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1.
Phytoplankton growth and microzooplankton grazing were studied during the 2007 spring bloom in Central Yellow Sea. The surveyed stations were divided to pre-bloom phase (Chl a concentration less than 2 μg L−1), and bloom phase (Chl a concentration greater than 2 μg L−1). Shipboard dilution incubation experiments were carried out at 19 stations to determine the phytoplankton specific growth rates and the specific grazing rates of microzooplankton on phytoplankton. Diatoms dominated in the phytoplankton community in surface waters at most stations. For microzooplankton, Myrionecta rubra and tintinnids were dominant, and heterotrophic dinoflagellate was also important in the community. Phytoplankton-specific growth rates, with an average of 0.60±0.19 d−1, were higher at pre-bloom stations (average 0.62±0.17 d−1), and lower at the bloom stations (average 0.59±0.21 d−1), but the difference of growth rates between bloom and pre-bloom stations was not statistically significant (t test, p=0.77). The phytoplankton mortality rate by microzooplankton grazing averaged 0.41±0.23 d−1 at pre-bloom stations, and 0.58±0.31 d−1 during the blooms. In contrast to the growth rates, the statistic difference of grazing rates between bloom and pre-bloom stations was significant (after removal of outliers, t test, p=0.04), indicating the importance of the top-down control in the phytoplankton bloom processes. Average potential grazing efficiency on primary productivity was 66% at pre-bloom stations and 98% at bloom stations, respectively. Based on our results, the biomass maximum phase (bloom phase) was not the maximum growth rate phase. Both phytoplankton specific growth rate and net growth rate were higher in the pre-bloom phase than during the bloom phase. Microzooplankton grazing mortality rate was positively correlated with phytoplankton growth rate during both phases, but growth and grazing were highly coupled during the booming phase. There was no correlation between phytoplankton growth rate and cell size during the blooms, but they were positive correlated during the pre-bloom phase. Our results indicate that microzooplankton grazing is an important process controlling the growth of phytoplankton in spring bloom period in the Central Yellow Sea, particularly in the “blooming” phase.  相似文献   

2.
The feeding, egg production, and respiration rate of the dominant pteropod Limacina helicina have been studied in Russia’s Arctic seas. The sinking rates of fecal pellets and dead individuals have been measured to estimate their role in vertical carbon flux. As has been shown, the rate of ecophysiological processes taking place in the pteropods is higher than that of copepods, the main consumers of phytoplankton. The gut pigment content in Limacina (3084 ng ind–1 as a maximum) was two orders of magnitude higher than in copepods. The egg production rate in Limacina even without feeding reached 4000 eggs ind–1 versus 350–450 egg ind–1 typical of the dominant copepods even with excess food. A close correlation between the pteropod feeding rate and individual body weight was observed for Limacina rather than a correlation with food concentration. The experimentally estimated sinking rate of Limacina fecal pellets was 270 m day–1, higher than for most copepods. The sinking rate of dead pteropods reaches 2000 m day–1. According to the literature, discarded mucous feeding nets sink at a rate of 80 to 1080 m day–1. Evidently, pteropods play a significant role in biogeochemical cycles by accelerating sedimentation. High rates of all studied processes suggest that Limacina are an important component of plankton communities and play the most important role in trophodynamics at sites of their accumulation.  相似文献   

3.
Abstract. The patterns and rates of feeding by the copepod Acartia hudsonica and larvae of the polychaete Polydora sp. were investigated during the spring in an estuarine embayment. These dominant macrozooplankters fed upon the natural particulate assemblages (predominantly dino-flagellates) spiked with the toxic dinoflagellate Gonyaulax tamarensis. G. tamarensis was ingested by both zooplankters, as was Heterocapsa triquetra , the most abundant alternative food item. Ingestion rates generally increased as dinoflagellate concentrations increased, resulting in a relatively constant (and low) filtration rate for each grazer. Dinophysis acuminata , another dominant dinoflagellate, was essentially ungrazed. Thus, the zooplankters did not ingest one dinoflagellate and consumed others in proportion to their availability but at low rates. Based on these low rates and the small number of A. hudsonica observed during the spring, we infer minima! grazing impact on a 1980 G. tamarensis bloom. In contrast, the impact of polychaete larvae may have been substantial, since their extreme numerical abundance more than compensated for low filtration rates.
In one instance, the tintinnid Eutintinnus pectinis was accidentally included in a grazing experiment. Our ingestion data demonstrate that A. hudsonica , when presented with a combination of tintinnids and several species of phytoplankton (G. tamarensis and D. acuminata) ingested the tintinnids at high rates, in proportion to their high abundance. Since the nanoflagellate Chroomonas amphioxea was found within the loricae of many of the surviving tintinnids, this also provided a qualitative demonstration of the often-hypothesized nanoplankton to tintinnid to copepod link in a marine food chain.  相似文献   

