© PLOSI o
OPEN 3 ACCESS Freely available online
-
The Symbiosis between Lophelia pertusa and Eunice
norvegica Stimulates Coral Calcification and Worm
Assimilation
Christina E. M ueller1", Tom as Lundälv2, Jack J. M iddelburg3, Dick van O ev elen 1
1 D epartm ent o f Ecosystem Studies, Royal Netherlands Institute for Sea Research (NIOZ-Yerseke), Yerseke, The Netherlands, 2 Sven Lovén Centre for Marine Sciences,
Tjärnö, University o f Gothenburg, Strömstad, Sweden, 3 D epartm ent of Earth Sciences, Geochemistry, Utrecht University, Utrecht, The Netherlands
Abstract
We investigated th e interactions b etw een th e cold-w ater coral Lophelia pertusa and its associated polychaete Eunice
norvegica by quantifying carbon (C) and nitrogen (N) b u d g ets of tissue assimilation, food partitioning, calcification and
respiration using 13C and 15N enriched algae and Zooplankton as food sources. During incubations b o th species w ere kept
either to g e th e r o r in sep arate cham bers to study th e net o u tco m e of their interaction on th e above m entioned processes.
The stable iso to p e ap p ro ach also allowed us to follow metabolically derived tracer C further into th e coral skeleton and
therefore estim ate th e effect of th e interaction on coral calcification. Results show ed th a t food assimilation by th e coral was
not significantly elevated in presence of £ norvegica b u t food assimilation by th e polychaete w as up to 2 to 4 tim es higher
in th e presence o f th e coral. The corals kept assimilation co n stan t by increasing th e consum ption of sm aller algae particles
less favored by th e polychaete while th e assimilation of Artem ia w as unaffected by th e interaction. Total respiration of tracer
C did not differ am ong incubations, although £ norvegica en h an ced coral calcification up to 4 times. These results to g e th e r
with th e reported high a b u n d an ce of £ norvegica in cold-w ater coral reefs, indicate th a t th e interactions betw een £ pertusa
and £ norvegica can be o f high im portance for ecosystem functioning.
C i t a t i o n : Mueller CE, Lundälv T, Middelburg JJ, van Oevelen D (2013) The Symbiosis betw een Lophelia pertusa and Eunice norvegica Stimulates Coral Calcification
and Worm Assimilation. PLoS ONE 8(3): e58660. doi:10.1371/journal.pone.0058660
E d i t o r : Andrew Davies, Bangor University, United Kingdom
R e c e i v e d Septem ber 26, 2012; A c c e p t e d February 7, 2013; P u b l i s h e d March 11, 2013
C o p y r i g h t : © 2013 Mueller e t al. This is an open-access article distributed under the term s of th e Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided th e original author and source are credited.
F u n d i n g : This research was carried o u t within th e CALMARO Project (www.calmaro.eu), a European Marie Curie Initial Training Network (ITN), supported by
funding under th e Seventh Framework Program m e o f th e European Community. The funders had no role in study design, data collection and analysis, decision to
publish, or preparation o f th e manuscript.
C o m p e t i n g I n t e r e s t s : The authors have declared th a t no com peting interests exist.
* E-mail: Christina.Mueller@nioz.nl
m etabolism : A q u aria observations by M o rten sen [15] have show n
th a t E. nowegica occasionally steals food from its host coral while at
the sam e tim e it cleans the living coral fram ew ork from detritus
a n d protects it from potential p re d ato rs th ro u g h aggressive
territorial behavior. A gain, the n et outcom e o f these different
processes o n the m etabolism o f the coral a n d the polychaete has
never b e en quantified.
Sym biosis are long term interactions betw een different biolog­
ical species [17,18] w hich c an involve positive (m utualism (++),
com m ensalism (+0)) a n d negative feedbacks (com petition (—),
parasitism (—+)) b etw een the species [19,20], B ased on qualitative
observations the relations b etw een L. pertusa a n d E. nowegica range
from parasitic (food stealing) to m utualistic (cleaning a n d
p ro tec tio n o f coral branches) [15,16], H ow ever to b e tte r estim ate
the n et o utcom e o f the interplay o f the different process involved
q u antitative data, especially w ith respect to species m etabolism are
necessary [21]. T hese d a ta will fu rth er help to assess the
significance o f this in teractio n for the structure a n d functioning
o f cold-w ater coral reefs, w hich can be crucially influenced by
species interactions [22].
In this study w e directly quantify the interactions betw een L.
pertusa a n d E. nowegica w ith respect to food assim ilation,
calcification a n d respiration, key processes in species m etabolism
a n d highly involved in the interaction b etw een L. pertusa a n d E.
nowegica. T o trace a n d quantify these processes w ith respect to the
Introduction
In the N o rth E ast A tlantic, the scleractinian cold-w ater coral
Lophelia pertusa is the d o m in a tin g re e f form ing species. Its com plex
fram ew ork offers a m ultitude o f different habitats [1,2,3] used b y a
g reat variety o f species [4,5,6], A m ong 1300 do cu m en ted species
[7] various sym biotic relations betw een scleractinian cold-w ater
corals a n d associated invertebrates have b e en re p o rte d [8]. So far,
m ost o f these relationships are n o t clearly defined a n d th eir role in
the functioning o f the ecosystem is poorly u n d ersto o d [8,9].
O n e ubiquitous species th a t is ab u n d an tly (12-17 ind. m 2,
based o n o u r d a ta a n d the following references [10,11]) observed
in close con tact w ith the cold-w ater coral L. pertusa is the
polychaete Eunice nowegica [12,13,14], It form s parchm ent-like
tubes w ithin living coral b ranches w hich later are calcified by its
coral host [15]. R oberts [16] suggested th a t E. nowegica strengthens
the re e f fram ew ork b y thickening a n d connecting coral branches.
M oreover, by aggregating coral fragm ents the polychaete m ight
en h an ce the developm ent o f large re e f structures [16], H ow ever,
the relationship m ight com e a t a m etabolic cost for the coral due
to e n h an c ed precip itatio n o f C a C 0 3 So far how ever, no d a ta is
available to quantify this aspect o f the relationship b etw een coral
a n d polychaete.
A dditional to the indirect m etabolic effect via calcification the
polychaete also m ight have a m o re direct effect on coral
PLOS ONE I www.plosone.org
1
March 2013 | Volume 8 | Issue 3 | e58660
Coral-Worm Symbiosis
interaction b etw een b o th species we used two 13C a n d 15N labeled
food sources th a t are considered im p o rta n t for cold-w ater coral
re e f com m unities, i.e. algae a n d Z ooplankton [23,24,25]. T h e use
o f two food sources also allow ed us to investigate food com petition
a n d niche segregations betw een L. pertusa a n d E. nowegica. D u rin g
the ex p erim en t corals a n d polychaetes w ere either kept separate or
in association w ith each o th er to allow singling o u t the net
outcom e o f the association o n different m etabolic processes. By
using isotopically en rich ed food sources we w ere able to direcüy
trace n o t only C a n d N tissue assim ilation by L. pertusa a n d E.
nowegica, b u t also calcification based o n m etabolically derived Cdeposition in coral skeleton. M etabolically derived C, i.e. inorganic
C originating from respired food, is one o f the two sources th a t
sustain the d e m a n d for inorganic C b y calcification [26]. Since
13C -labeled food was used in o u r e x perim ental design, the
subsequent deposition o f respired 13C into the coral skeleton was
used as pro x y for calcification as discussed below.
ad a p te d after G uillard [31] on the base o f artificial seaw ater in
w hich 90% o f eith er the unlabeled N a H C 0 3 or N a N 0 3 w ere
exchanged w ith the isotopically en rich ed equivalent (C am bridge
Isotopes, 99% 13C, 99% 15N). A fter 3 weeks o f culturing cell
densities w ere a ro u n d 3 -4 * IO 6 cells m l 1 a n d the algal suspension
was co n ce n tra ted b y centrifugation a t 450 g. T h e concentrates
w ere rinsed three tim es w ith 0.2 p m filtered seaw ater to rem ove
residual label. T h e isotopic en ric h m e n t o f the algal concentrates
w ere 59% 13C (S13C 125908 %o) a n d 64% 15N (S15N 472590 %o),
respectively. T h ey w ere stored frozen until use in the ex p erim ent
(for details o n isotope analysis, see below).
