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1.
Marta Illyová 《Biologia》2006,61(5):531-539
The species composition, seasonal dynamic of biomass and density of zooplankton were studied in two arms with a different
hydrological regime. The samples were collected in two hydrologically different years — extremely wet in 2002 and extremely
dry in 2003. In the first arm the mean annual chlorophyll-a concentration was 31.6 μg L−1 (2002) and relatively high 64.7 μg L−1 during 2003. Mean seasonal zooplankton wet biomass was low and varied: 11.6 g m−3 (2002) and 2.93 g m−3 (2003). Total zooplankton density was high (7,370 N L−1) in 2002, when rotifers predominated in an open water zone and contributed up to 81% of the total zooplankton biomass and
83% of the total zooplankton density. In medial and littoral zone, in total, 22 cladoceran and 15 copepod species were identified.
In the second arm the mean annual concentration of chlorophyll-a was high: 74.8 μg L−1 (2002) and 61.4 μg L−1 (2003). Mean seasonal zooplankton wet biomass varied from 92.5 g m−3 (2002) and 44.10 g m−3 (2003). In 2002 the planktonic crustaceans predominated; their mean biomass was 87.1 g m−3 and B. longirostris formed more than 91% of this value. In 2003, the zooplankton density was high (15,687 N L−1), when rotifers contributed up to 94% of this value. The boom of rotifers (58,740 N L−1) was recorded in June 2003. In total, 45 cladoceran and 14 copepod species were recorded in the medial and littoral zones.
During observation we concluded that the structure of zooplankton, particularly species composition, abundance, biomass and
seasonal dynamics are affected by the fluctuation of water levels in the arms of the rivers’ inundation areas. This unstable
hydrological regime prevented the development of planktonic crustaceans. 相似文献
2.
Mesozooplankton assemblages in the shallow Arctic Laptev Sea in summer 1993 and autumn 1995 总被引:2,自引:0,他引:2
Mesozooplankton distribution and composition in the very shallow part of the Siberian Laptev Sea shelf were studied during
the German-Russian expeditions “Transdrift I” (August/September 1993) and “Transdrift III” (October 1995). Maximum abundances
were found close to the outflow of the Lena River (7,965 ind. m−3) and in the Yana river mouth (38,163 ind. m−3). Lowest abundances occurred in the northeast and west of the Laptev Sea (64–95 ind. m−3). Highest biomass values (104–146 mg DM m−3) were determined in the northern and northeastern part of the shallow Laptev Sea, as well as close to the river outflows,
with a record biomass maximum in the Yana river mouth (270 mg DM m−3). Biomass minima were situated north of the Lena Delta and in the western part of the shallow Laptev Sea (0.3–1.0 mg DM m−3). Copepods dominated in terms of abundance and biomass. Cluster analyses separated four mesozooplankton assemblages: the
assemblage “Lena/Yana” in the southern part, “Eastern-central” in the centre, “Kotelnyy” in the eastern part and “Taimyr”
in the western part of the shallow Laptev Sea. The small-sized neritic and brackish-water copepods Drepanopus bungei, Limnocalanus grimaldii and Pseudocalanus major occurred in enormous numbers and made up the bulk of zooplankton abundance and biomass in the very shallow part of the Laptev
Sea close to the rivers Lena and Yana. In the more northern and northeastern areas, Calanus glacialis, P. minutus and P. major were dominant copepod species, whereas Oithona similis and Acartia sp. became important in the western Laptev Sea. Appendicularians, as well as hydromedusae and the chaetognath Sagitta sp., contributed significantly to abundance and biomass, respectively, but not over the entire area studied. One can identify
taxon-specific distribution patterns (e.g. Sagitta predominated the biomass in a zone between the area heavily influenced by Lena/Yana and the offshore area to the north),
which differ from the patterns revealed by cluster analysis. Hydrographic features, especially the enormous freshwater inflow,
apparently determine the occurrence and formation of zooplankton aggregations. Extremely high numbers of small-sized neritic
and brackish-water copepods occurred locally, which were probably also supported by excellent feeding conditions. 相似文献
3.
