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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.
George Kehayias Ekaterini Chalkia Stavroula Chalkia George Nistikakis Ierotheos Zacharias Anastasios Zotos 《Biologia》2008,63(5):699-710
The investigation of the zooplankton community in the upstream part of Stratos reservoir during a 24 months survey (September
2004–August 2006) revealed 26 invertebrate species (14 rotifers, 6 cladocerans, 5 copepods and one mollusk larva). The mean
abundance of the total zooplankton was higher in the first sampling period (2004–2005) and ranged between 8.81 and 47.74 ind.
L−1, than the second period (2005–2006) when fluctuated between 1.91 and 43.09 ind. L−1. The seasonal variation was strongly influenced by the presence of rotifers, which accounting on average for 68.4% in total.
Among them Keratella cochlearis and the order Bdelloidea were numerically the most important, while Macrocyclops albidus prevailed among the copepods and Bosmina longirostris among the cladocerans. Dreissena polymorpha was the only mollusk found in the zooplankton community. Rotifers, copepods and cladocerans showed a seasonal succession
with the former preceding in the abundance having their first maximum in spring, while copepods and cladocerans followed,
having peaks of abundance in early summer and in autumn, respectively. No seasonal succession among the cladoceran species
was observed. The intense water flow in the upstream part of the reservoir, as well as temperature, conductivity, DO, pH,
phosphates and silicates, were significant parameters controlling abiotic and biotic elements of the ecosystem and consequently
influencing the seasonal variation and the dynamics of the zooplankton community. 相似文献
3.
Phyto/zooplankton composition, chlorophyll a, and some water quality parameters were investigated in a spring-originated pond in Central Anatolia between February 2001
and January 2002. Water temperature, pH, dissolved oxygen, Secchi depth, total and calcium hardness, nitrate-nitrogen, nitrite-nitrogen,
ammonia-nitrogen, total phosphorus, and soluble reactive phosphorus levels were analyzed. A total of 49 species belonging
to Bacillariophyceae, Chlorophyceae, Cyanophyceae, Cryptophyceae, and Dinophyceae were identified. The highest phytoplankton
abundance was found in August, whereas the lowest was determined in January. Phytoplankton abundance increased from February
to August and declined in the following months. The Bacillariophyceae were dominant in the phytoplankton community. A total
of 21 species of Rotifera, 2 species of Cladocera, and 1 genus of Copepoda were found. The zooplankton community was dominated
by Rotifera. The highest abundance of zooplankton was recorded in July and the lowest value in November. The annual mean concentration
of chlorophyll a was measured as 1.90 μg l−1. In spite of these eutrophic levels (mean values of total phosphorus and nitrate-nitrogen: 0.069 mg P l−1 and 0.68 mg N l−1), phytoplankton cannot grow satisfactorily because of the short water retention time (0.6 day−1). The shallowness of the pond together with the low phytoplankton biomass and the high concentrations of nutrients are discussed. 相似文献
4.
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
5.
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
6.
Ekaterini Chalkia Ierotheos Zacharias Anna-Akrivi Thomatou George Kehayias 《Biologia》2012,67(1):151-163
Zooplankton species composition and abundance variation was studied in Lake Amvrakia, which is a deep, temperate, gypsum karst
lake situated in the western Greece. The two year survey of zooplankton revealed 33 species (23 rotifers, five cladocerans,
four copepods and one mollusc larva). The mean integrated abundance of the total zooplankton ranged between 83.6 and 442.7
ind. L−1, with the higher density to be recorded in the surface 0–20 m layer. Small numbers of specimens of almost all species were
found also in the hypoxic or anoxic hypolimnion. Copepods and especially the calanoid Eudiaptomus drieschi dominated the zooplankton community throughout the sampling period, followed by Dreissena polymorpha larvae, rotifers and cladocerans. Seasonal succession among the cladocerans and the most abundant rotifer species was observed.
The concentration of chlorophyll-a was the most important factor for the variation of total zooplankton, as well as for the rotifers’ community. Dissolved oxygen
affected copepods and cladocerans, water level correlated mainly with the molluscs larvae of D. polymorpha, while temperature influenced the variation of several rotifers, the cladoceran Diaphanosoma orghidani and the mollusc larvae. Negative correlation of conductivity with the cladoceran Daphnia cucullata and the copepods E. drieschi and Macrocyclops albidus was found. The differences in species composition found in Lake Amvrakia in comparison to the nearby lakes are probably ought
to the geographical isolation and perhaps to its particular chemistry (e.g., elevated conductivity). 相似文献
7.