Artemia spp. n auplii (~ 3 0 0 pm) w ere chosen to represent large
zooplankton-derived P O M substrates reach in g cold-w ater coral
reefs [23]. T h e y resem ble n a tu ra l Zooplankton a n d have b een
successfully used in food studies o n Lophelia pertusa before
[32,33,34], 13C a n d 15N e n ric h ed nauplii w ere cu ltu red by
h a tc h in g 0.6 g Artemia cysts (Sera) in 10 L incubation cham bers
filled w ith 0.2 p m filtered seaw ater u n d e r n a tu ra l light conditions
a n d m ild aeration. A fter the larvae h a d developed to a state at
w hich they take up particulate food (1 to 2 days after eclosión o f
larvae), larvae w ere fed every second day w ith a suspension
c o ntaining 13C o r 15N e n ric h ed pre -c u ltu re d algae (at a ro u n d
1.5 m g C L - a n d 0.15 m g N L - respectively). T h e uptake o f
algae was confirm ed visually u n d e r the m icroscope as green food
particles in the anim al guts. A fter seven days o f feeding, larvae
w ere co n ce n tra ted by filtration o n a 200 p m filter, rinsed off the
filter w ith filtered seaw ater, co u n ted u n d e r the bin o cu lar a n d
stored frozen. W ithin the Artemia con cen trate different early larval
stages could b e detected. T h e final isotopic en ric h m e n t o f the
larvae was 4% (S13C 2909 %o) for 13C a n d 7% (815N 21800 %o) for
15N respectively.
T o standardize the a m o u n t o f C a d d ed to the incubations,
substrates w ere analyzed for C a n d N c o n te n t (see below for
m ethodological description). T h e 1:1 m ixture o f 13C A rtem ia : 15N
algae a n d 13C algae : 15N Artemia, b o th a t total c o n ce n tra tio n o f
800 p g C L ’, rep resen ted the two food treatm ents. T o g eth er
w ith the treatm en ts “Lophelia sep arate” , “Eunice sep arate” a n d
“Lophelia - Eunice to g eth e r” gives a total o f 6 treatm ents, each o f
th em p erfo rm ed in triplicate.
M aterials and M ethods
Sampling Location and Maintenance
All coral pieces a n d polychaetes used in the experim ents w ere
o b tain e d from the N orw egian T isler Reef, w ith all necessary
perm its o b tain e d from the D irecto rate o f Fisheries, N orw ay to
co n d u ct the described study. T h e R e e f is situated a t 70 to 155 m
d e p th in the N E Skagerrak, close to the b o rd e r betw een N orw ay
a n d Sw eden. T h ro u g h o u t the year, the c u rre n t velocity over the
re e f norm ally varies from 0 to 50 cm s *, w ith peaks in excess o f
70 cm s- 1 , while the flow direction fluctuates irregularly betw een
N W a n d SE [27,28]. T e m p e ra tu re a t the re e f site typically varies
betw een 6 to 9°C th ro u g h o u t the y ear [27,28]. T h e a m o u n t a n d
quality o f particu late organic c arb o n (PO C) re ac h in g the re ef
depends o n the location w ithin the reef, so th a t P O C c o n ce n tra ­
tions can range from 43.5 to 106.3 p g C L -1 [28].
S pecim ens w ere collected from a d e p th o f a ro u n d 1 1 0 m
(N 58°59,800’ E 10°58,045’) w ith the rem otely o p e rated vehicle
(RO V ) S perre Subfighter 7500 D C . W ith in a few hours they
arrived in the lab o ra to ry a t the Sven L ovén C en tre in T jä rn ö
(Sweden) in cooling boxes filled w ith K oster-fjord seaw ater (7°C,
salinity 31). Before used in the ex p erim en t organism s w ere kept 1—
8 days for acclim ation in a d ark tem p eratu re-co n tro lled lab o rato ry
a t 7°C w ith sand-filtered ru n n in g seaw ater from 45 m d e p th o u t o f
the ad ja ce n t K oster-fjord (sand particle size 1-2 m m , w ater
exchange ra te o f ca 1 L m in - *). N o ad ditional feeding was offered
d u rin g the m ain ten an ce p erio d since the sand-filtered K oster-fjord
w ater still c o n ta in ed a lo t o f particles < 1 - 2 m m (pers. observation)
w hich could be used as food source [24]. D u rin g the acclim ation
phase corals w ere kept w ithout polychaetes, w hile polychaetes
w ere kept in a q u a ria w ith coral rubble including also living
colonies in response to their n e ed o f shelter. O n e day before used
in the ex p erim en t larger coral colonies w ere clipped to ap p ro x ­
im ately the sam e size, d e term in ed b y dim ension a n d b u o y a n t
w eight, to allow using com p arab le coral sam ples p e r c ham ber.
Polychaetes w ere selected solely o n the base o f their dim ension.
A fter the ex p erim en t all sam ples w ere also m easured for dry
w eight (DW) to allow standardization am o n g treatm ents.
Experimental Set up and Procedure
In c u b atio n cham bers (Fig. 1) w ere p laced in a th erm o ­
controlled ro o m a t 7°C a n d filled w ith 5 p m filtered K oster-fjord
b o tto m w ater p rio r to the start o f the experim ent. A total o f 29
coral fragm ents (2 to 3 coral pieces c h a m b e r- 1 , 3 .2 ± 1 .3 3 g D W
p iece- 1 ; 9 .7 8 ± 1 .1 6 g D W c h a m b e r- 1 ; 1 6 .5 5 ± 5 .4 3 polyps
c h am b er 1, w ith no significant difference o f coral w eight betw een
treatm ents, p > 0 .0 5 ) a n d 12 polychaete specim ens (1 polychaete
c h a m b e r- 1 , 0 .4 8 ± 0 .1 2 g D W po ly ch aete- 1 , w ith no significant
difference o f polychaete w eight betw een treatm ents, p > 0 .0 5 ) w ere
selected a n d placed separately or to gether in the m iddle o f the
incubation cham bers. T o stabilize the corals fragm ents in an
u p rig h t position, they w ere gently inserted into a 1 cm elastic
silicone tube o n a n acrylic plate th a t was a tta ch e d on the c h am b er
base. T o provide refuge space in treatm en ts w ith only polychaetes
p re sen t bleached coral skeleton a n d plastic tubes w ere placed in
the cham bers. B oth substitutes w ere indeed used as refuge b y the
polychaetes d u rin g the experim ent, a lthough the tubes w ere not
p re sen t d u rin g the acclim ation phase. C h am b ers w ith corals a n d
polychaetes co n tain ed only living coral specim ens, used as shelter
by the polychaete d u rin g the incubation. W ater circulation was
m ain tain ed d u rin g the ex p erim ental p erio d by a m otor-driven
p ad d le in the u p p e r p a rt o f the in cu b atio n c h am b er (Fig. 1, ro to r
speed 30 rpm ). T h e m o to r section was n o t directly a tta ch e d to the
Preparation o f Food Substrates
C old-w ater corals are exposed to various food particles a n d they
are considered to feed o n a m ixed diet including phyto- a n d
Zooplankton [23,25,29,30]. T h e diato m Thalassiosira pseudonana
(5 pm ) was chosen to represent small phytoplankton-derived
particulate organic m a tte r (PO M ) substrates re ac h in g cold-w ater
coral reefs [25]. T h ey w ere cu ltu red axenically in f /2 m edium
PLOS ONE I www.plosone.org
2
March 2013 | Volume 8 | Issue 3 | e58660
Coral-Worm Symbiosis
incu b atio n c h am b er a n d efFectively avoided heatin g o f the
cham bers d u rin g the incubations. C orals a n d polychaetes w ere
left in the c h a m b e r for 12 h for acclim atization p rio r to feeding.
At the start o f the experim ent, 400 |ig C I,
o f each food
source was gently p ip etted into the w a ter colum n o f each cham ber.