A recent drastic decrease in sea ice cover area was observed in the western Arctic Ocean during summer, yet little information
is available for its effect on zooplankton community. To evaluate the effect of sea ice reduction on zooplankton, we studied
year-to-year changes of zooplankton community structure in the Chukchi Sea during summers of 1991, 1992 (when sea ice extended),
2007, and 2008 (when sea ice reduced). Zooplankton abundance ranged from 4,000 to 316,000 ind. m−2 (mean: 70,000) and was greater north of Lisburne Peninsula in 2008. Zooplankton biomass ranged from 0.07 to 286 g wet mass
m−2 (mean: 36) and was greater south of Lisburne Peninsula in 2007. Cluster analysis based on zooplankton abundance showed a
division of the zooplankton community into four groups. Occurrence of each group was separated geographically and interannually,
and geographic distributions of each group in 1991 and 1992 were similar but those in 2007 and 2008 were shifted northward.
Abundance and biomass in 2007/2008 were higher than in 1991/1992, indicating that further sea ice reduction would have a positive
effect on zooplankton production (e.g. invasion of large Pacific species and temperature effects on their growth rate). The
northern shift in geographic distribution of the zooplankton community in 2007/2008 indicates that sea ice reduction would
have a negative effect on the zooplankton community (loss of characteristic Arctic species) in part of the Chukchi Sea. These
apparently contradictory effects of sea ice reduction on zooplankton community emphasize the critical need for continued monitoring
in this area. 相似文献
4.
Claudia Costa Bonecker Mariza Yuri Nagae Martin Cesar Maria Bletller Luiz Felipe Machado Velho Fábio Amodêo Lansac-Tôha 《Hydrobiologia》2007,579(1):115-123
In order to test the hypothesis that zooplankton biomass distribution (total and taxonomic groups) was influenced by the nutrient
concentration and primary productivity distribution in three tropical reservoirs, subsurface samples were taken in the fluvial,
transitional and lacustrine regions of three reservoirs (oligotrophic, mesotrophic and eutrophic) in southern Brazil (Paraná
State) in March and September 2002. Zooplankton biomass ranged from 0.04 to 264.47 mg DW m−3. Higher biomass values were observed for cladocerans (73.60%; 0.01–259.86 mg DW m−3), followed by copepods (22.05%; 0.01–69.69 mg DW m−3) and rotifers (4.35%; 0.01–11.52 mg DW m−3). In general, the total zooplankton, rotifer, cladoceran and copepod biomass, and chlorophyll-a and total nutrient concentrations showed a similar longitudinal distribution within the reservoirs. Total zooplankton, rotifer
and cladoceran biomass were related to the chlorophyll-a concentration, and zooplankton biomass was related to the total phosphorus distribution. This may have been due to the significant
multicolinearity between the chlorophyll-a and total phosphorus concentrations. Cyanobacteria influenced the taxonomic group biomass results by interfering with the
filter feeding in larger zooplankton species, which favoured the dominance of smaller species. As regards the longitudinal
distribution of copepod biomass, cyanobacteria biomass determined the displacement of the microcrustaceans to the fluvial
region of Iraí Reservoir. Our results supported the hypothesis formulated and the primary productivity was the major predictor
of the zooplankton biomass distribution in the reservoirs.
Handling editor: S. Dodson 相似文献
5.
Copepods are considered to be the main component of the Arctic marine zooplankton. We examined the copepod distribution and
diversity off Franz Josef Land (northern Barents Sea) in August 2006 and 2007. A total of 18 and 14 copepod taxa were identified
from the sampling layers (100–0 m or bottom–0 m) in 2006 and in 2007, respectively. There were no significant differences
in the total copepod abundance between the years (means ± SE: 118,503 ± 24,115 individuals m−2 in 2006 vs. 113,932 ± 28,564 individuals m−2 in 2007). However, the copepod biomass in 2006 (4,518 ± 1,091 mg C m−2) exceeded clearly the value in 2007 (1,253 ± 217 mg C m−2). The copepod community showed low species richness and diversity in both years (Simpson index D: 0.34 and 0.38, respectively).
