Limnol.
Ocecrnogr., 25(2), 1980, 338351
@! 1980, by the American
Society of Limnology
and Oceanography,
Inc.
Volatile liquid hydrocarbons
in waters of the
Gulf of Mexico and Caribbean Seal
Theodor
C. Sauer, Jr.2
Department
of Oceanography,
Texas A&M
University,
College
Station 77843
Abstract
Concentrations
of volatile liquid hydrocarbons
(VLH), C,-C,, hydrocarbons,
wcrc determined in 1977 in coastal, shelf, and open-ocean surface waters of the Gulf of Mexico and
Caribbean
Sea. In open-ocean,
nonpetroleum-polluted
surface water, VLH concentrations
were ~60 ngalitcr-’
while in heavily polluted
Louisiana
shelf and coastal water values
reached ==500 ng* liter-‘.
Caribbean
surface samples had very low concentrations,
-30
ngalitcr I. The relationship
between anthropogenic
gaseous hydrocarbons
and VLH was approximately
linear. Aromatic VLH accounted for 60-85% of the total VLH in surface waters.
Cycloalkanc
concentrations
were Cl.0 ng*liter--’
in open ocean water, 60-100 ngeliter-’
in
polluted water (20% of total VLII). Alkancs were = 15 ng. liter-’ in open ocean water, -40
ng* liter -’ in polluted water. The concentrations
of five major VLH compounds (aromatics) in
water samples -benzene,
tolucne, ethylbenzene,
m-, p-xylencs, and o-xylene (called BTX)were
sllfficient
to predict
the total VLII. The empirically
determined
relationship
is
VLII(ng*litcr’)
= 1.42 BTX (ngalitcr-I);
r = 0.96.
Subsurface VLH concentrations
in samples of polluted waters collected from depths’ of 50
m were only 3540 ngeliter-’
below surface concentrations.
Open ocean subsurface samples
had concentrations
of only =30 ngmliter-L at 30-50-m depths, comparable to those of Caribbean surface water.
Research on hydrocarbons
in water,
sediment,
and organisms has received
considerable
attention,
largely because
of problems
associated
with the discharge of these compounds
into the
ocean. Although
analytical
techniques
have bccomc increasingly
available to resolve complex mixtures of hydrocarbons,
the types of hydrocarbons
investigated
arc dictated by the methodology.
Gaseous (C,-C,)
hydrocarbons
and the
higher-molecular-weight
(>C,.,) hydrocarbons have been dctcrmined
extenmethods for
sively because analytical
them are well developed. The C&,., hydrocarbons have received comparatively
little consideration
even though many of
them are the most toxic components
of
petrol cum (Raker 1970; Anderson 1975;
McAllliffc
1977n). Those of interest,
called
volatile
liquid
hydrocarbons
(VLH), include the relatively highly soluble aromatics (benzene, toluene, methyl-, ethyl-, propyl-substituted
benzene,
and naphthalene),
aliphatics (normal and
branched C&-C,, alkanes), and cycloalkanes (alkyl-substituted
cyclopentanes
and cyclohexanes),
Much of the research involving
VLH
has been concerned with laboratory studies of the exposure of marine organisms
to the water-soluble
fraction of petroleum
(e.g. see Anderson et al. 1974; Natl. Acad.
Sci. 1975; Vandermeulen
and Ahern
1976). Although the data arc incomplete,
especially
in the area of sublethal and
chronic effects, VLH in seawater have
been folmd to have greater effects on
marine organisms at lower concentrations than any other fraction of petrolcurn. Unfortunately,
few analyses of VLII
in the ocean have been made to see
whether
concentrations
there are in a
range that would be detrimental to organisms. In fact, baseline distributions
of
VLH in marine waters have not been established.
Except for McAuliff’c’s
studies of VLH
conccntrati ons in formation waters and
oil spill slicks (e.g. McAuliffe
1966, 1974,
’ The expcrimcntal
work was supported by NSF
1977n, h), there has been little quantitagrant OCE76-8 1493. Preparation of this manuscript
tive work on VLH in seawater and next
was made possible by NSF grant EAR77-21774 and
to none at the ngeliter-l
level. Koons and
ONR contract N00014-75-C-0537.
Monaghan (1973) and Koons (1977) de2 Present address: Exxon Production
Research
Company, P.O. Box 2189, IIouston, Texas 77001.
termined
C&-C,, hydrocarbons
in sam338
Volatile
liquid
ples taken with Niskin bottles and a galvanized bucket near oil platforms in the
Gulf oE Mexico and along tanker routes
in the Pacific Ocean. Schwarzenbach
et
al. (1979) determined
volatile constituents in a few samples from the coastal
waters and marshland of southeast Massachusetts.
The biological
effects of VLH are of
major concern, but the role played by
VLH in the cycling of organic matter in
the sea is also important.
Duct
and
Duursma (1977, p. 328) stated that “the
only way to answer most of the fundamental questions concerning the processes involved in the cycling of organics in
seawater is to know just what organic
substances, with their characteristic
reactivities,
solutions,
biological
activities,
etc. are present.” Volatile liquid hydrocarbons have relatively
high solubilities
and vapor pressures: they make up the
major constituents
of anthropogenic
organic material in the atmosphere (Duce
1978) and are discharged
into marine
coastal waters near industrial
and urban
areas in environmentally
significant
amounts (Sauer 1978). Almost all of these
hydrocarbons are associated with the gasoline and kerosene fractions of petrolcurn, which make up 30% of crude oil and
50% of refined
oils (Natl. Acad. Sci.
1975). The lack of information
about
these hydrocarbons
in the marine cnvironment prompted this work,
I thank W. M. Sackett, L. M. Jef‘frey,
and J. W. Farrington
for advice in preparing this manuscript, and J. M. Brooks
for help in sampling and analyzing samples for gaseous hydrocarbons.
Procedures and sampling
Analytic&
procedzhres-The
dynamic
headspace stripping procedures used by
Sauer et al. (1978) for determining
volatile liquid hydrocarbons
were modified
in the desorbance system and CC analysis. The apparatus and conditions
for
stripping
VLII from sample water and
trapping them onto the adsorbent TenaxCC remained unchanged.
After stripping
VLH from the water
sample, the Tenax-GC tube was placed
hydrocarbons
339
in a heating unit, on line with a 6-port
valve and a gas chromatograph.
A schematic diagram of the desorbance system
in shown in Fig. 1. The heating unit consists of a cored solid aluminum cylinder
with four 600-W symmetrically
placed
heating tubes, The valve is a 6-port stainless steel Carle valve. A Hewlett-Packard
5700A gas chromatograph
with a flame
ionization
detector was modified to accommodate the desorbance system.
The Tenax-GC was heated to 250°C for
15 min to desorb the trapped components. The desorbed compounds passed
through the 6-port valve and were then
trapped on a liquid-nitrogen-cooled
sample loop (precolumn).