We investigated monogonont rotifers in two natural Macedonian lakes that greatly differ in age, size and trophic state: Lake
Ohrid and Lake Dojran. A main characteristic of Lake Ohrid is the scarcity of nutrients and consequently a low level of primary
production. Lake Dojran represents a typical eutrophic lake. Results clearly indicate that species numbers are negatively
correlated with trophic degree. Qualitative analyses of rotifer compositions in Lakes Ohrid and Dojran showed the presence
of 70 and 55 taxa, respectively. Rotifer assemblages differed in their community structure, population densities, and the
occurrence pattern of dominant species. The density of rotifers increased with increasing nutrient concentration, varying
from min. 0.67 ind. L−1 in June, 2006 to max. 8.2 ind. L−1 in July, 2004 in Lake Ohrid, whereas min. 28.8 ind. L−1 (in December, 2005) and max. 442.5 ind. L−1 (in September, 2005) were recorded in Lake Dojran. Gastropus stylifer and Keratella cochlearis were the most abundant species
in the pelagic zone of Lake Ohrid, averaging monthly densities of 1.2 ind. L−1 and 0.6 ind. L−1, respectively, thereby contributing 29% and 15% to rotifer abundance. In contrast, Lake Dojran rotifers were dominated by
Brachionus spp. Brachionus diversicornis and Brachionus calyciflorus f. amphiceros were most abundant, comprising 40% and 25% of the total rotifer density. These results corroborate our idea, that the trophic
state is an important factor in determining the composition of rotifer communities. 相似文献
8.
We investigated the distribution of mesozooplankton in waters north of Svalbard (north of 78°50′N) at 38 stations in August
and September of 2002, 2003 and 2004. The zooplankton community was numerically dominated by copepods (58–98% of the total
abundance). Zooplankton abundance ranged from 115 individuals m−3 at the northern most location to 12,296 individuals m−3 on the shelf. Cluster analysis revealed four different groups with distinct geographic integrity that were identified by
variation in species densities rather than by variation in taxonomic composition. Water temperature and salinity differed
significantly between the different cluster groups indicating that part of the observed variations in species distribution
relate to differences in hydrography. Numerous significant regressions between zooplankton abundance at species level and
hydrographical parameters suggest that variability in water masses has measurable effects on zooplankton distribution and
species composition in the study area. 相似文献
9.
Raphaël N’doua Etilé Aka Marcel Kouassi Maryse N’guessan Aka Marc Pagano Valentin N’douba N’guessan Joël Kouassi 《Hydrobiologia》2009,624(1):171-189
Zooplankton constitutes a sensitive tool for monitoring environmental changes in coastal lagoons; however, the available information
on zooplankton communities is not sufficient to optimize their rational management. The relationships between zooplankton
distribution and environmental factors were studied in a tropical lagoon to test whether the indicator properties of zooplankton
assemblages could be used to monitor water quality, in a context of expected eutrophication provoked by an increasing anthropogenic
activity. Twenty-one (21) stations were sampled monthly from January to December 2004. The community was composed of 65 taxa
including Copepoda, Rotifera, and Cladocera. Copepoda was the most abundant group (81% of total numbers). The main zooplankton
species were Oithona brevicornis, Acartia clausi, and Brachionus plicatilis. The highest zooplankton abundance (171–175 ind. l−1) was recorded during the long, dry season (February–April) and the lowest (40–45 ind. l−1) during the rainy and the flood periods (June–July). At a spatial level, the lowest abundance was observed in the estuarine
zone. During the dry seasons (December–April and August–September), marine zooplankton taxa were abundant near the channel
of Grand-Lahou, and brackish water taxa dominated in the other sites. Multivariate analyses (Co-inertia) showed that the composition
of zooplanktonic communities and their spatio-temporal variations were mainly controlled by salinity variations closely linked
to the climatic and hydrological context. The role of the trophic state on zooplankton communities could not be clearly evidenced.
Our results and a comparison with previous studies in the neighboring, highly polluted Ebrié Lagoon suggest that the ratio
between Oithona and Acartia abundance could be used as biological indicator for the water quality.
Handling editor: S. I. Dodson 相似文献
10.
A survey of oligotrophic Lake Rara, the biggest lake in Nepal, was carried out from 1982 till 1984. Mean depth is 100 m, and
maximum depth is 167 m. The surface area covers 9.8 km2, and the lake contains 0.98 km3 volume of water.