Biomass of the large and small copepod species strongly decreased from 2006 to 2007. The total abundance of copepods was negatively
correlated with water temperature in 2006 and positively correlated with salinity in 2007. The patchiness in copepod distribution
was associated with local hydrography and temperature conditions. 相似文献
6.
The seasonal variations in biomass, abundance and species composition of zooplankton in relation to hydrography and chlorophyll
a were studied in the subarctic waters north of Iceland. The sampling was carried out at approximately monthly intervals from
February 1993 to February 1994 at eight stations arranged along a transect extending from 66°16′N–18°50′W to 68°00′N–18°50′W.
The mean temperature at 50 m depth showed a clear seasonal pattern, with lowest water temperatures in February (∼1.1°C) and
the highest in July (∼5.4°C). The spring growth of the phytoplankton began in late March and culminated during mid-April (∼7.0 mg
Chl a m−3). Both the biomass and the abundance of total zooplankton were low during the winter and peaked once during the summer in
late May (∼4 g m−2 and ∼38,000 individuals m−2). A total of 42 species and taxonomic groups were identified in the samples. Eight taxa contributed ∼90% of the total zooplankton
number. Of these Calanus finmarchicus was by far the most abundant species (∼60% of the total zooplankton). Less important groups were ophiuroid larvae (∼9%),
Pseudocalanus spp. (∼8%), Metridia longa (∼4%), C. hyperboreus (∼3%), Acartia longiremis (∼2%), chaetognaths (∼2%) and euphausiid larvae (∼2%). The dominant copepods showed two main patterns in seasonal abundance:
C. finmarchicus, C. hyperboreus and C. glacialis had one annual peak in numbers in late May, while Pseudocalanus spp., M. longa and A. longiremis showed two maxima during the summer (July) and autumn (October/November). Ophiuroid larvae and chaetognaths (mainly Sagitta elegans) peaked during the middle of July, while the number of euphausiid eggs and larvae was greatest from May to July. The succession
in population structure of C. finmarchicus indicated its main spawning to be in April and May, coincident with the phytoplankton spring bloom. A minor spawning was
also observed sometime between August and October. However, the offspring from this second spawning contributed only insignificantly
to the overwintering stock of C. finmarchicus.
Received: 12 September 1997 / Accepted: 1 March 1998 相似文献
7.
The influence of river flow on the fish community was assessed for the Tagus estuary (Portugal), based on sampling surveys
carried out between 1979 and 2002. Four estuarine areas were sampled using similar fishing gear and effort in all the years
considered in this study (1978–1980; 1995–1997; and 2001–2002). According to river freshwater flow values, sampling years
were classified as wet (mean value of 714 m3 s−1, sd = 110 m3 s−1) or dry (mean value of 164 m3 s−1, sd = 19m3 s−1). Species richness varied between 22 and 39 according to the year, but no significant differences were related to river flow.
The number of species per ecological guild was also similar in wet and dry years. Fish assemblage was dominated by marine
occasional, estuarine resident and marine-estuarine opportunist species that represented near 90% of all fish species. The
highest densities were represented by estuarine resident species. Fish density in dry and wet years differed significantly
(mean density of 10.51 individuals 1,000 m−2 and 3.62 individuals 1,000 m−2, respectively), and the major differences were registered for estuarine resident, marine-estuarine opportunist and catadromous
species. These differences probably reflected the estuarine habitat availability and also differences in fish densities in
some estuarine areas under different flow conditions. The multivariate ordination analyses performed outlined both seasonal
and spatial variation trends in fish distribution and abundance. The estuarine longitudinal gradient and its relationship
with species distribution were less evident in dry years. Relationships between species abundance and river flow were different
according to species, which is probably due to different needs in the timing and magnitude of river flow.
Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users. 相似文献
8.