The prccolumn
is
needed to trap the desorbed components
because the compounds adsorbed on the
Tenax-CC are not all released at the same
time when heated. The gas flow rate
through the Tenax-CC
precolumn
line
was regulated at 40 ml-min-l.
Between
the Tcnax-CC tube and Carlc valve is an
injection port where standards were introduced. The entire desorbance line to
the sample loop, including the valve, was
heated to around 125°C with heating
tape.
When the dcsorption process was completed, the 6-port valve was switched so
that the prccolumn
became online with
the Chromatographic collmm. The trapped
components on the prccolumn were then
“injected”
onto the column by replacement of the coolant with 150°C mineral
oil. The Chromatographic
column carrier
gas was regulated at 20 ml-min-I.
Two chromatographic
columns of different polarities
were used to separate
the volatiles; one was a copper chromatographic column (3.2 mm x 4.6 m) packed
with nonpolar
10% SP-2100 on 80/100
Supelcoport.
The column was temperature-programmed
at 0°C for 2 min, 0°C to
180°C at 4°C *min-l,
and 180°C for 16
min. The 0°C temperature,
achieved by
introducing
liquid nitrogen into the oven
through a solenoid valve, is needed to resolve cyclohexane
from benzene adeqllately. The other column used-a more
polar liquid phase-was
a 3% OV-I7 on
100/120 Gas-Chrom Q column (3.2 mm x
340
Sauer
than that of n-hexane, such as branched
pentanes,
can be qualitatively
determined by this method.
Volatile
components
were identified
on a Hewlett-Packard
5982A dodecapole
mass spectrometer interfaced to a 5710A
gas chromatograph
with a single stage,
glass jet separator and supported by a
5933A Data System. The SP-2100 chromatographic column from the desorbance
system with the volatile components cryogenically trapped near the inlet part of
the column was transferred to the GC/MS
system. The trapped components
were
released for GC separation and MS identification when the coolant-liquid
nitrogen-was
replaced with 150°C mineral
oil. Mass spectra were recorded at the
Fig. 1. Schematic drawing of heating unit and
precolumn
used in desorbance
of volatiles
from
rate of one per 2.0 s from 40 to 350 amu
Tenax-GC
and “injection”
onto gas chromatowith an electron ionization
source voltgraphic column.
age and temperature of 70 eV and 170°C.
Mass spectra were identified
from the
Eight peak index of muss spectra (Imp.
4.0 m). The programming
was - 10°C for Chem. Ind. Ltd. 1970) and Interpretation
4 min, - 10°C to 150°C at 8°C. min-‘, and of mass spectra (McLafferty
1973). Many
150°C for 8 min. Samples were run in du- of the identifications
were confirmed by
plicate on each different polarity column.
standard GC retention times.
Since VLH in marine waters are presThe flame ionization
detector
responses of all the components were mea- ent in ng per liter concentrations,
thorsured relative to the responses of the ough cleaning of glassware both for the
standard normal alkanes, n-Cc, through n- stripping apparatus and the sample bottle
is imperative.
C,,. The response factors of the aliphatic,
All glassware was acidwashed with a HF-HNOB water mixture
alicyclic, and aromatic hydrocarbons
relwater. Beative to the n-alkanes are around 1.0. an d rinsed with volatile-free
fore use, the stripping apparatus (Sauer
However, the small response differences
for hydrocarbons
were incorporated
in et al. 1978: fig. 1, gas bubbler) was placed
in a 2-liter
sample bottle filled with
the calculations
of concentrations
as givclean, uncontaminated
seawater, and alen by Dietz (1967). Concentrations
were
determined
by comparing ratios of peak lowed to strip for 1 h at ~80°C and at a
areas to those of standard n-alkanes. Peak helium flow rate of 600 mlsmin-* to clean
areas from the chromatograms were mea- it. Sample bottles were purged and filled
with helium or nitrogen for storage besured by a 3933A Hewlett-Packard
intefore sampling.
grator, peak height x Y2 peak-height
Use of the e-liter bottle as both a samwidth, or planimetry.
The component sensitivity
of the en- ple bottle and stripping container minifrom laboratory air.
tire stripping and analytical method is < 1 mized contamination
Unlike other methods where the sample
ng *liter-l. The VLH determined
by this
is transferred from sample bottle to a sepmethod range in boiling points from near
arate stripping
container,
this method
n-hexane (69°C) to n-tetradecane (254”C),
permitted
stripping of VLH from water
(pentadecane is also determined).
Organic compounds outside this range are not without transfer through laboratory air.
Tests showed that transferring
volatilereadily
determined.
However,
some
free water from one clean bottle
to
compounds
with boiling
points lower
342
Sauer
Table 1. Gaseous hydrocarbons
13 and 77-G-8 (-: not determined;
(nleliter-l)
and total VLH
nd: not detected).
(ngaliter-‘)
concentrations
for cruises 77-G-
Total
%
Station
77-G- 13 Caribbcun
7 Surf
8 Surf
10 Surf
11 Surf
IMethane
Sea
39.4
66.4
43.5
50.8
77-G-13 Gulf of Mexico
54.9
13 Surf
30 m
11.6.0
14 Surf
83.6
15 Surf
8,528.0
17 Surf
>11,150
18 Surf
7,050
21 Surf
25 m
1,800
333
,50 m
280
24 Surf
560
25 m
144
50 in
77-G-8 Gulf of Mexico
Sackett’s
2,060
Bank
EFG 13 Scp
Surf
200
EFG 15 Scp
200
Surf
Ethcne
Ethane
Propcnc
Propane
alkanes
c cloal ryants
aromatics
@TX)*
VLH
Aromatics
(%BTX)*
4.4
4.4
3.7
4.7
0.3
tr
tr
tr
-
-
nd
nd
nd
14.3
nd
nd
nd
3.4
l&8( 18.8)
12.2( 12.2)
24.9(24.9)
45.5(40.5)
18.8
12.2
24.9
58.2
lOO( 100)
lOO( 100)
lOO( 100)
79( 70)
3.8
0.6
3.2
20.1
20.7
8.1
1.7
0.7
2.9
3.5
3.8
tr
0.6
.