4.
The abundance of tintinnid ciliates in lower Narragansett Bay was measured at weekly intervals over the period 1980–1982. Twenty-nine species representing nine genera ranged in abundance from 101 to 105 tintinnids l−1. Tintinnopsis was the most numerous genus in terms of numbers of species and individuals. Total abundance increased with water temperature above 6°C, and with nanoplankton chlorophyll a (<10 μm and <5 μm chl a) averaged over the water column. Exceptions occurred during blooms of phytoplankton previously demonstrated to be poor food for tintinnids (Olisthodiscus, Thalassiosira). Tintinnids aggregated near the bottom during periods of low nanoplankton chl a. Abundances and distributions were not correlated with particulate organic carbon. Seasonal changes in length and oral diameter of loricas of individual species were inversely related to temperature. Oral diameter was a more constant feature of lorica morphology than length. Seasonal patterns in the mean oral diameter of the lorica of all species reflected decreases in the oral diameter of individual species with increasing temperature, and changes from small to large species coincident with similar shifts in the size of phytoplankton. The production rate of tintinnids was 3·3 mgCl−1 year−1, equivalent to the ingestion of 26% of total annual net primary production and 52% of the estimated production of <10 μm phytoplankton.  相似文献   

5.
The temporal change in the microzooplankton community during the decay of a bloom ofHeterosigma akashiwo was investigated over a 10-day period in June–July 1991 at a site in western Hiroshima Bay, the Seto Inland Sea, Japan. The density ofH. akashiwo was at the order of 104 cells·ml–1 during the first 5 days, and decreased drastically when vertical mixing occurred.Heterosigma akashiwo cells disappeared after the eighth day. When the density ofH. akashiwo decreased suddenly, the density of microzooplankton increased rapidly. The increase in microzooplankton density was due to non-tintinnid ciliates. The species diversity of tintinnids was significantly higher in 1 and 2-m layers during the post-bloom period than during the bloom period. One species of tintinnid,Codonellopsis nipponica, was the most abundant in the bottom layer during the bloom period but decreased in abundance during the decay of the bloom. Populations of two species of hyaline tintinnids,Eutintinnus tubulosus andHelicostomella longa, were at low levels during the bloom period, and then developed suddenly after the bloom disappeared. It was demonstrated that the abundance and species composition of the ciliate community change dramatically during the decay of theHeterosigma bloom.  相似文献   

6.
Normal and accelerated sinking of phytoplankton in the sea   总被引：1，自引：0，他引：1  
The sinking and deposition of phytoplankton remains lead to sediment varving, the formation of sedimentary oozes, and the transport of partially decomposed and viable, autotrophic cells to great depths. Some specific examples are discussed, and the associated settling rates, depositional characteristics and individual species responses are examined in relationship to experimentally determined sinking rates of both living and dead, intact phytoplankton. The data include field and experimental observations on the sinking behavior for the same species. The in vitro rates are too low, and a mechanism or mechanisms causing accelerated rates of phytoplankton sinking in situ seems necessary to account adequately for some of the observed transport of phytoplankton remains to great depths and to the sea floor.  相似文献   