Some biological characteristics of early larvae Dacodraco hunteri (Notothenioidei: Channichthyidae) in the western Ross Sea 总被引:1,自引:0,他引:1
Ichtyoplankton surveys were carried out in the western Ross Sea by the R/V Italica in the austral summer 1996 and 1997–1998
to study species composition and spatial distribution of larval stages of fish. One of the most abundant icefish caught was
Dacodraco hunteri, a poorly known channichthyid inhabiting the high-Antarctic Zone. Based on 382 yolk-sac larvae and 13 preflexion larvae,
the study was focused to estimate spatial distribution and abundance, as well as diet and growth rate. The pigmentation pattern
and some morphometric measurements were also recorded for comparative purposes. The specimens were caught in relatively restricted
areas located in Terra Nova Bay and north of the Ross Ice Shelf on the Challenger and Joides Basins. The standardized abundance
of early larvae ranged between 0.03 and 1.72 individuals 10−3 m3 in 1996 and 0.16–4.53 individuals 10−3 m3 in 1997–1998, respectively. Fitting a linear model to the mean length increase in larvae collected in subsequent catch dates,
the growth rate was estimated to be approximately 0.11 mm/day. Based on back calculation of growth rate and presumed hatch
size of 11 mm, larval hatching probably took place in mid-December. Diet of preflexion larvae consisted exclusively of larvae
of the pelagic nototheniid Pleuragramma antarcticum, a key species of the high-Antarctic pelagic food web. Hence, D. hunteri probably plays a more important role than previously thought in the pelagic community of the Ross Sea. 相似文献
9.
Poor quantity of zooplankton was recorded in a Danube arm situated on the right side of the Danube River in Slovakia (river
km 1857) in 2002 and 2003. All over the year the arm is significantly influenced by groundwater by reason of seepage. Because
of low mean water temperature (12°C) and poorly developed macrovegetation in particular, the arm reminds gravel pit-like.
The annual average of zooplankton biomass was low and ranged from 0.35 g m−3 (2002) to 1.28 g m−3 (2003), because of low crustacean abundance. Total cladoceran abundance was excessively low in both years and ranged from
3.5 N L−1 (2002) to 16.6 N L−1 (2003). Small species, Bosmina longirostris and Chydorus sphaericus were dominant. Only four adult Copepoda — Cyclops vicinus, Thermocyclops crassus, Eurytemora velox and Eudiaptomus gracilis — were recorded in quantitative samples of both years. In the zooplankton assemblage dominated rotifers (Synchaeta pectinata, Synchaeta oblonga, Polyarthra dolichoptera and Keratella cochlearis) which represented 78% and 67% of total abundance respectively. The total of 19 species of rotifers, 34 Cladocera species
and 16 taxa of Copepoda were found. 相似文献
10.
Mesozooplankton community in the Bay of Bengal (India): spatial variability during the summer monsoon 总被引:2,自引:0,他引:2
This study addresses the spatial variability in mesozooplankton biomass and composition in the Central and Western Bay of
Bengal (India) during the summer monsoon season of 2001. Perennially warmer sea surface temperatures (>28°C), stratified top
layer (sea surface salinity, 28–33 psu), high turbidity, and low nutrient concentrations due to weak/null upwelling and light
limitation make the Bay of Bengal a region of low primary productivity. Despite this, mesozooplankton biomass values, i.e.
2.9–104 mg C m−3 in the Central Bay and 1.3–31 mg C m−3 in the Western Bay, observed in the mixed layer (2–51 m) during the summer monsoon were in the same range as reported from
the more productive Arabian Sea. Mesozooplankton biomass was five times and density 18 times greater at stations with signatures
of cold-core eddies, causing a higher spatial heterogeneity in zooplankton distribution. Among the 27 taxonomic groups recorded
during the season, Copepoda was the most abundant group in all samples followed by Chaetognatha. The dominant order of Copepoda,
Calanoida, was represented by 132 species in a total of 163 species recorded. Oncaea venusta was the key copepod species in the Bay. In the Central Bay, the predominant copepod species were carnivorous/omnivorous vis-a-vis
mostly herbivores in the Western Bay. Pleuromamma indica increased to its maximum abundance at 18°N in the Central Bay, coinciding with the lowest dissolved oxygen concentrations.
