夏季南海浮游植物光合固碳对不同波长阳光紫外辐射的响应

阳光紫外(UV)辐射影响浮游植物光合固碳,且不同波长UV辐射的生理效应不一.本文以夏季南海近岸海域浮游植物为研究对象,采用生物加权函数(Biological weighting function,BWF,亦被称为UV辐射作用光谱)的研究方法,探讨了不同波长UV辐射对浮游植物群落光合固碳的作用.结果表明,在只有可见光情况...     

Comparison of the effects of short-term UVB radiation exposure on phytoplankton photosynthesis in the temperate Changjiang and subtropical Zhujiang estuaries of China

We examined the effect of solar ultraviolet radiation B (UVB, 280–315 nm) on photosynthesis of natural phytoplankton assemblages in the temperate Changjiang River Estuary (CRE) in the East China Sea (ECS), and the subtropical Zhujiang River Estuary (ZRE) in the South China Sea (SCS) from August 2002 to April 2003. The short-term effect of UVB was assessed by exposing samples in quartz tubes/bottles to solar radiation under three treatments: (1) natural sunlight (NS) with UVB (NS-UVB); (2) photosynthetically active radiation (PAR, NS cut off UVB); and (3) NS with additional artificial UVB (NS + A-UVB). Solar UVB apparently inhibited phytoplankton photosynthesis rates. In the temperate CRE-ECS, solar UVB reduced surface phytoplankton photosynthesis by about 28% in August and February, while in the subtropical ZRE-SCS the inhibition was only 22% in September and October. In the CRE-ECS, phytoplankton in the stratified water column displayed stronger UVB inhibition when deeper water samples were exposed to surface UVB. Phytoplankton in the mixed water column did not show strong UVB inhibition, while light shift exposure of deeper phytoplankton in the same water column to surface light produced similar results, indicating that mixing moderates UVB effects. In the ZRE-SCS, surface phytoplankton showed greater photoinhibition in January (sunny). However, in April (cloudy), phytoplankton showed little UVB inhibition. Incubation for a short time without UVB showed a large increase in Chl a at two stations in the ZRE-SCS, but a large decrease at the other station in the presence of UVB. In contrast, in the CRE-ECS, a similar incubation experiment without UVB showed a decrease in Chl a, and small UVB inhibition of Chl a at two stations. Nutrient conditions might have played a role in the difference of UVB inhibition between the two regions as the ZRESCS had relatively high concentrations of all nutrients while PO₄ was only 0.21 μM at one of the CRE-ECS stations. The results suggest that phytoplankton in temperate waters would be more responsive to variation of UVB than ones in subtropical waters.     

Impacts of solar UV radiation on grazing, lipids oxidation and survival of Acartia pacifica Steuer (Copepod)

UV radiation is known to affect aquatic primary producers and their grazers. However, little has been documented on its effects on zooplankton grazing. In this study, the authors investigated the effects of photosynthetically active radiation (PAR, 400-700 nm), ultraviolet-A (UV-A, 320-400 nm) and ultraviolet-B (UV-B, 280-320 nm) radiation on grazing, mortality and lipids oxidation of the copepod Acartia pacifica collected from the Xiamen Bay. After 30 min of the exposures, the copepod was fed in darkness with the diatom Phaeodactylum tricornutum at two cell concentrations (2.5 × 10 4 and 2.5 × 10 5 cells/ml). At the low cell concentration, the individuals pre-exposed to PAR (218.0 W/m 2 )+UV-A (48.2 W/m 2 ) or PAR+UV-A+UV-B (2.1 W/m 2 ) showed suppressed clearance and grazing activities compared with those receiving PAR alone, by 22.7% and 17.1% for clearance and by 22.6% and 5.5% for grazing rates, respectively. However, the suppression on clearance and grazing became indistinctive at the high food concentration. Exposures to UV-A and UV-B led to increased lipid oxidation and higher mortality, furthermore, the mortality linearly increased with enhanced oxidation of lipid.     

