[Advances in Marine Biology] Advances in Marine Biology Volume 15 Volume 15 || Pollution Studies with Marine Plankton

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<ul><li><p>Adv. mar. B i d , Vol. 15, 1978, pp, 289-380. </p><p>POLLUTION STUDIES WITH MARINE PLANKTON PART I . PETROLEUM HYDROCARBONS AND </p><p>RELATED COMPOUNDS </p><p>E. D. S . CORNER The Laboratory, Marine Biological Association, </p><p>Plymouth, England </p><p>I. </p><p>IT. </p><p>1x1. </p><p>IV. </p><p>V. </p><p>VI. </p><p>VII. </p><p>v m . </p><p>IX. </p><p>X . </p><p>XI. </p><p>Introduction . . .. .. .. .. .. .. .. .. Hydrocarbon Levels in Sea Water . . .. .. .. .. .. </p><p>A. Studies Primarily concerned with Alkanes . . .. .. .. B. " Dissolved " and Particulate Hydrocarbons .. .. .. C. Hydrocarbons in or near the Surface of the Sea . . .. .. D. Comprehensive Analyses . . .. .. .. .. .. </p><p>Hydrocarbons in Plankton . . .. .. .. .. .. .. A. Phytoplankton .. .. .. .. .. .. .. </p><p>Phytoplankton and Crude Oil as Sources of Hydrocarbons in the Sea . . .. ., .. .. .. .. .. .. </p><p>C. Zooplankton . . .. .. .. .. .. .. .. Toxicity Studies with Phytoplankton .. .. .. .. .. </p><p>B. Studies using Naphthalene . . .. .. .. .. .. Mechanisms of Phytotoxicity . . .. .. .. .. .. .. Controlled Eco-system Experiments . . .. .. .. .. .. Fate of Hydrocarbons in Zooplankton .. .. '. .. .. </p><p>A. Uptake and Release . . . . .. .. .. .. . . B. Quantitative importance of the Dietary Pathway .. .. C. Long-term Exposure Experiments . . .. .. .. .. E. Release of Hydrocarbons in Faecal Pellets . . .. .. .. </p><p>Toxicity Studies with Zooplankton . . .. .. .. .. .. A. CrudeOil .. .. .. .. .. .. .. .. B. Water-soluble Hydrocarbons . . .. .. .. .. .. C. Possible Effects of Hydrocarbons on Reproduction by Zooplankton D. Summary and General Comments . . .. .. .. . . </p><p>Conclusions . . .. .. .. .. .. .. .. .. A. Chemical Analyses . . .. .. .. .. .. .. B. Toxicity Studies .. .. .. .. .. .. .. C. Biochemical Work . . .. .. .. .. .. .. </p><p>Acknowledgements . . .. .. .. .. .. .. .. </p><p>B. </p><p>A. Studies using Crude Oils and their Water-soluble Fractions . . </p><p>D. Metabolism .. .. .. .. .. .. .. .. </p><p>References . . .. .. .. .. .. .. .. .. 289 </p><p>290 </p><p>290 291 293 294 300 </p><p>303 305 </p><p>309 311 </p><p>317 319 327 </p><p>329 </p><p>331 </p><p>335 335 339 340 342 348 </p><p>351 352 354 356 357 </p><p>362 362 363 364 </p><p>365 </p><p>365 </p></li><li><p>290 E. D. 5. UOBNER </p><p>I. INTRODUCTION Marine organisms, including plankton, having been exposed to </p><p>petroleum hydrocarbons released from submarine seeps throughout geological time, are likely to have evolved physiological and bio- chemical mechanisms allowing them to adapt to the presence of small quantities of these compounds in their natural environment. Never- theless, there is considerable current interest in understanding what might happen to planktonic organisms exposed to the additional and localized inputs of hydrocarbons and related compounds that result from accidental spillages arising from relatively recent industrial activities such as the off-shore production and transport of crude oil. Accordingly, consequent upon incidents such as the wrecking of the tanker " Torrey Canyon ' ) ) a vast and widely dispersed literature has arisen during the past ten years dealing with the effects of petroleum hydrocarbons on numerous marine organisms. </p><p>The publications on plankton considered in the present review, most of which refer to laboratory studies, are discussed in the context of a simplified food-chain model that begins with sea water and proceeds through phytoplankton to zooplankton. Although such a frame-work serves to carry the main theme of the treatment, several additional but relevant topics have had to be included. For example, in dealing with hydrocarbons in sea water attention has had to