AN ABSTRACT OF THE THESIS OF
MILTON CHARLES CISSELL for the
(Name)
in
OCEANOGRAPHY
(Major)
MASTER OF SCIENCE
(Degree)
presented onC\
\
(Date)
Title: CHEMICAL FEATURES OF THE COLUMBIA BIVE PLUME
OFF OREGON
Redacted for Privacy
Abstract approved:
P. Kilho Park
An intensive chemical investigation, that includes the
determinations of salinity, oxygen, nutrients, pH, alkalinity, and
total carbon dioxide of the Columbia River plume off the Oregon
coast in July 1967 shows the following unique features:
1.
Along the axis of the river plume both the salinity minimum and
temperature maximum occur. The location of these extrema at zero,
ten, twenty meters depths differ considerably, suggesting different
patterns of water flow at different depths.
2.
Throughout the plume region, at salinities less than 32.
5%o,
the
plume water is supersaturated with respect to dissolved oxygen,
and a subsurface oxygen maximum exists at the depths of 3.0-50
meters.
3.
The relationship between apparent oxygen production by marine
organisms and nutrient concentrations shows biological production
of dissolved oxygen is a definite cause for the oxygen supersaturation
in the plume region.
4.
The plume area off Oregon is a source of oxygen transfer from
the ocean into the atmosphere.
Chemical Features of the Columbia
River Flume off Oregon
by
Milton Charles Cissell
A THESIS
submitted to
Oregon State University
in partial fulfillment of
the requirements for the
degree of
Master of Science
June 1969
APPROVED:
Redacted for Privacy
Associate Professor of Oceanography
in charge of major
Redacted for Privacy
hairm n of Departme
of Oceanography
Redacted for Privacy
Dean oE Graduate School
Date thesis is presented
(j
pU
Typed by Suelynri Williams for
vIL9
Milton Charles Cissell
ACKNOWLEDGEMENTS
I thank Dr. P. Kilho Park for directing this thesis project.
I
also would like to express my thanks to the following people who
kindly analyzed seawater samples during the cruise 6707A of RflV
YAQUINA:
salinity by Mrs. Diane Merten and John Brooks, oxygen
by Douglas Coughenower and "Doc" Sutton, phosphate by Louis
Gordon and Dr. Yoshio Sugiura of Tokyo, pH by Wesley Bradford,
alkalinity by my major professor, silicate by Stephen Hager and
total carbon dioxide by Mrs. Magdalena Catalfomo. I also want to
thank Dennis Barstow, James Washburn, Jack Query, Asa
Robinson, and Richard Hoepner of Bell Telephone Company for their
operation of the hydrographic casts arid collection of water samples
and obtaining temperature data. I want to acknowledge Dr. Robert L.
Smith, Dr. Allen B. Scott and Dr. Harold E. Enlows for serving as
the members of my Master's degree program committee.
Additional thanks I extend to Mrs. Lynda Barstow and David
Ball for their help in drafting the final figures, and special thanks to
Mrs. Suelynn Williams for her help in typing of this thesis and
drafting of final figures.
This work was supported by Office of Naval Research Grant
Nonr 1286(10), and the National Science Foundation Grant GP-5317.
TABLE OF CONTENTS
Chapter
I. INTRODUCTION
II.
OBSERVATIONS
III. RESULTS
Salinity
Temperature
Oxygen
Page
1
6
9
9
9
Phosphate
12
12
alkalinity and total carbon dioxide
Vertical distribution
15
15
Surface distribution of nitrate, silicate, pH,
IV. DISCUSSION
Salinity and temperature
Alkalinity and total carbon dioxide
Oxygen and pH
Nutrients
Gas-nutrient relationship
Boundary of the Columbia River plume
BIBLIOGRAPHY
24
24
27
29
30
34
40
LIST OF FIGURES
Figure
1.
2.
3.
4.
5.
Page
The cruise track and positions of the hydrographic
stations of the R/V YAQUINA 6707A, July 5-15, 1967.
Transects I-IV are along the east-west line. Transect V is approximately perpendicular to axis of
Columbia River plume, while transect VI follows
closely to the plume axis.
Salinity distributions in the Columbia River plume;
surface, 10 m, 20 m, 50 m and 100 m. Salinity
minimum is shown by broken line.
10
Temperature (° C) distribution in the Columbia River
plume; surface, 10 m, 20 m, 50 rn and 100 m.
Temperature maximum is shown by broken line.
11
Oxygen distribution (ml/liter) in the Columbia River
plume; surface, 10 m, 20 m, 50 m and 100 m.
13
Phosphate distribution (iiM) in the Columbia River
plume; surface, 10 m, 20 m, 50 mand 100 m.
6.
7.
8.
9.
10.
7
14
Surface distributions of nitrate (PM), silicate (FLM),
pH, alkalinity (meq/liter), and total carbon dioxide
(mM).
16
Vertical distributions of salinity, temperature,
oxygen, phosphate, nitrate, silicate, pH, alkalinity
and total carbon dioxide along transect I.
18
Vertical distributions of salinity, temperature,
oxygen, phosphate, nitrate, silicate, pH, alkalinity
and total carbon dioxide along transect II.
19
Vertical distributions of salinity, temperature,
oxygen, phosphate, nitrate, silicate, pH, alkalinity
and total carbon dioxide along transect III.
20
Vertical distributions of salinity, temperature,
oxygen, phosphate, nitrate, silicate, pH, alkalinity
and total carbon dioxide along transect IV.
21
LIST OF FIGURES Continued
Figure
11.
12.
13.
14.
15.
16.