7:1
21510
44.4
2.5
0.9
2.5
4.1
1.5
-
-
-
-
10.5
7.0
17.9
nd
nd
0.1
91.9
67.1
-
6;2
166.4
-
31.5
15.1
14.7
10.3
(55)
(35)
15.8
(30)
(30)
5:*;
1lO:S
34.3
0.0
7.6
3.2
0.8
0.1
55.5(53.1)
8.1(7.1)
30.0(26.8)
54.8(50.6)
246.0(220.9)
332.8(320.4)
138.3( 129.4)
125.0( 117.0)
130.2(97.5)
41.0(24.8)
16.7( 14.1)
10.0(3.5)
66.0
15.1
48.0
71.3
336.2
458.4
182.9
147.0-t
152.8-t
60.0
26.2-t
15.2-I
81(80)
54(48)
63( 56)
77(71)
73( 66)
73( 70)
77(71)
83( 80)
84( 64)
69(41)
64( 54)
66(23)
3.7
2.2
1.5
0.5
15.2
1.8
42.5(39.3)
59.5
71(66)
5.0
1.0
1.0
0.6
9.4
5.3
98.9(96.6)
113.2
85(83)
5.0
1.0
1.0
0.6
12.6
1.5
66.2(40.4)
80.3
82( 50)
* BTX i\ WI abbreviation
for benzene, toluene,
ethylbenzene,
and m-, I-, o-xylenes.
Only these concentrations
which reprcscnt
t Total VI,H concentrations
do not include
values listed under total al k nnes in parenthescb
contamination
from the atmosphere
or
loss of volatiles through the transfer process. One disadvantage is its depth limitation: the e-liter bottles implode at a
depth of about 60 m.
Rem1 ts (lncl discussion
Scawwtcr samples were collected during cruise 77-G-13 (November 1977, RV
G!/re, Texas A&M University,
Gulf of
Mexico and Caribbean). Figure 3 shows
the locations of the sample stations and
the 77-G-2 cruise locations for reference
to Saucr ct al. (1978). Two other sets of
samples were obtained on cruise 77-G-8
(September
1977) from Sackett’s Bank
(26”32,0’N, 94’04.O’W) and East Flower
Garden (EFG: 27”54.0’N, 93’53.O’W). Table 1 shows total concentrations
of gaseous hydrocarbons and VLH fractions: nalk;lnes,
cycloalkanes,
and aromatics.
are considcrcd
concentrations
oi C,,, Clz, C,,,
Specific VLH compound concentrations
from these cruise samples were given
elsewhere (Sauer 1978).
Gaseous and VLIII distribution
relations/zips-In
the Caribbean
samples
(Table 1) at stations 7, 8, and 10, the only
VLH present were the aromatics; no nalkanes or other volatiles were evident.
These samples were taken just off Cozumel and in the middle of the Cayman
Sea and had the lowest concentrations
found in this study. The water at these
stations originates from surface waters of
the Caribbean Sea.
Concentrations
of methane at stations
7 and 10 were unusually
low, 39-43
nl *liter-‘.
The saturation methane concentration at station 11 (with essentially
the same hydrographic
conditions as stations 7 and 10) was calculated to be 38
nl *liter-’ (TOC = 26.45 and S%o = 35.815).
Volntile
liquid
343
hydrocarbons
Table 2. VLH concentrations
of water sample
(No, 1194) taken at 1,000 m (station 5: 77-G-13) with
Niskin sampling bottle.
RT*
Compound
600
Chloroform
630 + 690
Benzene
Toluene
650
756
834
1000
1204
1330
* Rctcntion
Fig. 3. Locations of sample stations taken during 77-G-13 and 77-G-2 (Sauer et al. 1978) cruises
(------: loo-fathom
contour; -*-a
: l,OOO-fathom contour).
The water in this area may be upwelled
subsurface water, but if it is not, the low
methane concentrations
like the VLH
concentrations
indicate that there is no
from
anthropogenic
contamination
sources. These VLH samples were analyzed on the same day aboard ship. An
internal standard was rur1 with one of the
samples with almost complete recovery,
indicating
no unusual VLH loss or contamination
during the processing at sea.
None of the surface samples from the
Gulf of Mexico showed such low VLH
concentrations:
about 60 ngaliter-’
typified open ocean concentrations.
The absence of any very low concentration
of
VLH (as in the Caribbean) in the surface
water samples of the gulf suggested that
perhaps the sample bottles had been contaminated
during either processing
or
storage, but a deep water sample (1,000
m) analyzed a month after collection
at
the same time as other surface samples
indicates that this is not true. All bottles
were identically
cleaned and samples
stored under the same conditions. Table
2 shows the concentrations
of VLH found
in the deep water sample, The large unresolved component mixture is a result of
the Niskin bottle used for sampling (cf.
Sauer et al. 1978). The total organic vol-
timcs
from chromatogmphic
VLII
(ng. liter-‘)
24.5
Large unresolved
component mixture
1.6
1.5
2.7
0.6
0.7
1.7
column
SP-2100.
atile concentration
from the 1,000-m sample, excluding
the RT No. 600 peak, is
8.8 ng*liter- I. The No. 600 peak (24.5
rig-liter-l)
is believed to be contamination-most
likely chloroform-from
laboratory air. The No. 650 and 756 peaks
are benzene and toluene. The No. 834,
1000, and 1204 peaks are found in glass
bottle blanks at almost the same concentrations. The No. 1330 peak is never seen
in glass bottle blanks. The absence of
VLH concentrations
as low as those in
the Caribbean is probably the result of
the selection of the sample sites coupled
with the surface circulation
patterns of
the Gulf of Mexico.
The VLH distribution
in marine surface waters of the gulf are influenced
by
both known anthropogenic
sources and
surface currents.
VLH concentrations
range from 48458 ng *liter-l (Table 1).
The concentrations
in certain arcas of the
gulf fluctuate considerably
depending on
the locations of the anthropogenic
inputs
and the direction of surface currents.
The surface circulation
of the Gulf of
Mexico has significant
influence
on the
direction
of the Mississippi
River outflow. Immediately
south of the Mississippi River is a strong northerly
current
(Austin 1955) which causes the river outflow to be channeled east along the Florida coast and across the Louisiana coast.
Little of the outflow extends into the open
ocean, This is evident from the transect of
stations 13-17 (77-G-13: Table 1). Stations
13 and 14 have open ocean gaseous hy-
Fig. 4. Locutions of oil field formation
water (brine) discharges and sample stations (A-77-G-13,
O-77-G-2:
Suer et al. 1978) on Louisiana shelf‘ (adapted from Brooks 1975). Discharge was 45,800,OOO
litcr.d-’
in October 1973. Solid syml~ols, >160,000 liter*&‘;
cross-hatched, 16,000-160,000 liter *d-l; open,
< 16,000 liter* d-l. Rules indicate block boundaries.
Contours (seaward) are about 30, 60, and 200 m.
drocarbon and VLH concentrations.
Station 15, only 45 km away, still shows relatively
little
influence
from
the
Mississippi
River. Station 17, a f’ew kilometers from the mouth, finally shows the
hydrocarbon
contribution
oc’ the Mississippi.
Water samples taken near known anthropogenic
sources have high concentrations of VLH and gaseous hydrocarbons. Extremely high VLH concentrations
(>300 ng* liter-‘) at stations 17 and 18 are
attributable
to the outflow of the Mississippi River and to the discharge of formation waters and hydrocarbon
venting
from offshore oil production.