7.
A time-series sediment trap deployment was carried out in the marginal ice zone (MIZ) of the Antarctic Ocean (64°42′ S, 139°58′E; sea depth of 2930 m), during the austral summer. Cylindrical fecal pellets were the predominant sinking particles at 537 m in the middle of January and most of them disappeared below that depth, the loss of which were 25.3 mg C m−2 day−1 in the depth range of 537–796 m. Small-sized sinking particles other than fecal pellets increased in that depth range. Analyses of fecal pellets for remnant DNA corresponding to 16S mitochondrial RNA and 28S ribosomal RNA suggested that the large cylindrical fecal pellets at 537 m were produced by Antarctic krill (Euphausia superba) and copepods. According to the presence of the DNA associated with sinking particles, E. superba fecal pellets rapidly disappeared below 537 m, while copepod fecal pellets still remained in the mesopelagic and bathypelagic layers. Small-sized amorphous sinking particles at 537 m also contained E. superba- and copepod-derived DNA. The abundance of trap-collected copepods (Oithona spp. and Oncaea spp.) which are known to be coprophagous increased at 796 m where many fecal pellets disappeared. We suggest that those rapidly sinking pellets were fragmented by copepods with intensified coprorhexy activity (fragmentation of fecal pellets) in the mesopelagic layers, reducing their sinking rates. These smaller and slower sinking particles can be important food sources for detritivorus or coprophagous animals in mesopelagic and bathypelagic layers in the MIZ. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

8.
汕头沿岸水体沙壳纤毛虫季度变化   总被引：1，自引：0，他引：1  
在2007年枯水期(4月)和丰水期(11月)期间,对汕头沿岸海区沙壳虫进行了采样研究,探讨了沙壳虫的空间分布和种类组成.调查发现,除了表层海水温度以外,表层海水盐度、硝酸盐浓度、硅酸盐浓度均是春季低于秋季.在两个季节的5个采样点共鉴定出7属14种沙壳纤毛虫,其中优势种均为简单薄铃虫Lepmtintinnus simpl...  相似文献   

9.
Ichthyoplankton and microzooplankton were collected twice monthly for one year at a single station in Biscayne Bay, Florida. Based on approximate 10-m3, 333-μm mesh bongo net samples, the mean annual densities were 17·7 m?3 and 1·8 m?3 for fish eggs and larvae, respectively. Ichthyoplankton was most abundant in spring-summer. The most common fish larvae were bay anchovy (Anchoa mitchilli), spotted dragonet (Callionymus pauciradiatus), thread herring (Opisthonema oglinum) and gobies (Gobiidae), which comprised 50% of all larvae collected. A comparison of 35-μm and 333-μm mesh, bongo net collections revealed that mean densities of fish larvae were 8·5 times higher in the smaller mesh. The most abundant microzooplankton, based on 35-μm bongo net collections, were copepod nauplii, <100 μm in width, which averaged 90·41?1 and tintinnids which averaged 168·51?1. The mean density of microzooplankton <100 μm wide, potentially suitable food for first-feeding fish larvae, was 104·91?1, exclusive of tintinnids, and 273·41?1 including tintinninds. Excepting tintinnids, seasonal variability in microzooplankton abundance was low relative to that for ichthyoplankton. High microzooplankton densities, combined with low seasonal variability, indicated that feeding conditions for fish larvae were usually good in Biscayne Bay. Copepods, especially nauplii, were the predominant food of fish larvae (71% of all food items). Only mollusc veliger larvae (18% of all food items) were highly preferred prey but they were a small component of most larval fish diets. Average width of prey eaten by first-feeding larvae was 74 μm. Prey size increased in relation to larval length.  相似文献   

10.
为了评估海洋酸化和富营养化耦合作用对近海浮游生态环境的影响,本研究以天津市近岸海域浮游植物群落的生物地球化学指标为研究对象,分别采用一次性及连续培养的方式模拟自然水华及稳态条件,探究其对二氧化碳(CO2)和硝酸盐浓度变化及二者耦合作用的响应。实验条件设置如下:1)对照:二氧化碳分压p(CO2)40.53 Pa、无硝酸盐添加;2)酸化:p(CO2)101.3 Pa、无硝酸盐添加;3)加N:p(CO2)40.53 Pa、添加硝酸盐50 μmol·L–1;4)酸化加N:p(CO2)101.3 Pa、添加硝酸盐50 μmol·L–1。实验结果表明,硝酸盐加富比酸化更加显著地促进浮游植物群落总叶绿素(Chl a)生物量及颗粒有机碳(POC)和颗粒有机氮(PON)积累,酸化和加N使浮游植物群落粒径大小升高。连续培养实验表明,酸化和N加富对Chl a、生物硅(BSi)、PON浓度、PON与颗粒有机磷(POP)比值(N/P)、POC与BSi比值(C/BSi)及沉降速率有协同交互作用,对POP和POC浓度及POC与PON比值(C/N)有拮抗性交互作用。在一次性培养后,酸化显著降低了浮游植物群落的沉降速率;而在连续培养后,酸化和N加富使浮游植物群落沉降速率显著升高。这些结果表明酸化和N加富对与近岸浮游植物相关的生物地球化学循环及在不同生长阶段的种群碳沉降存在不同的潜在影响及交互效应。  相似文献   