17.
18.
Page
Vertical distributions of salinity, temperature,
oxygen, phosphate, nitrate, silicate, pH, alkalinity
and total carbon dioxide along transect V.
22
Vertical distributions of salinity, temperature,
oxygen, phosphate, nitrate, silicate, pH, alkalinity
and total carbon dioxide along transect VI.
23
Seasonal distribution of temperature and chemical
parameters in the Astoria estuary at zero salinity
for 1967 (Park, Osterberg and Forster, 1969).
25
Surface specific alkalinity (alkalinity/chlorinity)
distribution in the Columbia River plume, July 1967.
28
Percent saturation of oxygen along transect VI in
the Columbia River plume. Percent oxygen maximum
is shown by broken line.
31
The salinity-nutrient and salinity-AOP relationships
in the Columbia River plume July 1967. Solid lines
are calculated from the river and sea surface
nutrient away from the plume area.
35
AOU-nutrient relationships. The straight lines are
from the biochemical oxidation model of Richards
(1965) and from Park (1967).
37
AOP-nutrient relationships in the Columbia River
plume, July 1967. Symbols represent the following
ranges: ., over 30%o; x, between 25-30%G; A,
between
19.
20-25%o; 0,
below
20%o.
Vertical distribution of salinities in the Columbia
River plume area at selected stations. Notice that
salinity lines converge at 30 meters depth.
38
41
CHEMICAL FEATURES OF THE COLUMBIA
RIVER PLUME OFF OREGON
I.
INTRODUCTION
The Columbia River empties into the northeastern Pacific
Ocean at a latitude of 46 026? north along a nearly north- south coastline. The 1967 annual discharge was 2. 3 x io14 liters (Park,
Osterberg and Forster, 1969). The flow of the Columbia River
varies seasonally with a maximum in early summer and a secondary
maximum in January.
The Columbia River is the largest single contributor of fresh
water to the coastal environment between southeastern Alaska and
southern California. During the early summer when river discharge
is the highest and coastal runoff is the lowest, the Columbia River
may make up to 95 percent of the total fresh water added to the
northeastern Pacific Ocean. In winter when river discharge is not
generally maximum and coastal runoff is high, the Columbia River
may contribute some 65 percent of the total fresh water input into
this region (Budinger, Coachman and Barnes, 1964).
The current system off the Washington and Oregon coasts con-
sists principally of the poorly defined California Current. This
southward moving current is produced by the divergence of the West
Wind Drift Current as it approaches the North American continent
2
at a latitude of 45 north. The divergence takes place well offshore,
with the northern branch feeding the gyre in the Gulf of Alaska thus
its name the Alaskan Current. The southern branch gives rise to the
California Current. In winter a secondary current is observed near
the coast which moves to the north. This is the Davidson Current.
Tibby
(1957)
and Rosenberg
(1962)
have analyzed the area off
the Oregon and Washington coasts for water mass characterization.
Rosenberg found the presence of four different water masses
contributing to the overall makeup of the area.
The chemical composition of the Columbia River system has
been tabulated by Livingston
(1963).
Livingston!s table gives the
major species of cations and anions. Park, Osterberg and Forster
(1969)
prepared the chemical budgets of the river, which consist of
alkalinity, total carbon dioxide, phosphate, nitrate and silicate, for
1966
and
1967.
The rivers in the Columbia River system appear to
be mainly dilute calcium bicarbonate waters.
The chemical composition of the Columbia River discharge
varies seasonally. Park, Osterberg and Forster
(1969)
show the
seasonal fluctuation in certain chemical and physical parameters
throughout the year
1967.
The maximum in temperature occurs in
late summer with a minimum in winter and spring. Maxima in the
phosphate, silicate and nitrate concentrations occur in early spring
and decline to a minimum level in late summer.
3
Prior to 1961, little was known about the chemistry of the
Columbia River plume formed off Washington and Oregon.
.
Anderson,
Barnes, Budinger, Love and McManus (1961) give a bibliographic
review of the chemical literature and cruise data available prior to
1961.
Stefánsson and Richards (1963) give the first general descrip
tion in the plume area on a seasonal basis. For the winter season
the concentration of nutrients in the plume could be predicted from
salinity-nutrient relationships when biological activity was low.
Stefns son and Richards (1963) discuss the physical and biological
process important in determining the observed chemical distribu-
tions in the plume area. Park (1967) discusses the nutrient relationships and distributions plus the preformed nutrients for waters off
Or e g on.
The exchange rates of oxygen across the sea surface off
Oregon, away from the river plume, has been determined by
Pytkowicz (1964). According to him the subsurface oxygen maximum
formed in summer is due to the warming of the surface layer with a
loss of oxygen above the level of maximum production.
In order to discuss the difference between river water, open
ocean water and upwelled water, a determination of the Columbia
River plume boundary is necessary. Budinger, Coachman and
Barnes (1964) use a plot of salinity versus logarithm of depth.
4
They find that 32. 5%o is a good approximation of the plume boundary.
Park (1966a) employs specific alkalinity to determine the Columbia
River plume boundary. He concludes that the plume water possesses
a salinity of less than 32.5%o.
Anderson (1964) discusses the distribution of chlorophyll aand
phytoplankton productivity off the Washington and Oregon coasts.
Plume water, in general, contains more phytoplankton and has a
higher rate of photosynthesis than ambient waters. Hobson (1966)
discusses the influence of fresh water runoff on the standing crop of
marine phytoplankton.
Plume water possesses higher concentrations
of diatoms than does the ambient water.
