c e n tr a ti o n s were c o rr e c t e d for blan ks. P r e c is io n o f the m e t h o d is
5% for most el ements and 10% for Pb.
3. Results
3.1
Sediment
c h a r a c te r is ti c s
T h e s ed im en ts of the D o g g e r b a n k a re a a nd v ic in ity ha ve
a coar se
s a n d y t e x t u r e a n d c o n c o m i t a n t l o w p o r o s i t y ( ta b le 2). O n the
D o g g e r b a n k p ro p e r the grain size a ver ag e s 200 (im (stas. 21, 56, 67,
75 ), the tex ture b e c o m i n g slightly m ore fine g r a in e d a w a y fr o m the
D o g g e r b a n k (sta. 15 = 160 |im , stas. 8 and 98 aver age grain size is
about
100-130
u m ) . At stations 21, 56, 67 a nd 75 the a m o u n t of
pa rti cles s ma ll er tha n 20 (im (siltsize) is less th a n 1 %, w h e re a s the
a m o u n t o f particles smaller than 2 | i m (clay fraction) w as b e lo w the
d e te c ti o n limit. At station 15 a bout 3% o f the pa rti cl es was smal ler
th a n 20 | i m , while no particles s m al le r th a n 2 | i m w e r e m e a s u r e d .
At stations 8 and 98 about 5-10 % o f the particles was s m al ler than
20 (im, the a m o u n t of particles smal ler tha n 2 (im bei ng less th a n 1
%. T h e poros ity o f the sediments range s fr o m 35 % to 4 5 % at stations
21, 56, 67 and 75. P o r o s i t y was not m e a s u r e d fo r s ta ti on 15, At
statio n 16a, loc ated near station 15 it a ver ag es 4 5 % w hile at stations
8 and 98 the porosity is about 4 5 -5 5 % (table 3).
T h e organic c ar b o n cont ent (table 3) is less than 0.5 % at stations 21,
56, 67 and 75. At stat ion s 8 and 98 the org a nic c a r b o n c o n te n t is
a bout 0.5 -0 .7 % . N o da ta are a vai la ble fo r station 15. At st ation 16a
the org a nic c a r b o n c o nt en t is less than 0.5%. At stations 21, 56, 67
and 75 the Al-c onte nt (table 3) is about
1% w hil e at stations 8 and
98 the A l- c o nt e nt is about 2%.
A c c o r d i n g to a b o v e c h a r a c t e r i s t i c s the s e d i m e n t s c a n be d i v i d e d
into tw o d is tin c t g ro u p s with only station 15 ta k in g an in te rm e d ia te
p o s it io n . S t a t i o n s 2 1 , 56, 67 and 75 h a v e c o a r s e s e d i m e n t t e x tu r e
and lo w p o ro s it y , with also low org a nic c a r b o n a n d A l -c o n te n t. At
st at ion s 8 a nd 98 s e d i m e n t t e x tu r e is less c o a r s e w it h a m o d e s t l y
h i g h e r p o r o s i t y tha n at the o th e r stations. Also th e o r g a n ic c a r b o n
a nd the A l -c o n te n t are h ig h e r at these stations.
3.1.1 Ti, Fe, M n
T h e T i - c o n t e n t ( t a b l e 4, Fig .
2a) d o e s not e x h i b i t s i g n i f i c a n t
d i f f e r e n c e s b e t w e e n s ta ti on s. T h e c o n c e n t r a t i o n va rie s b e t w e e n 0.1
and 0.4 % wt. w hil e no c lea r trends c an be di sce rne d. I n te rp r et a tio n
is d iff ic ul t w it h o u t i n f o r m a t i o n on the m i n e r a l o g i c a l c o m p o s i t i o n o f
th e s e d i m e n t .
T h e F e c o n t e n t (ta bl e 4, Fig.
2b) e x h i b i t s i n t e r e s t i n g d i f f e r e n c e s
b e t w e e n the two g ro u p s o f sedim ent s. At stations 21, 56,
67 and 75
the total F e - c o n t e n t is l o w e r th a n at st at io ns 8 , 15 a n d 98 by a
fa c t o r of a b o u t 1.5. T h e re la tiv e p e r c e n t a g e o f a c i d - l e a c h a b l e Fe is
h o w e v e r lo w e r by a fac tor 2. T hi s implies that at stations 8 , 15 and
98 a g r e a t e r p a r t o f th e Fe is p r e s e n t as F e ( M n ) o x y h y d r o x i d e s
h a v i n g i m p l i c a t i o n s f o r th e i n t e r s t i t i a l w a t e r Fe c o n c e n t r a t i o n s ,
s in c e u n d e r r e d u c i n g c o n d i t i o n s F e - o x y h y d r o x i d e s go int o so lu tio n.
N o n e o f t h e s e d i m e n t s s h o w F e e n r i c h m e n t at t h e t o p o f the
s e d i m e n t c o l u m n . U p w a r d m i g r a t i o n o f d i s s o l v e d Fe f o l l o w e d by
o x i d a t i v e p r e c i p i t a t i o n in the oxic zon e w a s not o b s e r v e d . T h e Fec o n c e n t r a t i o n s f o u n d in th e s e s e d i m e n t s fall in th e r a n g e o f Fel e v e l s g e n e r a l l y e n c o u n t e r e d in s a n d y s e d i m e n t s ( D R E V E R , 1982)
a nd are a bo ut a fa c to r of 5-7 lo w e r tha n e s tu a ri n e clays a nd op en
o c e a n s e d im e n ts ( G R A Y B E A L and H E A T H , 1984; S A L O M O N S and
FO E R S T N E R , 1984).
M n c o n c e n t r a t i o n s ra n g e fr o m 80 to 300 m g / k g (table 4, Fig. 2c)
a n d a ls o fall in th e r a n g e n o r m a l l y f o u n d f o r s a n d y s e d i m e n t s
( D R E V E R , 1982). As for Fe the cl earest trend s are d is p la y e d by the
r e l a t i v e a m o u n t o f a c i d - l e a c h a b l e M n . In t h e s e d i m e n t s o n th e
D o g g e r b a n k less than 10% o f the M n is a c id - le a c ha bl e. T h i s implie s
th a t the a m o u n t o f r e a c ti v e M n w h ic h c a n go into s o l u t i o n u n d e r
r e d u c i n g c o n d i t i o n s is also ve ry low. At s ta t io n 21 a b o u t 2 5 % is
le a c h a b le and at the stations a w a y f r o m the D o g g e r b a n k a bou t 35%
(stas. 8 and 98) to 60% (sta. 15)
o f the M n is a c id - le a c hab l e. At
s t a t i o n s 15, 75 and 98 t h e r e is c l e a r e v i d e n c e o f d i a g e n e t i c M n
e n r i c h m e n t in the to p l a y e r o f th e s e d i m e n t , r e s u l t i n g f r o m the
u p w a r d m ig r at io n o f re d u c e d M n and pre c ip it a ti o n in the oxic u p p e r
c e n t i m e t e r s o f the se d im e n t. T h i s e n r i c h m e n t is b e s t d i s p l a y e d by
t h e a c i d - l e a c h a b l e f r a c t i o n s in c e the p r e c i p i t a t e d M n c o n s i s t s o f
M n(Fe)-oxyhydroxides.
3.1 .2 T r a c e
e le m e n ts
F o r a fe w e le m e n ts the le a c h a b le m e ta l c o n t e n t is la rg e r th a n the
total m e ta l co nten t, a lt h o u g h the d if f er en c e is m o s tl y small. F o r Ni
this is always the case, for Co and C u at a few stations and for Zn at
one station. It sugg est s that a m a j o r a m o u n t o f the me ta l c on tent is
p r e s e n t in the l e ac h a b le fr action.
P o o r h o m o g e n i z a t i o n o f th e s a m p l e s e s p e c i a l l y o f s a m p l e s w h ic h
w e r e not g r o u n d (i.e. all e xce pt stations 67 and 75) p r o b a b ly part ly
e x p l a i n s this o b s e r v a t i o n . P r e c i p i t a t e s , f o r m e d in the m a t r i x u s e d
f o r t o t a l d e s t r u c t i o n o f t h e s e d i m e n t , w h i c h c o p r e c i p i t a t e t ra c e
m e ta ls is possible, th ou gh not ve ry likely. T h e low c on c e n tr a ti o n s in
t h e s e s e d i m e n t s , o ft e n n e a r the d e t e c t i o n li m it p o s s i b l y p r e v e n t a
g o o d r e p ro d u c ib il it y as well.
Cd: T o t a l C d - c o n c e n t r a t i o n s (ta bl e 4, Fig . 2d) s h o w c o n s i d e r a b l e
s c a tt e r a nd do not e x h i b i t s ig n if ic a n t d i f f e r e n c e s b e t w e e n s tat ion s.
T h e re la ti v e a m o u n t o f a c i d - l e a c h a b l e C d is slightly h i g h e r at the
stations o ff the D o g g e r b a n k (stas. 8 , 15, 98, a bout 20 % le ach ab le Cd)
th a n at the stations on the D o g g e r b a n k (stas. 21, 56, 67 and 75, with
about 10% leach ab le Cd). At stations 21, 67, 75 and 98 there is
e n r i c h m e n t in t h e u p p e r c e n t i m e t e r s o f t h e s e d i m e n t .
diagenetic processes and anthropogenic input sources m ay
su ch e n r i c h m e n t s , but f u r t h e r the re is no e v i d e n c e f o r la rg e
a n t h r o p o g e n i c i n f l u e n c e in t h e s e s e d i m e n t s . C o n c e n t r a t i o n s
c ha ra c te ris tic for s an dy s ed im en ts ( D R E V E R , 1982).
som e
Both
yield
scale
are
Co: At m o s t st ations the a m o u n t o f a c id - le a c h a b l e Co (table 4, Fig.
2e) is larger th a n the total Co-c onten t. F o r this re a s o n only leach ab le
C o - p r o f il e s are
d i s p l a y e d in Fig. 2e fo r st ations 8 , 21, 56, 67, 75.
T h e d a t a m u s t be c o n s i d e r e d m e r e l y as a n i n d i c a t i o n
o f the
c o n c e n t r a t i o n le vel s. O n l y f o r s ta t io n s 15 a n d 98 b o t h t o t a l and
a c id - le a c h a b l e Co are d is pla ye d. M o s t Co is p r e s e n t in the le ac ha ble
fr a c ti o n (8 0 % ). S in c e Co has its o w n o x i d a t i o n - r e d u c t i o n c h e m i s t r y
pa rt o f th is l e a c h a b l e Co c o u l d go into s o l u t i o n u n d e r r e d u c i n g
co nditi on s at a bout the sam e r e do x- po te nti a l as for M n ( H E G G I E and
L E W I S , 1984). T h e a m o u n t of l e a c h a b le Co is m u c h h i g h e r at the
stations o f f the D o g g e r b a n k th a n at the st ations on the D o g g e r b a n k .
No e vidence of e ith er diagenetic en ric h m en t or a n thropogenic
i n p u t s c a n be
i n f e r r e d f r o m the da ta . C o n c e n t r a t i o n s fa ll
in the
r a n g e re port e d for s a n d y sed im en ts ( D R E V E R , 1982)
Cu: C on ce ntra tio ns (table 4, Fig. 2f) fall in the range typical o f sandy
s e d i m e n t s ( D R E V E R , 1982). C o n c e n t r a t i o n s o f l e a c h a b l e C u are
low est on the D o g g e r b a n k (stas. 67, 75, ab out 50 % C u is leachable),
th e d i f f e r e n c e b e i n g less o b v i o u s fo r t o ta l C u - c o n c e n t r a t i o n s . At
s ta t io n 98 a b o u t 7 0 % o f the t o ta l Cu c o n t e n t is p r e s e n t in the
leachable
f r a c t i o n . T h e r e is no e v i d e n c e f o r d i a g e n e t i c o r
a n t h r o p o g e n i c e n r i c h m e n t in the s e d im e n t.
Ni: At all stations the le ac ha bl e Ni frac tio n w as h ig h e r th a n the total
N i c o n te n t (table 4, Fig. 2g). T h e da ta m u s t th u s be r e g a r d e d as an
i n d i c a t i o n o f the c o n c e n t r a t i o n le v e l s at b e st . C o n c e n t r a t i o n s are
t y p i c a l f o r s a n d y s e d i m e n t s ( D R E V E R , 198 2) . As f o r t h e o t h e r
m e ta ls , also le a c h a b l e Ni c o n c e n t r a t i o n s are h i g h e s t at the stat ion s
o f f the D o g g e r b a n k .