Lipids of Antarctic Ocean amphipods: food chain interactions and the occurrence of novel biomarkers

Antarctic hyperiid (Themisto gaudichaudi, Hyperia macrocephalus, and Primno macropa) and gammarid amphipods (Eusirus perdentatus and Orchomene rossi) were collected near Elephant Island, located in the South Shetland Islands, during January and February 1997 and 1998. Polar lipid (PL) was the major lipid class in all amphipods (58–88% of total lipid), except for T. gaudichaudi in which triacylglycerol (TAG) was dominant (62%). Cholesterol was the major sterol in the gammarid amphipods (89–91% of total sterols), and the hyperiid P. macropa (70%). The hyperiids T. gaudichaudi and H. macrocephalus had a more diverse sterol composition including trans-dehydrocholesterol, desmosterol, 24-nordehydrocholesterol, 24-methylcholest-5,22E-dien-3β-ol, 24-methylenecholesterol, and stanols (mostly cholestanol). Eicosapentaenoic acid [EPA, 20:5(n−3)] and docosahexaenoic acid [DHA, 22:6(n−3)] were the major polyunsaturated fatty acids (PUFA) in all amphipods. The PUFA octadecapentaenoic acid [18:5(n−3)] was not detected in 1997 samples, but comprised 0.3–1.2% in all 1998 samples. The PUFA 18:4(n−3) comprised 0.2–4.2% in all samples from both years. Very long chain PUFA (VLC-PUFA) (C₂₄ and C₂₆) were not detected in the one 1997 sample but comprised 0.6–2.8% of total fatty acids in almost all 1998 amphipods. Monounsaturated fatty acids included 18:1(n−9)c, 18:1(n−7)c, and 16:1(n−7)c. Principal saturated fatty acids in all amphipods were 16:0, 14:0, and 18:0. Examination of biomarker lipids has helped clarify trophic interactions for these Antarctic amphipods, and revealed annual differences in their food sources.     

刺参体壁脂肪酸组成的季节变化分析

对不同季节刺参(Apostichopus japonicus)体壁的脂肪酸组成进行了分析.结果表明刺参体壁的脂肪酸组成和相对质量分数具有明显的季节变化.在秋季和冬季,多不饱和脂肪酸(PUFA)的相对质量分数最高,其次是单不饱和脂肪酸(MUFA),饱和脂肪酸(SFA)的相对质量分数最低;春季MUFA的相对质量分数最高,其次是PUFA和SFA;夏季MUFA的相对质量分数最高,其次是SFA,PUFA的相对质量分数最低.在所有季节,相对质量分数最高的SFA和MUFA分别是16:0和16:1n-7,相对质量分数较高的PUFA是20:5n-3,20:4n-6和22:6n-3.n-3PUFA与n-6PUFA相对质量分数比值在1.87～2.42之间,冬季和春季显著高于夏季和秋季(P<0.05).     

Effects of UV-B radiation and different light repair conditions on the early development of the tetraspores of Chondrus ocellatus Holm

The effects of exposure to UV-B radiation,280-315 nm,and dark or dark repair conditions on the early development of Chondrus ocellatus Holm collected from Qingdao coast were studied under the laboratory condition.After being exposed to different doses [0,36,72,108,144 and 180 J/(m 2 · d)] of UV-B radiation,one treatment of tetraspores were put back to normal culture condition (PAR),the other treatment were put into dark condition to repair for 2 h.During the cultivation,the diameter of the tetraspores were recorded every 4 d till the 50th day when vertical branches formed in all treatments.Then at the 50th day,CPDs,phycoerythrin,chlorophyll a and MAAs (Palythine and asterina-330) were measured.The results showed that low doses UV-B radiation could significantly accelerate the growth rate of the tetraspores of C.ocellatus and the growth rate reduced gradually with UV-B radiation keep on increasing.The variation trend of both the phycoerythrin and chlorophyll a concentration reduced significantly ( P < 0.05) once given the UV-B radiation. Under UV-B stress,the CPDs were induced,and the concentrations of CPDs were significant low in dark repair groups.The data of MAAs analyzed by LC/MS in the tetraspores of C. ocellatus suggested that there were two MAAs formed (palythine and asterina-330) after UV-B radiation induced, and low dose of UV-B irradiation could significantly induced the concentration of MAAs.From the growth and development state of the tetraspores,negative effects of UV-B radiation on the dark repair groups were more serious than PAR.     