A major source contributing artificial radionuclides to the
ocean off Oregon is the nuclear facilities at Hanford, Washington,
which is located along the major stream of the Columbia River.
Radioactive waste induced by the nuclear reactor operations provide
convenient radioactive tracers to identify the existence of the river
effluent off Oregon. Osterberg, Cutshall and Cronin (1965) use
chromium-51 as a radioactive tracer of Columbia River water at
sea. Undoubtedly other radioactive elements could be used for the
same purpose. In addition, in the event there exists appreciable
thermal pollution in the river water by the reactor operation,
temperature also may become an additional water tracer in the river
plume.
S
The purpose of this thesis is to investigate:
1.
The precise chemical makeup of the river plume by multicomponent studies including such parameters as pH, alkalinity,
and total carbon dioxide. This will establish the chemical
reference for summer
1967,
which in turn will be used for
future oceanic pollution studies.
2.
The relationship between the
1967
(Park, Osterberg and Forster,
river water chemical studies
1969)
and the offshore chemical
system.
3.
The availability of various physical-chemical tracers for the
Columbia River effluent in the ocean.
4.
The in situ biological alteration of the Columbia River plume on
the chemical makeup.
II.
OBSERVA TIONS
The physical and chemical cruise 6707A to study the Columbia
River plume formed off the Washington, Oregon, and northern
California coasts was conducted by the R/V YAQUINA of Oregon
State University from July 5 to July 15, 1967. The cruise track and
positions of the hydrographic stations are shown in Figure 1. Station
numbers given on the east-west line off Newport, Oregon, refer to
the distance in nautical miles from the coast. All other station
numbers refer to the particular spots sampled on this cruise.
Seventy-four hydrographic casts were taken of which 52 casts
were 200 meters or less while 9 casts were over 1200 meters deep.
Water samples were measured at sea for salinity, temperature,
oxygen, phosphate, silicate, pH, alkalinity and total carbon dioxide.
Samples were collected, frozen and analyzed for nitrate ashore.
Salinity was determined by an inductive salinometer manufactured by
Industria Manufacturing Engineers Pty. Ltd., Sydney, Australia
(Brown and Hamon, 1961).
"A Manual of Sea Water Analysis" by
Strickland and Parsons (1965) was followed for oxygen, phosphate,
and alkalinity determinations.
Silicate concentration was measured by an automated analysis
given by Armstrong, Stearns and Strickland (1967) using the
Technicon Autoanalyzer® (Hager, 1969).
The only modification of
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Figure 1. The cruise track and positions of the hydrographic stations of the R/V YAQUINA 6707A,
July 5-15, 1967. Transects I-IV are along the east-west line. Transect V is approximately perpendicular to axis of Columbia River plume, while transect VI follows closely
to the plume axis.
the procedure was the introduction of a third sampling tube (0. 1
mi/mm) to allow samples up to 250 M to be measured. Analytical
precision was about ±1% (Hager, Gordon and Park, 1968).
pH was determined by a glass-electrode technique described by
Park (1966b). A Beckman pH meter, Model 7600, expanded scale,
was used to measure the pH values.
Total carbon dioxide was measured by a gas chromatographic
technique (Park, 1965). Samples were usually run within several
hours after collecting.
III.
RESULTS
Salinity
Surface salinity pattern (Figure 2) shows the following two
features.
Fresh water originating from the Columbia River is
found, in general, to the direction southwest from the river mouth.
It is shown by the low salinity isopleths. However, near the coast
the summer coastal upwelling introduces high salinity water to the
surface.
At 10 meters depth the same trends, the low salinity water in
the plume and the saline water in the upwelling region, are observable distinctly. At 20 meters dept1 we observe an evidence of the
low salinity Columbia River water offshoreof less than 32. o%o. How-
ever, at
50
meters depth we can barely detect the influence of the
river plume as shown by the scanty existence of low salinity water
having salinity less than 32.
5%o.
At 100 meters depth, there exists
no trace of river water.
Throughout all these depths, the influence of the summer
coastal upwelling is evident.
Temperature
Surface temperature distribution (Figure 3) shows higher
temperature, greater than 16°c, in the Columbia River plume and
10
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Figure 2. Salinity distributions in the Columbia River plume;
surface, lOm, ZOm, 50 m, and 100 m. Salinity
minimum is shown by broken line.
ii
H-S
I
/ TEMP
cJ
Om
14
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16
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16
55.5 -
-
-
1514
10
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9
5Om
ATZ__
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10
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Figure 3. Temperature C) distribution in the Columbia River
plume; surface, 10 m, 20 m, 50 m and 100 m.
Temperature maximum is shown by broken line.
(0
12
lower temperature, less than 12°C, in the coastal upwelling region.
Near the river mouth the temperature maximum follows the major
direction of the axis of plume (Figure 3).
Below 50 meters, only the influence of coastal upwelling is
observable. At 50 meters depth the 9°C line shows it and at 100
neters the 8° C line indicates it.
Oxygen
Oxygen distributions are complex (Figure 4). At the sea
surface0
one can divide the oxygen distribution into three areas:
near the coast, 30 kilometers offshore, and farther offshore. Near
the coast we find patchy low oxygen areas. Thirty kilometers off-
shore, between the Columbia River mouth and Cape Blanco, we
observe the maximum oxygen value ranging from 7 to 10 ml/liter,
Farther offshore oxygen concentration is essentially featureless with
a typical value of 6 ml/liter. In general, between 10 and 50 meters
the oxygen concentration increases with depth except in the
upwelling region.
At 100 meters depth, the coastal upwelling region possesses an
oxygen value of less than 3 mi/liter.