Pb: O n l y total Pb d a ta are a v ai l ab le (table 4, Fig. 2h). S in c e Pbc hl o ri d e is very ins ol ub le the aci d- le a c h m e t h o d c a n n o t be u s e d for
Pb. B a s e d on reult s fo r s a n d y s e d i m e n t s in th e W e s t e r n S c h e l d t
( S A A G E R , 1986) it is re aso na ble to a ss um e about 3 0 -5 0 % o f the Pbc o n t e n t will be pre s e n t in the l e ac h a b le frac tio n. As fo r the o th e r
m e t a l s h i g h e s t c o n c e n t r a t i o n s are f o u n d at t h e s t a t i o n s o f f th e
D o g g e r b a n k w i t h o u t any e v i d e n c e fo r d i a g e n e t i c or a n t h r o p o g e n i c
i n p u t s o u r c e s . Pb le v e l s are c h a r a c t e r i s t i c f o r s a n d y s e d i m e n t s
(DR EVE R, 1982).
Zn: C on cen tra tio n s (Table 4, Fig. 2i) are hig he st of f the D o g g e r b a n k
(stas. 8 , 15 and 98) and a large part (ab out 70 % ) is f o u n d in the
le ach ab le fraction, w he re a s at stations 56, 67 and 75 on ly 4 0 - 5 0 % is
p r e s e n t as l e ac h a b le Zn, the total Z n c o n te n t s h o w i n g c o n s i d e r a b l e
s c a tt e r . Z n c o n c e n t r a t i o n s fall in th e r a n g e r e p o r t e d f o r s a n d y
s e d i m e n t s ( D R E V E R , 1 9 8 2 ). T h e r e is no e v i d e n c e f o r e i t h e r
d ia g e n e ti c or a n th r o p o g e n ic inp ut sources.
G en era l: A m a jo r part o f the trace e l e m e n t c o n te n t is f o u n d in the
a c id - l e a c h a b l e fraction. T h i s fra c tio n r e p r e s e n ts the re a c t i v e part o f
the me ta ls in the sedi me nt. At the stations o f f the D o g g e r b a n k the
a m o u n t o f r e a c t i v e m e ta l in the s e d i m e n t is h i g h e r t h a n on the
D o g g e r b a n k itself. Part o f this can be e x p la i n e d by the d if f er en c e in
te x tu ra l c o m p o s i ti o n . T h e a m o u n t o f fine g r a in e d par ticles is h ig h e r
in th e s e d i m e n t s o f f the D o g g e r b a n k . S m a l l e r p a r t i c l e s h a v e a
g r e a t e r a f f i n i t y to a d s o r b t r a c e m e t a l s b e c a u s e o f t h e i r h i g h e r
specifi c su rface area (the total su rface area o f on e c ub ic c e n ti m e te r
o f particles). G e n e ra ll y the m a jo r part o f r e a ct iv e m e ta ls is th o u g h t
to be pre sen t in the fraction smaller than 63 (im ( S A L O M O N S a nd
FO E RS TN ER , 1984).
3 .2
I n te r s ti ti a l
water characteristics
General: Nu trient results are sh ow n in Ta b le 5. N o final o x y ge n data
a nd only p r e li m in a r y prof iles w ere a vai la ble at the ti m e this repo rt
w a s m a d e . T h e o x y g e n c h a r a c t e r i s t i c s a re s u m m a r i z e d b r i e f l y
b e lo w . T h e re s u lt s fo r M n and Fe as well as o f the o th e r trace
e le m e n ts are s how n in table 6 and figures 3-8.
At all st at io ns the s e d i m e n t s are a n o xi c b e lo w 4-6 m m de p th . At
station 75 a no xic c o n d it io n s set in at 1 c m dep th. In the u p p e r one
c e n t i m e t e r n i t r a t e c o n c e n t r a t i o n s r e a c h a m a x i m u m r a n g i n g fr o m
10 | i M (sta. 56) to 45 | i M (sta.8). At station 75 the nitrate m a x i m u m
is r e a c h e d at 3 c m de pt h. B e l o w this m a x i m u m c o n c e n t r a t i o n s d ro p
e x p o n e n t i a l l y as a r e s u l t o f n i t r a t e r e d u c t i o n a n d r e a c h l e v e l s
b e t w e e n 0 .5 - 5 (iM , the low le v e l s p o s s i b l y r e s u l t i n g f r o m fi lt er
bl an ks . Ju st at or b e lo w the onset o f nitrate re d u c ti o n M n re d u c ti o n
s tar ts, r e s u l t i n g in e l e v a t e d M n c o n c e n t r a t i o n s in t h e i n t e r s t i t i a l
w a t e r s . At t h e s a m e d e p t h or at s o m e s t a t i o n s j u s t b e l o w , Fe
r e d u c t i o n sets in as wel l, also l e a d i n g to e l e v a t e d d i s s o l v e d Fe
c o n c e n t r a t i o n s in t h e i n t e r s t i t i a l w a t e r s . B e l o w t h e o x i d a t i o n
s e q u e n c e for the b r e a k d o w n of o r g a n ic m a tt e r is gi v e n , a s s u m i n g
reactive M n and Fe are present in the s ed im en t as M n 0 2 a n d F e O O H
r e s p e c ti v e ly . A v e r a g e org a n ic m a t t e r is r e p r e s e n t e d b y th e f o r m u l a
( C H 20 ) i o 6 ( N H 3) i 6 (H3PO4) (f ro m F R O E L I C H et al., 1979):
ox id a n t is oxygen:
(C H 2O )i06 (NH3) i 6 (H3PO4) + 138 O2 = 106 CO2 + 16 HNO3 + H3PO4 + 122 H2O
o x i d a n t is nitrate:
(C H 20)106 (NH3)i6 (H3PO4) + 94.4 HNO3 = 106 CO2 + 55.2 N2 + H3PO4 + 177.2 H2O
o x i d a n t is m a n g a n e s e :
(C H 2 O )i0 6 (NH3) i 6 (H3PO4) + 236 MnC>2 + 472 H+ = 236 Mn2+ + 106 CO2 + 8N2 +
H3PO4 + 366 H2O
ox id a nt is iron:
(C H 2O )i06 (NH3)i 6 (H3PO4) + 424 FeOOH + 484 H+ = 424 Fe2+ + 106 CO2 + 16 NH3 +
H3PO4 + 742 H2O
S u l f i d e w a s no t m e a s u r e d b u t
gre y -b la c k Fe-sulfides were
o b s e r v e d fr o m 3-4 c m d o w n w a r d s . A m m o n i a c o n c e n t r a t i o n s also
i n c r e a s e d o w n w a r d s r e a c h i n g l e v e l s r a n g i n g f r o m 1 5 -7 0 j i M .
A m m o n i a is a produ ct of iron- and sulphate red uc tion ( F R O E L I C H et
al., 1979). A m m o n i a c on ce ntra tio ns are at the (very) low e n d o f the
r a n g e r e p o r t e d for o p e n o c e a n p o r e w a t e r st u d ie s. T h e c y c li
of
s i l i c a t e a n d p h o s p h a t e a l s o a p p e a r to b e i n f l u e n c e d to
a
co nsi d e ra ble degre e by the redox cycle o f Fe but dis cu s s io n o f these
e l e m e n t s is b e y o n d the sco pe o f this r e p o r t . Also f o r s ili cat e and
p h o s p h a t e th e c o n c e n t r a t i o n s are at th e l o w e n d o f t h e r a n g e
n o r m a l l y e n c o u n t e r e d in op e n o c e a n se d im en ts .
M n and Fe: B e c a u s e o f a noxic c o n d it io n s p r e v a i l i n g at all stations
in te rs tit ia l w a t e r M n and Fe c o n c e n t r a t i o n s i n c r e a s e d o w n w a r d s in
the s e d i m e n t (Fig. 3,4). T h e m a x i m u m c o n c e n t r a t i o n s r e a c h e d are
h o w e v e r la rge ly d e t e r m i n e d by the a m o u n t o f M n F e - o x y h y d r o x i d e s
in the solid state, this is the a m o u n t o f pot e ntia lly r e du c ib le M n and
Fe . As w i t h s o li d st at e s e d i m e n t c h a r a c t e r i s t i c s t h e s a m e tw o
dis tinct grou ps can be identified on basis o f the interstitial M n
and
Fe c o n c e n tr a ti o n s , statio n 15 b e in g i n te r m e d ia te . A t the st ations on
the D o g g e r b a n k M n valu es start in c re a s in g at a d e pth o f 1 c m and
reach
m axim um
concentrations
of
only
1-2
|iM !
These
concentrations
are
a m o n g st the
low est reported
for anoxic
s ed im e n ts thus far. At station 15 ju s t o f f the D o g g e r b a n k m a x i m u m
M n co n ce n tr a ti o n s are r e a c h e d in the u p p e r fe w m il li m et er s (4 | i M )
a n d d e c r e a s e s h arp ly to c o n s t a n t v a lu es a r o u n d 1.5 (iM at 3-7 cm
de p th . At the st ations o f f the D o g g e r b a n k M n
c o n c e n t r a t i o n s are
b e l o w det ect io n limit near the su rface
and inc re ase fr o m 0.2 to 0.7
c m depth re a ch in g m a x i m u m co n ce n tr a ti o n s o f a bou t 28 a nd 41 | i M
at 1-3 c m depth at stations 8 and 98 re sp ec tiv e ly . T h e s e valu es are
still at the low e nd o f interstitial w a te r M n c o n c e n t r a t i o n s n o r m a ll y
f o u n d fo r r e d u c i n g (fine gra in e d ) s e d im e n ts . B e l o w t h e s e m a x i m a
M n l e v e l s d r o p s h a r p l y to a b o u t 10-15 ( i M at 4 - 6 c m d e p t h .
C o n c e n t r a t i o n s d e c r e a s i n g b e l o w t h e M n m a x i m u m c o u l d b e the
r e s u lt o f the fo r m a ti o n
of M n-carbonates
or p o ssib ly
Mn
i n c o r p o r a t e d in Fe -s u lf id e s .
Fe c o n c e n t r a t i o n s also i n c r e a s e d o w n in th e s e d i m e n t . T h e r e is
h o w e v e r c o n s i d e r a b l e s c a t t e r o b s c u r i n g d e t a i l e d s t u c t u r e s . At the
stations on the D o g g e r b a n k m a x i m u m Fe c o n c e n t r a t i o n s are only 210 (iM. As for M n hig he st Fe co n ce n tr a ti o n s are f o u n d at station 98
of f the D o g g e rb a n k . At a depth o f 2 cm d is so lv e d Fe levels rea ch 85
(iM w h i c h is in the r a n g e o f in te rs ti ti a l w a t e r Fe c o n c e n t r a t i o n s
r e p o r t e d fo r a n o x i c s e d i m e n t s . Fe c o n c e n t r a t i o n s d r o p b e l o w this
d e p th as a result o f F e-su lfi de for ma ti on.
3.2.1
Trace elements
Co: Co is the o n ly trace e l e m e n t in this stu dy w h ic h has its ow n
redox chemistry: C o ^ + + e" = Co^+,
w h e r e like fo r M n a nd Fe the r e d u c e d fo r m is th e b e tt e r so luble.
C o u p l i n g b e t w e e n M n a n d Co in i n t e r s t i t i a l w a t e r s h a s b e e n
r e p o r t e d for r e d u c i n g op e n o c e a n s e d i m e n t s ( H E G G I E a n d L E W I S ,
1984). At stations 8 and 98 Co goes into solu tion at the s am e de pth
as M n (Fig. 5), clearly ex hibiting the same features as Mn . M a x i m u m
c o n c e n t r a t i o n s a re a b o u t 17-23 n M w h i c h is t w o o r d e r s o f
m a g n i t u d e h i g h e r t h a n in o v e r l y i n g N o r t h S e a w a te r s ( K R E M L I N G
an d H Y D E S , 1988). T h e d e cr ea se d e e p e r d o w n the s e d i m e n t c o l u m n
c a n r e s u l t f r o m i n c o r p o r a t i o n in M n - c a r b o n a t e s as w e l l as f r o m
c o p r e c i p i t a t i o n in F e - s u l f i d e s .
