淡水中型浮游动物群体与悬浮物碳氮磷比耦联研究

通过对湖北省13个湖库悬浮物和中型浮游动物群体碳氮磷比的分析, 探讨了浮游动物与食物之间的元素耦联和不平衡性是如何随食物质量的改变而变化, 以及这种不平衡性对生态系统浮游动植物间能量传递效率的影响。结果显示: 中型浮游动物C﹕N比和C﹕P比分别随悬浮物C﹕N比和C﹕P比的增加而变大。悬浮物-中型浮游动物之间的元素不平衡性不仅与悬浮物C﹕N比显著正相关(r=0.97, P<0.001), 且与悬浮物C﹕P比也显著正相关(r=0.81, P=0.001)。浮游动植物之间的能量传递效率与悬浮物-中型浮游动物C﹕P比差值呈显著负相关(r= –0.58, P=0.037), 但与其C﹕N比差值关系不显著(P>0.05)。此外, 中型浮游动物生物量也随其与悬浮物之间C﹕P比差值的增大而下降(r= –0.59, P=0.033)。这些结果表明, 悬浮物碳氮磷比能显著影响中型浮游动物群体的碳氮磷比组成, 两者之间的元素不平衡性随前者的增加而变大并进而降低能量向后者的传递。     

Beiträge zum Mesozooplankton des Nordsylter Wattenmeers

Contributions to the mesozooplankton of the northern Wadden Sea of Sylt. From June 1975 to June 1976 temperature, salinity, mesozooplankton (>76 µm), phytoplankton and seston (dry weight, particulate organic carbon and nitrogen) were measured at different stations in the northern Wadden Sea of Sylt (German Bight, North Sea). Maxima of the planktonic copepods, which form the biggest part of the zooplankton, occurred in the summer months from June to September. Larval development from nauplii to adults was observed inAcartia clausi, Acartia discaudata, Centropages hamatus andTemora longicornis; generation times ranged from 3 (Temora longicornis) to 7 1/2 weeks (Centropages hamatus) at ca. 20 °C. Organic carbon produced by zooplankton was about 0.4 g C m^–3 year^–1 and zooplanktonic carbon decomposed in the area studied amounted to about 1.4 g C m^–3 year^–1. Meroplanktonic larvae made up ca. 60 % of the organic carbon produced by zooplankton, indicating great influence of the benthos on the water column in this very shallow part of the German Bight.     

Mesozooplankton structure in the northern White Sea in July 2008

The mesozooplankton of the northern White Sea and Mezen Bay was investigated at nine stations in July 2008 using a Juday net (168 μm mesh size). A total of 39 taxa (species and higher taxa) were found in the samples. Average abundance, biomass, and diversity (Shannon index) were (±SE) 120,793 ± 70,439 ind. m⁻², 443 ± 216 mg DW m⁻², and 1.41 ± 0.11, respectively. Copepods were most numerous. Overall, herbivores dominated primarily Cirripedia nauplii and Pseudocalanus minutus. Significant correlations were observed among mean temperature, salinity, and mean mesozooplankton abundance and biomass. Our data suggest that salinity and intensive local currents could be the main factors responsible for the distribution of mesozooplankton in the northern White Sea. The average mesozooplankton biomass was higher than in previous studies, indicating a possible climatic impact on the mesozooplankton community.     

Different zooplankton structures in the German Bight

In August 1982, a net of 48 stations with altogether 208 samples was investigated in the eastern German Bight with respect to temperature, salinity, as well as the amount and species composition of the mesozooplankton (>80 μm). The data were arranged into different structures by means of a cluster analysis. Four different clusters were found: (a) a “Wadden sea water” with few holoplankton organisms but a higher amount of spionid larvae; (b) a “German Bight water” with a maximum occurrence of turbellaria (Alaurina composita) and medium concentrations of copepods; (c) a mixing area between these two water masses with highest amounts ofOikopleura dioica, Temora longicornis, Acartia sp., mussel larvae and larvae of the spionid worms; (d) a “North Sea water” mass with highest concentrations ofPseudocalanus elongatus, Paracalanus parvus undOithona similis. The differences in the concentrations of the species mentioned between the four clusters were significant on the 0.1%-level.     