Phosphate
Phosphate distribution is also complex (Figure 5). At the sea
13
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2Cm
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3
7
'7
6
4
CALIF
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lOOm
3
4
(
-
>5
5\ /
\
/
--H
CALIF
Figure 4. Oxygen distribution (mi/liter) in the Columbia River
plume; surface, 10 m, 20 m, 50 m and 100 m.
14
0,5
0.3
'SlO
lOm
Om
0.2
L
I
T
I
I
0
20m
50m
<o
0.4
0405
4
lOOm
'1.5
I.,
Figure 5.' Phosphate distribution (PM) in the Columbia River plume;
surface, 10 m, 20 m, 50 m and 100 m.
15
surface very low phosphate content was observed in the river plume,
as low as 0. 1 pM. In the upwelling region its concentration goes up
to as much as 1.5 pM. The 10-meter phosphate distribution is
essentially the same as that observed at the sea surface. Below
20 meters, phosphate concentration increases near the coast. This
is due to the coastal upwelling.
Surface distribution of nitrate, silicate, pH, alkalinity and total
carbon dioxide
Surface silicate, alkalinity and carbon dioxide distributions
(Figure 6) display their similarities with the surface salinity
distribution (Figure 2). These three distributions essentially
reflect the contribution of river water chemical composition. The
surface pH distribution (Figure 6), however, resembles that of the
oxygen distribution (Figure 4); the area which has high pH,greater
than 8. 4,corresponds to the oxygen concentration of greater than
7. 0 mi/liter.
Over a wide region ctf Oregon,except near the river mouth and
the upwelling region, the surface nitrate concentration (Figure 6)
shows essentially zero concentration.
Vertical distribution
In order to show the vertical distribution of all the measured
16
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Figure 6. Surface distributions of nitrate (F.LM), silicate (FIM), pH,
alkalinity (meq/liter), and total carbon dioxide (mM).
17
parameters clearly, six transects were selected in and near the
river plume. The location of these transects are shown in Figure 1.
They consist of four east-west lines (Transects I-IV) (Figures 7-10),
one transect perpendicular to the axis of the river flow (Figure 11)
and the last transect being close to parallel to the axis (Figure 12).
All of these vertical distributions distinctly show the influence of
coastal upwelling by the upward trend of their isopleths as we
approach the coast (Figures 7-12).
The vertical distribution of salinity of these transects shows
the depth and width of the river plume. In general, the depth of the
plume is confined within the upper 50 meters as exemplified by the
isohaline of 32. 5%o (Figures 7-1). The width of the plume varies
from one transect to another.
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alkalinity and total carbon dioxide along transect I.
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alkalinity and total carbon dioxide along transect III.
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-e00
o -
- -
-
400
::
130W
W.----E
3
-_
400
1200
5oM,,, No.
T
_- _____.___2_____r
-- -
200
6
_-600
N 600
1000
I000-
T
>I60
00
°° T
/28W
/3.07W
Sioll.o No.
OP-fl
T59 W--.E
60
56
17
(26W
62
61
204
200
200
400.
-
-
-000
600
600
s00
oJo
000
-lZ00
000
230
ISO
I NO2 (ol)
::
S*olio,, No
f28W
T W---.E /26W
T
/30W
T
S/oi/00 No.
/27W
W
/Sf
/307W
S/ot/oo,
W---.--E
No.
004
200
400
!
:
j
-
606
600
1000
1000-
600
000
1600-
LI7
600
000
T W---.E T
00
21
----.--------.--- --
-
-2
__
600
-000
1000
2.40._
'!J
23 -____-----
400
_:_--2 30
000
200-
,ZrW
200
200
200
200
T
02.40
000
0T24.24
1200
400
*00
600
600
/
400
>-_.
LE
200
*00
600
Figure 10. Vertical distributions of salinity, temperature, oxygen, phosphate, nitrate, silicate, pH,
alkalinity and total carbon dioxide along transect IV.
S/NI.,,, N.
/24.W
PIW-.--SE
S/NIb,, N
IW
NW-.--.----SF
IZEW
NW - SE
L'
].MIN
-//J(
(s)7
00
S/NI,,,, N
/çW
NW
SE
S/NI
O//
LO2
N
p28W
NW
SE
Figure 11. Vertical distributions of salinity, temperature, oxygen, phosphate, nitrate, silicate, pH,
alkalinity and total carbon dioxide along transect V.
SMI/,o No.
SloliO4 No.
/2fW
SW.--NE
SIo#Ioo No.
SW--.----NE
Slot!.., No.
SW---.--N
sw-.---,
51011.0 No.
£
M4-lSS
isçw
SW.-----NE
M5-145
20-4
l?TW
7
I
S
$0
II
$215 $4
215 $1
I
I:
.
Slotlo,, No
5WNE
N'
si.,,.. No.
20O
SWlE
stg,No No.
.
SW-'-.-Nf
__
Figure 12. Vertical distributions of salinity, temperature, oxygen, phosphate, nitrate, silicate, pH,
alkalinity and total carbon dioxide along transect VI.
24
IV.
DISCUSSION
Salinity and temperature
An effective way to determine the influence of the Columbia
River water off Oregon is by the examination of salinity. Budinger,
Coachman and Barnes (1964) suggested that a salinity value of 32. 5%o
is a good index salinity for ascertaining the horizontal and vertical
extent of the river effluent. Temperature also becomes an effective
way to monitor the axis of the river plume. It is based on the fact
that river water temperature differs considerably from surface sea-
water temperature. According to Park, Osterberg and Forster
(1969), the river temperature ranged from 7. 0° C in February to
21.4°C in August in 1967 (Figure 13). Off the Oregon coast outside
of the river plume the annual temperature range is between 9° C and
17° C.