Conservative estimates for the amount of VLH discharged into Texas-Louisiana
shelf surfact waters from these sources are 56x 10” g VLH per year for formation
water discharges; 5-14 x 10’ f;* yr-‘, hydrocarbon venting; and 4-8 x 10’ g *yr-I,
Mississippi
River runoff’ (Sauer 1978).
Figure 4 shows the location OF the stations with respect to known anthropogenic sources. Stations 17 and 18 are surrounded
by known
sources and have
correspondingly
high VLH concentrations while stations 15 and 21, fatha
away from the sources, have lower concentrations.
Station
15 has low enough
VLH concentrations
to be considered
part of the group of open ocean stations
(stations 13, 14, and 24). These concentrations (~60 ng. liter-‘) arc: the lowest in
the gulf and approximate
open ocean or
baseline concentrations
of gaseous hydrocarbons (45 nl *liter-’ for methane and
<I nl. liter-’
for ethane and propane:
Swinncrton
and Linncnbom
1967; Swinnerton et al. 1969). Station 21 has slu-face
water VLH conccn trations of = 100-200
ng *liter-‘,
intermediate
to open ocean
and polluted
concentrations.
The East
Flower Garden station (77-G-8) also approximates this range. Both stations have
VLII concentrations
that correspond to
intermediate
values for gaseous hydrocarbons. The proximity of anthropogenic
sources to the stations (Fig. 4) verifies
these intermediate
concentrations.
At most of the stations in Table 1, a
direct correlation between VLH and gaseous hydrocarbons can be observed. This
is especially good between VLH and the
gaseous ethane and propane hydrocarbons. Values for methane, however, do
not. always parallel those of VLH, be-
Voldile
345
liquid
c:nlsc) methane has not only petrogcnic
solutes lout also biogenic sources which
can contribute significantly
to the amount
in the water. These are either in situ production by microorganisms
in the water
column or diffllsion out of delta and shelf
sediments. Stations 13, 24 (77-G-13), and
Sackett’s Bank (77-G-8) have relatively
high methane values, while ethane values
are low and propane is very low or not
detectable, sllggesting that the mcthanc
there is of biogenic, not petrogenic, origin.
The VLH concentrations
at these stations
are very close to the open ocean total
VLII values of -60 ng. Kiter-‘. The lack
of gaseous ethane and propane and the
low VLH values indicate that these stations are not significantly
contaminated
by petroleum.
The relationship
bctwecn
VLII and
gaseous ethane and propane from my
data is shown in Fig. 5. The lmlabeled
points near the origin of the graph rcpresent the remaining stations not indicated in the figure. The relationship
bcpwrametcrs
is
these
two
tween
approximately
1inear, but nlorc data are
needed to make statistically
acceptable
predictions
of VI,11 concentrations
in
seawater from gaseous hydrocarbon
concentrations.
The relationship
does however support the contention of Swinnerton and Lamontagne (1974), Sackett and
Brooks (1975), and Brooks ct al. (1977)
that Cl-C:, gaseous hydrocarbons
arc
valuable indicators
of petroleiim
pollution.
VLH fractiorzs -Aromatics
make up
most of the VLII in seawater (Table 1).
Toluene and many of the C,-C, alkylsubstitllted
bcnzenes were also the most
abundant and consistently present grollp
of organic volatiles
in coastal samples
taken by Schwarzcnbach
ct al. (1979). In
the Caribbean water samples, aromatics
are the only volatile constituents
in seawater. Toluene
is present in all these
samples and in those from the Gulf of
Mexico. The persistence of toluene was
also observed by Schwarzenbach
et al.
(1979) who suggested that perhaps toluenc has a natural geochemical
origin.
In the Glllf of Mexico, aromatics rep-
240 I
STA
018
0 - Ethane
•! - Propane
018
160
t
40
021
0
EFG
0
100
,
200
II"
300
400
500
600
VLH (ng/llter)
tions.
resent from 63 to 85% of the total VLII
with only slight differences between open
ocean samples and antllropogenically
pollllted samples. Most open ocean samples (stations 11, 13, 15 and Sackctt’s
Bank) show aromatics to be =71-81% of
the total VLH, while heavily polluted
samples (stations 17 and 18) have about
73% aromatics. The reason for t-he relative paucity of aromatics in polluted seawater is because of the considerable contribution of cycloalkanes to those samples:
cycloalkane
concentrations
are close to
zero in open ocean waters, while in polluted waters they increase to 60-110
ng* liter-’ (,Yt,SL
t ions 17, I 8)-about
20% of
the total VLH. The n-alkancs
do not
sea-n to change apl>rcciahly,
although
contaminated
waters do show doubled
concentrations.
For siq?licity
in predicting
VLII conccntrations
in seawater, I huvc summed
up the five major components of VLH in
seawater and compared the concentrictions to the total VLH dete~mincd. These
major components
are the aromatics:
benzene, toluenc, ethyll)enzcne,
m-, IIxylene, and o-xylene. Their concentnttions are listed in Table 1 (as BTX). The
BTX fractions of total VLH are tabulated
in the percent aromatics column. Except
346
Sauer
for station 24 surf(41%), the percent BTX
in surface water ranges from 56 to 80%,
with most percentages around 70%. From
all of the Gulf of Mexico surface water
analyses in Table 1 (cruises 77-G-13 and
77-G-8), an estimate of the amount of
VLH in surface seawater can bc deduced
by determining
the concentration
of the
BTX aromatics and using the relationship
VLH
= 1.42 x BTX(ng*liter-I).
(1)
The standard error of estimates is 18.6.
The corre1ation coefficient for this equation is 0.96 (linear least-squares best fit).
The use of the VLH-BTX
relationship
reduces the amount of effort needed to detcrminc all the VLH in water samples.
The major aromatics can easily be analyzed by GC alone, eliminating
the need
for difficult GUMS analysis.
In heavily polluted seawater samples,
chromatograms
show unresolved
component mixtures
of unknown
nature.
Their contribution
is usually 20-30% of
the total resolvable
VLH. The components in the mixtures arc probably not all
VLH but the relative amount of VLII is
undeterminable.
In samples where an
unresolved mixture is evident, the VLH
concentration
predicted
from Eq. 1
should be considered a lower limit.
At three stations (13, 21, and 24: Table
l), VLH seawater samples were taken at
depth with the specially built sampler
(Fig. 2). In the open ocean sample (station 13) taken at 30 m, the concentrations
of VLH are very low (= 15 ng *liter-‘),
comparable
to the concentrations
observed in the Caribbean.