Zooplankton nutrition,storage and fecal lipid composition in different water masses associated with the Agulhas and Subtropical Fronts

Fecal pellets of zooplankton can be important carriers of organic matter from surface to deep waters of the oceans. The summer cruise ANTARES 4 gave us the opportunity to collect zooplankton from the frontal subantarctic zone (station 7 or s-ant) and adjacent subtropical waters (station 8 or s-trop). Triglyceride fatty acid profiles were used to assess the trophic position of two copepods (Metridia lucens and Pleuromamma spp.), three euphausiids (Euphausia spinifera, Nematoscelis megalops, and Thysanoessa sp) and a decapod Acanthephyra sp. The euphausiid E. spinifera was studied at the two sites and its reaction to contrasting trophic environments and hydrology was highlighted by variations in its lipid composition. Most species showed various degree of omnivory: E. spinifera from subantarctic showed the highest degree of herbivory on phytoplankton (high proportion of 16:4(n-1), 18:5(n-3), 16:1(n-7)), while the same species at the subtropical station, as well as Thysanoessa sp and M. lucens from the subantarctic station displayed more omnivorous feeding characteristics, partly linked to the abundance of microzooplankton cells. Acanthephirasp, N. megalops and Pleuromammasp from station 8 (s-trop) appear to be essentially carnivorous (high 18:1n-9/18:1n-7 ratio, high levels of 20:1(n-9) or 22:1(n-11)). The trophic position influenced the composition of feces, with higher PUFA percentages in fecal pellets from carnivorous species. Hence, the surface faunal assemblage and the season controlled not only the quantity but also the quality of the food supply as PUFA exported towards the benthic domain.     

大西洋庸鲽(Hippoglossus hipoglossus L.)精液脂肪酸分析及激素GnRHa诱导对其组成的影响

采用气相色谱检测的方法,进行大西洋庸鲽精液脂肪酸组成分析及激素GnRHa诱导对其组成影响的研究。结果表明,大西洋庸鲽精液中含量最高的脂肪酸种类为22:6n-3(DHA,二十二碳六烯酸),占总脂肪酸比例25.67%±0.94%;其次为16:0(PA,棕榈酸)、20:5n-3(EPA,二十碳五烯酸);重要必需不饱和脂肪酸20:4n-6(AA,花生四烯酸)含量较低,为1.76%±0.01%。精液中高不饱和脂肪酸(PUFA)含量较高,为44.25%±0.30%;饱和脂肪酸(SAT)含量为27.72%±0.22%。重要脂肪酸比例DHA/EPA为2.33±0.26;EPA/AA为6.30±0.51;n-3/n-6为9.22±0.60。激素诱导未对精液中脂肪酸组成产生显著影响。重要必需脂肪酸DHA、EPA、AA,以及n-3、n-6等重要种类的脂肪酸总量在激素诱导组与非诱导对照组样品间无显著差异;在激素诱导后的三个取样时间的样品间也无显著差异(P0.05)。     

7株海洋微藻强化褶皱臂尾轮虫效果的研究

该文用 7株富含 EPA、DHA的海洋微藻对褶皱臂尾轮虫 (Brachionus plicatilis)进行强化 ,通过检测轮虫的脂肪酸组成和含量来研究这几种微藻对轮虫的营养价值。结果表明 :轮虫中的脂肪酸组成和含量与所用饵料密切相关 ,尤其是 EPA、DHA等多不饱和脂肪酸 (PUFA)主要取决于这些脂肪酸在藻中的含量 ;强化 12 h后 ,轮虫中的 n- 3PUFA含量一般为饵料中含量的 75 %左右 ,强化 2 4 h达 80 %以上 ,强化 7d的轮虫可达 90 %以上。     

紫外辐射对南极棕囊藻细胞DMSP合成和DMS释放率的影响

在不同紫外辐射波段下,南极棕囊藻(Phaeocystis antarctica)细胞的生长率、叶绿素a、细胞内DMSP含量和DMS释放量变化的测定结果表明;UV-B对南极棕囊藻细胞生长率和叶绿素a含量有抑制效应,UV-B还可加快DMSP分解成DMS和丙烯酸的分解速率,而UV-A对该藻细胞的DMSP合成有强烈的抑制效应。鉴于在每年春季极地海洋浮游植物繁殖期间,南极棕囊藻在南极海冰带海洋浮游植物种群结构中占有的优势地位,以及该藻是极地海洋浮游植物中DMS的主要释放者,推测南极“臭氧空洞”所增加的紫外辐射可能会对南极海域的DMS释放率产生一定的影响。     

UV-tolerance and instantaneous physiological stress responses of two Antarctic amphipod species Gondogeneia antarctica and Djerboa furcipes during exposure to UV radiation