The Central Bay had higher mesozooplankton biomass, copepod species richness and diversity than in the Western Bay. Although
zooplankton biomass and densities were greater at the eddy stations, correlation between zooplankton and chl a was not statistically significant. It appears that the grazer mesozooplankton rapidly utilize the enhanced phytoplankton
production in cold-core eddies. 相似文献
11.
The abundance, composition and dynamics of zooplankton were followed in two reservoirs of the River Douro catchment. The Serra
Serrada Reservoir is subject to marked fluctuations in water levels. The highest values of total phosphorus, soluble reactive
phosphorus, nitrate, water colour and chlorophyll a were found during the minimum level phase. Rotifera was dominant except in late summer and autumn when the cladoceran Ceriodaphnia quadrangula or the copepod Tropocyclops prasinus replaced them as the dominant zooplankton. Among the rotifers the most common taxa were Keratella cochlearis, Conochilus sp. and Asplanchna priodonta. Maximum rotifer density was about 80,000 ind m−3 in 2000, 200,000 ind m−3 in 2001 and 100,000 ind m−3 in 2002. Among the crustacean zooplankton C. quadrangula achieved densities of up to 45,000 ind m−3 and T. prasinus, up to 80,000 ind m−3. Canonical correspondence analysis revealed a strong contribution of the variation in the stored water volume, temperature,
total phosphorus, chlorophyll, nitrates, and water transparency to the observed, significant association between zooplankton
assemblage and environmental variables. In the Azibo Reservoir, fluctuations in water level are smaller. Only total phosphorus,
cholorophyll and conductivity varied seasonally. Cladocera and Copepoda were dominant during the whole study period. The most
abundant taxa were Ceriodaphnia pulchella, Daphnia longispina, Diaphanosoma brachyurum, Bosmina longirostris and Copidodiaptomus numidicus. Cladocera achieved densities of up to 25,000 ind m−3 and Copepoda up to 15,000 ind m−3. Rotifera in general reached densities of up to 6,000 ind m−3. On the basis of canonical correspondence analysis only temperature and conductivity were significantly associated with zooplankton
assemblage. 相似文献
12.
Net sampling and continuous acoustic measurements within the Antarctic Polar Frontal Zone (APFZ) and in the vicinity of the
Prince Edward Islands were conducted during austral autumn (April/May) 1997 to describe the composition and distribution of
macrozooplankton and micronekton, and to investigate their relations to the prevailing oceanographic regime in the area. Two
major circulation patterns associated with the Subantarctic (SAF) and Antarctic Polar (APF) Fronts existed in the oceanic
environment surrounding the Prince Edward Islands, promoting high cross-frontal mixing both upstream and downstream of the
islands. Average abundance and biomass of macroplankton/micronekton in the top 300-m layer were 21 ind. 1000 m−3 and 467 mg DW 1000 m−3, respectively. Pelagic crustaceans (euphausiids and amphipods), fish, chaetognaths and gelatinous zooplankton dominated numerically
and by biomass. Continuous acoustic measurements displayed elevated pelagic biomass at the SAF and APF. Although four groupings
of stations were identified using cluster analysis, a single macroplankton/micronekton community was recognized in the top
300-m layer throughout the offshore area of the APFZ. A modification of the APFZ community was observed within the inter-island
region. Subantarctic species dominated zooplankton samples throughout the APFZ, although subtropical species were also well
represented at stations occupied in the northern region of the APFZ. A biological response reflected in macroplankton community
composition, resulting from an extensive cross-frontal mixing, was observed within the APFZ around the Prince Edward Islands.
Accepted: 27 November 1999 相似文献
13.
The zooplankton of a Rift Valley lake in Ethiopia, Awasa, was sampled at 3 stations for 2 years (1986 and 1987) concurrently
with various meteorological and limnological measurements. The spatial and temporal variation in abundance of some numerically
dominant crustaceans, Mesocyclops aequatorialis similis (Copepoda), Thermocyclops consimilis (Copepoda) and Diaphanosoma excisum (Cladocera) is discussed. Temporal (months, sampling dates) rather than spatial (station) variability accounts for more than
50% of the total variance in zooplankton abundance but horizontal patchiness exists during periods of high zooplankton density.