Transparency was about 16 m, photoquantum yield decreased exponentially with depth below 5 m, and the extinction coefficient
was 8.3 × 10−2. The concentration of Chl.-a was in the range of 0.06–0.46 mg m−3, and total nitrogen was 18–30 μg 1−1. The whole water column was well oxygenated. Primary productivity was extremely low. It has more than 30 inflowing brooks
and one outlet. The water quality of the brooks changes drastically with their location. The pH, electrical conductivity,
and EDTA hardness in the waters from a landslide area were high. In the waters from a rich pine forest they were extremely
low.
The zooplankton consisted of two species of protozoa, five species of rotifers, two species of Cladocera, and two species
of Copepoda. The zooplankton density range was 6200–16200 individuals m−3. The minimum was on November 11th, 1983 and the maximum on August 19th, 1983. 相似文献
11.
Effects of NaCl salinity on the population dynamics of freshwater zooplankton (rotifers and cladocerans) 总被引:1,自引:0,他引:1
S. S. S. Sarma S. Nandini Jesús Morales-Ventura Israel Delgado-Martínez Leticia González-Valverde 《Aquatic Ecology》2006,40(3):349-360
Salinization of freshwater bodies due to anthropogenic activity is currently a very serious problem in Mexico. One of the consequences may be changes in the rotifer and cladoceran populations, both of which are generally abundant in freshwater bodies. Under laboratory conditions we evaluated the effect of different salt (sodium chloride) concentrations (0–4.5 g l−1) on the population dynamics of ten freshwater zooplankton species (rotifers: Anuraeopsis fissa, Brachionus calyciflorus, B. havanaensis, B. patulus and B. rubens; cladocerans: Alona rectangula, Ceriodaphnia dubia, Daphnia pulex, Moina macrocopa and Simocephalus vetulus). All of the zooplankton species tested were adversely affected by 1.5–3.0 g l−1 NaCl. In the range of salt concentrations tested, the population growth curves of B. patulus and B. rubens showed almost no lag phase and reached peak abundances within a week or two; A. fissa had a lag phase of about a week, while both B. calyciflorus and B. havanaensis started to increase in abundance immediately following the initiation of the experiments. Increased NaCl levels reduced the population abundances of A. fissa, B. calyciflorus and B. havanaensis at or beyond 1.5 g l−1. NaCl at 1 g l−1 had little effect on the population growth of cladocerans. M. macrocopa, which was more resistant to NaCl than the other cladoceran species, showed positive population growth even at 4.5 g l−1. The rates of population increase (r, day−1) were generally higher for rotifers than for cladocerans. Depending on the NaCl concentration, the r of rotifers ranged from +0.57 to −0.58 day−1, while the r for cladocerans was lower (+0.34 to −0.22 day−1). 相似文献
12.
The composition and temporal abundance patterns of zooplankton community in Lake Prespa pelagic zone were studied throughout an annual cycle (October 2008–September 2009). Eighteen species (10 Rotifera, 5 Cladocera, 2 Copepoda, 1 Mollusca) were evidenced. It includes Arctodiaptomus steindachneri, an endemic calanoid of the Western Balkans. The zooplankton density varied during the investigated period and certain seasonal successions in temporal transpositions of their maximal development were noticed. The total zooplankton density was much higher in spring and summer period. The representatives of subclass Copepoda were dominant during the whole year. The dominant species was A. steindachneri. At the second place (with exception of the winter period) were the Cladocera representatives. The dominant species was Daphnia cucullata. At the third and fourth place were rotifers and larval form of Dreissena polymorpha, respectively. The quantitative presence of the Copepoda representatives was significantly lower in terms of the previous investigations. The Cladocera quantity reached high values during this period, particularly in summer. Such altering in the quantitative ratio between Copepoda and Cladocera in favor of the Cladocera, especially high quantitative presence of D. cucullata, typical for eutrophic lakes, imply of significant changes in zooplankton community and changes of the water quality in Lake Prespa pelagial. 相似文献
13.
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
14.
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
15.
Field and experimental studies were conducted to evaluate the combined impacts of cyanobacterial blooms and small algae on
seasonal and long-term changes in the abundance and community structure of crustacean zooplankton in a large, eutrophic, Chinese
lake, Lake Chaohu. Seasonal changes of the crustacean zooplankton from 22 sampling stations were investigated during September
2002 and August 2003, and 23 species belonging to 20 genera were recorded. Daphnia spp. dominated in spring but disappeared in mid-summer, while Bosmina coregoni and Ceriodaphnia cornuta dominated in summer and autumn. Both maximum cladoceran density (310 ind. l−1) and biomass (5.2 mg l−1) appeared in autumn. Limnoithona sinensis, Sinocalanus dorrii and Schmackeria inopinus were the main species of copepods. Microcystis spp. were the dominant phytoplankton species and formed dense blooms in the warm seasons. In the laboratory, inhibitory effects
of small colonial Microcystis on growth and reproduction of Daphnia carinata were more remarkable than those of large ones, and population size of D. carinata was negatively correlated with density of fresh large colonial Microcystis within a density range of 0–100 mg l−1 (r = −0.82, P< 0.05). Both field and experimental results suggested that seasonal and long-term changes in the community structure of crustacean
zooplankton in the lake were shaped by cyanobacterial blooms and biomass of the small algae, respectively, i.e., colonial
and filamentous cyanobacteria contributed to the summer replacement of dominant crustacean zooplankton from large Daphnia spp. to small B. coregoni and C. cornuta, while increased small algae might be responsible for the increased abundance of crustacean zooplankton during the past decades. 相似文献
16.