We investigated the shielding against solar ultraviolet radiation and inducible damage, as well as the short-term response of whole animal metabolic rate in two Antarctic shallow water amphipod species. Light absorbance by the carapace of Gondogeneia antarctica and Djerboa furcipes was higher in the UVR (UVB+UVA) range (42.1% and 54.5% on average respectively) compared to the PAR (photosynthetically active radiation) range (38.1% and 50.1% respectively) of the solar spectrum. Bands of higher absorbance correlated with maximal absorbance ranges of sunscreening compounds indicating mycosporine-like amino acids (MAAs) and carotenoids to be innate compounds of the exoskeleton of these species. Though the antioxidant enzyme catalase was photoinhibited, protein damage products did not accumulate under experimental exposure to a daily dose of 6.84 kJ m(-2) d(-1) UVB, 66.24 kJ m(-2) d(-1) UVA and 103.14 kJ m(-2) d(-1) PAR. Animal oxygen consumption during UV-exposure was measured as an indicator of immediate behavioural and physiological stress response. UVB as well as UVA induced a response with altered and highly variable respiratory intensity. Our findings indicate that sub-lethal UVR exposure causes increased oxygen consumption in polar amphipods due to radiation avoidance, shelter seeking behaviour, and presumably also from cellular repair processes.     

Fatty acid composition of phytoplankton, settling particulate matter and sediments at a sheltered bivalve aquaculture site

Fatty acid biomarkers were used to investigate the biogeochemistry of a former blue mussel (Mytilus edulis) aquaculture site in a shallow, sheltered cove in northeastern Newfoundland. High levels of polyunsaturated fatty acids (PUFA) in net-tow and sediment trap samples indicated a substantial phytoplankton source of organic matter, and fluctuations in specific fatty acid biomarkers reflected the changing abundances of diatoms and dinoflagellates. In comparison, sediments contained very low levels of PUFA (<15%) and were dominated by terrestrial and bacterial markers. In a separate study, blue mussels were grown at this closed site, providing the opportunity to examine the relationship between lipid supply, as recorded by net-tow and trap samples, and bivalve requirements. The average plankton fatty acid composition throughout the year agreed well with that of the adult blue mussels, suggesting that fatty acids were provided in proportions very similar to the bivalves' requirements. The fatty acid composition of the blue mussels was typical of those collected elsewhere, with PUFA proportions near 50%. However, examination of fatty acid data of plankton sampled in other areas revealed that the plankton in the current study may have been unusual in providing fatty acids at levels required by the bivalves.     

Lipid biomarkers of deep-sea hydrothermal vent polychaetes—Alvinella pompejana, A. caudata, Paralvinella grasslei and Hesiolyra bergii

The lipid composition was determined for 5 species of polychaete annelids collected by the Deep Submergence Vehicle ALVIN from high temperature chimneys at the 2500 m depth hydrothermal vent field of the East Pacific Rise. These are the first lipid biomarker analyses reported for these hydrothermal vent polychaetes. Lipid content was low in all samples (1.6–35.9 mg g^–1 wet mass) and was dominated by polar lipid (78–90% of total lipid) with 8–19% sterol (ST), and very low storage lipid (triacylglycerol and wax ester). Total polyunsaturated fatty acids (PUFA) were moderately high (22–31% of total fatty acids (FA)) with extremely low or no docosahexaenoic acid (DHA, 22:6(n-3)). Eicosapentaenoic acid (EPA, 20:5(n-3)) levels were 5–6% in Alvinella pompejana and A. caudata and 10.3–13.7% in an errantiate polychaete (likely Hesionidae) and Hesiolyra bergii. There were greater PUFA and a greater EPA/AA (AA is arachidonic acid, 20:4(n-6)) ratio in the anterior versus the posterior half of A. pompejana, which may correlate to the strong temperature gradient reported in its tube. Total nonmethylene interrupted diunsaturated fatty acids (NMID) were 4–9% of total FA for most polychaete species and included several 20:2 and 22:2 components. The principal monounsaturated fatty acids (MUFA) included 18:1(n-7)c (14–19%), 16:1(n-7)c (2.6–10%) and 20:1(n-11)c (3–7% of total FA). These polychaete species may desaturate and elongate the bacterial-derived 18:1(n-7)c to obtain the essential FA EPA and AA. The major ST in the polychaetes is cholesterol (89–98% of total ST) with less cholesterol in the gut contents of A. pompejana. Other ST included 24-ethylcholesterol (1.5–5% of total ST) with lesser amounts of 24-methylenecholesterol, desmosterol, lathosterol, 24-methylcholesterol, 24-ethylcholesterol, and the stanols dehydrocholestanol and cholestanol. The high ST levels could play a role in thermal adaptation of membranes at the hydrothermal vent environment. Differences in the FA profiles separated the closely related species A. pompejana and A. caudata from Paralvinella grasslei, H. bergii, and the errantiate polychaete (likely Hesionidae).     