Sampling errors were generally low, except for counts of cyclopoid nauplii (subsampling) and Diaphanosoma (inter-replicate variance).
Zooplankton showed distinct seasonality associated with the mixing cycle of the lake. Total numbers increased to more than
200 000 m−3 during the unstratified period (July to September). Low numbers were evident during stratification (February to May) when
zooplankton numbers did not exceed 15 000 m−3. Individual zooplankton species and age classes showed variable seasonal amplitudes, ranging from 6.4 (nauplius 3) to 44.8
(copepodite 3 of Mesocyclops). We discuss some possible causes for zooplankton seasonality in Lake Awasa, and also review zooplankton seasonal cycles
in other tropical lakes, especially African ones. 相似文献
14.
A macrozoobenthic community study was conducted in an East Greenlandic fjord (Young Sound, 74°18′N; 20°15′W) during the ice-free
period from July to August in 1996. Grab samples as well as underwater photography were used for quantifying the macrozoobenthos
at water depths between 20 and 85 m. Abundance decreased with depth from 2700 ind. · m−2 at 20 m to 900 ind. · m−2 at 85 m. At a time series station at 35 m, abundance increased from 700 ind. · m−2 in mid-July to 1400 ind. · m−2 in mid-August. Polychaetes dominated in grab samples but bivalves constituted an important part of the benthic fauna, especially
at the shallow part of the depth gradient. Photographs revealed high abundances of large epifaunal species, especially brittle
stars. Diversity was generally high, with around 45 species per 201 individuals, as calculated by Hurlbert's rarefaction term.
A gradual change in community structure with depth was observed, which could be related to variation in sediment composition
and disturbance intensity.
Accepted: 20 May 2000 相似文献
15.
Martin Emil Blicher Lars Maltha Rasmussen Mikael Kristian Sejr Flemming Ravn Merkel S?ren Rysgaard 《Polar Biology》2011,34(8):1105-1116
The number of common eiders (Somateria
mollissima borealis) in west Greenland declined dramatically during the twentieth century, supposedly because of human activities. However, their
sensitivity to alternative drivers of variation, such as climate conditions, diseases or food availability, remains unstudied.
In this study, we describe prey availability and assess the trophic coupling between eiders and their macrobenthic prey in
a shallow inlet, Nipisat Sound; a key wintering habitat in the south-west Greenland Open Water Area. Macrobenthic species
abundance and biomass were studied, and annual production was estimated by an empirical model, including environmental characteristics,
fauna composition and individual biomass. In spring 2008, average macrozoobenthic abundance and biomass were 6,912 ind m−2 and 28.4 g ash-free dry mass (AFDM) m−2 (647 kJ m−2), respectively. Annual production was estimated at 13.9 g AFDM m−2 year−1 (317 kJ m−2 year−1). During the winters of 2008–2010, we monitored the number of common eiders (S. mollissima borealis) and king eiders (Somateria spectabilis) and observed a distinct peak in abundance during winter with up to 15.000 birds in Nipisat Sound. Based on physiological
costs of different activities in combination with the observed behavioural pattern, we obtained an estimate of the energy
required for eiders to balance their costs of living, which amounted to 58% of the estimated total annual production of macrobenthos
in Nipisat Sound. This result suggests that eider predation affects macrobenthic species composition and biomass and demonstrates
the potential importance of variations in prey availability for the population dynamics of eiders in Greenland. 相似文献
16.