Station
21
shows considerably
higher VLH concentrations at 25- and 50-m depths, quite
close to those of the surface water sample. The location of station 21 (near the
mouth of the Mississippi
and among offshore platforms)
and the intermediate
VLII
concentrations
indicate
polluted
subsurface waters. The pollution
influence is shown throughout almost the entire wwtcr column (bottom is 63 m), down
to at least 50 m, with only a 30-40
difference
between
surface
ng *liter-’
and subsurface samples. The percentage
of aromatics in these subsurface samples
is also like that in the surface water. The
subsurface samples (25 and 50 m) at station 24 have concentrations
similar to
those of the Caribbean and the 30-m sample at station 13. The surface water concentration at station 24 indicates an open
ocean type of water, similar to that of the
surface waters at station 13. Generally, it
stems that the subsurface VLH concentrations for stations 13, 21, and 24 reflect
their respective surface concentrations.
An uncertain
aspect of these subsurface samples, especially
at stations 21
and 24, is their unusually
high component concentrations
around the Cll, C12,
Cj3, and C,,, n-alkane retention times. At
station 21 the 25-m sample has values for
these n-alkanes of ~55 ngaliter-I.
The
50-m samples are 35 ngsliter-‘.
These nalkane concentrations
are anamolously
high in comparison to the corresponding
surface water values. The reason is not
known, but it may be due to contamination during cleaning or assembly of the
equipment.
In any case, the values at
these n-alkane retention times were not
included in the totals.
VLH Juxes-Sauer
(1978) determined
that reservoir and material fluxes of VLH
to and from marine surface waters can be
most appropriately
estimated by the stagnant film model (Treybal 1955; Kanwisher 1963; Broecker and Peng 1974). This
model simply predicts that the flux, F, of
gas (VLH) from the ocean to the atmosphere is dependent
on the molecular
diffusivity
of the gas and the thickness of
the stagnant diffusion-controlled
boundary layer, x:
(2)
or simply
F = KiACi
(3)
where Ki = D//X, Di = coefficient of molecular diffusion (cm2. s-l), x = film thickness (cm), and ACi = concentration
difference across the film layer, Gil - C,
(mol. liter-‘). [C, is gas concentration
at
equilibrium
with the overlaying
air,
Ci, = acp, where cy is the solubility
of gas
and p is the partial pressure of gas in the
Volatile
liquid
atmosphere. (In these flux estimates, Cl,
is assumed to he negligible.)
Gil = concentration of gas in aqueous mixed layer.]
The film thickness, x, is dependent
on
the degree of water agitation from subsurface winds and turbulence
in the
water column.
Fluxes are determined on the assumption that there is no contribution
from the
in
atmosphere. If VLH are appreciable
Ci, z 0, and the HUX
the atmosphere,
from marine waters will be reduced due
to the decrease in the concentration
difference, Cjl - Ci,. Near urban areas atmospheric concentrations
are usually significant enough to retard the flux from the
water column and possibly in some nearshore areas can act as a source of VLH
into the water column. In most urban
areas, toluene ranges from 10 to 50 ppbv,
benzene lo-50 ppbv, and xylenes 6-30
ppbv (Altshuller
and Bufalini
1971;
Bertsch et al. 1974; Holzcr et al. 1977).
Table 3 shows equilibrium
concentrations of some VLII in marine waters as
dictated by atmospheric
concentrations
ranging from 1 to 50 ppbv. From the
equilibrium
water concentrations
(Table
3), the importance
of the atmospheric
contribution
in flux calculations
is more
than evident even though marine water
VLII are not in equilibrium
with those in
the atmosphere.
To estimate the reservoir and fluxes of
VLH in the Gulf of Mexico, the VLH distribution
in the water must be known.
Since VLH concentrations
in the water
column are not known throughout
the
gulf, VLH in unknown areas will have to
be approximated
from known data; these
are mostly from samples taken along the
Louisiana-Texas
shelf-an
area of hydrocarbon pollution.
There are, however,
open ocean samples [stations 13, 14, 15,
(77-G-13), and Sackett’s Bank (77-G-8)]
from outside the Louisiana-Texas
shelf;
these will be representative
of other unknown arcas proposed to be not significantly polluted. Areas in the gulf selected
as VLH-polluted
or nonpolluted
waters
are the same areas extensively
surveyed
for gaseous hydrocarbons by Brooks et al.
(1977). The partially
polluted
shelf
h ydrocarhons
347
waters east of the Mississippi River along
the Mississippi,
Alabama, and west Florida coast will not be included in the flux
estimates, however, since no VLH samples were taken in this region.
In the Louisiana-upper
Texas shelf region, the flux of VLH from surface waters
is estimated
to be 4.7-6.3 X 10M2
g *md2 *yr-l,
assuming that the VLH conccntration
range is 150-200 ng *liter-l,
and the transfer velocity,
Ki , is 1 X 10H3
cm-s-’
(D = 1~10~” cm”*s-*); x = 100
pm, corresponding to mean wind speed
of -450 cm * s-l. The flux (g *mh2* yr-‘)
from areas near heavy pollution
inputs
and the Mississippi
River will be 3-6
times greater, however, because of the
higher VLH water concentrations
(assuming Ci, = 0). The total flux from the
Louisiana-Texas
shelf becomes 7.1-9.4X
10” g.y.r-l (mean surFace area is 1.5X1O11
m2). If VLH are appreciable in the atmosphere over these wiLtcrs, the flux will be
less.
We could not estimate the reservoir of
VLH in these shelf waters until we had
proposed a depth of VLH extinction.
Station 21 is the only subsurface station in
the shelf typical of polluted waters; the
other two (13 and 24) arc characteristic
of
open ocean waters. We therefore needed
additional
subsurface information.
The
profiles
of gaseous hydrocarbons
that
Brooks et al. (1974) took along the TexasLouisiana coast suggest that a depth of 50
m is appropriate, and station 21 VLH concentrations showing pollution
do exist to
that depth. IF we assume a 150-200
ng. liter-’
concentration
to 50 m, and
nothing beneath that, the reservoir value
for VLH ranges from 1.1-1.5X 10y g.
For the Gulf of Mexico except the shelf
waters cast of the Mississippi,
the VLH
concentrations
will be those of the open
ocean samples. Most of the central gulf
estimate depends on the concentrations
at station 13, although stations 14, 15, and
24 also indicate open ocean concentrations. Some question
may arise as to
whether station 13 is representative
of
open gulf surface waters, since we took
only one group of samples in the area.
Station 13 is supposedly
far removed
348
Sneer
Tal)lc 3. Equilibrium
concentrations
centrations of 1 arid 50 pphv of VLII.
(ng*liter-‘)
in marine
waters equilibrated
with atmospheric
con-
C,t (ng.litc~-‘)
VI,11
n-hexane
n-decane
Mctl~ylcyclolicxanc
I~enzcnc?