T h e cham bers w ere closed from flow th ro u g h for 2.5 days to allow
feeding (feeding period). V isual observation confirm ed th a t the
circulating w a ter kept the food particles in suspension. A fter the
feeding period, the cham bers w ere flushed to rem ove rem ain in g
food particles a n d w aste p roducts by p u m p in g 5 p m filtered
K oster-fjord b o tto m w a ter th ro u g h the cham bers at a flow speed
o f 140 m l m in 1 for 12 h. T his p a tte rn was c o n d u cted twice. A fter
the last flushing p e rio d (140 m l m in
5 p m filtered K oster-fjord
w ater, lasting 12 h), incu b atio n cham bers w ere closed w ithout
food addition for a n o th e r 24 h. D u rin g this p e rio d the respiration
o f the ad d ed 13C e nriched food substrates was quantified by
m easuring the p ro d u c tio n o f dissolved inorganic 13C in the w ater
(13C -D IC ) [35,36,37], W a te r sam ples w ere taken before (control)
a n d after the respiration in cubation, a n d filtered (G F /F ) in a 20 m l
headspace vial. E ach sam ple was poisoned w ith 10 pi H g C E ,
closed w ith an alu m in u m cap fitted w ith a ru b b e r septum an d
stored upside dow n.
In parallel to the m ain experim ent, 3 control corals a n d 3
control polychaetes w ere in cu b ated w ithout food for stable isotope
13C a n d 15N b a ckground m easurem ents. A fter a total ex p erim en ­
tal tim e o f 7.5 days, coral a n d polychaete sam ples w ere frozen at
—2 0 UC a n d tran sp o rte d to the N etherlands Institute for Sea
R esearch-Y erseke, w here they w ere freeze-dried a n d stored frozen
for fu rth er analysis.
Sample Treatment and Analysis
T is s u e a s s i m il a ti o n . P rio r to isotopic analysis frozen coral
a n d polychaete sam ples w ere freeze-dried, w eighed a n d h o m o g ­
enized by grinding w ith a ball M ill for 20 s (M M 2000, R etsch,
H a a n , G erm any). A subsam ple o f a ro u n d 30 m g o f g rinded coral
m aterial an d 2—3 m g g rinded polychaete m aterial was transferred
to pre-co m b u sted silver boats a n d decalcified by acidification.
W hile polychaete sam ples w ere directly acidified w ith c o n ce n tra t­
ed HC1 (12 m ol L '), coral sam ples w ere first placed in an acidic
fum e for 3 to 4 days to rem ove m ost o f the inorganic C. C oral
sam ples w ere th e n fu rth er acidified by stepwise addition o f HC1
w ith increasing c o n ce n tra tio n (m axim um co n cen tratio n 12 m ol
L ') until the inorganic C fraction (skeleton) was fully rem oved (as
evidenced by the absence o f bubb lin g after fu rth er acid addition).
T h e rem ain in g fraction after acidification resem bled the organic
fraction o f each sam ples, w hich in case o f the coral sam ples
includes the coral tissue a n d the organic m atrix in the skeleton th at
represents only a very small organic fraction [38], A fter com plete
décalcification each sam ple was m easu red for 13C a n d 15N using a
th erm o E lectro n Flash E A 1112 analyzer (EA) coupled to a D elta
V isotope ratio m ass spectrom eter (IRM S).
All ob tain ed stable isotope d a ta w ere expressed in |tg C g
C
biom ass a n d (tg N g 1 N biom ass. T h e y w ere calculated as
follow ing on the base o f the delta notations ob tain ed from the
IR M S : § X (%„) = (RSampie/Rref —1)* 1000, w here X is the elem ent,
Rsampie is the heavy : light isotope ratio in the sam ple a n d R ref is
the heavy : light isotope ratio in the reference m aterial (V ienna Pee
D ee B elem nite sta n d ard for C a n d atm ospheric nitro g en for N).
W h en used for C the R ref = 0.0111797 a n d w hen used for N th en
Rref = 0 .0 0 3 6 7 6 5 . T h e atom ic % o f heavy isotope in a sam ple is
calculated as F = R sample/ ( R sample+ l). T h e excess (above back ­
ground) atm % is the difference betw een the F in a n experim ental
sam ple a n d the atm % in a control sam ple: E = F sampie — Fcontroi.
T o arrive to total tra c e r C a n d trac er N uptake o f labeled food
I. Larsson
Figure
1. Exp erim en tal set up (Mississippi cham bers), a)
E x p e rim en ta l s e t u p in c lu d in g th e w a te r re serv o ir fo r filtered se a w a te r
(1), th e d ire c tio n o f th e w a te r flo w in d ic a te d w ith a rro w s (2), 5
in c u b a tio n c h a m b e r s (3) a n d th e m o to r d riv in g th e c h a m b e r p a d d le s
(4). b) C lo se -u p o f o n e in c u b a tio n c h a m b e r (10 L) p ro v id e d by A. I.
Larsson.
d o i:1 0 .1 3 7 1 /jo u rn a l.p o n e .0 0 5 8 6 6 0 .g 0 0 1
PLOS ONE I www.plosone.org
3
March 2013 | Volume 8 | Issue 3 | e58660
Coral-Worm Symbiosis
substrates, the excess inco rp o ratio n was divided b y the a tm % o f
each specific food source.
C a lc if ic a tio n
(tra c e r
C
i n c o r p o r a ti o n
in
c o ra l
s k e le to n ) . T o m easure the in co rp o ra tio n o f trac er C in coral
skeleton 30 m g o f each coral sam ple (including tissue, organic
m atrix a n d skeleton) was direcüy tran sferred to a silver b o a t a n d
m easured on the E A -IR M S for total 13C content. T h e sam e
calculations used to calculate tra c e r C tissue assim ilation w ere th en
used to calculate trac er C in co rp o ra tio n in the total C pool o f the
coral sam ple. In c o rp o ra tio n o f tra c e r C in the inorganic skeleton
was finally d e term in ed b y subtracting tra c e r C assim ilation in the
organic C fraction (tissue a n d organic m atrix) from the trac er C
in co rp o ratio n in the total C pool (tissue, organic m atrix a n d
skeleton). T his allow ed us to trace the m etabolically derived trac er
C , i.e. from food respiration, into the coral skeleton a n d to
quantify calcification rates based on this C source. A lthough this
calcification process m ay b e o f lim ited im p o rtan ce to total
calcification by cold w ater corals [39], a com parison can reveal
calcification differences betw een treatm ents. A n o th e r ad vantage is
th a t small changes w ithin a small tim e p e rio d can b e detected,
sim ilar to the 45C a labeling m eth o d [40,41], b u t w ith o u t the
necessity o f radioactive isotopes.
R e s p i r a t i o n . R espiration o f labeled food substrates was
m easured b y analyzing the c o n ce n tra tio n a n d isotopic ratio o f
the C 0 2 in the w ater sam ples taken a t the b eginning a n d the e n d
o f the 24 h incu b atio n a t the e n d o f the experim ent. A fter creating
a headspace o f 3 m l in each sam ple vial b y injecting N 2 gas
th ro u g h the vial septum [36,42], sam ples w ere acidified w ith 20 pi
o f co n ce n tra ted H 3P 0 4 to transform D IC into C 0 2. A fter C 0 2
h a d exchanged w ith the vial headspace 10 pi sam ple o f the
headspace gas was injected into an elem ental analyzer isotoperatio m ass spectrom eter (EA-IRM S). T h e final calculations for
trac er C respiration follow ed the description for p a c e r C tissue
assim ilation.
C respired by the polychaete in these incubations was derived
from its feeding o n Artemia (Fig. 3a). T o ta l respiration in
incubations w ith only the polychaete p re sen t did n o t differ from
incubations w ith E. norvegica a n d L. pertusa p re sen t (P E R M A N O V A
p = 0.7, Fig. 3a).