At s ta t io n s 67 a n d m o r e c l e a r l y
s ta t io n 75, Co c o n c e n t r a t i o n s in c re a s e t o g e t h e r w it h M n ( a nd Fe)
b u t t h e m a x i m u m c o n c e n t r a t i o n s are m u c h l o w e r t h a n at t h e
s t a t i o n s o f f t h e D o g g e r b a n k (4- 7 n M at s t a t i o n s 75 a n d 67
respectively.
Cd: R e l i a b l e inters tit ia l w a te r Cd pro fi les ha ve o nl y b e e n m e a s u r e d
f r o m st at io n s 75 a n d 98, f o r t u n a t e l y r e p r e s e n t i n g on e D o g g e r b a n k
sed im en t and one sedim ent located o ff the d o g g e rb a n k .
Cd
r e g e n e r a t i o n s ta r ts in th e u p p e r l a y e r o f t h e s e d i m e n t (F ig. 6 )
re s u lti ng in C d m a x i m a o f 35 n M at a de pth o f 2.8 c m at station 75,
w h i c h is m o r e th a n tw o orde rs o f m a g n i t u d e h i g h e r t h a n o v e r l y i n g
N o r t h Sea w a te r c o n c e n tr a ti o n s ( K R E M L I N G a n d H Y D E S , 1988; also
thi s s tu d y) . I m m e d i a t e l y b e l o w this m a x i m u m C d l e v e l s d e c r e a s e
sharp ly to val ues of 2-5 nM, pro ba bly as a result o f the f o r m a ti o n of
i n s o l u b l e C d - s u l f i d e s or i n c o r p o r a t i o n in F e - s u l f i d e s . T h e s a m e
feature
is
observed
at
station
98,
w here
m axim um
Cd
c o n c e n t r a t i o n s (22 n M ) are r e a c h e d at 7.5 m m d e p th , also tw o
o r d e r s o f m a g n i t u d e h i g h e r th a n o v e r l y i n g N o r t h S e a w a te r s . At
s ta t io n 98 c o n c e n t r a t i o n s in c r e a s e a g a in as f r o m 4 c m d e p th . In
contrast
to
the
redox
type
elem ents
highest
m axim um
c o n c e n tr a ti o n s are re a ch e d at the D o g g e r b a n k station. It is not c le a r
w h y C d b e h a v e s d if f e r e n tl y fr o m the re d o x ty p e e l e m e n t s in this
respect. It is c le a r that the Cd c ycle in the interstitial w a te r c o lu m n
is not g o v e r n e d by the re d o x cy cle o f M n a nd Fe. M o r e likely the
r e g e n e ra ti o n o f Cd is related to that o f orga nic matter.
N itr a te p r o d u c t i o n as a result o f the b r e a k d o w n o f org a n ic ma tte r
c o n t i n u e s to a bout the s am e d e pt h as fo r C d at both stations. Th e
s tr o n g c o n c e n t r a t i o n g r a d i e n t s d r i v e the t r a n s p o r t o f d i s s o l v e d Cd
both in an u p w a r d and in a d o w n w a r d direc tion, p os si bl y le a d i n g to
large flu x e s a c r o s s the s e d i m e n t - w a t e r interfa ce.
T h e C d - p r o f i l e s b e a r a s t r i k i n g r e s e m b l a n c e w i t h th e p r o f i l e s
m e a s u r e d for the L a u re n ti a n T r o u g h by G O B E I L et al. (1987). T h e y
r e p o r t d i s s o l v e d C d m a x i m a in th e v e r y t o p o f th e s e d i m e n t
fo l l o w e d by a shar p d e c r e a s e in c o n c e n t r a t i o n fu r th e r d o w n in the
s e di m en t. At tw o stations the y too find i n c re a s in g c o n c e n t r a t i o n s at
the b o tt o m o f th ei r s e d im e n t cores. M a x i m u m C d c o n c e n t r a t i o n s in
t h e L a u r e n t i a n T r o u g h s e d i m e n t s (2 - 5 n M ) a re an o r d e r
of
m a g n i t u d e lo w e r tha n at ou r stations. T h e y a ttr ib ut e the Cd m a x i m a
to b r e a k d o w n of org a n ic matt er, t h e re b y r e le a s in g a d s o r b e d C d to
the inte rs tit ia l w at ers . P r e c ip it a ti o n as s u lf id e s p r o b a b l y c a u s e d the
sh ar p c o n c e n t r a t i o n de cr ea se , w h i l e the in c r e a s i n g c o n c e n t r a t i o n s at
th e b a se o f th e s e d i m e n t w o u l d be c a u s e d b y the f o r m a t i o n o f
stable pol ysulfide co m ple xe s (also J A C O B S et al., 1985).
Cu: T h e o nly re lia bl e interstitial w a t e r C u p ro f ile w a s m e a s u r e d at
s t a t i o n 8 (F ig. 7).
The profile shows evidence
of rapid
Cu
r e g e n e r a t i o n in the u p p e r fe w m i l l i m e t e r s o f th e s e d i m e n t le a d i n g
to c o n c e n t r a t i o n s o f 75 nM, a bo ut 30 ti m e s h i g h e r t h a n o v e r ly in g
N o r t h S e a w a t e r s ( B A L L S , 19 85 a ; a ls o t h i s s t u d y ) . D o w n th e
sedim ent colum n interstitial w ater c o n centrations drop sharply.
C o p r e c i p i t a t i o n w it h M n c a r b o n a te s or, d e e p e r in the s e d i m e n t
Fesulfides co uld result in this decrease. As for Cd the Cu cycle appears
to g o v e r n e d by the de g ra d a ti o n o f org a nic matter.
Ni:
T w o re li a b le p o re w a t e r pr o f il es h a v e
b e e n m e a s u r e d fo r Ni
(stas. 8 and 75, Fig. 7)
re p r e s e n t i n g the D o g g e r b a n k are a and the
a re a
o f f the D o g g e r b a n k . T h e pr o f il e s b e a r
a s tr ik in g r e s e m b l a n c e
with the Cd profiles.
At t h e s t a t i o n o f f
th e D o g g e r b a n k Ni
re g e n e r a t i o n p r o c e e d s in
the u p p e r c m o f the s e d i m e n t c o l u m n with
m a x i m u m Ni c o n c e n t r a t i o n s o f 20 0 nM, t w o
o rd e rs o f m a g n i t u d e
hig h e r than the ove rly ing North Sea waters ( K R E M L I N G and H Y D E S ,
198 8; also th is s t u d y ) . D e e p e r d o w n th e s e d i m e n t c o n c e n t r a t i o n s
d e c r e a s e a g a in , p r o b a b l y as a r e s u l t o f i n c o r p o r a t i o n in s e v e r a l
m i n e r a l p h a s e s like M n - c a r b o n a t e s and F e - s u l f i d e s . As f o r C d and
Cu the interstitial w a te r Ni cy cle see ms to be largely d e t e r m i n e d by
the
re g e n era tio n of organic matter. T h e
strong concentration
g r a d i e n t s e s p e c i a l l y at s ta t io n 8 , w h e r e
th e
la r g e s t c o n c e n t r a t i o n
gr a d ie n t is lo c at ed at the surface, large Ni flu xe s into th e o v e r ly in g
w a te r s m a y be e x p e c t e d . T h e c o n c e n t r a t i o n le ve ls are o f the s am e
o r d e r o f m a g n i t u d e as t h o s e r e p o r t e d f o r
open ocean interstitial
w aters.
Zn: At all stations the profiles sho w Z n re ge n e ra ti o n and c o n c o m i ta n t
i n c re as e d c o n c e n tr a ti o n s near or at the top o f the s e d i m e n t fo ll o w e d
by a d e c r e a s e in Z n level s d e e p e r d o w n the s e d i m e n t (Fig. 8 ). At
s t a t i o n s 21 a n d 56 c o n c e n t r a t i o n s st art to i n c r e a s e
im m ediately
b e l o w a Zn m i n i m u m lo c at ed at 1-2 c m dep th. F o r m a t i o n o f stable
Z n - s u l f i d e c o m p l e x e s w h ic h are b e tt e r so lu b le has b e e n in v o k e d to
e x p l a i n a c o m p a r a b l e c o n c e n t r a t i o n i n c r e a s e in a n o x i c b a s i n s like
F r a m v a r e n F jo r d ( J A C O B S et al., 1985). It is not clear, ho w e v e r, w hy
this c o n c e n t r a t i o n in c re as e is not o b s e r v e d at the o th e r t w o stations.
It is p o s s i b l e tha t at th e s e stat ion s Z n c o n c e n t r a t i o n s still in c re a s e
d e e p e r d o w n th e s e d i m e n t , s in c e at all s t a t i o n s t h e p r e s e n c e o f
s u lf id e s w as o b s e r v e d . In te rs tit ia l w a t e r Z n c o n c e n t r a t i o n s are tw o
o r d e r s o f m a g n i t u d e h i g h e r th a n o v e r l y i n g N o r t h S e a w a t e r s a nd
ar e c o m p a r a b l e w i t h v a l u e s f o u n d fo r th e e a s t P a c i f i c ( S H A W ,
19 87 ). T h e r e is no s i g n i f i c a n t d i f f e r e n c e in c o n c e n t r a t i o n le v e l s
b e t w e e n st at io ns on and st at io ns o f f th e D o g g e r b a n k . C o n c e n t r a t i o n
g r a d i e n t s are s t e e p n e a r t h e s e d i m e n t w a t e r i n t e r f a c e p r o b a b l y
giv in g rise to la rge Z n fluxes to the ov e rl y in g wa ters. It is h o w e v e r
p o s s i b l e tha t a s ig nif ic a nt a m o u n t of d i s s o l v e d Z n is c o p r e c i p i t a t e d
in f r e s h l y p r e c i p i t a t e d M n F e - o x y h y d r o x i d e s
m i l l i m e t e r s o f the sedi me nt.
4.
Suspended
Particulate
in
the
upper
few
Matter
S u s p e n d e d Pa rt i c u la te M a t t e r (S P M ) has o n ly b e e n a n a l y s e d fo r the
t r a c e e l e m e n t c o m p o s i t i o n a n d f o r M n a n d F e ( T a b l e 7).
C o n c e n t r a t i o n s fall in the r a nge r e p o r t e d fo r S P M in the s am e area
by N O L T I N G and E I S M A (1989). T h e tim e section at station 75 will
not be d is cu s s ed in detail here. Also, Co da ta are too scan ty to allow
fo r an e x t e n s i v e d i s c u s s i o n . It i m m e d i a t e l y a p p e a r s f r o m T a b l e 7
tha t the S P M c o n c e n t r a t i o n levels o f all e l e m e n t s are m u c h h ig h e r
t h a n so lid state s e d i m e n t c o n c e n t r a t i o n s . S P M c o n s i s t s to a la rg e
d e g re e o f au th ig e ni c partic le s like org a ni c matter, o rg a n ic a ll y c oa te d
p a r t i c l e s and M n F e - o x y h y d r o x i d e s w h i c h h a v e a h ig h a f f i n i t y for
t r a c e m e t a l s . In th e s e d i m e n t a la r g e p a r t o f t h e p a r t i c l e s is
r e g e n e r a t e d t h ro u g h b re a k d o w n o f org a n ic m a t t e r or d i s s o l u t i o n of
M n F e -o x y h y d ro x id e s thus releasing the ad so rb ed trace elem ents
b a c k into s o lu tio n. T h i s is e v i d e n c e d b y th e o r d e r o f m a g n i t u d e
h i g h e r tra ce e l e m e n t c o n c e n t r a t i o n s in the in te rs tit ia l w a te r s o f the
s e d i m e n t s c o m p a r e d to o v e r l y i n g s e a w a t e r c o n c e n t r a t i o n s .
Both M n and Fe c oncen tra tio ns in S P M a nd the actual pa rticulate M n
a n d F e c o n c e n t r a t i o n s in th e w a t e r c o l u m n ( e x p r e s s e d as the
c o n c e n t r a t i o n o f p a r t i c u l a t e M n o r F e in n a n o m o l e s p e r liter)
i n c r e a s e t o w a r d s th e s e a f l o o r f o r all s t a t i o n s . T h i s s u g g e s t s
regenerative
fluxes from the
sedim ent are im p o rtan t w here
d i s s o l v e d M n a n d Fe r e p r e c i p i t a t e as a u t h i g e n i c o x y h y d r o x i d e s
u p o n en terin g the o x y g e n a te d o v e rly in g w a ter co lu m n . T h e se
f r e s h l y p r e c i p i t a t e d M n F e - o x y h y d r o x i d e s m a y t h e n s c a v e n g e tr a c e
e le m e n ts fr o m the w a te r c o l u m n ( B A L I S T R I E R I et al., 1981). After
d e p o s i t i o n on the s e a f l o o r th e p a r t i c l e s c a n b e p a r t l y d i s s o l v e d
a g a i n in th e in t e r s t i t i a l w a t e r s o f th e s e d i m e n t c o l u m n t h e r e b y
r e l e a s i n g the a d s o r b e d tra ce e l e m e n ts .