be given to matters such as their spatial distribution and the relative amounts in solution and in particulate form. Again, in discussing the levels and types of hydrocarbons in plankton it has been necessary to consider compounds of recent biogenic origin, some of which can also occur in crude oil. Furthermore, as certain studies with zooplankton have shown that the animals do not exclusively accumulate hydrocarbons from phyto- plankton diets, work is also described that deals with the direct uptake of these compounds from solution in sea water. Finally, although the simplified food-chain model is not extended to include fish and benthic animals, consideration is given to factors affecting the retention of hydrocarbons by zooplankton, particularly copepods, which is of key importance in the transfer of these compounds to fish ; as well as to the release of hydrocarbons in faecal pellets, a possible means by which such compounds originally present in the euphotic zone could be eventually transferred to animals that dwell in sediments. </p><p>11. HYDROCARBON LEVELS IN SEA WATER When studying the accumulation and fate of hydrocarbons in </p><p>plankton, and the possible effects of these compounds on the organisms, </p></li><li><p>POLLUTION STUDIES WITH MARINE PLANKTON-I 291 </p><p>it is necessary to bear in mind the levels of hydrocarbons that plankton normally encounter in various sea areas. Accordingly, a brief review of the available data is attempted by way of introducing the more detailed treatment of studies with plankton that are dealt with in later sections. </p><p>Although numerous attempts have been made to ascertain the levels and types of hydrocarbons present in sea water under a variety of conditions, the methods used (reviewed by Farrington and Meyer, 1975) have usually provided data for only a particular fraction of the various kinds of hydrocarbons present. More comprehensive analyses have occasionally been made (Barbier, Joly, Saliot and Tourres, 1973; Brown, Searl, Elliott, Phillips, Brandon and Monaghan, 1973), but generally the data still refer to groups of hydrocarbons (e.g. mono- cyclic aromatics) rather than to individual compounds. Data for individual hydrocarbons do exist, but most deal with n-alkanes and the iso-alkanes pristane and phytane (see Figs 2 and 3). </p><p>A. Studies primarily concerned with alkanes Swinnerton and Linnenbom (1967) detected the simplest n-alkane, </p><p>methane, at concentrations ranging from 0.025 to 0.283 pg/l at various depths in sampling areas in the Gulf of Mexico and 0.047-0.060 pgll in the North Atlantic. Frank, Sackett, Hall and Fredericks (1970) found somewhat higher concentrations of methane, 0-06-1.25 pg/1, near oil seeps in the Gulf of Mexico: ethane and propane were also present, but at much lower levels. </p><p>It is known from the work of Blumer (1970) that dissolved organic compounds in coastal waters include a variety of hydrocarbons. Thus, in a qualitative study he identified n-alkanes from C,, to C,, with maximum concentration at C,,-C,, : the compounds included those with odd and others with even numbers of carbon atoms in roughly equal amounts, a distribution different from that in recent marine sediments (where odd-numbered n-alkanes preponderate) but similar to that in marine algae (Clark and Blumer, 1967). Isoprenoid hydro- carbons were represented by pristane ((&amp;), which is also found in marine algae (Clark and Blumer, 1967) and zooplankton (Blumer, Mullin and Thomas, 1963, 1964), as well as phytane (C2,,) which is not commonly detected in marine organisms. Olefinic hydrocarbons were also found, one being identified as squalene which is also present in copepods (Blumer et aZ., 1964) and the liver oils of various species of shark (Heller, Heller, Springer and Clark, 1957 ; Blumer, 1967 ; Corner, Denton and Forster, 1969). </p><p>Some of the hydrocarbons detected by Blumer (1970) have been </p></li><li><p>292 1. D. 5. CORNER </p><p>identified and estimated by Whittle, Mackie, Hardy and McIntyre (1973) in water samples collected from 13 stations off the Scottish coast. Using sub-surface samples (3 m depth) that had been filtered through a 20 pm mesh they found levels of 0.3-1.5 pg/l for total alkanes, 0.015-0-043 pg/l for pristane and &lt; 0.001-0.014 pg/l for phytane. Similar to Blumers (1970) observations the peak levels for individual n-alkanes were usually obtained with C,,-C,, compounds. </p><p>Hydrocarbon levels vary considerably with sea area. Thus, Mackie, Platt and Hardy (1978), using techniques similar to those of Whittle et al. (1973), found that sea-water samples from King Edward Cove, South Georgia, contained 5.8 pg/l of n-alkanes within the range n-C,5-n-C33, together with 0.18 pg pristane/l; Iliffe and Calder (1974), studying hydrocarbons in the Gulf of Mexico and Caribbean Sea, found an average level of 47 pg/l for non-polar hydrocarbons in the Florida Strait, 12 pg/l in the mid-Gulf region, 12 pg/l in the Yucatan Strait, 5 pg/l in the Cariaco Trench and 8 pg/l in the Caribbean Sea, the samples containing n-alkanes in the range C,, to C,, with peak concentrations in the C,, to C,, region ; Carlberg and Skarstedt (1972), using infrared spectroscopy, obtained values in the range &lt; 50 to 120 pg/l for non-polar hydrocarbons a t ten stations in the Baltic and Kattegat. Hardy, Mackie, Whittle, McIntyre and Blackman (1977) have recently described further data for the amounts of n-alkanes (C15 to CS3) in samples of sea water from various regions surrounding the U.K. The lowest value for n-alkanes in the surface film (mean value 5.7 pg/m2) was found in samples from the open sea (Celtic Sea) ; the the mean value for off-shore samples from sites near urban areas (62.9 pg/m2) was close to that for samples taken near oil refineries (64.2 pg/m2) and greater than that for those collected close to North Sea oil fields (32.8 pg/m2). Mean values for n-alkanes in sub-surface (Im depth) samples ranged from 0.57 pg/l (Celtic Sea) to 4.6 pg/l (North Sea oil fields). </p><p>Studies described later (Section VII) show that hydrocarbons can enter zooplankton in two different ways: first, by direct uptake from solution in sea water ; second, by assimilation from particulate diets. In considering the quantities of hydrocarbons available to the animals in the sea it is therefore useful to know the relative amounts of the compounds that are present in solution and as particulate material. In addition, as certain species of zooplankton feed near the surface of the sea it is necessary to consider the spatial distribution of hydrocarbons, especially evidence for the presence of high concen- trations in the surface micro-layer. These topics are discussed in the next two sections. </p></li><li><p>POLLUTION STUDIES WITH MARINE PLANKTON-I 293 </p><p>B. " Dissolved " and particulate hydrocarbons </p><p>Spillage of Bunker C oil from the grounded tanker " Arrow " in Chedabucto Bay, Nova Scotia, led to several studies of oil levels in that area and along the coast to Halifax Harbour and beyond (Levy, 1971, 1972; Forrester, 1971). Quantitative data were obtained by Levy (1971) for the levels of petroleum residues in the open ocean off Nova Scotia and in the St Lawrence system. Water samples were filtered through a 0.45 pm millipore membrane and the hydrocarbon content of the retained material was determined as equivalents of Bunker C oil using U.V. fluorescence spectroscopy. Similar analyses were made of hydrocarbons that passed through the filter, these being described as " dissolved ". The fluorescence technique is a rapid way of detecting aromatic compounds and allows a large number of samples to be processed in ship-board experiments ; occurring organic material can produce interference that is difficul to quantify (Gordon, Keizer and Dale, 