Tohlcnc
o-xylcne
Ethylbenzene
1,2,4-trimcthyl
Naphtldenc
* E&dive
IIcnry’s
t (P,Illi,jRT)
1itc:r.g
X (mol
tnol
‘,“K
benzcnc
nlol wt
Iii,,
86
142
47
252
*
98
11.4
78
92
106
106
130
128
0.12
0.18
0.24
0.25
0.20
8.4 x10-3
Law constant &lived
from vapor pressure
wt,) X 10”; C,-conct~ntl‘ation
in \cawatcr
‘), and T = 290°K.
and solubility
(ng,litc:r-I),
from obvious anthropogenic
sources; it
has surface VLH concentrations
higher
than the Caribbean but the sllbsurface
concentrations
arc similar. Possible reusons for this arc considered below.
Slrrfkce currents pussing through palItsted uxters bring VLH to the centml
gulf. The Stagnant-Film
model sllggcsts
that the mean residence time (7) of a VLII
in the mixed layer of sin-face water is
r = hxlD, where h = water column height.
Modcling
calculations
give a mean residence time for aromatics (benzene) in 1
lul of
water
of ~15 h, or, in 50 m of -30
days. This is enough time for a 50 cm * s-’
cllrrent from the Louisiana shelf to carry
150 ng* liter-’ of shelf water 300 km to
station 13 and retain a concentration
of
This simple calculation
==60 ng. liter-l.
ass~~mcs that the changes in advection
and horizontal mixing are unidirectional
with vertical md cross-horizontal
mixing
and advection changes negligible.
The utrnosphere acts as CLsource ofsurfilcc? w(rlel* VLH. A 1 ppbv concentration
of’ an aromatic in air could conceivably
yi cl d a single component
equilibrium
concentration
of 20 ng* liter-’ in smfacc
water (Table 3). Winds from the north
containing polluted coastal and industrial
air could result in atmospheric
concentrations sufficient for air-sea exchange to
surface waters. The prevailing
winds in
the glllf are, however, from the south.
Open ocem dischurges from tunkers
1 ppbv
50 pglw
0.063
0.024
3.8
1.2
0.36
18.0
27.0
21.0
19.0
18.0
27.0
640.0
data (Chcm. Hubl~c~r Co. 1972; McAuliffc
P,-concentration
in atmosphere
(atm),
1,370.o
1,070.o
930.0
890.0
1,370.o
32,000.0
1966).
R = 82.05x10-1
(atm
and other ships are wfficient
to prodwe
concentrations.
About
185~ 10” g*yr-’ of crude oil and petrol cum products are transported by tankers
in the Gnlf of Mexico (U.S. Dep. ‘Interior
1976), of which
0.008-0.11%
is discharged as VLH f&n tanker cleaning operations at sea. About 10% of the amount
discharged can bc assumed to dissolve in
the surface water (90% is immediately
lost to the atmosphere). Thcreforc,
the
inpllt by tankers at sea to the surface
waters of the Gulf of Mexico is 0.152.0X 10”’ g* yr-I, an order of magnitude
larger than the VLII discharged into the
surface waters of the Texas-Louisiana
shelt’ from the Mississippi
River, offshore
hydrocarbon venting, and formation water
discharges combined (Sauer 1978).
The VLH found in ojxm ocean su$me
muters are truly residual concentrations.
VLH concentrations
arc extremely
low
(parts per trillion) and may represent the
amount
of VLH that cannot transfer
across tllc air-sea interface.
Aromatic
VLII do have higher solubilitics
than
gases. Caribbean surf&c waters with abnormally
low VLEI concentrations
are
perhaps subsurface or surface waters that
have not come in contact with VLII contamination.
The VLH concentrations
in station 13
samples clre due to contmnination.
The
deep (1,000 m) sample (Table 2) indicates that the sampling, storage, and an-
detectclblc! VLII
Volatile
liquid
alytical procedure produce at the most a
total 8 ng* liter-’ terror of mostly unidentifiable compounds.
111open ocean surface waters and other
nonpolluted
shelf waters, the concentration of VLII
is assumed
to bc 45
ng *I iter-l, based on concentrations
at stations 13, 14, 15, 24, and Sackett’s Bank.
The flux is therefore
estimated
to be
1.4X 10e2 g*m-2*yr-1
(transfer velocity,
Ki , of 1 X lo-” cm *S-‘) with the total flux
for the area becoming 2~ 1O1” g* yr-I, using 14X 10” in2 as the surf&e arca for the
gulf (less Lollisiana-upper
Texas shelf).
If the concentration
of VLII in the atmospherc over these waters is apprcciablc, the flux will be less. An aromatic conccntration
of 1 ppbv in the atmosphere
would decrease the flux by almost half
(1 ppbv aromatic in the atmosphcrc = 20
of
ng . liter- ’ in water). The reservoir
VLH in the open ocean gulf area is estimated to bc 2.0~ 10” g. This assumes 45
VLII for the upper 20 m of
ng *liter-’
~OI
wutcr (1.3~ 10” g), and 10 ng*liter-’
the remaining
50 m to the thermocline
(0.7 x 109 g). No VLH are expected below
the thermocline
(cf: the deep water, 1,000
m, sample: Table 2). The 10 ng. liter-’
vallle for the water bctwecn 20 m and the
thcrmoline
was estimated from subsurface samples at stations 13 and 24.
The total VLH flux for the entire Gulf
of Mexico (less the Alabama, Mississippi,
and western Florida shelf waters, which
make up ~5% of the total arca) is estimated to be 28.0~ 10” ,g*yr-I. The reservoir of VLH is 33.0~ IOx g. The flltx and
reservoir of VLEI for methane from the
entire Gulf of Mexico arc 370~ 10” ,q*yr-’
and 38.5~ lo! g (Brooks 1975). A residence time in the gulf for VLEI estimated
from these data is 0.12 years (40 days).
I did not consider biological
dcgradation of VLII in the water in these cstimates because rates of microbial
clegrwdation for VLII have not hecn established
due to the lack of standardization
of testing and the abscncc of llnits for cxprcssing rates of degradation.
Considerable
work on microbial mechanisms of metal)olizing VLII has l>een done (Van der Linden and Thijsse 1965; Docile 1975; Gib-
hydrocarbons
son 1977), but unfortunately,
there have
been no conclusive in situ studies of rates
of petroleum degradation in estuarine or
marine
environments,
althollgh
such
rates have been estimated from field or
laboratory experiments
(Floodgate 1972;
Walker ct al. 1976).
VLH hiologicnl
ejfects-Extensive
research has been done on the toxic effects
of the higher molecular weight (solvcntextractable)
hydrocarbons
of petroleum
on marinc organisms, but comparatively
little on VLII. Almost all the work that
has included VLII 11;~sbeen concerned
only with acute effects (Anderson et al.
1974; Atkinson et al. 1977; Malins 1977;
Wolfe 1977). The short term studies of lcthal effects at high dosages do not address
the realistic stress that may be encountered by organisms from waters polluted
by VLII. The sublethal effects are most
important and include those which cause
damage to physiology,
growth, development, reproduction,
and behavior.