11.
We measured abundance and biomass of 3 major groups of microzooplankton, i.e. tintinnids, naked ciliates and copepod nauplii, at 21 stations in the Inland Sea of Japan in October 1993, January, April and June 1994. The average abundance of the microzooplankton over the entire Inland Sea of Japan ranged from 2.39×105 indiv. m–3 in January to 4.00×105 indiv. m–3 in April. Ciliated protozoans, i.e. tintinnids plus naked ciliates, numerically dominated the microzooplankton. The average biomass of the microzooplankton was exceedingly high in October (8.62 mg C m–3) compared to that in the other months (2.06, 2.79 and 2.68 mg C m–3 in January, April and June, respectively). The ciliated protozoans also dominated in terms of biomass except in October, when copepod nauplii were more important. Estimated production rate of the microzooplankton was highest in October (average: 6.02 mg C m–3d–1) and followed in order by June, April and January (1.94, 1.14 and 0.54 mg C m–3d–1, respectively). Due to higher specific growth rate, the production rate by the ciliated protozoans far exceeded that by the copepod nauplii. The trophic importance of the microzooplankton in the pelagic ecosystem of the Inland Sea of Japan was assessed by estimating carbon flow through the microzooplankton community.  相似文献   

12.
The effect of pressure on upper ocean free-living bacteria and bacteria attached to rapidly sinking particles was investigated through studying their ability to synthesize DNA and protein by measuring their rate of 3H-thymidine and 3H-leucine incorporation. Studies were carried out on samples from the NE Atlantic under the range of pressures (1–430 atm) encountered by sinking aggregates during their journey to the deep-sea bed. Thymidine and leucine incorporation rates per bacterium attached to sinking particles from 200 m were about six and ten times higher, respectively, than the free-living bacterial assemblage. The ratio of leucine incorporation rate per cell to thymidine incorporation rate per cell was significantly different between the larger attached (18.9:1) and smaller free-living (10.4:1) assemblages. The rates of leucine and thymidine incorporation decreased exponentially with increasing pressure for the free-living and linearly for attached bacteria, while there was no significant influence of pressure on cell numbers. At 100 atm leucine and thymidine incorporation rate per free-living bacterium was reduced to 73 and 20%, respectively, relative to that measured at 1 atm. Pressure of 100 atm reduced leucine and thymidine incorporation per attached bacterium to 94 and 70%, and at 200 atm these rates were reduced to 34 and 51%, respectively, relative to those measured at 1 atm. There was no significant uncoupling of thymidine and leucine incorporation for either the free-living or attached bacterial assemblages with increasing pressure, indicating that the processess of DNA and protein synthesis may be equally affected by increasing pressure. It is therefore unlikely that bacteria, originating from surface waters, attached to rapidly sinking particles play a role in particle remineralization below approximately 1000–2000 m. These results may help to explain the occurrence of relatively fresh aggregates on the deep-sea bed that still contain sufficient organic carbon to fuel the rapid growth of benthic micro-organisms; they also indicate that the effect of pressure on microbial processes may be important in oceanic biogeochemical cycles.  相似文献   

13.
Laboratory experiments were conducted to determine the feeding performances of Uca zoeae and the estuarine copepods Acartia tonsa and Tortanus setacaudatus when these zooplankton preyed upon the co-occurring tintinnids Favella panamensis (length 265 μm) and Tintinnopsis tubulosa (length 148 μm). Predation by Favella on Tintinnopsis was also studied. Over the range of experimental prey densities used, Acartia ingested Tintinopsis at rates linearly related to prey density. Favella was ingested by Aractia at higher rates than was Tintinnopsis. Tortamus ingested Favella more readily than did Acartia, but Tortanus did not ingest Tintinnopsis. Uca ingested both Tintinnopsis and Favella while Tintinnopsis was also ingested by the larger tintinnid Favella. Comparisons of Acartia predation on tintinnids with published data on ingestion of nauplii and phytoplankton showed that when the phytoplankton are dominated by small (diameters < 10 μm) species, tintinnids in concentrations exceeding 103 organisms 1?1 can be important items in the diets of Acartia. At lower tintinnid concentrations or when algal species with diameters > 10 μm are present in significant concentrations, tintinnids merely supplement algae in the diet of Acartia. Generally, tintinnids are more important food items for Acartia than are comparably sized nauplii. Only at concentrations exceeding 104 cop. m?3 can Acartia depress tintinid population growth.  相似文献   