1974), particularly highly con- jugated alkenes (Farrington and Meyer, 1975). </p><p>The total levels of petroleum residues found in Chedabucto Bay by Levy (1971) were in the range 1fj-41 pg/l (as Bunker C oil equivalents). At several stations substantially higher concentrations of dissolved than particulate compounds were detected. Thus, in surface samples (1 m depth) particulate levels ranged from 5 to 16 pg/l and dissolved from 15 to 90 pg/l. </p><p>Zsolnay (1971) measured what he terms '' non-olefinic '' hydro- carbons and describes as saturated hydrocarbons and aromatic com- pounds with only one ring in the Gotland Deep, a Baltic basin. Thin- layer chromatography was used to separate the hydrocarbons which were then estimated as total carbon. Average concentrations, based on samples from all depths (20-200 m) and expressed as carbon equiva- lents, were 57-2 pg C/1 for the dissolved hydrocarbons and 1.1 pg C/1 for the particulate, dissolved material in this case being defined as that passing through a pair of Whatman GF/C glass filters. Another study using thin-layer chromatography to separate the hydrocarbons from other lipids was that of Jeffrey (1970), who measured unsaturated hydrocarbons in Baffin Bay (Texas) and found 180 pg/l as dissolved (passing through a 0.3 pm filter) and 70 pg/l as particulate material. The particulate material was mainly phytoplankton, Baffin Bay being a shallow, warm region of high primary production. </p><p>Nevertheless, the distribution of hydrocarbons between dissolved and particulate forms does not always favour the soluble fractions. Sediments, for example, adsorb levels of these compounds far higher </p><p>but natur??- </p></li><li><p>201 E. D. S. CORNER </p><p>than those found in the associated sea water. Thus, Di Salvo and Guard (1975), studying the hydrocarbons attached to suspended sedi- ments in San Francisco Bay, found them to contain alkanes and aro- matic compounds in concentrations ranging from 190 to 6 188 mg/kg dry weight; by contrast the levels in the associated sea water were o d y 15-450 11.811. </p><p>Marty and Saliot (1976) have shown that the relative amounts of n-alkanes in particulate and dissolved form depend upon whether the samples are taken from polluted or unpolluted areas. Thus, for coastal waters of the English Channel (Roscoff area) the concentra- tions of total dissolved (i.e. passing through a Whatman GF/C filter) C,, to C,, n-alkanes at 0.5 m depth was 0.11 pg/l compared with 0.28 pg/l for those in particulate form; by contrast, for off-shore waters near the West African coast (2 m depth), the total quantity in solution was 5.66 pg/l but that in particulate form only 0.32 pg/l. One would expect the hydrocarbons detected off the West African coast to be associated with the high primary production in a region of upwelling, for Zsolnay (1973) has described a close correlation between hydrocarbon and chlorophyll a levels in water samples from the same sea area. Likewise Parker, Winters, Van Baalen, Batterton and Scalan (1976) detected higher levels of n-alkanes in spring (0.64 pg/l) than at other seasons (0.13-0.23 pg/l) in sea water samples from the Gulf of Mexico. </p><p>C. Hydrocarbons in or near the surface of the sea </p><p>The presence of high concentrations of hydrocarbons in the surface micro-layer of the sea was noted by Garrett (1967) in samples from various Atlantic and Pacific sites near North America, but the com- pounds were not identified. Swinnerton and Linnenbom (1967) measured n-alkanes of low molecular weight (mainly methane) by gas- chromatography in water samples from the Gulf of Mexico (South of Mobile, Alabama) and North Atlantic (500 km west of Ireland). They found higher concentrations a t the surface than a t depth (500 m) in the Gulf of Mexico samples, although peak concentrations occurred a t 30-40m....</p></li></ul>

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