T h e S P M tr a c e m e ta l c o n c e n t r a t i o n d o e s not s y s t e m a t i c a l l y in c re as e
t o w a r d s the s e a f l o o r s u g g e s t i n g a d s o r p t i o n on M n F e - o x y h y d r o x i d e s
is n o t t h e o n l y f a c t o r d e t e r m i n i n g t h e i r S P M d i s t r i b u t i o n .
A d s o r p t i o n on or g a n ic partic les or or g a n ic al l y c o a te d m in e ra l ph ase s
is likely to play an im po rt an t role as well.
S P M trac e e l e m e n t c o n c e n t r a t i o n s in the a re a near the D o g g e r b a n k
are a m o n g the lo w e st re p o rt e d for the en tire N o rt h S e a ( N O L T I N G
and E I S M A , 1989).
5. D is so lv e d trace e le m e n ts
T h e resu lts for d is s o l v e d trac e e l e m e n t c o n c e n t r a t i o n s are s h o w n in
Ta b le 8 . B e c a u s e o f its low di s so lv e d c o n c e n tr a ti o n M n also be lo ngs
to the category o f trace e lements in seawater. Fo r Mn, Cu, Cd and Zn
c o n c e n t r a t i o n s are c o m p a r a b l e with p r e v i o u s l y r e p o r t e d re s u lt s fo r
the N ort h Sea ( K R E M L I N G and H Y D E S , 1988; B A L L S , 1985a; 1985b;
N O L T I N G , 1986; D U I N K E R and N O L T I N G , 1982). T h e results for Ni
m u s t be r e g a r d e d w i t h c a u t i o n s i n c e a l a r g e r e a g e n t b l a n k
c o n c e n t r a t i o n h a d to be s u b s t r a c t e d a nd th e c o n c e n t r a t i o n s are
p r o b a b ly s o m e w h a t too low. R esu lts for Fe a n d Co w e r e not relia ble
d u e to c o n t a m i n a t i o n a n d are no t i n c l u d e d in t h e T a b l e .
A
c o m p a r i s o n w it h the S P M t r a c ; e l e m e n t c o n c e n t r a t i o n s s h o w s tha t
on an a v er ag e 5 0 - 9 0 % o f the trac e e le m e n t c o n c e n t r a t i o n is p r e s e n t
in the d is s o l v e d state. Su r fa c e w a t e r c o n c e n t r a t i o n s o f M n , P b a nd
Z n are about a fa c to r o f 2 (Pb) to 20 (Zn) h i g h e r tha n in the op en
ocean, while su rface w a te r Cu and Ni co n ce n tr a ti o n s are o f the s am e
or d e r as op e n o c e a n su rfa ce w a t e r c o n c e n tr a ti o n s . S u r f a c e w a t e r Cd
concentrations
in
the
open
ocean
depend
largely
on
the
n u t r i e n t c o n c e n t r a t i o n in the w a t e r c o l u m n a n d v a r y g r e a t l y . In the
N o rt h Sea c a d m i u m c o n c e n tr a ti o n s vary on ly very little. T h e r e is no
a p p a r e n t re l a t i o n s h i p with ei th e r nitrate or p h o s p h a t e (T a b le 9).
A t m o s p h e r i c d e p o s i t i o n o f tr a c e e l e m e n t s is an i m p o r t a n t s o u r c e
esp ec ial ly for Pb, C d and Zn in the ocean. A land e nc lo s e d basin like
the N orth Sea thus receives large inputs from a tm o sp h eric
d e p o s i t i o n b o t h f r o m n a t u r a l a n d m a n - m a d e s o u r c e s . It is no t
p o s s i b l e to d i s t i n g u i s h b e t w e e n the r e l a t i v e i m p o r t a n c e o f e i t h e r
n a t u r a l or m a n - m a d e in p u ts . R i v e r in p u ts f u r t h e r s u p p l y a n o t h e r
im p o r t a n t s ou rc e o f trace e le m e n ts to the oc eans.
ACKNOW LED G EM ENTS:
M a n y th a nks go to H e r m a n B oekel, H a ns E l l e r m e i j e r and J o h a n van
H e e r w a a r d e n fr om the w o rk s h o p at N I O Z for the c o n st r u c ti o n o f the
c e n t r i f u g e tu b e s , n i t r o g e n g l o v e box, T e f l o n f il te r u n it s a n d the
C h e l e x - c o l u m n s . O ff ic e rs and c re w
o f the T Y R O are t h a n k e d for
p r o v i d i n g o p ti m a l w o r k i n g c o n d i t i o n s d u r i n g the c ru is e. T h e N I O Z
t e c h n i c i a n s on b o a r d ship are t h a n k e d fo r th e i r a s s i s t a n c e d u r i n g
s a m p l i n g . W i t h o u t t h e s e p e o p l e th is r e p o r t w o u l d n o t e xis t. M y
c o l l e a g u e s on bo a rd ship a nd e s p e c ia ll y Jan S c h i j f are t h a n k e d for
c r e a t i n g a p le a s a n t w o r k i n g a t m o s p h e r e a n d th e ir a s s is ta n c e d ur in g
s a m p l i n g a n d s a m p l e p r o c e s s i n g . M a n y f r u i t f u l d i s c u s s i o n s w it h
Lo es Gerringa, Hei n de Baar, W i m H el der , R o b Nolti ng, L u t z Lohse ,
W i m v a n R a a p h o r s t a nd P i m K i e s k a m p h a v e h e l p e d to s e t- u p a
re s e a r c h p r o g r a m m e in the first p la c e a n d h a v e c o n t r i b u t e d gr ea tly
to the results and in te rp re ta tio n o f the data. R o b a n d L o e s are also
t h a n k e d fo r th ei r a ss is ta n c e with the m e a s u r e m e n t s .
S p e c ia l th a n k s go to M a r i a n R e i th f r o m th e D e p a r t m e n t o f E a r t h
Sc ie n c e s o f the U n iv e rs it y o f U tr e c h t w ho did the s e d i m e n t tex ture
analyses. Prof. Dr. I.S. Oen is th an ked for allow in g me to do the trace
me ta l c h em i st r y in the ex ell ent c le a n la bo ra to ry at IGO , A m s te r d a m .
R eferences
Balistrieri L., B re w e r P . G. and M u r r a y J.W. (1981) Sc a v en g in g
re s id en c e ti m e s of trace metals and s urfa ce c h e m i s tr y o f
sinkin g particle s in the d e ep ocean. D e e p - S e a Res. 28, 101-121.
Balls P.W. (1985) T r a c e metals in the nort he rn N orth Sea. Mar.
P o l. B u ll .16,
203-207.
Balls P.W . (1985) Co pper, lead and c a d m i u m in co astal wa te rs o f the
w e ste rn N or th Sea. Mar. Ch em . 15, 363- 378 .
D a n ie ls s o n L-G. (1979) Tr ac e metals in m a ri n e wa ters, an alytic al
in v e st ig at i ons on c a d m i u m , cobalt, c opper , iron, lead, nickel and
zinc. Ph. D. Dissertation, Univ er si ty o f G ote borg.
De Baa r H .J.W. (1983) Th e ma rine ge o c h e m is tr y o f the Rar e Earth
Elem en ts . Ph. D. Thesis, M I T / W H O I , W H O I - 8 3 - 4 5 , 278 pp.
De Baa r H .J.W. , Elderfield H. , Ge rm a n C.R. and Van G aan s P. (1988)
Rar e earth e l e m e n t d is tr ib u tio ns in ano xic w a te r s o f the Ca ri ac o
Tr en c h. G e o c h im . C o s m o c h i m . Acta. 52, 1203-1219.
D uin k e r J.C. and Nolting R.F. (1982) Disso lve d copper, zinc and
c a d m i u m in the S ou the rn Bight o f the North Sea. Mar. Pol. Bull.
13, 9 3 -9 6 .
D r e v e r J. I. (1982) Th e ge o c h e m is tr y o f natural waters. Pr en ti ce
Hall, inc. N e w Jersey, 388 pp.
Froelich P.N., K li n k h a m m e r G.P., B en der M.L., Lu e dtk e N.A., Heat h
G.R., Cullen D., Daup hin P., H a m m o n d D., H a rt m a n B. and
M a y n a r d V. (1979) Early oxid a ti o n o f orga nic m a tt e r in
pe lagic s e d i m e n n t s o f the e as te rn e q u a to r ia l Atlantic: s u b ox ic
dia ge ne s is . G e o c h im . C o s m o c h i m . Ac ta 43, 10 75- 1090.
Gobeil C., Silverberg N., Sundby B. and Cossa D. (1987) C a d m iu m
di a g e n e s is in L a u re n ti a n T r o u g h sedim ent s. G e o c h im .
C o sm o c h im . Acta
51, 5 8 9 - 5 9 6 .
G ra yb ea l A.L. and Heat h G.R. (1984) R em o b il iz at io n o f transition
me ta ls in surficial pelagic s ed im en ts fr o m the e as te rn Pacific.
G e o ch im . C o s m o c h im . Ac ta 48, 965-976.
H e g g ie D. and Lew is (1984) Cobalt in pore waters o f m ar ine
s e d i m e n t s . N a t u r e 311, 4 5 3 - 4 5 5 .
J ac ob s L. , E m e rs o n S. and Skei J. (1985) Partitioning and transport
o f m e ta ls across the O 2 / H 2 S in te rfa c e in a p e r m a n e n t l y a n ox ic
basin: F r a m v a r e n Fjord, N o r w a y .
K r e m l i n g K. and H y d e s D. (1988) S u m m e r d is tr ib u tio ns o f dis so lv e d
Al, Cd, Co, Cu, M n and Ni in surface waters around the British
Isles. Cont. Sh el f Res. 8 , 89-105.
N olt ing R.F. (1986) Copper, zinc, c ad m i u m , nickel, iron and
ma ng an e s e in the South ern Bight of the N or th Sea. M ar.
Bull. 17, 113-117.
Pol.
N o lt in g R.F. and E i s m a D. (1988) E le m e nt a ry c o m posi tio n o f
s u s p e n d e d partic ula te m a tt e r in the N o rt h Sea. N e th . J. Se a Res.
22, 2 1 9 - 2 3 6 .
S a a g e r P.M . (1986) Sequen tia l e x tr a ct io n o f h e av y m e ta ls fr o m a
salt mars soil profile (W e ste rn Scheldt). St u d i er ap p o rt no. 8 ,
" W e s t e r s c h e l d e Studies" edition, U trecht, T h e N e t h e r l a n d s , 71
pp.
Sa a ge r P.M. , Sweerts J-P. and Eller mij er H.P. (1989) A simp le pore
w a te r s a m p l e r for coarse, s and y s ed im en ts wi th low porosity.
S u b m i tt e d to Li m n ol . Oc ea nog r.
S a lo m o n s , W. and Foers tner U. (1984) Met al s in the hydroc yc le.
Sp r in g er Verlag Berlin, Heid elbe rg, N e w Yo rk, T o kyo, 349 pp.
S h a w T. J. (1987) T h e early d iagen es is of tran sition meta ls in
nearshore sediments. Ph. D. Dissertation U C S D , Sa n D iego, 164
pp.
Strick land J.D.H . and Pars ons T.R. (1968) A practical h a n d b o o k of
sea w at er analysis. C a n a d a Fish. Res. Bd. Bull. 167, 311 pp.
List o
T a b le
Tables.
1. A cid-l eac h test.
T a b le 2. S e d i m e n t te xtu re an alyses. M e a n g ra in size in m ic r o m e te r s
is s h o w n for each dep th interval.
T a b le 3. S e d i m e n t c h ar ac te ri s ti c s. C o n c e n t r a t i o n o f a l u m i n i u m , total
carbon, total nitrogen and C:N ratio as well as sediment
p o ro s it y are given.
Ta b le 4. S e d i m e n t trace e le m e n t c o n c e n tr a ti o n s (stations 8 , 15, 21,
56, 67, 75, 98).