In June 1992, an extensive investigation programme was carried out in the turbidity zone of the Elbe river. Special attention
was paid to salinity and suspended particulate matter (SPM) and their influence on bacteria, phytoplankton, zooplankton, mysids
and fish. SPM was separated into three fractions of different settling velocities. Mean settling velocity (ws) was 0.05 cm s−1. The major part of SPM belonged to the slow settling fraction (ws<0.02 cm s−1).
Bacterial exoenzymatic activity showed a positive correlation with SPM and chlorophyll-a content, and also to total dissolved free amino acids.
Phytoplankton biomass reached maximum values of 5.7 μg chlorophyll-a l−1 at ebb tide. Chlorophyll-a correlated negatively with salinity, indicating riverine input of phytoplankton. A positive correlation was found between
chlorophyll-a and dissolved oxygen.
Abundance of zooplankton species and their developmental stages varied over the tidal cycles; abundance of cirriped larvae
and copepodite stages of the dominant speciesEurytemora affinis (Copepoda, Crustacea) was positively correlated with salinity. Individual filtering rates (IFR) ofEurytemora affinis were negatively affected by the SPM content of the water. Maximum IFR for adults was 7.2 ml h−1. Community grazing reached maximum rates of 30.3 ml l−1 h−1 (i.e. 72.7% d−1).
The dominant mysidNeomysis integer showed maximum abundance at night, possibly resulting from diel vertical migration. Abundance ofN. integer was positively correlated with SPM content.
The fish community, consisting of 17 fish species, was characterised by high densities of smelt (Osmerus eperlanus). A positive correlation was found between salinity and abundance of typical marine fish species, such as sprat (Sprattus sprattus). Similar temporal variation of abundance of smelt, sprat, andEurytemora copepodites indicates processes of habitat preference of these planktivorous fish in relation to optimal food supply.
SPM was the factor controlling both distribution of organisms and the turnover of nutrients. Salinity only was important for
the distribution of organisms. 相似文献
17.
Mesozooplankton biomass and abundance were evaluated in epipelagic waters at 59 stations covering the Italian sector of the
Ligurian Sea (north-western Mediterranean) in December 1990. This region is characterised by a cyclonic circulation which
encloses a central divergence zone and is associated with a main thermohaline front offshore the western Ligurian coast. At
the end of autumn, mesozooplankton biomass (range: 0.80–4.24 mg DW m−3) and the abundance (range: 83.8–932 ind. m−3) were lower in the divergence zone. On the contrary, in the Ligurian frontal zone at the periphery of the divergence and
on the eastern continental shelf the greatest values of biomass and abundance were recorded. Copepods and appendicularians
dominated the mesozooplankton community, the main taxa being the copepods Clausocalanus spp. (46% of total zooplankton) and Oithona spp. (15%) and the appendicularian Fritillaria spp. (12%). Three hydrological sub-regions, i.e. the divergence, the eastern continental shelf and the periphery of the divergence,
were characterised by different zooplankton communities and characteristic species. Environmental differences between the
three zones were mainly related to changes in bottom topography, sea surface temperatures and quantity of particulate organic
matter. Vertical mesozooplankton abundance and taxa distribution from the surface to 1,900 m depth were also examined in one
station. The results showed that the bulk of the community was concentrated in the upper 200 m, small copepods being dominant
particularly in the upper 50 m. The copepod community was more diversified in sub-superficial waters, with a maximum observed
in the 200–400 m layer. The distributions of main zooplankton taxa described in epipelagic waters in the eastern Ligurian
Sea in autumn were compared with their distribution at surface in the north-western Mediterranean obtained by sampling performed
with the Continuous Plankton Recorder in 1997–1999. The analysis of the zooplankton community in CPR samples confirms the
dominance of small copepods (Paracalanus spp., Clausocalanus spp., Oithona spp.) and appendicularians in the north-western Mediterranean in late autumn-winter and shows that their distribution is
mainly related to the main mesoscale hydrographic features characterising this basin.