Tissue Assimilation, Calcification and Respiration by
Lophelia Pertusa
In total L. pertusa assim ilated 149 ± 5 6 p g C (day * g C biom ass
coral) 1 a n d 473 ± 3 7 5 p g N (day * g N biom ass coral) 1 w h en E.
norvegica was absent (Fig. 2a). N e ith e r the uptake o f C n o r the
uptake o f N was significandy affected by the presence o f the
polychaete (P E R M A N O V A p = 0.3, Fig. 2a). E ven tho u g h the
presence o f E. norvegica did n o t change total C a n d N tissue
assim ilation o f L. pertusa, it did change the con trib u tio n o f food
sources (Fig. 2a, b). In the absence o f the polychaete L. pertusa
significandy assim ilated m o re Artemia th en algae (P E R M A N O V A
p = 0.02, Fig. 2b). In the presence o f E. norvegica how ever L. pertusa
increased the assim ilation o f algal-derived C from 16% to 33%
(P E R M A N O V A p = 0.07, Fig. 2b), w hich resulted in equal
assim ilation rates o f b o th food sources (P E R M A N O V A p = 0 .1 ,
Fig. 2b). T his tre n d was n o t visible for N assim ilation, w here no
significant influence by E. norvegica o n food utilization by L. pertusa
could be observed (P E R M A N O V A p = 1) a n d Artemia rem ain ed
the d o m in a n t source o f N for the coral in d ep en d en d y o f E. norvegica
presence or absence (P E R M A N O V A p < 0 .5 , Fig. 2b).
M etabolic derived coral calcification was significandy en h an c ed
up to 4 tim es b y the presence o f the polychaete (Kruskal-W allis p
= 0.05, Fig. 4a). O n average, Artemia c o n trib u ted 68% a n d 85% to
total inorganic C form ation, w hereas algae a cco u n ted for 32% a n d
15% in absence a n d presence o f the polychaete respectively
(Fig. 4b). T hese contributions w ere how ever n o t significandy
different (Kruskal-W allis p = 0.2, Fig. 4b).
C oral respiration in the absence o f E. norvegica acco u n ted for
1242 ± 699 pg C (day * g C biom ass coral)- . Artemia was the
p rim a ry C source a n d supplied 85% o f the respired C, in contrast to
algae, w hich c o ntributed only 15% (Fig. 3a, 3b). R espiration in the
absence o f the polychaete was n o t significandy different from
incubations w here E. norvegica was presen t (P E R M A N O V A p = 0 .5 ,
Fig. 3a).
Statistics
T h e p ro g ram P E R M A N O V A [43] was used to investigate
interactions b etw een the different factors (food a n d treatm ent) by
p erm u tatio n al m ultivariate analysis o f variance (PE R M A N O V A ).
T h e outcom e o f each P E R M A N O V A test w as expressed in M onte
C arlo P-values, w hich are m ore ro b u st in case o f sm aller num bers
o f replicates. If the variance betw een d a ta was n o t hom ogeneous
(tested using Fligner-K illeen test) a K ruskal-W allis test was used as
tru e n o n -p a ra m etric app ro ach .
C budget o f Lophelia Pertusa and Eunice Norvegica
Separately and Together
P a rtitioning o f trac er C b etw een tissue assim ilation, calcification
a n d respiration was m erged into a C b u d g e t for each trea tm e n t
based o n total trac er C trac er uptake by L. pertusa a n d E. norvegica.
T his revealed th a t in the absence o f E. norvegica, L. pertusa invests
10% o f total a cq u ired C in tissue, 10% in calcification a n d 80% in
respiration (Fig. 5a, T ab le 1). W ith E. norvegica present, how ever,
this picture changed, m ainly due to h igher calcification rates
stim ulated by the presence o f the polychaete. O n average 14% o f
total acq u ired C was transferred into tissue, 39% was recovered in
c arb o n a te a n d 47% lost b y respiration (Fig. 5b, T ab le 1).
F o r E. norvegica, the m ain change in the C b u d g e t was higher
food assim ilation in the presence o f the coral. W h en L. pertusa was
absent E. norvegica assim ilated 6 o f total a cq u ired C in the tissue
while 94% o f total acq u ired C was lost by respiration (Fig. 5c,
T ab le 1). W ith L. pertusa p re sen t E. norvegica increased its tissue Cuptake up to 28% while only 72% o f a cq u ired C was used for
respiration (Fig. 5d, T ab le 1).
Results
Tissue Assimilation and Respiration by Eunice Norvegica
E. norvegica assim ilated in total 9 5 ± 6 7 p g C (day * g C biom ass
polychaete)-1 a n d 175.51 ± 8 3 .0 5 p g N (day * g N biom ass
polychaete)-1 in the absence o f L. pertusa (Fig. 2a). Flow ever w hen
L. pertusa was present, the assim ilation o f E. norvegica was
significandy e n h an c ed 4 tim es for C a n d 2 tim es for N
(P E R M A N O V A p = 0.03, Fig. 2a).
C p artitio n in g betw een different food sources did n o t differ
significantly am o n g treatm en ts (P E R M A N O V A p > 0 .1 ), although
a tren d o f h igher Artemia uptake in the presence o f the coral was
re co rd e d (Fig. 2b). Flow ever in b o th , absence a n d presence o f
corals, Artemia was the d o m in a n t N -source for E. norvegica,
a ccounting for 87% o f total assim ilated N in polychaete tissue
w hen corals w ere p re sen t to 91% w h en corals w ere absent
(P E R M A N O V A p < 0 .0 2 , Fig. 2b).
D u rin g incubations w ithout corals, E. norvegica respired
1423± 1431 p g C (day * g C biom ass polychaete)- 1 . M ost o f the
PLOS ONE I www.plosone.org
4
March 2013 | Volume 8 | Issue 3 | e58660
Coral-Worm Symbiosis
Lophelia (L)
Eunice (E)
a) Total tissue uptake
1000
1---------------
*
800 -
1
1
□ Total C
■ Total N
600 -
1—
L-
4 00 -
CO
o
-
E
HI
200
C/3
C/3
03
1
■
o
o
Tissue uptake separated by sources
03
V
03
TO
03
zs
6 00 4 00 -
i
separate E
L
together E
separate L
^
Algae C
□
Artemia C
^
Algae N
I Artemia N
together L
Figure 2. Tissue u p ta ke by £. n o rv e g ic a (E) and L. p e rtu s a (L.). a) T otal tra c e r C a n d tra c e r N tis s u e u p ta k e , b) T rac e r C a n d tra c e r N tis su e u p ta k e
s e p a r a te d b y fo o d s u b s tr a te (alg ae, Artem ia). A n im als w e re in c u b a te d s e p a r a te o r to g e th e r in o n e c h a m b e r; statistic a l sig n ific a n c e b e tw e e n
tr e a tm e n ts is in d ic a te d a s fo llo w e d : * * p < 0 .0 0 9 , * p < 0 .0 5 , • 0 .0 5 < p < 0 .0 6 . T h e b a rs in e a c h fig u re re p r e s e n t a v e r a g e ± SD.
d o i:1 0 .1 3 7 1 /jo u rn a l.p o n e .0 0 5 8 6 6 0 .g 0 0 2
T h e observed high influence o f coral presence on polychaete
n u tritio n evidences th a t the in teraction n o t only provides
settlem ent an d shelter b u t also increases tile fitness o f tile
polychaete. C o ral ru b b le a n d d e ad fram ew ork can also provide
shelter, b u t they are n e ith e r able to help in tube strengthening by
calcification n o r in food supply, since the coral is dead. T h e
increased food in p u t by proxim ity to living corals m ight explain
the co m m o n occurrence o f E. norvegica w ithin living coral branches
as one o f two species so far d o cu m en ted living in direct c o n ta ct to
c oral tissue [11]. T h e advantage o f living w ithin the live coral
becom es even clearer w ith re g ard to the location o f tile tube
selected by tile polychaete an d its re e f aggregating behavior
described by R o b e rts [16]. T o ensure its benefits, the polychaete
places its tube openings close to big coral polyps [2,15] an d m oves
sm all broken coral bran ch es w ithin reach o f its tube [16].