Ta b le 5. Int erstitial w a te r n u tr ie nt c o n c e n t r a t i o n s
21, 56, 67, 75, 98).
(s ta tio ns
T a b l e 6 . Interstitial w a te r trace e l e m e n t c o n c e n t r a t i o n s
8,15, 21, 56, 67, 75, 98).
8 , 16a,
(stations
T a b l e 7. S u s p e n d e d pa rti c ul a te trace e l e m e n t c o n c e n t r a t i o n s (6
item s).
T a b le 8 . D is s o lv e d trace e l e m e n t c o n c e n tr a ti o n s .
T a b l e 9. D i s s o l v e d nu tri en t c o n c e n tr a ti o n s , salinity, te m p e r a t u r e .
N u tr ie n t c o n c e n tr a ti o n s w e re m e a s u r e d on b o a r d ship by
autoanalyzer according to S T R I C K L A N D and P A R S O N S ,
1972. Salinity and te m p e ra t u re d a ta are p ro v i d e d by C T D
on bo a rd ship.
Ta b le 1. A c i d - l e a c h e x p e r im e n t . E x p l a n a ti o n is g iv e n in the text. Th e
'• d if f e r e n c e b e t w e e n th e total metal c o n t e n t (total d e s t r u c t i o n
only) o f the sedim ent, s ho w n in the last c o lu m n , and the
sum o f the a c id - le a c h a b l e frac tion plus re fr a c to ry metal
fraction is only 5% for Mn, Fe, Ni, Zn, Cd. For Cu the
d if f e r e n c e is very large. C o n c e n t r a t i o n s are in m g /k g , for Fe
in % wt.
HCl-leach (L)
Cd
Cu
Fe
Mn
Ni
Zn
0.34
1.1
0.08
35
1. 6
6.7
Refractory (R)
0.61
2 .3
0.65
99
9.9
14.8
Sum (L+R)
0.95
3.4
0.73
134
11.5
21.5
Total
1.02
2.3
0.69
131
1 1.3
2 1.9
Tabl e 2.
S e d i m e n t Te x tu re , m e a n grain size per de pth interval is
given in | i m .
Station 08
depth
(mm)
2.5
7.5
12.5
17.5
22.5
27.5
32.5
37.5
grain
size
128
134
1 25
128
1 13
1 13
109
106
Station 56
Station 15
depth
(mm)
Station 21
grain
size
2.5
7.5
15.0
25.0
35.0
45.0
55.0
65.0
161
159
161
163
156
159
157
156
Station 67
depth
(mm)
2 .5
7.5
15.0
25.0
35.0
35.0
55.0
65.0
grain
size
203
199
204
202
195
192
194
1 94
Station 75
Station 98
depth
(mm)
grain
size
depth
(mm)
grain
size
depth
(mm)
grain
size
depth
(mm)
grain
size
5.0
15.0
25.0
35.0
45.0
55.0
191
193
189
196
187
187
2.5
7.5
15.0
30.0
50.0
80.0
213
201
201
208
203
190
2.5
7.5
15.0
30.0
50.0
80.0
189
197
193
194
1 97
182
2.5
7.5
15.0
25.0
35.0
4 5.0
55.0
65.0
96
100
99
100
102
90
98
98
Tabl e 3.
Sediment Characteristics
(ele me nt s in % weight).
Depth
(mm)
Porosity
2.5
7.5
15.0
30.0
50.0
80.0
C:N
0.72
0.50
0.45
0.39
0.46
0.48
2 .3
1.7
2.0
2.1
2.2
2.2
0.55
0.46
0.45
0.63
0.62
0.82
0.05
0.05
0.04
0.06
0.03
0.06
12.8
10.7
13.1
12.3
24.1
15.9
Porosity
A1
C-tot
N-tot
C:N
0.45
0.45
0.43
0.44
0.41
0.41
1.3
1.4
1.4
1.3
1.3
1.5
0.26
0.28
0.34
0.44
0.37
0.48
0.05
0 .04
0.05
0.06
0.04
0.06
6. 1
8.2
7.9
8.6
10.8
9.3
Porosity
A1
C-tot
N-tot
C:N
1. 0
1. 0
0.9
1.1
1. 0
1. 2
0.46
0.51
0 .16
0.12
0.16
0.41
0.05
0.02
0.02
0.05
0.06
0.07
10.7
29.8
9.3
2.8
3.1
6.8
(1/ 1)
2.5
7.5
15.0
30.0
50.0
80.0
Depth
(mm)
N-tot
16a
Depth
(mm)
Stat ion
C-tot
(1/ 1)
2 .5
7.5
15.0
30.0
50.0
80.0
Stat ion
A1
21
(1/ 1)
0.41
0.41
0.38
0.38
0.38
0.37
T a b le 3, c o ntin ue d.
Sediment Characteristics
(elements in % weight).
Depth
(mm)
2 .5
7.5
15.0
30.0
50.0
80.0
Station
2.5
7.5
15.0
30.0
50.0
80.0
C-tot
N-tot
C:N
0.39
0.38
0.37
0.38
0.36
0.36
1.1
1.3
1.1
1.1
1.1
1. 2
0.28
0.50
0.40
0.26
0.43
0.19
0.08
0.03
0.03
0.04
0.05
0.03
4.1
19.4
15.6
7.6
10.0
7.4
A1
C-tot
N-tot
C:N
0.8
0.8
0.7
0.9
1. 0
1.1
0.17
0.29
0.31
0.78
0.28
0.76
0.08
0.03
0.00
0.06
0.05
0.05
2.5
1 1 .3
Porosity
(1/ 1)
A1
C-tot
N-tot
C:N
0.38
0.41
0.41
0.39
0.37
0.39
0.9
1. 0
1.1
1. 0
1. 0
1. 0
0.22
0.24
0.20
0.19
0.19
0.29
0.07
0.04
0.09
0.07
0.03
0.06
3.7
7.0
2.6
3.2
7.4
5.6
Porosity
(1/ 1)
2.5
7.5
15.0
30.0
50.0
80.0
Depth
(mm)
A1
67
Depth
(mm)
Stat ion
Porosity
(1/ 1)
0.41
0.46
0.37
0.41
0.38
0.33
15.2
6.5
17.7
75
T a b l e 3, c o ntin ue d.
Sedim ent Characteristics
(e le me nt s in % weight).
Statio n
Depth
(mm)
2.5
7.5
15.0
30.0
50.0
80.0
98
Porosity
A1
C-tot
N-tot
C:N
2.0
2.0
2. 1
2.2
2. 1
2. 1
0.64
0.77
0.76
0.77
0.71
0.75
0.10
0.10
0.09
0.09
0.08
0.07
7.5
9.0
9.9
10.0
10.4
12.5
(1/ 1)
0.56
0.56
0.55
0.52
0.49
0.45
T a b l e 4.
Sedim ent Metal Concentrations
(Ti, Fe in %, oth er e le m e n ts in mg/kg).
T = total, L = leachable
Depth
(mm)
Ti-T
Mn-T
M n -L
Fe-T
Fe-L
Co-T
Co-L
Cd-T
Cd-L
2.5
7.5
12.5
17.5
22.5
27.5
32.5
37.5
0.3
0.31
0.30
0.28
0.29
0.28
0.31
0 .34
130
1 10
1 14
1 19
118
107
105
121
47
37
37
39
50
52
47
54
0.66
0.62
0.65
0.64
0.79
0.71
0.76
0.86
0.36
0.33
0 .35
0.38
0.42
0 .45
0.42
0.47
1.8
1.5
1.4
1.7
1. 2
1. 0
2.2
1. 2
1. 6
1.4
1.5
1.5
1. 8
2.0
1.8
2.0
0.13
0.08
0.52
0.06
0.05
0.23
0.05
0.13
0.03
0 .05
0.02
0.02
0.02
0.01
0.03
0.05
Pb-T
Pb-L
Ni-T
Ni-L
Cu-T
Cu-L
12.6
10.9
9.8
1 1.5
9.3
7.7
13.7
8.0
0.5
0.7
0.5
0.6
0.6
0.5
0.8
0.6
4.0
3.1
3.0
3.2
3.0
2.3
4.7
3.1
4.0
3.7
3.8
4.5
5.2
5.5
5.3
5.7
1.8
2.0
1.5
1. 6
1.6
1. 2
2.5
1. 6
Depth
(mm)
Zn-T
2.5
7.5
12.5
17.5
22.5
27.5
32.5
37.5
13.2
12 . 1
13.2
12 . 1
15.4
14.3
16.5
18.7
Zn-L
9 .9
9 .2
9 .2
9 .3
10.6
11.1
10.6
11.3
1.2
1.3
1. 2
1. 2
2.1
1.7
1.6
1.8
T a b l e 4, c o n t i n u e d .
S e d i m e n t M eta l C o n c e n t r a t i o n s
(Ti, Fe in %, other e le m e n ts in mg/kg).
T = total, L = leachable
Stati on
Depth
(mm)
2.5
7.5
15.0
25.0
35.0
4 5.0
55.0
65.0
Depth
(mm)
2.5
7.5
15.0
25.0
35.0
45.0
55.0
65.0
15
Ti-T
Mn -T
M n- L
Fe-T
Fe-L
Co-T
Co-L
Cd -T
Cd -L
0.09
0.13
0.15
0.16
0.14
100
96
8 1
89
8 1
0.59
0.60
0.58
0.57
0.61
0.65
0.78
1.8
2.1
1.5
1.4
1 .4
1.3
1.4
1.5
1.4
1.8
0.24
0.48
0.07
0.18
0.16
89
106
0.34
0.36
0.32
0.30
0.33
0.33
0.36
0.43
1.6
1.9
1.7
1.8
1.8
0.15
0.19
90
68
56
55
52
56
59
66
0.74
0.09
0.02
0.02
0.04
0.06
0.04
0.03
0.04
0.03
Pb-T
Pb-L
Ni-T
Ni-L
Cu-T
Cu -L
10.6
1 1.4
10.9
1 2 .3
1 1. 0
8.0
10.9
12.2
0.6
0.4
0.9
0.6
0.3
0.4
1. 0
0.3
2.8
3.4
3.2
3.9
3.6
4.2
4.1
4.1
3.7
3.8
4.1
4.6
5.3
1.7
1.8
2.1
1.8
2.0
Zn-T
9.9
10.7
10.5
1 0 .5
11.2
13.7
15.2
Zn -L
6.8
7.2
6.7
6.6
7.1
8.0
7.6
8.4
3.2
4.7
1.8
2.2
1.3
1.3
1. 6
1.1
1.2
1.5
3 .5
2.5
T a b l e 4, c o n ti n u e d .
S e d i m e n t M et a l C o n c e n t r a t i o n s
(Ti, Fe in %, oth er e le m e n ts in mg/kg).
T = total, L = leachable
Station
Depth
(mm)
2.5
7 .5
15.0
25.0
35.0
45.0
55.0
65.0
Depth
(mm)
2 .5
7.5
15.0
25.0
35.0
45.0
55.0
65.0
21
Fe-T
Fe-L
Co-T
Co-L
Cd-T
Cd-L
33
33
34
35
35
29
27
25
0.44
0.42
0.46
0.46
0.57
0.50
0.63
0.16
0.17
0.15
0.18
0.19
0.17
0.15
0.16
1. 0
0.7
0.5
0.7
1.1
0.9
1.4
0.7
0.7
0.6
0.7
0.8
0.6
0.6
0.7
0.10
0.44
0.20
0.57
0.19
0.14
0.10
0.05
0.02
0.01
0.02
0.01
0.01
0.01
0.01
Pb-T
Pb-L
Ni-T
Ni-L
Cu-T
Cu-L
0.4
0.4
0.2
0.2
0.4
0.3
0.2
0.3
1.4
1. 2
1. 0
1.3
2.5
1. 6
1.4
2.1
1.9
2.1
2.6
2.0
1.9
1. 6
1. 8
0.7
0.9
0.8
0.9
2.1
1. 0
0.9
Ti-T
Mn-T
M n-L
0.14
0.12
0.14
0.12
0.17
0.16
0.31
0.15
1 10
96
111
99
134
120
173
1 19
Zn-T
5.5
3.4
4.7
4.8
6 .3
6.2
5.0
Zn-L
4.1
4.1
3.3
4.8
4 .3
3 .6
3 .2
3 .7
5.6
4.8
4.5
5.0
6.0
5.6
6.2
0.6
0.7
0.5
1. 0
0.6
0.6
0.5
0.6
T a b l e 4, c on ti n u e d .