北部湾近岸海域浮游动物群落结构特征及季节变化 总被引:2,自引:0,他引:2
2017年3月(枯水期)、7月(丰水期)和10月(平水期)分别对北部湾近岸海域44个站位的浮游动物进行了调查。结果共检出浮游动物251种和浮游幼体24类,其中枯水期138种(类),丰水期134种(类),平水期191种(类),分属河口低盐、近岸暖温、近岸暖水和外海暖水4个生态类群。优势种9种,其中枯水期以原生动物占绝对优势,丰水期以枝角类、桡足类和浮游幼体类占优势,平水期以十足类和浮游幼体类占优势。浮游动物丰度年均值为789.95个/m~3,呈现出枯水期(1540.19个/m~3)明显高于平水期(457.58个/m~3)和丰水期(372.08个/m~3)的季节变化特征;浮游动物生物量年均值为252.40 mg/m~3,生物量的季节变化与丰度变化不一致,平水期生物量(385.01 mg/m~3)明显高于枯水期(221.41 mg/m~3)和丰水期(150.78 mg/m~3)。多样性指数平水期最高(3.16),丰水期(2.35)次之,枯水期(2.22)最低。枯水期和丰水期北部湾近岸海域浮游动物生物量和丰度水平分布特征基本呈现自河口近岸海域向外海递增的趋势,平水期浮游动物生物量与丰度的空间分布较为均匀。浮游动物的种类组成结构以及优势种的演替对浮游动物的生物量和丰度季节变化有着重要的决定作用。径流导致的悬浮物、营养盐等的变化可能是决定北部湾近岸海域浮游动物生物量和丰度空间分布的主要因素。研究还表明与其他海湾相比,北部湾近岸海域浮游动物群落结构趋于小型化,需加大关注。 相似文献
17.
Liu Zhensheng Wang Chunsheng Zhang Zhinan Cai Yuming Zhang Dongsheng 《Frontiers of Biology in China》2006,1(4):434-442
The species composition, biomass, abundance, and species diversity of zooplankton were determined for samples collected from
August 2002 to May 2003 from 14 stations in Yueqing Bay, China. Phytoplankton growth rate and microzooplankton grazing rate
were obtained by using the dilution method developed by Landry and Hassett. The spatial and temporal variations of zooplankton
and its relationship with environmental factors were also analyzed. The results showed that the zooplankton in the Yueqing
Bay could be divided into four ecotypes, namely coastal low saline species, estuary brackish water species, offshore warm
water species, and eurytopic species. A total of 75 species of zooplankton belonging to 56 genera and 17 groups of pelagic
larva were identified in the Yueqing Bay. The coastal low saline species was the dominant ecotype in the study area, and the
dominant species were Labidocera euchaeta, Acartia pacifica, Acrocalanus gibber, Pseudeuphausia sinica, and Sagitta bedoti among others.
There was considerable seasonal variation in zooplankton biomass and abundance in the surveyed areas. The peak biomass appeared
in August, descending in November and in May, and the lowest biomass appeared in February. Similarly, the highest abundance
of zooplankton was observed in August, with the abundance descending in the following months: May, November, and February.
There were similar horizontal distribution patterns for the biomass and the abundance of zooplankton. They both increased
from the upper to the lower bay in February and May, but decreased from the upper to the lower bay in August. Biomass and
abundance were evenly distributed in the Yueqing Bay in November. Moreover, there was marked seasonal variation in the species
diversity of zooplankton, which conformed to the abundance of zooplankton. Results of the dilution experiments indicated that
there was grazing pressure of microzooplankton on phytoplankton in the Yueqing Bay throughout the year though the rate of
microzooplankton grazing on phytoplankton varied seasonally. Phytoplanktons were growing at 0.26–2.07/d and grazed by microzooplankton
at a rate of 0.15–0.48/d in different seasons.
__________
Translated from Acta Ecologica Sinica, 2005, 25(8): 1853–1862 [译自: 生态学报, 2005, 25(8): 1853–1862] 相似文献
18.
Regional variations in mesozooplankton composition, abundance and biomass were studied during a cruise in August 2006 near
Novaya Zemlya Archipelago (eastern Barents Sea) using Juday net hauls from the bottom (or 100 m depth) to the surface. A comparison
with multiannual literature values revealed that the mean temperature and salinity in the south and centre of the study area
were similar to typical values, while temperature in the north was significantly higher. A total of 36 species and higher
taxa were identified. Mesozooplankton abundance and biomass varied from 47 to 851 ind m−3 and from 5 to 74 mg dry weight m−3, respectively. Copepods dominated the mesozooplankton community, reaching 73–98% and 61–97% of the total abundance and biomass.