14.
浮游纤毛虫是真核微型生物的重要类群,在浮游生态系统中发挥着重要作用。利用传统形态学与高通量测序技术相结合的方法,于2020年9月至2021年8月对莱州湾三山岛近岸浮游纤毛虫进行每月两次的调查。对环境DNA的18S rRNA基因的V4区进行高通量测序,结果显示无壳寡毛类(占纤毛虫序列丰度的40.14%)和砂壳纤毛虫(10.67%)是优势类群,并且具有明显的季节变化。无壳寡毛类在冬季序列相对丰度最高,主要由急游虫属(Strombidium)和急游虫科未定类群(Strombidiidae_X)组成;砂壳类在春夏季序列相对丰度最高,主要由砂壳目未定类群(Tintinnida_XX)和拟铃虫属(Tintinnopsis)组成。浮游纤毛虫群落的β多样性呈现显著的季节变化,而α和β多样性在站点间差异均不显著。与环境因子的RDA分析显示,总有机碳和溶解氧含量是影响纤毛虫群落结构的主要环境驱动因子。形态学方法共检获鉴定17种纤毛虫,分别隶属于7个属,其中砂壳类在多样性和检获频率上均为最优势类群。研究填补了莱州湾三山岛海域浮游纤毛虫的多样性、群落结构和季节动态研究的空白,同时为深入研究温带海湾近岸浮游纤毛虫群落的长期变化规律以及对环境因子的响应机制提供本底资料。  相似文献   

15.
As one of the important microzooplankton in marine pelagic habitats, tintinnids are classified as neritic genera,oceanic genera and cosmopolitan genera. Until now, we know little about the interaction between neritic and oceanic genera in continental shelves. Low species richness area was found in the mixing area between neritic and oceanic genera in the East China Sea. In this study, we investigated the spatial distribution of tintinnid community throughout the entire Bohai Sea in May(spring) of 2014 to find out:(1) whether the tintinnid assembalges differed in the three major bays bordering this shallow inland sea;(2) whether there was low species richness area in the Bohai Sea. Three genera and 11 species attributed to neritic and cosmopolitan taxa were reported from this region. Tintinnid abundance averaged(81±216) ind./L(0–1 234 ind./L). Tintinnid community differed within the three major bays, with each characterized by different tintinnid taxa. Referring to the average abundance of three bays, tintinnids were most abundant in the Laizhou Bay((328±445) ind./L), and least abundant in the Liaodong Bay((34±57) ind./L). A low species richness area occurred in the central Bohai Sea(20–40 m isobaths), in some stations of which no tintinnid was recorded. Our study demonstrates that tintinnid community varied greatly over small spatial scales, and low species richness area was found in the mixing area between neritic and oceanic genera within this inland sea.  相似文献   

16.
~(210) Po and ~(210) Pb are increasingly used to constrain particle dynamics in the open oceans, however they are less used in coastal waters. Here, distributions and partitions of ~(210) Po and ~(210) Pb were examined in the Taiwan Strait, as well as their application to quantify particle sinking. Activity concentrations of dissolved ~(210) Po and ~(210) Pb(0.6 μm)ranged from 1.21 to 7.63 dpm/(100 L) and from 1.07 to 6.33 dpm/(100 L), respectively. Activity concentrations of particulate ~(210) Po and ~(210) Pb varied from 1.96 to 36.74 dpm/(100 L) and from 3.11 to 38.06 dpm/(100 L). Overall,particulate ~(210) Po and ~(210) Pb accounted for the majority of the bulk ~(210) Po and ~(210) Pb. 210 Po either in dissolved or particulate phases showed similar spatial patterns to 210 Pb, indicating similar mechanisms for controlling the distributions of ~(210) Po and ~(210) Pb in the Taiwan Strait. The different fractionation coefficients indicated that particles in the Zhemin Coastal Current(ZCC) inclined to absorb 210 Po prior to 210 Pb while they showed an opposite effect in the Taiwan Warm Current(TWC). Based on the disequilibria between ~(210) Po and ~(210) Pb, the sinking fluxes of total particulate matter(TPM) were estimated to range from –0.22 to 3.84 g/(m2·d), showing an overall comparable spatial distribution to previous reported sediment accumulation rates. However, our sinking fluxes were lower than the sedimentation rates, indicating a sediment resuspension in winter and horizontal transport of particulate matter from the Taiwan Strait to the East China Sea.  相似文献   