S e d i m e n t M e ta l C o n c e n t r a t i o n s
(Ti, Fe in %, oth er e le m en ts in mg/k g).
T = total, L = leachable
Stati on
Depth
(mm)
5.0
15.0
25.0
35.0
45.0
55.0
Depth
(mm)
5.0
15.0
25.0
35.0
45.0
55.0
56
Ti-T
M n -T
Mn-L
Fe-T
Fe-L
Co-T
C o- L
C d- T
C d-L
0.34
0.29
0.21
0.32
0.44
0.30
275
208
155
239
329
238
20
20
13
17
14
11
0.62
0.56
0.44
0.57
0.76
0.58
0. 1 1
0 .1 3
0.10
0. 1 1
0.10
0.07
0.4
0.4
0.5
1. 1
1. 0
1.1
0.4
0.5
0.4
0.4
0.5
0.3
0.12
0.40
0.10
0.20
0.27
0.34
0.02
0.01
0.05
0.02
0.01
0. 1 2
Zn -L
Pb-T
Pb-L
Ni-T
Ni-L
Cu-T
C u-L
4.4
4.7
6.9
10.0
6.8
8.4
0.2
0.2
0.7
0.2
0.5
0.4
0.4
0.5
0.7
1.3
0.8
1.1
0.9
1 .3
1.4
1.3
2.2
0.9
0.4
0.4
0.6
0.9
0.6
0.9
Zn-T
4.8
4.2
2.8
3.9
4.8
4.3
1. 0
1.5
0.9
1. 8
2.1
1. 0
0.9
1. 0
(5.2)
1.5
1.5
0.6
T = total
Station
Depth
(mm)
2.5
7.5
15.0
30.0
50.0
70.0
Depth
(mm)
2 .5
7.5
15.0
30.0
50.0
70.0
L = leachable
67
Ti-T
Mn-T
M n- L
Fe-T
Fe-L
Co-T
C o- L
Cd -T
C d-L
0.32
0.24
0.15
0.23
0.27
0.41
182
13 1
80
134
146
207
11
6
8
11
11
10
0.4
0.4
0.3
0.3
0.4
0.5
0.08
0.09
0.08
0.08
0.08
0.07
0.2
0.5
0.5
0.2
0.5
0.6
0.2
0.3
0.2
0.2
0.2
0.2
0. 1 1
0.10
(0.93)
0.08
0.09
0.02
0.05
0.06
0.01
0.01
0.01
Zn-L
Pb-T
Pb-L
Ni-T
Ni-L
Cu-T
C u-L
0.4
0.3
0.5
0.3
0.3
0.3
0.8
0.6
1. 0
1. 2
1.5
0.9
0.9
0.9
1.3
2.2
2.5
2.0
1.8
2.4
Zn-T
0.7
(14.8)
1.5
( 8 .2 )
2.9
(5.5)
1.5
1. 0
1.3
0.6
0.9
1. 0
0.8
3.2
4.2
1. 2
3.5
3.1
0.3
0.2
0.6
0.7
0.8
0.6
1.1
0.8
1. 2
T a b l e 4, c onti n u e d .
S e d i m e n t M e ta l C o n c e n t r a t i o n s
(Ti, Fe in %, oth er el em en ts in mg/kg).
T = total, L = leachable
Station
2.5
7.5
15.0
30.0
50.0
70.0
Depth
(mm)
2 .5
7.5
15.0
30.0
50.0
70.0
Ti-T
Mn-T
M n- L
Fe-T
Fe-L
Co-T
Co-L
Cd-T
C d -L
0.22
0.27
0.31
0.42
0.34
0.23
149
162
174
21 1
201
1 17
52
29
18
13
16
20
0.32
0.38
0.44
0.51
0.48
0.40
0.12
0.13
0.12
0.10
0.1 1
0.13
0. 1
0.2
0.2
0.7
0.5
0.1
0.4
0.4
0.4
0.4
0.4
0.7
( 1.0 )
(5.0)
0.4
0.02
0.01
0.01
0.01
0.02
0.03
Pb-T
Pb-L
Ni-T
Ni-L
Cu-T
1.7
1. 2
1. 0
0.9
0.9
1.3
o
o
Depth
(mm)
75
1.2
1.1
1.1
1.4
1.4
2.5
1.7
1.9
2.3
2.6
2.3
2.6
Zn-T
3 .3
4.9
5.4
6.8
5.8
(2 . 1)
Zn-L
3.3
2.8
3.1
3.7
2.8
4.3
1.9
3.9
3.8
5.9
5.5
1.4
0.5
0.8
1.1
1. 6
(4.3)
(1.4)
Cu-L
0.8
0.9
0.6
0.8
1.7
1.7
T a b l e 4, c o n ti n u e d .
Sedim ent Metal Concentrations
(Ti, Fe in %, other e le m e n ts in mg/kg).
T= total, L = leachable
Statio n
Depth
(mm)
2.5
7.5
15.0
25.0
35.0
45.0
55.0
65.0
Depth
(mm)
2.5
7.5
15.0
25.0
35.0
45.0
55.0
65.0
98
Ti-T
Mn-T
M n -L
Fe-T
Fe-L
Co-T
Co -L
Cd-T
Cd- L
0.24
0.22
0.28
0.30
0.24
0.28
0.29
0.26
179
150
141
136
130
136
137
126
123
8 1
59
54
57
52
53
54
0.72
0.69
0.72
0.73
0.69
0.71
0.75
0.75
0.39
0.37
0.37
0.37
0.36
0.37
0.37
0.38
2.1
1.8
1.9
1.9
1.9
2.1
2.1
2.1
1.7
1.6
1.6
1.7
1.7
1.7
1.7
1.8
0.22
0.17
0.10
0.20
0.60
0.10
0.20
0.05
0 .07
0.02
0.03
0.03
0.04
0.02
0.02
Pb-T
Pb- L
Ni-T
Ni-L
Cu-T
Cu-L
17.2
15.6
19.6
14.2
13.6
1 1.2
14.9
1.0
0.7
1.1
0.9
0.9
0.7
0.7
7.4
7.9
7.1
6.8
7.9
6.8
4.8
7.7
6.1
5.9
5.8
5.9
5.9
6.3
6.2
6.5
3.1
2.7
5.1
2.7
2.7
2.5
3.1
2.9
Zn-T
16.9
16.0
17 .1
1 5 .1
17.4
15.0
18.0
21.6
Zn-L
10.7
11.4
1 1.5
11.9
12.0
13.1
1 1.9
19.0
2.0
1.8
2.0
2.1
1.9
1.9
1.9
2.2
Table 5.
Pore Water Nutrient Concentrations
(all concentrations are in ^xM).
Depth
0
2.5
7.5
15.0
30.0
50.0
70.0
90.0
1 10 . 0
Station
Si
NH4
0.62
10. 0
0.99
66. 1
1. 20
96.8
0.65
111.5
1.70 1 17.4
3.44
81.4
4.71
109.0
2 .5 8
77.6
3.55"
62.9
1.5
6.1
16.4
2 6 .8
61.9
71.8
48.4
5.3
3 4 .7
Si
NH4
PO4
NO2
0.06
2 .5 9
2 .5 0
1.82
1.42
1.05
1.24
1. 10
2.60
NO3
0.38
45.4
39.5
34.73
1 9 .4
20.0
4 .9
4 .6
7.8
16a
Depth
PO4
0
2.5
7.5
15.0
30.0
50.0
70.0
1.07
8.6 3
16.21
4.58
12.70
5.60
2.64
0.0
178.6
259.9
81.4
74.6
66.9
64.1
1. 22
13.1
27.4
22.2
40.6
46.0
46.8
NO 2
0.03
1.39
1.45
1.31
0.86
0.68
0.40
NO3
0.2
21.4
20.9
31.3
1 8 .2
4.8
1.5
Station 21
Depth
0
2.5
7.5
15.0
30.0
50.0
70.0
PO4
0.08
2 .7 5
5.18
2 .3 3
2.24
2.20
2.07
Si
NH4
0 .9
13.7
18.9
28.5
25.2
30.3
26.5
1.2
16.6
14.0
16.2
14.8
16.0
17.2
NO 2
0.00
0.57
0.46
0.32
0.43
0.35
0.32
NO 3
0 .0
15.6
10.5
7.5
7 .6
6.5
4.2
Ta b le 5, co nt in ue d.
Pore W ater Nutrient Concentrations
(all conce ntr ation s are in | i M ) .
S t a t i o n 56
Depth
P04
0
2.5
7.5
15.0
30.0
50.0
70.0
90.0
Station
1.95
0.97
0.72
0.28
2.45
2.17
3.30
2.46
Si
N H4
0.8
8. 5
11.8
24.5
27.9
32.1
39.5
33.4
0.6
9.8
9.5
6.2
11.3
8 .3
30.5
47.6
Si
NH4
0.4
15.9
22.1
27.3
31.6
31.0
29.5
48.2
1. 0
6.7
4.2
11.7
17 .1
24.4
80.8
39.7
N02
0 .04
0.87
0.51
0.38
0.38
0.33
0.34
0.45
N03
0. 1
9.5
9.7
1. 2
2.9
0.5
0.0
2.0
67
Depth
PO 4
0
2.5
7.5
15.0
30.0
50.0
70.0
90.0
0.21
1.15
2.18
3.81
3.84
1.61
14.36
2.01
NO2
0.11
0.73
0.93
0.36
0.48
0.29
1.03
0.52
NO3
0.4
1 6 .1
20.8
13.6
11.5
9.2
6.4
4.4
T a b le 5, c o nt in u e d .
Pore W ater Nutrient Concentrations
(all c on cen tra tio ns are in f i M ) .
S ta ti o n
75
Depth
0
2.5
7.5
15.0
30.0
50.0
70.0
90.0
110.0
S ta ti o n
PO4
1.01
3.58
3.58
5.53
2.72
3.76
5.66
3.07
3.03
Si
NH4
2.6
79.2
82.5
93.6
75.7
81.6
90.5
77.8
69.5
3.6
11.1
17.7
19.3
7.5
7.8
19.6
21.9
33.9
NO2
0.17
0.62
0.44
0.34
0.33
0.41
0.33
0.54
0.67
NO3
1.5
16.9
21.8
21.0
31.9
25.0
21.0
19.5
1 1.5
98
Depth
PO4
Si
NH4
0
2.5
7.5
15.0
30.0
50.0
70.0
1.58
2.80
10.85
16.79
12.87
9.09
102.7
148.4
192.9
199.6
205.3
239.6
0.9
1.1
23.0
54.5
51.6
52.8
NO2
0.84
0.96
0.45
0.69
0.42
0.36
NO3
19.0
6.9
1.1
2.1
0.7
0.5
T a b l e 6.
Pore W a t e r M eta l C o n c e n t r a t i o n s
(Mn, Fe in |iM., oth er e le m en ts in nM).
S ta ti o n 08
Depth
Mn
2.5
7.5
12.5
1 7 .5
22.5
27.5
32.5
37.5
23.6
21.4
1 1 .3
8.0
7.7
9.7
1 1 .2
11 .1
Fe
Co
Cd
Zn
Pb
Ni
Cu
3.1
7.3
1.4
3.4
0.6
0.6
(13.6)
1 .9
16.6
23.4
9.7
7.8
6.6
12.4
14.2
15.9
2.9
4.2
1.5
4.3
1.8
1.3
3.8
1 .4
357
505
50
295
540
215
34.9
38.2
19.8
8.9
15.5
21.7
34.3
10.6
185
208
146
83
129
127
75
63
45
26
47
5 1
125
35
172
Mn
4.0
3.2
3.4
2.3
1.9
1.7
1.6
1.8
2.0
1.7
2.3
2.2
2.0
1.4
Fe
Co
Cd
Zn
4.9
10.8
14.2
5.6
21.6
1 1.4
9 .5
16.4
21.9
12.2
9.8
14.6
14.2
8.4
5.8
3.9
7.8
3.5
1 1. 2
2.6
3.4
6.8
2.4
1.4
3.8
4.9
1.4
0.5
19.1
1.9
6.1
28.0
3.2
10 .3
6.1
5.0
8.9
4.2
6.4
13.7
3.2
6.0
2800
20
290
2820
863
1840
597
15 0 0
205
641
1060
13 2 2
120
640
Pb
Ni
Cu
15.0
18 .3
3.9
13.0
15.0
10.9
1 1.7
20.5
2.3
5.2
18.4
20.3
8.0
1 4 .3
59
4 1
40
48
1 16
42
44
60
33
28
50
58
24
29
129
25
13
33
60
25
13
33
7 1
8
89
34
16
30
-p*
l\D
T a b l e 6, c o n ti n u e d .