Behavioral activities especially arc mcdiated by chcmorcception
(Kahn 1961) and
arc sensitive to low concentrations
of hydrocarbon s,
Those pctrolclun
hydrocarbons
that
may have the most disruptive
cffcct in
chcmorcception
are those which most
easily mimic chemical spccics that mediate a organism’s behavioral
reaction.
The compounds that initiate behavioral
responses are usually very soluble and
intermediate
in size, such as 1,3,5-octatricnc (Cook and Elvidge 1951) and taurinc (Takahashi and Kittrcdge 1973). The
petroleum hydrocarbons with similar physical characteristics are the VLII. Very few
publications
report behavioral
or chcmorcccption
effects with VLH. The IXsponse of snails and crabs to chetnical
siibstanccs that normally initiate feeding
behavior was eliminated
by 1 pg. liter-’
concentrations
of the water-soluble
fraction of kerosene-mostly
benzcnes (Jacobson and I3oylan 1973; Takahashi and
Kittredgc 1973; Johnson 1977). Fcrtilization of macroalgae was complctcly
inhibited by 0.2 pg*litcr-L
of No. 2 fuel oil
(Steele 1977). Ch cmorcception
in marinc
bacteria was inhibited
by 100 ,q.liter-’
350
Suuer
of benzene (Walsh and Mitchell
1973).
These observations suggest that concentrations of VLH (aromatics) of the order
of a couple of micrograms per liter are
enough to disrupt chemosensory
bchavior.
Apparently
concentrations
of VLH of
about 1 ~8. liter-’ could be detrimental
to the life processes of many marinc organisms. Especially
in many coastal urban and industrial area waters, VLH concentrations
are in this damaging range.
The potential of these subtle behavioral
effects on organisms from VLH should be
careftllly reviewed and additional behavioral pollution
research should be done.
Long term (chronic) sublethal exposure
to VLH is regarded by many investigators
(Colwell and Walker 1977; Steele 1977;
Lee 1978; Rossi and Anderson 1978) to
induce harmfLl1 behavioral effects at lowcr concentrations
than those of severe,
acute contamination.
The polluted coastal
waters, especially,
have reached high
enough steady state concentrations
of
VLIi to make detrimental
long term effects on marine organisms probable.
References
AL-I'SIIULLER, A. P., AND J.J. BUFALINI. 1971. Photochemical
aspects of air pollution:
A review.
Environ. Sci. Tcchnol. 5: 39-64.
ANDERSON, J. W. 1975. Laboratory
studies on the
effects of oil on marine organisms: An overview. Am. Pet. Inst. Pub. 4249, p. l-70.
-,J.
M. NEFF, B.A. Cox, II. E. TATUM, AND
G. M. HIGI-ITOWER. 1974. Characteristics
of
dispersions and water-soluble
extracts of crude
and refined oils and their toxicity to estuarine
crustaceans and fish. Mar. Biol. 27: 75-84.
ATKINSON, L. P., W. M. DUNSTAN, AND J. G. NATOI,I. 1977. The analysis and control of volatile
hydrocarbon
concentration
(e.g. bcnzcne) during oil bioassays. Water Air Soil Pollut. 8: 235242.
AUSTIN, G. 13., JH. 1955. Some recent oceanographic surveys of the Glllf of Mexico. Trans. Am.
Geophys. Union 36: 885-892.
BAKER, J. M. 1970. The effect of oil on plants. Environ. Pollut. 1: 2744.
BEHTSCII, W., R. C. CIIANG, AND A. ZLATKIS.
1974. The determination
of organic volatiles in
air pollution
studies: Characterization
of profiles. J. Chromatogr. Sci. 12: 175-182.
BHOE~KEH, W. S., AND T. H. PE:NG. 1974. Gas cxchange rates between air and sea. Tellus 26:
2 1-35.
BROOKS,J. M. 1975. Sources, sinks, concentrations
and sublethal effects of light aliphatic and aromatic hydrocarbons
in the Gulf of Mexico.
Ph.D. thesis, Texas A&M Univ. 342 p.
--,
B. B. BERNARD, AND W. M. SACKETT.
1977. Input of low-molecular-weight
hydrocarbons from petroleum
operations into the Gulf
of Mexico, p. 373-384. Zn D. A. Wolfe [ed.],
Fate and effects of petroleum hydrocarbons
in
marinc organisms and ecosystems. Pcrgamon.
-,
J. R. GORMLY,AND W.M. SACKETT. 1974.
Molecular and isotopic composition of two seep
gases from the Gulf of Mexico. Geophys. Res.
Lett. 1: 312-316.
CHEMICALRUBBERCOMPANY. 1972. Handbookof
chemistry and physics, 53rd ed. CRC.
COLWELL, R. R., AND J. D. WAI,KE:R. 1977. Ecological aspects of microbial degradation
of petroleum in the marine environment,
p. 423445. Zn Critical reviews in microbiology.
CRC.
COOK, A. II., AND J. A. ELVIDGE. 1951. Fertilization in the Frtcacecle: Investigations
on the nature of the chemotactic substance produced by
eggs of Fucus serrntus
and F. desiculosus.
Proc. R. Sot. Lond. Ser. B 138: 97-114.
DIETZ, W. A. 1967. Response factors for gas chromatographic
analysis. J. Gas Chromatogr.
5:
68-72.
DOELLE:, II. W. 1975. Bacterial metabolism. Academic.
DUCE, R. A. 1978. Speculations on the budget of
particulate
and vapor phase non-methane
organic carbon in the global troposhcre.
Pure
Appl. Geophys. 116: 244-273.
-,
AND E. K. DUURSMA. 1977. Inputs of organic matter to the ocean. Mar. Chem. 5: 319339.
FLOODGATE, G. C. 1972. Microbial degradation of
oil. Mar. Pollut. Bull. 3: 4143.
GIBSON, D. T. 1977. Biodegradation
of aromatic
petroleum
hydrocarbons,
p, 3646.
Zn D. A.
Wolfe [ed.], Fate and effects of petroleum hydrocarbons
in marine organisms and ecosysterns. Pergamon.
HOLZER, G., AND OTIIERS. 1977. Collection
and
analysis of trace organic emissions from natural
sources. J. Chromatogr.
142: 755-764.
IMPERIAL CIIEMICAL INDUSTRIAL LTD. 1970.
Eight peak index of mass spectra, v. 1 and 2.
London.
JACOBSON,~. M., ANL) D.B. BOYLAN. 1973. Effect
of seawater soluble fraction
of kerosene on
chemotaxis in a marine snail, Nassnrius obsoZetus. Nature 24 1: 213-215.