Therefore the plume water, the mixture of river and sea-
water, would have different temperatures from that of sea surface
temperature.
In July 1967, an average river temperature was 19. 0° C (Park,
Osterberg and Forster, 1969) while the sea surface temperature
outside the plume was about 16.0°C; therefore, one should observe
the maximum temperature along the major axis of flow. Indeed, the
cruise data substantiates this hypothesis (Figures 2 and 3). Both the
salinity minimum and temperature maximum, shown by broken lines
Z5
20
T
(°C)
l0
1.0
0.5
NO3 20
M)
200
Si 02
M)
00
pH
7,6
7.8
7.4
.5
41k.
(meq/I)
1.0
05
I.5
ECO2
1.0
(mM) 05
02
8
(mi/I)
02
6
I
(% sat)
,j
l
M
A
M
J
J
A
S
0
N
D
1967
Figure 13. Seasonal distribution of temperature and chemical
parameters in the Astoria estuary at zero salinity for
1967 (Park, Osterberg and Forster, 1969).
in the upper 20 meters in Figures 2 and 3, agree very well. Here
at the sea surface we notice the salinity minimum and temperature
maximum go southward initially and turn west later. At 10 meters
depth the location of these minimum and maximum is different from
that at the sea surface. The intensity of initial southward direction
for the extrema decreases and they occupy more westerly positions
than at the sea surface.
At 20 meters depth the location of these extrema deviates
farther westward than at shallower depths. Although not shown, the
ship's thermograph clearly pinpoints the lowest surface salinity area
by its recorded temperature maximum. I, therefore, advocate the
use of continuous sea surface temperature monitoring to determine
the major flow of the Columbia River effluent off Oregon.
Since the river plume possesses low salinity and high
temperature, its sigrna-t is often lower than 20; while at salinity
of 32. 8%o and temperature of 16° C,its sigma-t is 24. Therefore, the
plume water rides over the normal surface seawater off Oregon.
Because of the strong vertical pycnocline within the river plume, the
normal seawater lying under the plume is covered by the plume water
and effectively insulated from the atmosphere. Any in situ production of organic matter in the seawater under the plume water would
accumulate the chemical changes and only diffusion would reduce its
accumulation. Many chemical extrema (oxygen maximum, silicate
27
minimum, pH maximum), therefore, should be found immediately
below the influence of the plume during the photosynthesis period.
The in situ organic production will be examined later.
Alkalinity and total carbon dioxide
From the study of Park, Osterberg and Forster (1969) we find
that both alkalinity and carbon dioxide in river water have very
small seasonal variance (Figure 13) with an average value of 1.0
meq/liter and 1.0 mM for alkalinity and total carbon dioxide,
respectively. Therefore, these two parameters can be utilized as
the river effluent tracers in the ocean, provided that they do not
undergo appreciable in situ changes. Since alkalinity is influenced
very little by marine organisms, it has been used by Park (1966a,
1968a) as water tracer in the Columbia River plume. Based on his
method, the specific alkalinity (alkalinity/chlorinity) distribution was
plotted near the river mouth (Figure 14). The surface distribution of
specific alkalinity resembles the salinity distribution and it is over
0. 150 near the river mouth while away from the plume it is reduced
to 0.123.
In first approximation the total carbon dioxide can be treated
exactly the same way as the surface specific alkalinity was plotted
to trace the river plume. The use of total carbon dioxide is, of
course, less preferred, for it is affected by biological activities
Specific
alinity
\
kOL
;:">
RIVER
(Alkalinity
Chiorinity)
1'
Figure 14. Surface specific alkalinity (alkalinity/chiorinity) distribution in the Columbia River plume,
July 1967.
29
by as much as 0. 2 mM.
Oxygen and pH
There are striking resemblances between oxygen and pH both
horizontally and vertically. Where high oxygen content, over 7. 0
ml/liter is found (Figure 14), also high pH, over 8. 4, is found
(Figure 6). When examining the vertical distribution of both oxygen
and pH, the near surface maximum in both oxygen and pH is consistently found immediately below the influence of the river plume. Its
depth is generally 50 meters. The oxygen minimum zone (800-900
meters) coincides with the pH minimum (Figures 7-12).
Park (1968b) discusses the basic relationship between the
oxygen and pH distribution in the oceans. His analysis indicates
that there exists a linear relationship between AOU (Apparent
Oxygen Utilization) and pH in the normal oceanic pH range between
7. 5 and 8. 3. AOU is defined as 100 percent oxygen saturation
minus oxygen concentration measured.
With respect to the formation of near surface oxygen maximum
there are two major ways to produce it. The first way is the degassing of oxygen from the surface layer into the atmosphere by the
increase in surface temperature from winter to summer. The
second way is by the biological production of oxygen in the seawater
immediately beneath the plume. In this case, the first mechanism,
30
the degas sing of oxygen, does not apply directly, for the surface
water is influenced strongly by the river effluent. The maximum
formed by physical force is therefore primarily due to covering of
low oxygenated plume water over the normal seawater. However,
the oxygen concentration at the oxygen maximum zone, near 50
meters depth, increases from winter to summer off Oregon (not
shown).
This net increase has to come from photosynthesis.