P o r e W a t e r M e ta l C o n c e n t r a t i o n s
(Mn, Fe in |iM , oth er e le m e n ts in nM).
S ta ti o n 21
Depth
2.5
7.5
12.5
17.5
22.5
27.5
32.5
37.5
42.5
47.5
52.5
57.5
62.5
67.5
Mn
0.20
4.40
1.15
0.61
0.74
1.11
0.65
0.81
1.38
0.97
1.04
0.56
1.42
0.48
Fe
Co
1.8
13.8
3 .5
5.1
3 .3
4.5
2.4
7.8
8 .7
8.1
10.5
5.1
17.7
6.4
13.6
6.0
2.4
3.9
3.6
3.1
5.8
5.7
7.3
4.2
10.0
6.9
3.9
Cd
Zn
Pb
Ni
47.2
22.2
21.4
35.6
17.2
17.2
30.7
19.9
42.1
22.4
20.7
17.7
7.4
27.9
422
502
646
755
132
5
186
360
265
164
529
351
210
443
18
7 1
23
63
14
19
26
25
33
18
60
24
38
34
94
127
107
15 1
59
98
84
87
136
125
12 1
106
200
193
Cu
57
136
52
1 93
32
59
149
73
55
33
107
48
1 13
St a t i o n
56
Depth
2.5
7 .5
12.5
17.5
22.5
30.0
40.0
50.0
60.0
Mn
0.25
0.26
0.23
0.35
0.51
0.78
1.03
2.48
1.28
Fe
0.60
0.48
0.56
1.42
0.90
(8.60)
1.70
5.00
1.68
Co
1.4
5 .5
4.6
7.1
4.5
(10.1)
4.6
5.8
3 .8
Cd
26.3
9.2
12.5
29.9
18.4
15.4
14.9
26.7
22.0
Zn
138
1 15
48
85
108
89
1 15
138
13 1
Pb
Ni
66
133
57
88
55
9 1
70
102
55
Cu
54
74
32
32
37
(150)
49
44
1 33
CO
T a b le 6, c on ti n u e d .
Por e W a t e r Metal C o n c e n t r a t i o n s
(Mn, Fe in ^ M , other el em en ts in nM).
Station
67
Depth
2.5
7.5
12.5
17.5
22.5
27.5
32.5
37.5
42.5
47.5
55.0
65.0
75.0
85.0
Mn
0.10
0.11
0.31
0.46
0.72
1.04
1.43
1.31
0.75
1.15
2.06
1.47
1.29
1.33
Fe
0.0
0.1
0.4
3.1
2.4
5 .5
7.3
5.6
1.9
11.2
11.9
6 .3
6 .3
10.1
Co
2.1
3.2
5.4
4.6
2 .5
3.6
3 .3
3.4
5 .3
7.1
6.5
4.7
6.8
Cd
Zn
Pb
6.7
7.8
6.8
10.3
7.6
8.2
7.9
8 .5
9.9
1 1 .4
3.3
3.9
30.8
3.3
145
214
257
442
242
408
345
362
350
175
142
226
6.4
18.6
24.6
33.3
15.9
34.7
27.9
22.5
27.5
42.3
40.7
32.4
36.7
222
Ni
Cu
37
74
53
60
44
83
80
79
62
54
58
89
85
58
34.0
27.6
35.9
79.3
42.0
83.3
5 2.9
4 0.6
5 4.4
40.2
60.3
40.8
71.4
86. 2
Station
75
Depth
2.5
7.5
12.5
17.5
22.5
27.5
32.5
37.5
42.5
47.5
52.5
57.5
62.5
67.5
Mn
0.31
0.50
0.76
1.18
1.63
1.51
1.76
1.08
2.00
1.96
2.00
2.00
1.91
1.69
Fe
Co
0.2
1.8
1.8
7.9
3.0
6.0
8.0
4.1
4.5
4.5
2.1
3 .5
4.2
4.4
1.2
2.2
2.0
2.5
2 .3
2.8
3.0
2.4
2.7
4.2
3.2
4.6
2.7
2.4
Cd
16.4
13.6
1 3 .3
23.2
26.1
34.9
14.4
5.6
6.1
7.4
1.6
4.9
5.2
4.6
Zn
Pb
182
129
100
126
129
223
79
147
117
55
42
13 1
173
80
3.2
6.0
3.1
12.3
5.9
20.3
6.6
20.0
18.2
18.0
5.6
7.1
9.3
18.1
Ni
30.5
27.5
30.4
2 8.2
58.5
40.7
37.3
35.2
34.2
27.2
3 1.1
22.7
3 1.0
Cu
22.8
19.6
18.0
19.5
1 1.8
24.7
1 6 .8
27.0
23.2
75.0
15.9
(320)
(168)
24.5
Station
98
Depth
Mn
Fe
Co
Cd
Zn
Pb
Ni
2.5
7.5
12.5
17.5
22.5
30.0
40.0
50.0
60.0
0.0
6.7
29.2
41.3
27.4
27.2
23.1
16.1
13.1
0.0
0.0
9.1
34.4
86.2
74.6
80.1
43.4
60.0
3.0
4.7
9.7
17.5
11.8
13.3
12.2
5.0
7.4
14.0
22.0
18.4
8.8
3.6
11.2
6.2
6.7
12.6
155
295
490
154
66
223
1 10
56
67
18.3
16.8
18.1
17.0
20.0
34.6
6.0
15.5
24.3
75
135
15 0
98
1 18
182
19 1
94
189
Cu
26.7
25.3
44.5
28.1
23.2
39.7
57.4
22.4
25.6
Sample
Ni
(M-g/g)
Ni
(nM)
(ng/g)
Zn
(nM)
(M-g/g)
Cd
(pM)
Zn
Cd
Cu
(Mg/g)
Cu
(nM)
08-30
08-45
15
7
0.33
0.12
54
135
1.07
2.06
0 .8
2.1
9
19
43
49
0.88
0.77
15-15
15-36
9
9
0.07
0.08
84
73
0.58
0.56
2 .8
11
159
48
1.13
0.38
17-10
6
0.10
85
1.3 0
1.7
15
48
0.76
21-15
21-24
32
121
0.22
0.82
100
24
0.61
0.15
1.5
5 .4
5
19
76
56
0.48
0.35
56-15
56-24
12
0.16
84
103
1.03
1.32
2.5
2.0
18
15
66
36
0.83
0.48
67-15
67-30
14
11
0.10
0 .2 1
270
77
1.65
1. 30
78
0 .4
280
4
1 67
25
1.05
0.43
68-30
4
0.14
66
2.12
1.7
32
14
0.46
- nI
-Pœ
Table 7, continued. Suspended Particulate Metal Concentrations.
Sample
Ni
(M-g/g)
Ni
(nM)
75-00-05
75-06-05
75-12-05
75-17-05
75-22-05
186
27
0.95
0 .11
75-00-31
75-06-33
75-12-33
75-17-33
75-22-32
17
26
13
26
46
0.35
0.19
0.16
0.22
0.39
Zn
(M-g/g)
Zn
(nM)
(Hg/g)
Cd
(pM)
Cd
1 19
75
87
2 1
0.45
0.29
0.27
0.14
18.4
25.4
1 7 .0
72
106
178
99
109
1. 32
0.70
1.9 9
0.76
0 .8 3
2 .4
1 2 .5
144
4.1
1.5
Cu
(ng/g)
Cu
(nM)
4 1
56
30
605
56
10 1
10 8
80
2.90
0.22
0.40
0.34
0.57
26
48
935
18
7
59
1 14
20
5
90
1.10
0.77
0.23
0.04
0.71
Sample
Ni
(ng/g)
88-25
88-30
24
Ni
(nM)
0.20
91-15
(Jig/g)
Cd
(pM)
(M-g/g)
Cu
(nM)
0.44
0.76
3.8
33
20
34
0.16
0.54
88
1.08
0.3
2
16
0.20
Zn
(nM)
57
50
Zn
(M-g/g)
Cd
Cu
93-15
93-34
30
5
0.20
0.06
163
64
1.00
0.73
1.6
6
19
12
0.12
0.14
95-20
95-46
2 1
15
0.18
0.11
44
77
0.34
0.53
1 0 .2
45
274
23
2.16
0.17
98-18
98-32
98-50
11
0.06
39
152
96
0.18
0.93
0.44
3 .4
12
18
87
9 1
0.09
0.55
0.43
CD
Ol
o
(^g/g)
Fe
(nM)
(Hg/g)
Pb
(pM)
17.1
23.1
10300
23495
239
420
38
102
183
492
8
13
154
224
737
848
6 .0
7 .7
8887
12037
7 1
107
268
106
582
256
14
12 1
17-10
368
6 .7
15256
272
30
145
14
239
21-15
21-24
62
82
0 .5
0.6
1987
5198
14
37
102
50
197
96
15
40
101
269
56-15
56-24
347
408
5.0
6.2
15470
17623
221
264
50
158
193
641
67-15
67-30
56
362
0.4
7.2
4685
13660
34
268
88
59
1 70
3 14
68-30
414
1 5 .8
21082
791
56
565
6
214
(ng/g)
Mn
(nM)
08-30
08-45
725
1268
15-15
15-36
Sample
Mn
Fe
Pb
Co
(M^g/g)
Co
(nM)
Sample
Mn
(M-g/g)
Mn
(nM)
Fe
(Mg/g)
Fe
(nM)
Pb
(Mg/g)
Pb
(pM)
Co
(M-g/g)
Co
(pM)
75-00-05
75-06-05
75-12-05
75-17-05
75-22-05
436
15
2 1
20
33
2 .4
0.07
0.10
0.07
0.27
1618
332
129
447
8.7
1.5
0 .6
1.6
55
193
6
27
5
80
223
7
26
10
15
65
75-00-31
75-06-33
75-12-33
75-17-33
75-22-32
11
363
51
382
197
0.24
2.8
0.68
3.47
1 .79
299
1408
944
4068
5177
6 .4
10.8
12.3
36.3
46.2
11
24
24
38
1 74
63
50
86
9 1
420
11
134
en
N>
Sample
Mn
(M-g/g)
Mn
(nM)
(Hg/g)
Fe
(nM)
(ng/g)
Pb
(pM)
Fe
Pb
Co
(ng/g)
Co
(pM)
88-25
88-30
516
329
4.7
6 .0
15094
11138
135
199
49
31
1 18
1 50
91-15
296
4 .3
11113
159
43
167
6
84
93-15
93-34
32
203
0.23
2.77
8908
1 19
43
29
84
1 05
14
1 85
95-20
95-46
28
270
0.25
2 .21
1447
7523
12 .9
6 1
385
481
930
1040
98-18
98-32
98-50
19
275
499
0.1
2 .0
2.70
323
1987
6392
1.7
14 .2
34.2
25
78
181
35
15 1
262
22
13
1 12
9 1
Table 8. Dissolved Trace Element Concentrations.
ample
Cu
Pb
(nM)
(pM)
Zn
(nM)
Cd
Ni
Mn
(nM)
(nM)
(nM)
08-0
08-30
08-45
2.18
2.65
2.5
263
480
2 04
3.1
5.0
6.1
0. 36
0. 19
0. 24
19.1
10.5
17.3
15-0
1 5- 0a
15 - 15
1 5- 36
2. 24
1.9
2.11
2. 15
299
20 4
261
87
5.4
2.9
4.1
1.2
0. 29
0. 26
0. 26
0 . 22
16.0
16.3
8.6
8.1
115
1.78
0. 15
403
2.75
3.1
0. 24
0 . 15
0. 29
2 . 08
14.2
9.7
8.9
0.7
10.2
7.4
17-10
21-0
21-15
21-24
1.75
1.66
56-15
56-24
1.59
71
1.32
0 . 19
67-0
67-15
67-30
0. 7 6
2.15
1.21
2.73
0 . 34
0 . 14
2. 5 2
114
10
127
68-30
1.92
151
3.98
75-00-05
75-06-05
75-12-05
75-17-05
75-22-05
2. 77
3 . 39
687
197
115
75-00-31
75-06-33
75-12-33
75-22-32
1.49
1.89
2. 15
24 5
88-25
88-30
1.31
10.6
6.1
0. 77
12.0
0 . 22
1.45
7.7
7.6
1.35
2. 36
1.96
3.27
0 . 37
0. 4
0 . 24
0 . 15
0. 22
1.69
1.0
9.7
2. 8
4.25
3. 78
4. 7
156
2 28
163
4. 78
3.43
2.9
0. 34
0. 28
0. 2 2
2. 17
0. 7
0.91
7.8
4. 2
5.7
4 . 75
5 86
264
2.78
0. 25
0 . 16
10.3
9.5
3.0
0.21
10.3
9.5
0 . 16
0 . 32
1.53
6. 6
12.5
3.11
0. 39
1.47
13.1
0. 32
0. 16
0.21
0. 27
0. 27
1.31
2.0
3.2
11.3
4. 84
3.7
3.5
3. 9
5.8
4. 0
91-15
1.54
116
93-15
93-34
2 .0 4
2. 05
271
95-46
4.21
342
98-0
98-18
98-32
98-50
98-84
2. 05
1.47
1.84
1.65
2 . 34
271
2 44
233
428
1.44
Table 9. D is so lv e d Nu trient C on ce ntra tio ns , Salinity and
T em perature.
ample
P
Si
no3
NCb
Sal.