JOI~NSON,F. G. 1977. Sublethal biological effects
of petroleum
hydrocarbon
exposure: Bacteria,
p. 271-318. Zn D. C.
d,l gae an d invertebrates,
Malins Led.], Effects of petroleum on arctic and
subarctic marinc environments
and organisms,
v. 2. Academic.
KANWISI-IEH,J, 1963. On the exchange of gases between the atmosphere and the sea. Deep-Sea
Res. 10: 195-207.
KEJZER, P. D., D. C. GORDON, AND J. DAIx.
1977. IIydrocarbons
in eastern Canadian marine waters determined
by fluorescence
spec-
Volatile
liquid
troscopy
and gas-liquid
chromatography.
J.
Fish. Res. Bd. Can. 34: 347-353.
KOHN, A. J. 1961. Chemoreception
in gastropods.
Am. Zool. 1: 291-308.
Kooks, C. B. 1977. Distribution
ofvolatilc
hydrocarbons in some Pacific Ocean waters, p. 589592. Zn Proceedings of the 1977 Oil Spill Conference, New Orleans. Am. Pet. Inst. Publ.
4284.
-,
AND P. II. MONAGIIAN. 1973. Pctrolcum
derived hydrocarbons
in Gulf of Mexico waters.
Trans. Gulf Coast Assoc. Geol. SOC. 16: 17O181.
LEE:, W. Y. 1978. Chronic sublethal effects of the
water soluble fraction of No. 2 fuel oil on the
marinc isopod, Sphnerorna
c~undridelatatzcm.
Mar. Environ. Res. 1: 5-19.
MCAULIFFE, C. D. 1966, Solubility in water of paraffin, cycloparaffin,
olefin, acetylene, cycloolefin and aromatic hydrocarbons.
J. Phys. Chcm.
70: 1267-1275.
1974. Determination
of C,-C,, hydrocar-.
bons in water, p. 121-125. Zn Marinc pollution
monitoring
(petroleum).
Natl. Bur. Std. Spcc.
P&l. 409. U.S. GPO.
1977a,h. Dispersal and alteration of oil dis-.
charged on a water surface, p. 19-35. Evaporation and solution of Cz to C,, hydrocarbons
from crude oils in the sea surface, p. 363-372.
Zn D. A. Wolfe Led.], Fate and effects of pctroleum hydrocarbons
in marine organisms and
ecosystems. Pergamon.
MCLAFFERTY, F. W. 1973. Interpretation
of mass
spectra. Benjamin.
MALINS, D. C. [Ed.] 1977. Effects of petroleum on
arctic and subarctic marine environments
and
organisms, v. 1 and 2. Academic.
NATIONAL ACADEMY OF SCIENCES. 1975. Petrolcum in the marine environment.
Washington,
D.C.
ROSSI, S. S., AND J. W. ANDERSON. 1978. Effects of
No. 2 fuel oil water-soluble-fractions
on growth
and reproduction
in Nennthes nsennceodentatn
(Polychacta:
Annclida).
Water Air Soil Pollut.
9: 155-170.
SACKETT, W. M., ANDJ.M.BROOKS. 1975. Origin
and distribution
of low-molecular-weight
hydrocarbons in Gulf of Mexico coastal waters, p.
21 l-230. Zn T. M. Church [cd.], Marine &emistry in the coastal environmcnt.
Am. Chem.
Sot. Symp. Ser. 18.
SAUER, T. C., JR. 1978. Volatile liquid hydrocarbons in the marine environment.
Ph.D. thesis,
Texas A&M Univ. 317 p.
--,
W. M. SACKETT, AND L. M. JEFFHEY.
1978. Volatile
liquid carbons in the surface
coastal waters of the Gulf of Mexico.
Mar.
Chcm. 7: 1-16.
SCHWARZENBACH, R. P., R. I-I. BROMUND, P. M.
GSCIIWEND, AND D. C. ZAFIFUOU. 1979. Vol-
351
hydrocarbons
atile organic compounds
in coastal scawatcr:
Preliminary
results. J. Org. Geochem. 1: 45-61.
STEELE, R. L. 1977. Effects of certain pctrolcum
products on reproduction
and growth of zygotes
and juvcnilc stages of the alga Fucus edentatus
Dc la Pyl (Phaeophyceae:
Fucalcs), p. 115-128.
Zn D. Wolfe [ed.], Fate and effects of petroleum
hydrocarbons
in marine ecosystems and organisms. Pergamon.
SWINNERTON, J. W., AND R. A. LAMONTAGNE.
1974. Oceanic distribution
of low-molecularweight hydrocarbons.
Environ. Sci. Technol. 8:
657-663.
AND V. J. LINNENBOM. 1967. Determinntioin of Cl-C,, hydrocarbons
in seawater by gas
chromatography.
J. Gas Chromatogr.
5: 570574.
-,
-,
AND C. II. CHEEK. 1969. Distribution of methane and carbon monoxide between
the atmosphere
and natural waters. Environ.
Sci. Tcchnol. 3: 838-842.
TAKAIIASHI, F. T., AND J. S. KITTREDGE. 1973.
Sublethal effects of the water soluble component of oil: Chemical
communication
in the
marine cnvironmcnt,
p. 259-264.
Zn D. G.
Ahern and S. P. Meyers [eds.], The microbial
degradation of oil pollutants. Publ. LSU-SC-7301, Center Wetlands Rcsour., Louisiana
State
Univ.
TREYBAL, R. E. 1955. Mass-transfer
operations.
McGraw-IIill.
U.S. DEPARTMENT OF THE INTERIOR. 1976. Draft
environment
statcmcnt, outer-continental
shelf,
Gulf of Mexico. OCS 44. Bur. Land Manage.
VAN DER LINDEN, R., AND G. T. I3. TIIIJSSE. 1965.
The mechanisms of oxidation of petroleum hydrocarbons,
p. 469-546. Zn F. F. Nord [cd.],
Advances in enzymology,
v. 27. Intcrsciencc.
VANDERMEULEN, J. II., AND T. P. AHERN. 1976.
Effect of petroleum
hydrocarbons
on algal
physiology;
review and progress report, p. lO7125. Zn A. P. Lockwood
Led.], Effects of pollutants on aquatic organisms. Cambridge.
WALKER, J. D., R. R. COLWELL, AND L.
PETROKIS. 1976. Biodegradation
rates of components of petroleum.
Can. J. Microbial.
22:
1209-1224.
WALSH, F., AND R. MITCHELL. 1973. Inihibition
of bacterial chemoreccption
by hydrocarbons,
p. 275-278. Zn D. G. Ahern and S. P. Meyers
[eds.], The microbial degradation
of oil pollutants. Publ. LSU-SC-73-01,
Center Wetlands
Resour., Louisiana State Univ.
WOLFE, D. A. [Ed.]. 1977. Fate and effects of petroleum hydrocarbons
in marine organisms and
ecosystems. Pergamon.
Submitted:
12 March
Accepted: 15 October
1979
1979