L o p h e lia p e r t u s a . In co n trast to E. norvegica total C o r N
u ptake by L. pertusa was n o t influenced by tile presence o f tile
polychaete. Instead, L. pertusa sw itched from preferential feeding
on Artemia to m ore opportunistic feeding by en h an c in g the uptake
o f sm aller particles in tile presence o f the polychaete. T h e higher
co n trib u tio n o f sm aller particles in the presence o f tile polychaete
is m ost likely caused by tile preferential stealing o f bigger particles
by tile polychaete (see above), leaving the coral to feed on w h a t is
left over. T his implies th a t the success o f L. pertusa to exploit a
certain food source depends n o t only on the availability o f tile
D iscussion
Assimilation and Calcification in the Sym biotic Coralpolychaete Relation
E u n ic e n o r v e g ic a . In this study we quantified the qualitative
observations o f the interactio n betw een E. norvegica an d L. pertusa to
infer the im p o rtan ce o f this interactio n for cold-w ater coral
ecosystems. R esults revealed th a t Eunice assim ilated 4 tim es m ore
C and 2 tim es m ore N in the presence o f tile coral. R espiration
how ever was in d ep e n d en t o f coral presence b u t well w ithin the
range o f form er observations [10], T h e polychaete fu rth er tended
to switch to a m ore selective food uptake, preferentially taking up
bigger particles w hen L. pertusa was p re sen t (Fig. 2b). T hese results
are in a g ree m e n t w ith previous behavioral observations, w here E.
nowegica has been re p o rte d to steal m ainly bigger food item s from
its coral host [15], W e hypothesize th a t larg er particles cause
longer h a n d lin g tim es by tile coral d u rin g the process o f feeding
[44,45], w hich gives the polychaete m ore tim e to rem ove these
particles from tile polyp surface. Sm all particles m ig h t be
consum ed faster by the coral host and also m ig h t be m ore
effectively a n ch o re d w ithin the m ucus layer o f the coral
[45,46,47], Since m ucus is used by the coral n o t only to trap ,
b u t also to tra n sp o rt particles to its m o u th , [48,49], a w eaker
bind in g o f larger particles w ithin the coral m ucus layer w ould
m ake it easier for tile polychaete to access an d rem ove those from
the coral surface.
PLOS ONE I www.plosone.org
5
March 2013 | Volume 8 | Issue 3 | e58660
Coral-Worm Symbiosis
A Total respiration
A Total calcification
3000
00
I—
o
o
1400 -
CO
$
1200
E
■§ 1000
o
03
o , 1500
*
CD
;o
O
03
>_
o
c
03
O
Eunice
separate L
Lophelia Together
together L
B R espiration by so urces
B Calcification by sources
3000
—
2500
o 1400 o
□ Artemia
C/3
CO
CD
S 2000
1200
E
o 1000
.2
22
O
™ 1500
03
-
□ Artemia
-
800 -
*
§,
CD
1000
o
^
0i_3
500 -
o
c
600 400 -
200
-
03
o
Eunice
separat L
Lophelia Together
Figure 4. Calcification by L. p e rtu sa , a) T otal c alcification, b)
c alcification s e p a r a te d by fo o d s u b s tr a te (alg ae, Artemia). L. pertusa w as
k e p t w ith a n d w ith o u t E. norvegica; s tatistic a l s ig n ific a n ce b e tw e e n
t r e a t m e n t s is i n d ic a te d a s f o llo w e d : ** p < 0 . 0 0 9 , * p < 0 . 0 5 ,
• 0 .0 5 < p < 0 .0 6 . T h e b a rs in e a c h fig u re r e p re s e n t a v e r a g e ± SD.
d o i:1 0 .1371/jo u r n a l.p o n e .0 0 5 8 6 6 0 .g 0 0 4
Figure 3. Respiration by E. n o rv e g ic a (E) and L. p e rtu s a (L.). a)
T o tal tra c e r C re sp ira tio n , b) tra c e r C re s p ira tio n s e p a ra te d by fo o d
s u b s tr a te (alg ae, Artem ia). A nim als w e re in c u b a te d s e p a r a te o r to g e th e r
in o n e c h a m b e r; s tatistic a l s ig n ific a n ce b e tw e e n tr e a tm e n ts is in d ic a te d
a s fo llo w e d : * * p < 0 .0 0 9 , * p < 0 .0 5 , • 0 .0 5 < p < 0 .0 6 . T h e b a rs in e a c h
fig u re r e p re s e n t a v e r a g e ± SD.
d o i:1 0 .1 3 7 1 /jo u rn a l.p o n e .0 0 5 8 6 6 0 .g 0 0 3
present, confirm ing the assum ption th a t the coral e n h an c ed
calcification while interactin g w ith E. nowegica [16]. H ence, this
interactio n m ay influence total calcification in a re e f a n d therefore
re e f developm ent. T h e coral pieces in ou r study show ed no
previous im pact o f polychaete presence like old tube rem ains,
p olyp-m alform ation or thickening. T his indicates th a t the
observed h igher calcification rate is related to the initial phase o f
the polychaete-coral relationship d uring the polychaetes’ tube
form ation. It is how ever likely th a t the positive feedback on
calcification continues d u rin g the entire coral-polychaete re la tio n ­
ship, since the polychaete keeps on elongating a n d re arra n g in g its
tube a ro u n d coral b ranches w ith tim e [16].
Surprisingly, how ever, this en h an c ed calcification was not
a ccom panied by h igher m etabolic activity rep resen ted by total
respiration. N a u m a n n et al. [32] found th a t changes in calcifica­
tion in the cold-w ater coral Desmophyllum dianthus are correlated to
changes in respiration.
source b u t also o n the interference w ith o th er species living in close
association w ith the coral.
W hile experim ents c o n d u cted on L. pertusa in isolation will help
to u n d e rstan d its capabilities a n d potential, interactions betw een
species have to be elucidated to advance ou r u n d e rstan d in g o f the
species in the context o f its n a tu ra l environm ent. T h e interactio n
w ith E. nowegica h ere implies th a t lab o rato ry studies done only w ith
corals a n d large food particles, m ight overestim ate the im p ortance
o f these sources for the coral in its n a tu ra l environm ent. H ow ever,
the ability to utilize a b ro a d range o f food sources p ro b ab ly ensures
th a t L. pertusa does not suffer from stealing by E. nowegica, as
indicated by the observation th a t total assim ilation a n d respiration
w ere not affected by the polychaetes’ presence. W e furth er show
th a t calcification by corals increased in the presence o f the
polychaete u p to 4 tim es c o m p ared to treatm ents w ith only corals
PLOS ONE I www.plosone.org
together L
6
March 2013 | Volume 8 | Issue 3 | e58660
Coral-Worm Symbiosis
A
L. pertusa
B
10%
L. pertusa with E. norvegica
10%
14%
39%
tissue
■tissue
■respiration
i respiration
calcification
calcification
80%
C
47 %
E. norvegica
D E. norvegica with L. pertusa
■ tissue
■ tissue
■ respiration
■ respiration
Figure 5. Carbon b u d g e t o f L. p e rtu s a and E n o rv e g ica , (a) C -b u d g e t fo r L. pertusa w ith a n d w ith o u t E. norvegica, b) C -b u d g e t fo r E. norvegica
w ith a n d w ith o u t L. pertusa. Each b u d g e t is b a s e d o n to ta l tra c e r re c o v ery . T h e p a rtitio n in g b e tw e e n tis s u e a ssim ila tio n , re s p ira tio n a n d calcification
a re e x p re s s e d relativ ely to to ta l tra c e r C u p ta k e (su m o f a ssim ila tio n , re s p ira tio n a n d calcification).
d o i:1 0.1371 /jo u rn a l, p o n e .0 0 5 8 6 6 0 .g 0 0 5
In contrast to th a t how ever a n d in ag reem en t w ith o u r
observations F o rm & R iebeseii [50] found th a t e n h an c ed
calcification b y L. pertusa u n d e r high GCC exposure did not entail
e n h an c ed respiration. T his im plies species-specific differences in
calcification as suggested b y A dkins et al. [39] resulting in a m ore
conservative calcification b y L. pertusa th a n b y D. dianthus.
th ro u g h o u t the co m m u n ity a n d so affect ecosystem functioning
[22,53,54] a n d persistence, especially u n d e r c hanging env iro n ­
m en tal conditions [55].