Temp.
(M-M)
(M-M)
Ol M)
(M-M)
(psu)
(°C)
08-27
08-43
0.67
0.44
2.08
6.09
0.41
0.59
0.05
0.08
34.65
34.66
12.00
8.88
21-0
21-15
21-24
0.01
0.13
0.03
0.58
0.62
1.41
0.07
0.63
0.83
0.00
0.04
0.03
34.80
34.80
14.34
14.25
56-10
56-20
56-24
0.20
0.27
0.68
1.97
0.00
0.60
0.07
0.11
0.10
0.03
0.05
0.02
34.82
34.81
34.82
13.85
13.85
13.85
68-30
0.4
2.0
0.13
0.03
34.87
13.1
75-00-05
75-06-05
75-12-05
75-17-05
0.11
0.17
0.51
0.41
0.34
0.23
0.58
0.05
0.07
0.00
0.22
0.01
0.00
0.01
0.04
0.02
34.87
34.88
34.88
34.87
14.63
14.61
14.62
17.73
75-00-31
75-06-33
75-1 2-33
0.25
0.39
0.49
0.58
1.84
1.47
0.03
0.04
0.09
0.01
0.05
0.05
34.95
34.91
34.94
7.33
7.60
7.56
88-25
88-30
0.22
0.24
1.58
2.01
0.00
0.08
0.03
0.03
34.80
34.80
15.16
15.14
91-11
0.17
1.02
0.05
0.02
34.82
14.00
93-10
93-34
0.08
0.19
0.72
0.39
0.00
0.04
0.00
0.02
34.83
34.82
13.96
10.72
95-40
95-52
0.48
0.52
3.06
3.02
0.96
1.02
0.13
0.13
34.00
34.84
7.84
7.84
98-18
98-32
98-50
98-80
0.16
0.35
0.76
0.45
0.31
1.34
3.46
1.72
0.00
1.59
6.20
3.03
0.02
0.15
0.53
0.26
34.99
35.00
35.05
35.05
13.63
10.50
6.85
6.84
Fi g u r e 1. C ru is e ch art s h o w i n g s a m p l in g stations at the D o g g e r b a n k
a n d v ic in ity .
Ti/s*d-e
(%)
0 .2
Ti/S«d-13
0.4
— —I___ ___ I
0 .0
(%)
0.1
0.2
D«pth
(m m )
0 .0
\
T i/S « d *2 1
(% )
T I/S « d -5 6
0 .2
0 .4
0 .0 0
(% )
0 .2 5
0.50
Oaplh
(mm)
0 .0
T I/S « d -6 7
(% )
0 .2 5
T l/S » d *7 5
0.5 0
Dtplh
(mm)
0 .0 0
T I/S « d -0 8
0 .1 0
(% )
0 .2 0
Depth
(mm)
0 .0 0
-00
to tal
0.30
0 .0 0
0 .2 5
(% )
0.50
F « /S « d *1 5
o.o
0 .0
(% )
0 .8
0 .4
to tal
lo a c h a b le
F « /S « d -2 1
F */S « d -5 6
(% )
0 .0
0 .4
0 .8
0 .8
D«pth
(m m )
0 .0
(% )
0.4
F « /S « d -8 7
F « /S « d -7 9
(% )
0 .3
0 .6
D«plh
(mm)
0 .0
F « /S « d-B 8
Dapth
(mm)
0 .0
0 .4
(% )
0 .8
0 .0
0 .2
(% )
0 .4
0 .0
M n /S «d -B
(m g /k g )
M n/S »d -15
O
50
100
M n/S »d -21
O
100
M n /S «d *6 7
O
150
M n /S «d *9 8
O
100
150
O
(m g /k g )
200
40
M n/S «d -56
O
(m g /k g )
200
120
(m g /k g )
200
(m g/kg)
300
(m g /k g )
80
M n/S «d -75
O
100
400
(m g /k g )
200
300
(m m )
Depth
Cd/S «d-21
0.1
(m g /k g )
0 .2
0 .3
C d /S «d -56
0 .0 0
(m g /k g )
0 .2 5
0 .5 0
Depth
(mm)
0 .0
C d /S «d -67
(m g /k g )
0 .0 8
0.12
_
n« nt h
,
mm
,
0 .0 0
C d /S « d -9 8
0 .0
0-
(mm)
'
'
-2
(m g /k g )
0 .2
0 .4
0 .6
- I ------ «------ 1____«___ I
r
Depth
-40
leachable
to ta l
C d /S « d -7 5
0 .0 0 0
0 .0 2 5
(m g /k g )
0.0 5 0
C o /S «d*15
(m g /k g )
1 .0
2 .0
D«pth
(m m )
0 .0
te a c h a b le
C o /S «d -21
0 .0
C o /S *d -5 6
(m g/kg)
0 .4
0 .0
0.8
(m g /k g )
0 .2
0 .4
0 .6
(mm)
-1 0 -
?
£
D«plh
JZ
a
•
o
-20-30
-40
-5 0 -60-
C o /S «d *6 7
0 .0
0.1
(m g /k g )
0 .2
0 .3
C o /S ed >75
D«pth
(mm)
0 .0
a
Q
C o /S «d-08
1.0
(m g/k g)
2.0
D«pth
(mm)
0.0
•
—
-o------
toteü
l e a c h a b le
0 .4
(m g /k g )
0 .8
(m g /k g )
C u / S * d -21
(m g /k g )
Depth
(m m )
C u /S «d -8T
C u /S «d -56
0 .5
(m g /k g )
1.0
Depth
(mm)
0.0
(m g /k g )
Depth
(mm)
C u /S « d -6 7
C u/S «d-Ö 8
Depth
(mm)
0
2
(m g /k g )
4
6
C u /S td -7 5
(m g/kg)
N I/S « d -6 7
O
NI/S«d-O B
0
2
(m g/kg)
4
8
-60-00 J
-o—
N I/S *d -75
(m g /k g )
1
teachable
0
1
(m g /k g )
2
3
P b/S « d-8
P b /S « d -1 5
(m g /k g )
5
10
15
5
(m g/k g)
10
15
D . pth
(m m )
3
P b /S « d -2 1T
(m g /k g )
4
8
P b/S «d*S 6T
0
4
(m g /k g )
8
12
D*pth
(mm)
0
Pb/S # d -6 7
(m g/kg)
P b /S «d-75
1
2
3
4
5
D.plh
(mm)
0
P b/S « d -0 8
10
(m g /k g )
20
(m g /k g )
Zn/S «d -8
5
Z n /S «d -15
(m g/kg)
10
15
20
O
(m g /k g )
5
10
15
Deplh
(m m )
O
Zn/S «d *5 6
1
2
3
4
5
O
(m g /k g )
10
20
D«pth
(mm)
0
Z n /S ad *6 7
(m g /k g )
Z n /S *d -7 5
Z n /S td -0 8
(m g/kg)
D«pth
(mm)
O
leachable
F ig u r e 2i. S e d i m e n t Z n - co nt e nt.
10
(m g /k g )
20
M n/P W -8
(uM )
M n /P W -1 5
20
2
(uM )
3
D * P ,h
(m m )
10
M n/P W -21
M n /P W -5 6
(u M )
(uM )
1
2
—I________ ______ I
o -10-
-20
-20 ■
D 'P " ’
< """>
E
E
-30
JZ
-40
a
®
a
-5 0 -60
-70-
M n /P W -67
1
M n /P W -7 5
(u M )
2
1
D .pth
(m m )
—
-60-
M n /P W -90
Depth
(m m )
25
(u M )
(u M )
2
I------------------------------------------------.______ I
F e /P W -5 6 G
F e/P W -6 7 G
(uM )
3
0 -10-
(uM )
6
12
__I
•
•
•
-
20-
Depth
(mm)
-20-30-4 0 -
!
-4 0 -
a
-60 -
ao
-50 -
-80
-60 -70 J
-100J
F e/P W -7 5 G
F e /P W -9 8
(uM )
50
0
5
10
0 4 - ----------------------------------- 1------------------ .------------------1
0
-10
Depth
(mm)
-
20-
-20
-30
-40 •
'
E
-40
£
-60 H
*
.
°
-50
-60
-80
-70 J
(u M )
100
_ l
F e /P W -5 6 G
(uM )
F e/P W -6 7 G
3
(u M )
DeP,h
<m m >
6
F e /P W -7 5 G
Depth
(mm)
5
F e /P W -9 8
(uM )
10
50
(uM )
100
Mn
0
Co
10
Mn
0
(u M ),
(u M ),
(n M )-P W -8
20
Co
25
30
(n M )-P W -9 8
50
M n,
Fe
Mn,
0
-
-20-
Fe
■
•
•
------------ 1
O
(■ )
o
•
■
O
(■ )
0
•
(■ )
o
•
■
o
■
•
Q.
0)
O
OH
o
«
•
-
■
o
•
■
(n M )-P W -7 5
O
•
-60
Co
(r» M )-P W -67
mo
•
-40 -
Co
1
•
?
.c
(u M ),
o
•
■
(u M ),
•
o
O
■
■
■
Fe/PW-75G
O
Co/PW-75
•
Mn/PW-75
-80 -
Figure 5
Interstitial water Mn, Fe and Co concentration
C d /P W -7 5
Depth
(mm)
Depth
(m m )
0
20
(n M )
40
N I/P W - 8
50
(n M )
150
200
_I___I___I_
250
__I
(m m )
- I _______ I—
1 00
__ I__
20-
Depth
-
-3 0 -
N I/P W - 7 5
(n M )
40
60
Depth
(mm)
20
C u /P W -8
80
Depth
(mm)
40
(n M )
Figure
7.
U p p e r t w o i te m s : I n t e r s t i t i a l w a t e r N i c o n c e n t r a t i o n
profiles.
Bo tto m: Interstit ial w a te r Cu c o n c e n t r a t i o n pr of iles .
Z n/P W -21
Z n /P W -5 6
(nM )
4 00
50
(n M )
100
(ui ui)
M,daa
Z n /P W -6 7
250
Z n /P W -9 8
(nM )
500
(UJUJ)
Mld3a
Q-
0)
Q
(nM )
NIOZ - RAPPORT 1989 - 8
CONTENTS
Summary
...................................................................................................................................................
1. Introduction
1
...........................................................................................................................................
3
2. Materials and methods .........................................................................................................................
2.1. Sediments .......................................................................................................................................
2.2. Interstitial water ................................................................................................... ......................
2.3. Suspended particulate m atter.........................................................................................................
2.4. Dissolved trace elements ...............................................................................................................
4
4
6
7
7
3. Results ...................................................................................................................................................
8
3.1. Sediment characteristics.................................................................................................................
8
3.1.1. Ti, Fe, Mn .............................................................................................................................
9
3.1.2. Trace elements ..................................................................................................................... 10
3.2. Interstitial water characteristics ..................................................................................................... 12
3.2.1. Trace elements ..................................................................................................................... 15
4. Suspended particulate matter ...............................................................................................................
18
5. Dissolved trace elements ....................................................................................................................... 19
Acknowledgements ...................................................................................................................................
References .................................................................................................................................................
List of Tables .............................................................................................................................................
Tables .........................................................................................................................................................
Figures .......................................................................................................................................................
20
21
24
25
55