Calanus finmarchicus and Oithona similis were the most abundant species at all stations. The biodiversities (Shannon indices) of the mesozooplankton community varied
between stations from 1.10 to 2.46 (estimated from species abundances) and from 0.19 to 1.92 (estimated from species biomasses),
averaging 1.93 ± 0.127 and 1.34 ± 0.151, respectively. Three groups at the 48% level of dissimilarity of species abundance
were delineated by cluster analyses. The clusters differed significantly with respect to temperature and salinity. The total
mesozooplankton abundance and biomass as well as quantitative parameters of most common taxa scaled negatively with temperature. 相似文献
19.
The physical structure of two riffles in a lowland Danish stream was studied and its importance for the composition and density
of the macroinvertebrate communities was evaluated. The two riffles were visually assessed to be very similar, but measurements
revealed that they differed in overall hydraulic conditions, stability, substratum composition and consolidation. Differences
affected abundance of both burrowing and surface dwelling macroinvertebrates. The unstable unconsolidated riffle had higher
total macroinvertebrate abundance (4137 m−2 vs. 1698 m−2), diptera abundance (2329 m−2 vs. 386 m−2) and total estimated species richness (31.7 vs. 28.8) as well as lower evenness (0.77 vs. 0.83) than the compact riffle.
Among samples within the unconsolidated riffle, variations in macroinvertebrate communities were related to differences in
mean substratum particle size. Here a linear log–log relationship existed between macroinvertebrate abundance, the abundance
of EPT taxa and the median particle size (r
2
total = 0.46, p = 0.002; r
2
EPT = 0.73, p < 0.001). No similar relationships were evident on the consolidated riffle. Moreover, macroinvertebrate communities on the
unconsolidated riffle were dominated by species with a high colonising potential. Despite being assessed to the same morphological
unit, physical variation between riffles was surprisingly high as the riffles differed substantially with respect to consolidation,
substratum heterogeneity and overall hydraulic structure. Macroinvertebrate community structure and composition also differed
between riffles despite being drawn from the same species pool. The findings address the question if we use the correct methods
and parameters when assessing the macroinvertebrate communities at the scale of the morphological unit. 相似文献
20.
舟山海域夏、秋季浮游动物的分布特征及其与环境因子的关系 总被引:6,自引:0,他引:6
为更好地了解舟山海域浮游动物的群落结构、生物量和丰度的时空分布特征及其与主要环境因子的关系,分别于2014年7月和10月进行了夏季、秋季两次生态综合调查,并用多维尺度分析法、典范对应分析法对浮游动物群落结构进行了研究。结果表明:夏季舟山海域调查的浮游动物有13类,64种,优势种为背针胸刺水蚤(Centropages dorsispinatus)、圆唇角水蚤(Labidocera rotunda)、中华哲水蚤(Calanus sinicus)、精致真刺水蚤(Euchaeta concinna)、百陶带箭虫(Zonosagitta bedoti)和真刺唇角水蚤(Labidocera euchaeta);秋季鉴定到浮游动物12类,45种,优势种为背针胸刺水蚤(Centropages dorsispinatus)、百陶带箭虫(Zonosagitta bedoti)、双生水母(Diphyes chamissonis)、瓜水母(Beroёcucumis)和中华哲水蚤。夏季浮游动物平均丰度及平均生物量(144.0 ind/m3和176.3 mg/m~3)都分别高于秋季(21.4个/m3和86.3 mg/m3);Shannon-Wiener多样性指数夏季(3.03)高于秋季(2.82),Pielou均匀度指数则是秋季(0.83)高于夏季(0.64);夏季不同区域浮游动物群落之间具有明显的差异,而秋季大部分站位群落之间差异不显著;温度、盐度、叶绿素a浓度和营养盐含量是影响舟山海域浮游动物分布的主要环境因子;与历史资料相比,舟山海域浮游动物丰度及生物量呈下降趋势,其优势种保持较稳定。 相似文献