In this study we show ed th a t Eunice norvegica positively influences
coral calcification a n d changes food partitioning, how ever w ithout
im pacting total energy uptake b y its coral host. So far, calcification
o f cold-w ater corals has b een studied in an isolated single-species
setting a n d quantified in the context o f env iro n m en tal changes
([56] a n d references therein), b u t know ledge on the influence o f
biological interactions is lim ited a n d qualitative [57,58], O u r
results suggest, how ever, th a t the im p o rtan ce o f biological
interactions for the process o f calcification in a re e f e nvironm ent
m ight have b een u n derestim ated, since we m easured a 4 tim es
increase o f calcification w hen interactio n betw een L. pertusa a n d E.
nowegica could take place. E n h an c ed calcification results in b ra n ch
thickening a n d anastom osis, w hich facilitates re e f grow th a n d
fram ew ork strength a n d thus can en h an ce ecosystem developm ent
Implications for Ecosystem Functioning
C old-w ater coral reefs have b een described as hotspots o f C
cycling [10] a n d biodiversity along co n tin en tal m argins [5,6,9]. So
far, m ost a q u aria studies focused on individual key species w ithin
the system, in p a rticu la r the cold-w ater coral Lophelia pertusa
[33,51,52]. H e re we evidently show th a t interactions betw een
species m ay substantially co ntribute to the developm ent a n d
functioning o f a reef. A pparently, not only com petition betw een
species, b u t also facilitation can shape ecosystem s b y cascading
T a b le 1 . Tracer C -partitioning betw een m etabolic co m p o n e n ts o f L. pertusa and E. norvegica se p arate and to g eth er, (n =3).
Component
L pertusa*
L pertusa+E. norvegica*
£ norvegica*
£ norvegica+L pertusa*
Tissue
150±56
266±95
95 ± 68
345 ±177
Respiration
1243 ±700
869 ±345
1423 ± 1431
869 ±45
Calcification
156 ± 141
720 ±336
*[gg C (day*g C biomass) '■
doi:10.1371 /journal.pone.0058660.t001
PLOS ONE I www.plosone.org
7
March 2013 | Volume 8 | Issue 3 | e58660
Coral-Worm Symbiosis
a n d persistence, since the developm ent o f coral skeleton is essential
for this ecosystem [16].
It is how ever y et un clear how this interaction is affected by
c hanging enviro n m en tal conditions, such as ocean acidification
a n d w arm ing, o r how this in teractio n reflects u p o n the im p act o f
such changes o n re e f developm ent. T o im prove o u r pred ictio n o f
the future o f cold-w ater coral reefs it is n o t only necessary to study
the coral itself u n d e r various conditions b u t also to acc o u n t for the
m an y organism s living in association w ith the coral a n d
con trib u tin g to the form ation o f this un iq u e ecosystem .
A ck n ow led gm en ts
Lisbeth Jonsson is thanked for helping in coral sampling. Pieter van
Rijswijk is thanked for help w henever it was needed the most. T he
analytical lab o f NIOZ-Yerseke is thanked for sampleanalysis. A nn I.
Larsson is thanked for providing the pictures of the experim ental set up.
T he editor and the two reviewers are thanked for their valuable input on
the m anuscript
Author C ontributions
Conceived and designed the experiments: C E M D vO JJM . Perform ed the
experiments: C E M TL. Analyzed the data: C E M D vO JJM . C ontributed
reagents/m aterials/analysis tools: T L CEM . W rote the paper: C E M T L
JJM D vO.
R eferences
1. B u h l-M o rte n s e n P. H o v la n d M . B r a tte g a rd T . F a re s tv e it R (1995) D e e p w a te r
b io h e rm s o f th e s c le ra c tin ia n c o ra l Lophelia pertusa (L.) a t 6 4 ° N o n th e N o rw e g ia n
shelf: s tru c tu re a n d a sso c ia te d m e g a fa u n a . S a rsia 80: 145—158.
2.
3.
B u h l-M o rte n s e n L, V a n re u s e l A , G o o d a y A J, L e v in L A , P rie d e I G , e t al. (2010)
B iological s tru c tu re s as a so u rc e o f h a b ita t h e te ro g e n e ity a n d b io d iv e rsity o n th e
d e e p o c e a n m a rg in s. M a rin e E c o lo g y -a n E v o lu tio n a ry P e rsp e c tiv e 31: 21—50.
24.
D u in e v e ld G C A , J e ffre y s R M , L a v a le y e M S S , D a v ie s A J, B e rg m a n M J N , e t al.
(2012) S p a tia l a n d tid a l v a ria tio n in fo o d su p p ly to s h a llo w c o ld -w a te r c o ra l reefs
o f th e M in g u la y R e e f c o m p le x (O u te r H e b rid e s , S c o d a n d ). M a rin e E cologyP ro g re ss S eries 4 4 4 : 9 7 - 1 1 5 .
25.
D u in e v e ld G C A , L a v a le y e M S S , B e rg h u is E M (2004) P a rd c le flu x a n d fo o d
su p p ly to a s e a m o u n t c o ld -w a te r c o ra l c o m m u n ity (G a lic ia B a n k , N W Spain).
M a rin e E co lo g y -P ro g ress S eries 277: 13—23.
F u ria P , G a lg a n i I, D u r a n d I, A lle m a n d D (2000) S o u rc es a n d m e c h a n ism s o f
in o rg a n ic c a rb o n t ra n s p o rt fo r c o ra l c a lc ific atio n a n d p h o to sy n th e sis. J o u r n a l o f
E x p e r im e n ta l B io lo g y 203: 3 4 4 5 -3 4 5 7 .
F re iw a ld A , F ossa J H , G r e h a n A , K o slo w T , R o b e rts J M (2004) C o ld -w a te r
c o ra l reefs. U N E P - W C M C , C a m b rid g e , U K .
26.
4.
F re d e rik se n R , J e n s e n A , W e s te rb e r g FI (1992) T h e d is trib u tio n o f th e
sc le ra c tin ia n c o ra l Lophelia pertusa a ro u n d th e F a ro e Isla n d s a n d th e r e la tio n to
in te r n a l tid a l m ix in g . S arsia 77: 157—171.
27.
5.
H e n r y L A , R o b e rts J M (2007) B io d iv ersity a n d ec o lo g ic al c o m p o s itio n o f
m a c r o b e n th o s o n c o ld -w a te r c o ra l m o u n d s a n d a d ja c e n t o ff-m o u n d h a b ita t in
th e b a th y a l P o rc u p in e S e a b ig h t, N E A d a n tic . D e e p -S e a R e s e a rc h P a r t I-
L a v a le y e M , D u in e v e ld G , L u n d ä lv T , W h ite M , G u ih e n D , e t al. (2009) C o ld W a te r C o ra ls o n th e T is le r R e e f- p re lim in a ry o b s e rv a tio n s o n th e d y n a m ic r e e f
e n v iro n m e n t. O c e a n o g r a p h y 22: 76—84.
28.
W a g n e r H , P u rs e r A , T h o m s e n L , J e s u s C C , L u n d ä lv T (2011) P a rtic u la te
o rg a n ic m a tte r flu x es a n d h y d ro d y n a m ic s a t th e T is le r c o ld -w a te r c o ra l reef.
O c e a n o g r a p h ic R e s e a rc h P a p e rs 54: 6 5 4 —6 7 2 .
6. J o n s s o n L G , N ilsso n P G , F lo ru ta F, L u n d ä lv T (2004) D is trib u tio n a l p a tte rn s o f
m a c ro - a n d m e g a fa u n a a sso c ia te d w ith a r e e f o f th e c o ld -w a te r c o ra l Lophelia
pertusa o n th e S w ed ish w e st c o ast. M a rin e E c o lo g y -P ro g ress S eries 284: 163—171.
29.
7.
R o b e r ts J M , W h e e le r A J, F re iw a ld A (2006) R eefs o f th e d e e p : T h e b io lo g y a n d
g e ology o f c o ld -w a te r c o ra l eco sy stem s. S c ien c e 312: 5 4 3 —54 7 .
8.
B u h l-M o rte n s e n L, B u h l-M o rte n s e n P (2004) Sy m b io sis in d e e p -w a te r corals.
30.
S ym biosis 37: 33—61.