Effect of UV-B radiation on the feeding behavior of the rotifer Brachionus plicatilis

Effect of UV-B radiation on the feeding behaviour of marine zooplankton is important to assessing the health harm of marine ecosystem due to the gradually enhanced UV-B radiation in air. However, there are a few studies on this topic. The feeding behavior of the rotifer, Brachionus plicatilis, under the treatment of UV-B radiation on five species of microalgae, i.e., Chlorella sp., Tetraselmis chuii, Isochrysis galbana Park 8701, Chaetoceros muelleri Lermumerman, and Nitzschia clostertum, was studied. The results showed that the filtering and feeding rates of the rotifer decreased significantly with the dose increase of UV-B radiation when fed with five species of microalgae respectively (P<0.05) which indicates UV-B radiation inhibits the feeding activities of the rotifer on microalage. The mixed culture experiments shows the rotifer preferred to feed Chlorella sp., then C. muelleri,I. galbana, N. clostertum and T. chuii in turn if without UV-B radiation. Under the highest dose of UV-B radiation treatment (2.70 kJ/m2), the rotifer preferred to feed C. muelleri, then Chlorella sp., N. clostertum, I. galbana and T. chuii in turn. Chlorella sp., I. galbana and C. muelleri became the more favorite foods of the rotifer while T. chuii and N. clostertum became less favorite foods. The change of feeding rate and feeding selectivity of zooplankton driven by the enhanced UV-B radiation will lead to the change in the structure of phytoplankton community.     

UV-B辐射对2种海洋微藻膜脂过氧化和脱酯化伤害

研究海洋生态系统在调节全球变化中的作用,采用生态毒理学的方法研究了UV-B辐射增强对2种海洋微藻膜的损伤及其差异性。结果表明,随着UV-B辐射剂量的增加,叉鞭金藻(Dicrateriasp.)和三角褐指藻(Phaeodactylum tricornu-tum)的光合速率降低。同时,膜相对透性增大,细胞内H2O2含量上升,微粒体膜中磷脂减少,游离脂肪酸增加。表明UV-B辐射增强使2种微藻的膜受到了严重伤害,而且膜伤害的加剧与活性氧的积累和由此引发的膜脂脱酯化有关。2种微藻细胞匀浆中丙二醛(MDA)含量无显著变化,而微粒体膜的MDA含量随着UV-B辐射剂量的加大显著提高。这表明UV-B辐射增强对2种海洋微藻膜的损伤可能是由膜脂过氧化和脱酯化作用共同引起的。     

角毛藻属(7株)总脂含量及脂肪酸组成的比较研究

在温度为25±1°C,盐度为28的条件下,用F/2培养基对七株角毛藻(Chaetocerosspp.)进行培养.在指数生长期末期进行收获.测定了七株角毛藻的总脂含量及脂肪酸组成.其主要脂肪酸为14:0(3.0-24.92),16:0(8.2-28.5%),16:1n-7(16.0-42.3%)和20:5n-3(4.2-10.42),其中B13的20:5n-3含量最高,占总脂肪酸的10.4%     

Iron nutritional status of the phytoplankton assemblage in the Okhotsk Sea during summer

To clarify the iron (Fe) nutritional status of the phytoplankton assemblage in the Okhotsk Sea, we conducted incubation experiments in summer 2006. Replicate surface seawater samples with the natural plankton community were incubated with three treatments: Fe enrichment; addition of the strong Fe chelator siderophore desferriferrioxime B (DFB) which strips Fe from the biologically accessible pool; and as a control, no addition. To prevent macronutrient limitation, we added surplus nutrients to all treatments. At all 4 stations in Sakhalin Bay near the mouth of the Amur River and around the east of Sakhalin Island, net specific growth rate showed no significant difference between the control and +Fe treatment, and was repressed in +DFB treatment both in large- and small-sized phytoplankton. These findings indicate that these waters contain sufficient bioavailable Fe and that the Amur River plume which is transported by the east Sakhalin current is a major source of the Fe. In the Bussol’ Strait, net specific growth rate in the control was significantly higher than +DFB treatment, suggesting a supply of bioavailable Fe through intense vertical mixing at this site. Iron enrichment treatment stimulated the net specific growth rate of large-sized phytoplankton, indicating that Fe still limits the growth for the large-sized phytoplankton assemblage, but not for small-sized phytoplankton, in this area. An index of Fe availability was defined to quantify the degree of ambient Fe availability in each station, and it revealed the spatial variability of ambient Fe availabilities among the sites.     