17.
Maps of the principal structures and geological-geophysical knowledge for the Azores-Gibraltar and Icelandic regions have been made. The geodynamic conditions of the Azores archipelago formation have been analyzed. It has been noted that the uplifting of the Azores plume (as well as the Icelandic one) might have been triggered by near-surface tectonic processes. The computer modeling has been performed with respect to the coefficients of the geodynamic sinking rates for the Azores fragment of the Mid-Atlantic Ridge. Based on the modeling results, this rate was ∼1.5 times higher than the average sinking rate for the mid-ocean ridges of the World Ocean in general. The high sinking rate of the Azores fragment is caused by the influence of the plume material on the sinking process. Based on the complex analysis of the seismicity, thermal flow, and seismic tomography data distribution, as well as the implemented numerical calculations, the European (northern) part of the diffuse boundary between the Eurasian and African plates has been identified for the first time. Along with the African (southern) boundary, it outlines the identified by the authors West Mediterranean plate.  相似文献   

18.
The effects of irradiance on the excystment of tintinids from marine sediments were examined by incubating sediment samples in filtered seawater under various light levels. The total incidence of tintinnid excystment over five days was significantly less at low irradiance at and less than 2.5 E m–2sec–1 comparing to that at higher irradiance, at and more than 6.9 E m–2sec–1 (p<0.01), indicating that excystment of tintinnids is inhibited under low irradiance conditions. These results imply that water depth, disturbance of surface sediments and vertical mixing of water influence the excystment of tintinnids in coastal areas because these factors determine the light levels to which the tintinnid cysts are exposed.  相似文献   

19.
2009年1月在南海北部海域的5个站位,采用稀释法和显微分析技术研究了浮游植物生长率及微型浮游动物对浮游植物的摄食压力,同时测定了微型浮游动物的丰度及类群组成.结果表明:南海北部微型浮游动物类群主要以无壳纤毛虫为主,南海北部微型浮游动物类群细胞丰度为33～529个/dm3.南海北部浮游植物生长率为0.45～1.83 d-1,微型浮游动物摄食率为0.44～1.76 d-1,摄食压力占浮游植物现存量的42.6%～82.8%,占初级生产力的97.3%～225.1%.近岸区摄食压力比陆架区高,表明冬季南海近岸区微型浮游动物摄食能够有效的控制浮游植物的生长,而陆架区浮游植物生长率大于摄食率,浮游植物存在着现存量的积累,微型浮游动物并不能完全控制浮游植物的生长.  相似文献   

20.
Quantitative research on composition, biomass and production rates of zooplankton community is crucial to understand the trophic structure in coral reef pelagic ecosystems. In the present study, micro‐ (35–100 μm) and net‐ (>100 μm) metazooplankton were investigated in a fringing coral reef at Tioman Island of Malaysia. Sampling was done during the day and night in August and October 2004, and February and June 2005. The mean biomass of total metazooplankton (i.e. micro + net) was 3.42 ± 0.64 mg C·m?3, ranging from 2.32 ± 0.75 mg C·m?3 in October to 3.26 ± 1.77 mg C·m?3 in August. The net‐zooplankton biomass exhibited a nocturnal increase from daytime at 131–264% due to the addition of both pelagic and reef‐associated zooplankton into the water column. The estimated daily production rates of the total metazooplankton community were on average 1.80 ± 0.57 mg C·m?3·day?1, but this increased to 2.51 ± 1.06 mg C·m?3·day?1 if house production of larvaceans was taken into account. Of the total production rate, the secondary and tertiary production rates were 2.20 ± 1.03 and 0.30 ± 0.06 mg C·m?3·day?1, respectively. We estimated the food requirements of zooplankton in order to examine the trophic structure of the pelagic ecosystem. The secondary production may not be satisfied by phytoplankton alone in the study area and the shortfall may be supplied by other organic sources such as detritus.  相似文献   

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