Guest editors: S. Souissi & G. A. Boxshall
Copepoda in the Mediterranean: Papers from the 9th International Conference on Copepoda, Hammamet, Tunisia 相似文献
18.
K. M. Gorbatenko S. I. Kiyashko A. Ye. Lazhentsev V. A. Nadtochii A. B. Savin 《Russian Journal of Marine Biology》2008,34(7):497-506
The composition, abundance, diet and trophic status of zooplankton, bottom invertebrates, fish and nekton were analyzed based
on the data collected by the staff of the TINRO-Center during complex bottom trawl catches on the Bering Sea shelf in the
fall of 2004. The stomach contents of mass fish species were analyzed and the nitrogen and carbon isotopic composition of
36 mass species of plankton, benthos, nekton and nektobenthos, which together make up the basis of pelagic and bottom communities,
was determined. It was found that zooplankton noticeably differ from benthic invertebrates in carbon isotopic composition:
δ13C values in zooplankton varied from −20.3‰ to −17.9‰; in benthos—from −17.5‰to −13.0‰; and in fish—from −19.2‰ (juvenile walleye
pollock) to −15.3‰ (saffron cod). The levels of 13C isotope in the tissues of fish depended mostly on the share of pelagic or benthic animals in their diet. δ15N values in the studied species ranged from 8.6‰ (in sea urchins) to 17.2‰ (in large Pacific cods), which corresponds to a
trophic level of 2.8. Obviously the δ15N values reflect the degree of predation and generally show the ratio of primary, secondary and tertiary consumers in a fish’s
diet. Trophic interactions manifest a high degree of interdependence between benthic and pelagic communities (even without
taking into account such lower components of the food web as phytoplankton, bacteria, and protozoa) occurring in most nektonic
species that depend on both bottom and pelagic food. 相似文献
19.
Jūratė Lesutienė Anna Semenova Evelina Grinienė Zita R. Gasiūnaitė Viktorija Savickytė Olga Dmitrieva 《Central European Journal of Biology》2012,7(1):91-100
The abundance and distribution of predatory cladoceran Leptodora kindtii was investigated in the estuarine lagoon (Curonian Lagoon, SE Baltic Sea). Three hydrodynamically different parts of the
lagoon were selected, representing transitory oligohaline, intermediate freshwater and stagnant freshwater sites. L. kindtii was least abundant at the oligohaline site, never occurring at salinities greater than 4 psu. At the two freshwater sites,
the abundance of L. kindtii varied from a low of <0.1 up to 2.2 indv. L−1 during peak abundance. Two peaks of L. kindtii abundance were observed with timing differences between stations: at the stagnant site the population of L. kindtii peaked two weeks earlier relative to the more hydrodynamically active sites, likely due to a 2°C higher May temperature.
The small body size of L. kindtii in the lagoon (seasonal mean 2.68±0.6 mm) shows high fish predation pressure and predicts small cladocerans, juvenile copepods
and rotifers being in the preferred prey size range. The calculated L. kindtii daily consumption during the population peak was as high as 100% of the daily zooplankton production, which implies high
potential of this predator to shape the grazing zooplankton community in the lagoon. 相似文献
20.
Long-term (1969–2002) data record of biomass distribution of rotifers in Lake Kinneret is combined with previously published information on their metabolic activity and newly calculated population dynamics parameters to synthesize a model of their seasonal dynamics in Lake Kinneret. Nineteen rotifer species were recorded in routine samples collected in Lake Kinneret (Israel) in 7 offshore (deeper than 5 m), stations, at 12 discrete depths during 1969–2002. Organisms were sorted and counted (including external egg carrying females), biomass was measured and calculated for the entire lake stock (gw.w m−2; mg l−1). Rates of grazing, respiration and production were measured experimentally at three different temperature ranges. Results were extrapolated to the lake community for months with similar temperatures. Rotifera comprised 7% of total zooplankton biomass in Lake Kinneret whilst Cladocera and Copepoda 58 and 35% respectively. Rotifers were found to be more abundant during December–June and decline in summer months. Monthly (1969–2001) means indicated total grazing capacity of rotifers as 11%, respiration as 9% and production as 3.7% of the total zooplankton metabolic activity. Positive relations were indicated between rotifer and small bodied cladoceran numerical concentrations. Population growth models suggest that rotifers are not food limited in Lake Kinneret but that fish predation plays an important role in regulating abundance in spring-summer and fall. 相似文献