To illustrate the in situ oxygen production, the vertical
distribution of percent oxygen saturation is employed along the
transect VI (Figure 15). Here, away from the upwelling region,
dissolved oxygen is supersaturated from the sea surface to 50
meters deep. At the oxygen maximum zone the percent oxygen
saturation is as much as 114 percent (Figure 15). At the same
depth pH is as high as 8. 29 while nitrate concentration goes down
to essentially zero. Since in situ temperature increase should
lower in situ pH, the high oxygen saturation with high pH does not
come from the in situ temperature increase, The active agent to
increase the in situ pH is photosynthesis. Depletion of nitrate also
supports the mechanism in the formation of subsurface maximum
from biological production.
Nutrients
The most striking features of the nutrient data are the
126°W
Stat/on No.
NH-145
KP-4
T
5
SW'
6
7
NE
e
8
9
10
ii
1213 14
50
(I)
100
150
50
200
Figure 15. Percent saturation of oxygen along transect VI in the Columbia River plume. Percent
oxygen maximum is shovn by broken line.
32
widespread subsurface silicate minimum at slightly above 50 meters
depth and the nonexistence of nitrate in a zone in the upper 50 meters.
The cause of their unique distributions appears to be biological.
The nutrient concentration in the river water for July 1967 was
0. 15 M for phosphate, 3 M for nitrate and 92 pM for silicate (Park,
Osterberg and Forster, 1969). The cruise 6707A data near the river
mouth (KP-14) agree with the river water data: it was 0. 17 iM for
phosphate, 2. 3 FLM for nitrate and 97 M for silicate at the surface.
According to Stefns son and Richards (1963), the waters of
the Columbia River plume consist primarily of two component
mixtures of Columbia River water and of surface seawater, but
they may contain variable fractions of entrenched and intermixed
deep water. Our cruise data indicate the possible mixing of river
water with the upwelled water as shown by the vertical distribution
of salinity at station KP-13 (Figure 12). At this station the upwelled
water having salinity of 33. 7%o exists at the depth of 10 meters while
at the surface its salinity was 15. 9%o. However, from the water
budgetary point of view the fraction of upwelled water in the plume
water does not appear large. Therefore, in first approximation the
nutrient distribution in the river plume should be determined by the
mixing ratio of surface seawater and river water provided we do not
consider any biological uptake.
33
In theory, if one has a representative nutrient reference for
the surface seawater one can calculate the nutrient concentration of
the plume water. However, such a calculation is difficult for the
surface water which undergoes chemical changes due to spring
phytoplankton bloom. In their nutrient studies, Stefnsson and
Richards (1963) used winter nutrient data as reference surface
seawater data. Their values were 1 M for phosphate, 6 }M for
nitrate and 9 iM for silicate. If we use their nutrient reference
data, we would expect higher phosphate and nitrate concentrations
for the plume water than for the river water data given by Park,
Osterberg and Forster (1969) and lower concentrations for silicate.
In reality the reference nutrient data given by Stefns son and
Richards cannot be accepted because of the possible spring phytoplankton bloom occurring in the surface water before it mixed with
the river water. Furthermore, the surface nutrient distribution
may not be the same from one year to another.
If the mean nutrient data in the upper 10 meters at station
KP-35 is assumed as a reference surface seawater, one finds the
nutrient concentrations of 0. 32 pM for phosphate, 0. 0 1iM for
nitrate and 2. 6 1tM for silicate. The station KP-35 is located at
the outermost of transect I and slightly north of the river mouth;
therefore, it should have the least influence of the river water, yet
it is not too far from the river mouth (Figure 7). Based on our own
34
reference nutrient data, the expected nutrient concentration for the
plume water can be expressed by the following equations.
(PO41
(NO
3
(SiO
2
)
plume
= 0. 15 + 0. 0053S(%o)
(1)
= 3. 0 - 0. 093S(%o)
plume =
(2)
92 - 2. 9S(%o)
(3)
The observed salinity-nutrient relationships (Figure 16) do
not agree satisfactorily with the above equations. The majority of
phosphate data are lower than the expected values. Nitrate values
are very low, less than 1 M, for the entire plume water samples.
For silicate approximately two-thirds of the samples agree with the
expected values but the remaining samples are low.
The primary cause of the low nutrient concentrations in the plume
water is photosynthesis, for the percent saturation of oxygen in the
plume is always greater than 100 percent (Figure
apparent oxygen production (AOP) is as much as
15)
2
and the
mi/liter (Figure
16). AOP is defined as the measured oxygen concentration minus
100 percent oxygen4saturation.
Gas-nutrient relationship
The basic relationship between AOU and nutrients off Oregon
has been discussed by Park (1967). Our cruise data concur with his
AOP
(ml /Iiter)
PO4
(pM)
NO3
(pM)
S102
(pM)
20
25
30
35
SALINITY %0
Figure 16. The salinity-nutrient and salinity-A OP relationships in
the Columbia River plume July 1967. Solid lines are
calculated from the rivr and sea surface nutrient away
from the plume area.
36
findings (Figure
17)
with AOU:
N:
P of
3. 09
mi/liter:
16
M: 1 1iM.
Our seawater samples came from below the Columbia River plume,
deeper than
50
meters, and from upwelled seawater samples.
For AOU-siiicate relationship, our data also agree with that
of Park
(1967).
Within the silicate concentration of 40 M the
AOU: A.Si ratio of
3.09
mi/liter: 23 M follows (Figure
our cruise data agrees with that of Park's
(1967),
17).
Since
the preformed
phosphate and nitrate distributions should be the same as the values
calculated by Park. They are approximately 1. 1
1.iM
and 8 pM for
preformed phosphate and preformed nitrate respectively from the
depths immediately below the plume,, at
50
meteçs and down to the
sea floor.