R o b e r ts J M , W h e e le r A , F re iw a ld A , C ra in s S, e d ito rs (2009) C o ld -W a te r
C o ra ls , T h e B iolog y a n d G e o lo g y o f D e e p -S e a C o r a l H a b ita ts : C a m b rid g e
U n iv e rsity Press.
31.
9.
10. v a n O e v e le n D , D u in e v e ld G , L a v a le y e M , M ie n is F , S o e ta e rt K , e t al. (2009)
T h e c o ld -w a te r c o ra l c o m m u n ity as a h o t s p o t f o r c a rb o n cy clin g o n c o n tin e n ta l
11.
m arg in s: A fo o d -w e b an aly sis fro m R o c k a ll B a n k { n o rth e a st A d a n tic ). L im n o lo g y
a n d O c e a n o g r a p h y 54: 1 8 2 9 -1 8 4 4 .
B u h l-M o rte n s e n P, F o ssa J H (2006) S p ecies d iv ersity a n d s p a d a l d istrib u tio n o f
in v e rte b ra te s o n d e e p -w a te r Lophelia reefs in N o rw a y . P ro c e e d in g s o f th e 1 0 th
I n te r n a d o n a l C o r a l R e e f S y m p o siu m , p p . 1849—1868.
12. W ilso n J B (1979) D is trib u tio n o f th e c o ra l Lopehlia pertusa (L) L . prolifera (Pallas) in
th e N o r th e a s t A d a n d c . J o u r n a l o f th e M a rin e B io lo g ical A sso c ia tio n o f th e
U n ite d K in g d o m 59: 1 4 9 -1 6 4 .
13.
Z ib ro w iu s S E S , D a y J H (1975) N e w o b s e rv a tio n o n a litd e -k n o w n sp ecies o f
L u m b rin e ris (P olych aeta) liv in g o n v a rio u s c n id a ria n s , w ith n o te s o n its re c e n t
a n d fossil sc le ra c d n ia n hosts. J o u r n a l o f th e M a rin e B io lo g ical A sso c ia tio n o f th e
U n ite d K in g d o m 55: 8 3 - 1 1 4 .
B u h l-M o rte n s e n P (2001) A q u a r iu m o b s e rv a tio n s o n th e d e e p -w a te r c o ra l
Lophelia pertusa (L., 1758) (scleractin ia) a n d se le c te d a sso c ia te d in v e rte b ra te s .
O p h e lia 54: 8 3 - 1 0 4 .
16. R o b e r ts J M (2005) R e e f-a g g re g a tin g b e h a v io u r b y s y m b io d c e u n ic id p o ly c h a e te s
fro m c o ld -w a te r corals: d o w o rm s a sse m b le reefs? J o u r n a l o f th e M a rin e
B iological A sso c ia tio n o f th e U n ite d K in g d o m 85: 8 1 3 —81 9 .
33.
P u rs e r A , L a rss o n A I, T h o m s e n L , v a n O e v e le n D (2010) T h e in flu e n c e o f flow
v e lo c ity a n d fo o d c o n c e n tr a tio n o n Lophelia pertusa (S cleractin ia) Z o o p la n k to n
c a p tu r e rate s. J o u r n a l o f E x p e rim e n ta l M a rin e B io lo g y a n d E c o lo g y 395: 5 5 —62.
34.
T s o u n is G , O r e ja s C , R e y n a u d S, G ili J M , A lle m a n d D , e t al. (2010) P reyc a p tu r e ra te s in f o u r M e d ite rr a n e a n c o ld w a te r corals. M a rin e E c o lo g y -P ro g ress
L im n o lo g y a n d O c e a n o g r a p h y 53: 1376—1386.
M o o d le y L, B o sc h k e r H T S , M id d e lb u rg J J , P e l R , H e r m a n P M J, e t al. (2000)
E c o lo g ic a l sig n ifican ce o f b e n th ic fo ra m in ife ra : C -1 3 l a b e ll i n g e x p e rim e n ts.
37.
M a rin e E co lo g y -P ro g ress S eries 202: 2 8 9 -2 9 5 .
G o n tik a k i E , M a y o r D J, T h o r n to n B, B lack K , W itte U (2011) P ro c essin g o f C 1 3 -lab elled d ia to m s b y a b a th y a l c o m m u n ity a t s u b -z e ro te m p e ra tu re s . M a rin e
D e B a ry A (1879) D ie E rs c h e in u n g d e r Sy m b io se: V e r la g v o n K a r l J . T r ü b n e r.
18.
39.
20. A d d ic o tt J F (1984) M u tu a lis tic in te ra c tio n s in p o p u la tio n a n d c o m m u n ity
processes; P ric e P W , S lo b o d ch ik o ff, G . N ., G a u d , W . S., e d ito r. N e w Y ork:
W illey.
21.
22.
40.
M a rtin D , B rita y e v T A (1988) S y m b io tic P o ly c h ae te s: R e v ie w o f k n o w n species.
O c e a n o g r a p h y a n d M a rin e B iology A n n u a l R e v ie w 36: 2 1 7 —340.
S ta c h o w ic z J J (2001) M u tu a lis m , fa c ilitatio n , a n d th e s tru c tu re o f eco lo g ical
41.
c o m m u n itie s . B io scien ce 51: 2 3 5 —246.
23.
42.
D o d d s L A , B lack K D , O r r H , R o b e r ts J M (2009) L ip id b io m a rk e rs rev e a l
g e o g ra p h ic a l d ifferen ces in fo o d su p p ly to th e c o ld -w a te r c o ra l Lophelia pertusa
(S cleractinia). M a rin e E co lo g y -P ro g ress S eries 397: 113—124.
PLOS ONE I www.plosone.org
8
S eries 398: 1 4 9 -1 5 5 .
d e G o eij J M , M o o d le y L , H o u te k a m e r M , C a r b a lle ir a N M , v a n D u y l F C (2008)
T r a c in g C -1 3 - e n r ic h e d d isso lv ed a n d p a rtic u la te o rg a n ic c a rb o n in th e b a c te ria c o n ta in in g c o ra l r e e f sp o n g e Halisarca caerulea: E v id e n c e fo r D O M feeding.
36.
38.
P a r a c e r S, A h m a d jia n V , e d ito rs (2000) Sym biosis: a n I n tr o d u c tio n to B io lo g ical
A sso ciatio n s. 2 n d ed . N e w Y o rk : O x f o r d U n iv e rsity Press.
19. D a le s R P (1957) I n te ra c tio n s o f o rg a n ism , a. C o m m e n s a lis m ; H e d g e p e th J ,
e d ito r. N e w Y ork: G e o lo g ic a l S o ciety o f A m e ric a .
7 29 p .
G u illa rd R R L (1975) C u ltu r e o f p h y to p la n k to n fo r fe e d in g m a r in e in v e rte b ra te s .
In : S m ith W L , C h a n le y M H , ed ito rs. C u ltu r e o f M a rin e I n v e r te b r a te A n im als.
N e w Y o rk : P le n u m Press, p p .26—60.
N a u m a n n M S , O r e ja s C , W ild C , F e rrie r-P a g è s C (2011) F irs t e v id e n c e fo r
Z o o p la n k to n fe e d in g su s ta in in g k ey p h y sio lo g ic a l p ro ce sse s in a s c le ra c tin ia n
c o ld -w a te r c o ra l. J o u r n a l o f E x p e rim e n ta l B io lo g y 214: 3 5 7 0 —3576.
15.
17.
K iria k o u la k is K , F ish er E , W o lff G A , F re iw a ld A , G r e h a n A , e t al. (2005) L ip id s
a n d n itro g e n iso to p e s o f tw o d e e p -w a te r c o ra ls fro m th e N o r th -E a s t A d a n tic :
in itia l resu lts a n d im p lic a tio n s fo r th e ir n u tritio n ; F re iw a ld A R T M , e d ito r. 715—
32.
35.
14. W in sn e s IM (1989) E u n ic id p o ly c h a e te s (A n n elid a) fro m th e S c a n d in a v ia n a n d
a d ja c e n t w a ters: F a m ily E u n ic id a e Z o o lo g ic a S c rip ta 18: 4 8 3 —500.