十四株海洋微藻脂肪酸组成的研究

对 4个门的 14株 (红藻门 8株 ,甲藻门 1株 ,隐藻门 2株 ,绿藻门 3株 )海洋微藻进行了脂肪酸含量测定 ,微藻在确定的条件下生长 ,指数生长末期收获。结果表明 ,各门的微藻都有其独特的脂肪酸特征 :红藻中含有大量的 2 0 :4 n- 6和 2 0 :5n- 3,其中紫球藻 R2 5含量最高 ,占总脂肪酸的4 9.8% (AA占总脂肪酸的 2 0 .5% ,EPA占总脂肪酸的 2 9.3% )。隐藻的主要脂肪酸是 16 :0、18:1n- 9、18:3n- 3、18:4 n- 3、2 0 :5n- 3、2 2 :5n- 3。与其它甲藻有别的虫黄藻 ,18:4 n- 3含量很少并且不含EPA,其主要合成的是 16 :0、18:1n- 9和 2 2 :6 n- 3。 C16和 C18的不饱和脂肪酸是本实验研究的 3株绿藻的主要脂肪酸     

卤虫无节幼体的营养强化对黑斑口虾蛄(Oratosquilla kempi)幼体发育的影响

用扁藻、酵母、“鱼油 酵母”强化和“不强化”4种方式处理的卤虫无节幼体投喂黑斑口虾蛄各期幼体,比较不同强化方法对黑斑口虾蛄幼体成活率、变态率、生长速度及总脂与脂肪酸组成的影响。结果表明,3种方式强化12h后的卤虫无节幼体与对照组相比,总脂含量都有不同程度的增加。卤虫无节幼体的脂肪酸组成与强化方式密切相关,其中“鱼油 酵母”强化的卤虫无节幼体20∶5n-3(EPA)和22∶6n-3(DHA)占总脂肪酸的比例最高,分别为5·74%和4·84%。投喂强化后富含EPA和DHA的卤虫无节幼体,可增加黑斑口虾蛄幼体体内脂肪酸尤其是EPA和DHA等不饱和脂肪酸的含量,从而提高其幼体的成活率、变态率与发育速度。     

Fatty Acid Composition and Community Structure of Plankton from the San Lorenzo Channel, Gulf of California

The structure of the plankton community and fatty acid composition of nano-, micro- and zooplankton are described during four seasons of 1994 from the San Lorenzo Channel. During August, the warmest temperature in the surface water was observed and a thermocline developed between 20 and 30 m. In the remaining months, a well-mixed layer occurred in the upper 30 m. The chlorophyllacontent of the nanoplankton fraction (<38 μm) was higher than the microplanktonic fraction (38–200 μm) year round. Maximal chlorophyll values (1·5–3 μ l⁻¹) occurred in January, which may be associated with organic matter, since phytoplankton was lower than at other seasons. The relative abundance of diatoms increased from January (57% of phytoplankton) to November (99%). The increment was mainly due toNitzschiaandChaetoceros. Dinoflagellates were always low (0·03–1·36 cells ml⁻¹). Copepods (mainlyEucalanus) dominated the zooplankton in winter and fall, while in spring and summer, the abundance of doliolids was similar to the copepods (Nannocalanus minordominated).Four fatty acids (16:0, 16:1, 18:0, 18:1) were the most conspicuous in the plankton, representing usually between 40 and 80% of the total fatty acids throughout the water column. In winter, higher fatty acid content and higher relative amounts of 16:0 and 16:1 were observed than in the warm months. Stearic acid (18:0) peaked during fall. The major seasonal differences occurred in the nanoplankton, which had peaks of 20:5 during January, and 16:4 in April. A strong decrease in polyunsaturated fatty acids (PUFA) occurred during the warm months. The fatty acid composition of microplankton and larger zooplankton was similar in winter–spring. Individual copepods of selected species (Eucalanus sewelli,Rhincalanus nasutus,Centropages furcatusandLabidocera acuta) showed fatty acid profiles similar to the mixed zooplankton, with some differences in content of PUFA.