The oxygen-nutrient relationship within the plume is complex.
Here two major processes that alter oxygen concentrations are the
air-sea oxygen exchange and in situ oxygen production by photo-
synthesis. Therefore, apparent oxygen production (AOP) we cal-
culated is a net result of both processes. If AOP is primarily due
to the biological oxygen production rather than the heating of sea-
water, then one should observe the inverse relationship between
the AOP values and nutrient concentrations we observed. In first
approximation one observes it (Figure 18). In the salinity range
of
25-30%o
the rate of decrease of phosphate is approximately 1 pM
per 2 ml of AOP. This phosphate uptake is much greater than the
37
00m
350
3.0
600m
.....
m
400m
2.50
..
2.00
'.5
AOU:Ap. 3.09m1 1pM
AOU (ml / liter)
l000m
5
BOOm
4
\o6m 600m
:°
A0U:N.3.09ml :16)JM
'.-;:
A0U (ml /liter)
2
/.
'4
-
_:
800m
12
N
2 0
80
1A0UAS 309m1
:
23pM
'BOOm
I
.;
60
:..
4
1000 m
400m
.
\
AOU (ml /Iitr)
Figure 1 7. AOU-nutrjerit relationships.
The straight lines are from
the biochemical oxidation model of Richards (1965) and
from Park (1967).
38
p
0.6Se 4
I. ..
C
.4
5
I
C
04-
&sI
w.
.
.
.
PO4
.
.
(jiM)
S
0.2-
Xe
.
.
:
I
p
.
X
XI
00
NO3
(pM)
2'
-
X
)C.
4
I
:
I
C
p
a
4
0
$'
:.
X
a
40Si02
(pM)
p..
20-.
S
S
s_c..
S
.
t"a.hI.U..
0
O
0.5
1.0
.
x.
.
1.5
5
I',
2.0
AOP (mi/liter)
Figure 18.
AOP-nutrient relationships in the Columbia River plume,
Symbols represent the following ranges:
between 20-25 %o; a
over 30%o; x, between 25-30 %o;
below 20 %o.
July 1967.
39
assimilation ratio of 3. 09 mi/liter: 1 pM between AOP and zP.
If the observed AOP: AP ratio of 2 mi/liter: 1 i.iM is the net
result of the air-sea exchange as well as the oxygen production
having the assimilation ratio of .AOP: P of 3. 09 mi/liter: 1 1iM, then
1
M uptake of phosphate should produce 3. 09 mi/liter of oxygen;
however, our estimation shows only 2 mi/liter of AOP. Therefore,
it may be possible that 1 mi/liter of oxygen produced could have
escaped into the atmosphere from the ocean. However, not enough
data are available to substantiate the possibility of this air-sea
exchange. Furthermore, nitrate uptake we observed does not
correlate with the normal assimilation ratio.
Therefore, it is
conceivable that the assimilation ratio we have here could be quite
different from the typical oceanic assimilation ratio of AOP: AN: AP
of 3.09 mi/liter: 16
M: 1
M.
The AOP-nitrate relationship shows a decreasing trend of
nitrate concentration with the increase in AOP. This observation is
consistent with the mechanism of nitrate uptake by marine organisms
during their photosynthesis. Throughout the plume zone nitrate
concentration never exceeds 1 iM/iiter. Furthermore, one does
not detect the presence of nitrate in the major portion of the river
plume. Therefore, it appears nitrate is a limiting nutrient for the
phytoplankton growth. However, whether or not nitrate is the
limiting nutrient has to wait for the analysis of ammonia distribution,
40
for ammonia is preferred to nitrate by phytoplankton as their
nutrient source.
Silicate concentration appears to decrease with the increase
in AOP (Figure 18). However, our data show substantial scatter.
the rate of decrease in silicate appears
Between the salinity
25-30%o
to be about
ml of AOP. This assimilation ratio is not too
30 1M/3
far from the initial dissimilation ratio of
23 M (Park,
AOU: ASi of
3. 09
mi/liter:
1967).
Boundary of the Columbia River plume
The establishment of proper boundary for the Columbia River
plume off Oregon is important in describing the various processes
that take place within the plume. Budinger, Coachman and Barnes
employ plots of salinity versus the logarithm of depth to
(1964)
determine the boundary. They find a salinity range of
32. 4
to
32. 7%o
being the boundary zone that separates from the plume zone to open
seawater. For the sake of simplicity they suggest that the isohaline of
32. 5%o
represents the plume boundary.
The vertical distribution of salinity from several stations of
cruise
Barnes
6707A
(1964)
was plotted by the method of Budinger, Coachman and
(Figure
19).
salinity convergence at
The salinity range we observed at the
30-40
meters depth was
the majority of the curves closer to the
32.5%o
32. 3
to
32. 6%o
isohaline. The
with
41
CAl
.JfrL..
0!
F00
NH- 165
i1
I0I
NH-85
40
6
80
100
20
4
Figure 19. Vertical distribution of salinities in the Columbia River
plume area at selected stations. Notice that salinity
lines converge at 30 meters depth.
42
32. 5%o
isohaline, therefore, can be
chosen
to represent the boundary
of the Columbia River plume for our cruise.
Sugiura (personal communication) employed a plot using
salinity and alkalinity as the variables in determining the boundary
of the plume. He concluded that the 32. 8%o isohaline may be taken
as the plume boundary. His conclusion is not far away from the
boundary salinity of 32. 5%o estimated by Budinger, Coachman and
Barnes (1964).
This discrepancy between the two methods may be
due to the scatter in the alkalinity data.