J o u r n a l o f M a rin e S ystem s 85: 1 9 -2 9 .
D u in e v e ld G C A , L a v a le y e M S S , B e rg m a n M IN , D e S tig te r H , M ie n is F (2007)
T r o p h ic s tru c tu re o f a c o ld -w a te r c o ra l m o u n d c o m m u n ity (R o c k a ll B a n k , N E
A d a n tic ) in r e la tio n to th e n e a r- b o tto m p a rd c le su p p ly a n d c u r r e n t reg im e.
B u lle tin o f M a rin e S c ien c e 81: 4 4 9 —467.
E co lo g y -P ro g ress Series 4 2 1 : 39—50.
A lle m a n d D , T a m b u tté E , G i r a r d J P , J a u b e r t J (1998) O r g a n ic m a tr ix synthesis
in th e sc le ra c tin ia n c o ra l Stylophora pistillata: R o le in b io m in e ra liz a tio n a n d
p o te n tia l ta r g e t o f th e o rg a n o tin trib u ty ltin . J o u r n a l o f E x p e r im e n ta l B iology
201: 2 0 0 1 -2 0 0 9 .
A d k in s J F , B oyle E A , C u r r y W B , L u trin g e r A (2003) S ta b le iso to p es in d e e p -se a
c o ra ls a n d a n e w m e c h a n is m fo r “ v ita l effects” . G e o c h im ic a E t C o s m o c h im ic a
A c ta 67: 1 1 2 9 -1 1 4 3 .
T a m b u tté E , A lle m a n d D , B o u rg e I, G a ttu s o J P , J a u b e r t J (1995) A n im p ro v e s
4 5 C a p r o to c o l fo r in v estig a tin g p h y sio lo g ic a l m e a c h n ism in c o ra l c a lc ific atio n
M a rin e B io lo g y 122: 4 5 3 —459.
M a ie r G , H e g e m a n J , W e in b a u e r M G , G a ttu s o J P (2009) C a lc ific a tio n o f th e
c o ld -w a te r c o ra l Lophelia pertusa u n d e r a m b ie n t a n d r e d u c e d p H . B iogeosciences
6: 1 6 7 1 -1 6 8 0 .
M iy a jim a T , Y a m a d a Y , H a n b a Y T , Y o sh ii K , K o ita b a s h i T , e t al. (1995)
D e te rm in in g th e stab le iso to p e ra tio o f to ta l d isso lv ed in o rg a n ic c a rb o n in lake
w a te r b y G G / G / I R M S . L im n o lo g y a n d O c e a n o g r a p h y 40: 994—1000.
March 2013 | Volume 8 | Issue 3 | e58660
Coral-Worm Symbiosis
43.
44.
45.
46.
47.
48.
49.
50.
A n d e rs o n M J (2005) U s e r g u id e o f th e c o m p u te r p r o g ra m P E R M A N O V A fo r
p e rm u ta tio n a l m u ltiv a ria te an a ly sis o f v a ria n c e . D e p a r tm e n t o f S tatistics,
U n iv e rsity o f A u c k la n d .
S h im e ta J , J u m a r s P A (1991) P h y sica l m e c h a n ism s a n d ra te s o f p a rtic le c a p tu re
b y su sp en sio n feeders. O c e a n o g r a p h y a n d M a rin e B io lo g y 29: 191—257.
S h im e ta J , K o e h l M A R (1997) M e c h a n is m s o f p a rtic le se le c tio n b y te n ta c u la te
s u sp e n sio n fee d e rs d u r in g e n c o u n te r , re te n tio n , a n d h a n d lin g . J o u r n a l o f
E x p e r im e n ta l M a rin e B io lo g y a n d E c o lo g y 209: 4 7 —73.
S a n d e rs o n S, S te b a r M , A c k e rm a n n K , J o n e s S, B a tja k a s II, e t al. (1996) M u c u s
e n tr a p m e n t o f p a rtic le s b y s u sp en sio n -fe e d in g Tilapia {Pisces: C ic h lid a e ). J o u r n a l
o f E x p e r im e n ta l B io lo g y 199: 1 7 4 3 -1 7 5 6 .
N a u m a n n M S , R ic h te r C , e l-Z ib d a h M , W ild C (2009) C o r a l m u c u s as a n
efficie n t t ra p fo r p ic o p la n k to n ic c y a n o b a c te ria : im p lic a tio n s fo r p e la g ic -b e n th ic
c o u p lin g in th e r e e f e co sy stem . M a rin e E co lo g y -P ro g ress S eries 385: 6 5 —76.
H e r n d l G J, V e lim iro v B, K ra u s s R E (1985) H e te ro tro p h ic n u tritio n a n d c o n tro l
o f b a c te r ia l d e n sity in th e c o e le n te ro n o f th e g ia n t sea a n e m o n e Stoichactis
giganteum. M a rin e E co lo g y -P ro g ress S eries 22: 101—105.
Lew is J B , P ric e W S (1975) F e e d in g m e c h a n ism s a n d fe e d in g stra te g ie s o f
A d a n tic r e e f corals. J o u r n a l o f Z o o lo g y 176: 5 2 7 —54 4 .
F o r m A U , R ie b e se ll U (2012) A c c lim a tio n to o c e a n a c id ific a tio n d u r in g lo n g ­
te r m C 0 2 e x p o s u re in th e c o ld -w a te r c o ra l Lophelia pertusa. G lo b a l C h a n g e
B iology 18: 8 4 3 - 8 5 3 .
PLOS ONE I www.plosone.org
51.
52.
53.
54.
55.
56.
57.
58.
9
M a ie r C , W a tr e m e z P , T a v ia n i M , W e in b a u e r M G , G a ttu s o J P (2012)
C a lc ific a tio n ra te s a n d th e e ffect o f o c e a n a c id ific a tio n o n M e d ite rr a n e a n coldw a te r c o rals. P ro c e e d in g s o f th e R o y a l S o ciety B -B io lo g ical S cien ces 279: 1716—
1723.
D o d d s L A , R o b e rts J M , T a y lo r A C , M a ru b in i F (2007) M e ta b o lic to le ra n c e o f
th e c o ld -w a te r c o ra l Lophelia pertusa (S cleractin ia) to te m p e ra tu re a n d dissolved
o x y g e n c h a n g e . J o u r n a l o f E x p e rim e n ta l M a rin e B io lo g y a n d E c o lo g y 349: 205—
214.
B e rg sm a G S , M a rtin e z C M (2011) M u tu a lis t-in d u c e d m o rp h o lo g ic a l c h a n g es
e n h a n c e g ro w th a n d su rv iv a l o f corals. M a rin e B io lo g y 158: 2 2 6 7 —2277.
G o c h fe ld D J (2010) T e r rito r ia l d am selfish es fa c ilitate su rv iv al o f c o ra ls b y
p r o v id in g a n a s so c ia tio n a l d efe n se a g a in s t p re d a to rs . M a rin e E c o lo g y -P ro g ress
S eries 398: 1 3 7 -1 4 8 .
S u td e K B , T h o m s e n M A , P o w e r M E (2007) Sp ecies in te ra c d o n s reverse
g ra s s la n d resp o n se s to c h a n g in g c lim ate . S c ien c e 315: 6 4 0 —642.
O s in g a R , S c h u tte r M , G riffio e n B, W ijffels R H , V e r r e t h J A J , e t al. (2011) T h e
B io lo g y a n d E c o n o m ic s o f C o r a l G ro w th . M a rin e B io te c h n o lo g y 13: 6 5 8 —671.
P a tto n W K (1967) S tu d ies o n Domecia acanthophora, a c o m m e n s a l c ra b fro m
P u e rto R ic o , w ith p a rd c u la r re fe re n c e to m o d ific a tio n s o f th e c o ra l h o s t a n d
fe e d in g h a b its. B io lo g ical B u lle d n 132: 56-& .
R in k e v ic h B, L o y a Y (1985) In tra sp e c ific c o m p e d d o n in a r e e f c o ral: effects o n
g ro w th a n d re p r o d u c d o n . O e c o lo g ia 66: 100—105.
March 2013 | Volume 8 | Issue 3 | e58660