In reality, the use of the isohaline of 32. 5%o to distinguish the
plume water from the normal seawater is not always applicable.
For example, during the 17-month period, July 1963 to November
1964, surface waters 150-200 kilometers west of Newport, Oregon,
had salinities of less than 32. 5%o (Park, 1968a).
Therefore, other
means for distinguishing plume water from low salinity surface
waters should be found. The Hanford originated radionuclides
(Osterberg, Cutshall and Cronin, 1965) as well as the use of the
unique chemical composition of the Columbia River water itself
should be potentially useful for making this distinction. Further
scrutinization on the chemical composition of the Columbia River
system is needed.
43
BIBLIOGRAPHY
Anderson, G. C. 1964. The seasonal and geographic distribution
of primary production off the Washington and Oregon coasts.
Limnology and Oceanography 9: 284-302.
Anderson, G. C., C. A. Barnes, T. F. Budinger, C. M. Love and
D. A. McManus. 1961. The Columbia River discharge area
of the northeast Pacific Ocean, a literature survey. Seattle,
University of Washington, Dept. of Oceanography. 99 p.
Armstrong, F. A. J., C. B. Stearns and J. D. H. Strickland.
1967. The measurement of upwelling and subsequent biological processes by means of the Technicon Autoanalyzer R
and associated equipment. Deep-Sea Research 14: 381-389.
Barstow, D., W. Gilbert and B. Wyatt. 1969. Hydrographic data
from Oregon waters, 1967. Corvallis, Oregon State University, Dept. of Oceanography. 77 p. (Data Report no. 35)
Brown, N. L. and B. V. Hamon. 1961. An inductive salinometer.
Deep-Sea Research 8: 65-75.
Budinger, T. F., L. K. Coachman and C. A. Barnes.
1964.
Columbia River effluent in the northeast Pacific Ocean, 1961,
1962: Selected aspects of physical oceanography. Seattle,
University of Washington, Dept. of Oceanography. 78 p.
(Technical Report no. 99)
Hager, S. W. 1969. Processes determining silicate concentrations
in the northeastern Pacific Ocean. Master's thesis.
Corvallis, Oregon State University. 57 numb, leaves.
Hager, S. W., L. I. Gordon and P. K. Park. ,968. A practical
manual for use of the Technicon Analyzei'in seawater
nutrient analys es. C orvallis, Oregon State University,
Dept. of Oceanography. 31 p. (Final report to the Bureau
of Commercial Fisheries on Contract 14-17-0001-1759.
Ref. 68-33)
Hobson, L. A. 1966. Some influences of the Columbia River
effluent on marine phytoplankton during January 1961.
Limnology and Oceanography 11: 223-234.
44
Livingston, D. A. 1963. Composition of rivers and lakes. 6th ed.
Washington, D. C. 64 p. (U. S. Geological Survey.
Professional Paper 440-G)
1955. The colorimetric determination of silicate with special reference to sea and natural
waters. Analytica Chimica Acta 2: 162-170.
Mullin, J. B. and J. P. Riley.
Osterberg, C. L., N. Cutshall and J. Cronin. 1965. Chromium-51
as a radioactive tracer of Columbia River water at sea.
Science 150: 1585.
Park, K. 1965. Gas chromatographic determination of dissolved
oxygen, nitrogen, and total carbon dioxide in sea water.
Journal of the Oceanographical Society of Japan 21(1): 28-29.
Park, K. 1966a. Co.umbia River plume identification by specific
alkalinity. Limnology and Oceanography 11: 118-120.
Park, K. 1966b. Surface pH of the northeastern Pacific Ocean.
The Journal of the Oceanological Society of Korea 1(1-2): 1-6.
Park, K. 1967. Nutrient regeneration and preformed nutrients off
Oregon. Limnology and Oceanography 12: 353-35 7.
Park, K. 1968a. Alkalinity and pH off the coast of Oregon. DeepSea Research 15: 171-183.
Park, P. K.
1968b. The processes contributing to the vertical
distribution of apparent pH in the northeastern Pacific Ocean.
The Journal of the Oceanological Society of Korea 3(1): 1-7.
Park, P. K., C. L. Osterberg and W. 0. Forster.
ChemiBioenvironmental
1969.
cal budget of the Columbia River. In:
studies of the Columbia River estuary and adjacent ocean
region. Washington, D. C., U. S. Atomic Energy Commission. (In press)
Pytkowicz, R. M. 1964. Oxygen exchange rates of the Oregon
coast. Deep-Sea Research 11: 381-389.
Richards, F. A. 1965. Anoxic basins and fjords. In: Chemical
oceanography, ed. by J. P. Riley and G. Skirrow. Vol. I.
London, Academic. p. 611-645.
45
Rosenberg, D. H. 1962. Characteristics and distribution of water
masses off the Oregon coast. Master's thesis. Corvallis,
Oregon State University. 45 numb, leaves.
1963. Processes contributing
to the nutrient distribution off the Columbia River and Strait
of Juan de Fuca. Limnology and Oceanography 8: 394-410.
Stefnsson, U. and F. A. Richards.
Stefáisson, U. and F. A. Richards. 1964. Distributions of
dissolved oxygen density and nutrients off the Washington and
Oregon coasts. Deep-Sea Research 11: 355-380.
Strickland, 3. D. H. and T. R. Parsons. 1965. A manual of sea
water analyses. Rev. ed. Ottawa. 185 p. (Fisheries
Research Board of Canada. Bulletin no. 125)
Tibby, R. B. 1957. The water masses off the west coast of
North America. Journal of Marine Research 43: 112-121.