Salinity-dominated change in community structure and ecological function of Archaea from the lower Pearl River to coastal South China Sea

Archaea have multiple roles in global biogeochemical cycles. However, we still have limited knowledge about how environmental factors affect the diversity and function of different archaeal lineages. The goal of this study was to examine the change in the abundance and community structure of Archaea in the sediments collected from the lower Pearl River (mainly North River tributary), its estuary, and coastal South China Sea (SCS) in order to evaluate how archaeal ecological function might change along the salinity gradient. Pyrosequencing of the 16S rDNA gene of Archaea was performed on sediment samples from Feilaixia Dam on the North River tributary to Wanshan islands, which have a salinity range of 0.1 to 31.2?‰. Consistent with the salt tolerance of cultivated representatives, methanogens in the genera Methanoregula, Methanosaeta, and Methanosarcina and Nitrososphaera within Thaumarchaeota of the ammonia-oxidizing Archaea (AOA) were abundant in freshwater sediments of the North River tributary, whereas the marine-associated genera Methanococcoides and Nitrosopumilus were the most abundant methanogens and AOA, respectively, in the estuary and coastal SCS. However, the percentages of total methanogens decreased and Thaumarchaeota increased with salinity, respectively. The phylum Crenarchaeota was largely represented by class-level lineages with no cultivated representatives, which collectively were more abundant in the estuary and coastal SCS in comparison to freshwater sites. This study indicates that salinity is the dominating factor affecting archaeal community structure and ecological function from the North River tributary of the Pearl River, its estuary, and coastal SCS, which is consistent with salinity control on microbial diversity in other regions of the world.     

Regulation of sodium in the shore crabCarcinus maenas,adapted to environments of constant and changing salinities

The activity of Na-K-ATPase was determined in the posterior gills of the shore crabCarcinus maenas during a period following transfer from 35 to 10 ‰ salinity and vice versa at 15 °C. After transfer from high to low salinity, Na-K-ATPase activity increased from 3.2 to 7.0 μmoles P_i mg protein^?1 h^?1 within a period of 2 to 3 weeks. Transfer of crabs from low to high salinity resulted in reduction of activity from 7.4 to 4.5 μmoles P_i mg protein^?1 h^?1 within about the same period. The relatively slow response following salinity change indicates that the amounts of Na-K-ATPase in the gills may play a role in hyperionic Na regulation in relatively constant brackish-water environments. Instant responses to salinity result from activation and inhibition of Na-K-ATPase activity by Na. Gill Na-K-ATPase is activated by the Na concentration of the incubation medium to attain a steep maximum at about 75 mM Na, which corresponds to the lowest environmental Na levels tolerated byC. maenas equivalent to a salinity of ca 6 ‰. Activity greatly decreased towards higher Na levels, equivalent to the salinity of normal sea water, at which hyperregulation no longer occurs. Selective addition of either Na or Cl to brackish water of 9 ‰ S resulted in effective hyperregulation of the non-increased ion, and passive distribution between medium and blood of the increased ion. These data indicate that under appropriate conditions the normally coupled transport of Na and Cl may be uncoupled and take place independently of each other.     

Zur Biologie des Planktons des Königshafens (Nordsylter Wattenmeer)

From May 1979 on, the following parameters were measured at a station in the inlet of Königshafen near List (Island of Sylt): temperature, salinity, mesozooplankton (>76 µm), chlorophyll-a, seston dry weight, oxygen and phytoplankton-nutrients (NH₄-N, NO₂-N, NO₃-N, PO₄-P, SiO₃-Si). A multiple regression analysis showed the interrelationships between the parameters measured. Tidal influences on zooplankton and seston dry weight could be observed. At low tide, the amount of zooplankton (not counting the harpacticoid copepods) declines and the number of harpacticoid copepods rises as does the seston dry weight too. The chlorophyll-a content is a function of the phytoplankton-nutrients. An increase in chlorophyll-a leads to a decrease in nitrogen and silicate concentrations. Phosphate, due possibly to a sewage inlet into the Königshafen, is not a limiting factor. The availability of nutrients is influenced by temperature, salinity and the tidal cycle. The amount of oxygen is dependent on water temperature and seston dry weight. High water temperatures and a high seston content lead to a decrease in oxygen concentrations.     

东海中华哲水蚤的年产量估算

1 997年至 2 0 0 0年在东海陆架区进行了 4个航次的大面调查 ,用获得的大型浮游生物网样品分析资料应用产量 /生物量比值 ( P/ B)法对中华哲水蚤的年产量做了初步估算。中华哲水蚤的 P/ B比值为6.735 3,在东海的平均年产量为 2 63.94C mg/ ( m2 / a)。全测区年产量为 1 1 0 .745× 1 0 3t碳 ,即 1 1万 t,相当于活体重 1 44 .3万 t。     

Mesozooplankton dynamics in the northern Baltic Sea: implications of variations in hydrography and climate

An 18-year mesozooplankton time series from 1967 to 1984 fromthe SW coast of Finland, northern Baltic Sea, was studied inrelation to climatic parameters (air temperature, air pressure,precipitation, and wind speed and direction), freshwater dischargeand hydrographical factors (water temperature, salinity andwater column stability). Climatic factors influenced mesozooplanktoncommunity through their effects on hydrography. The averagewater salinity responded to fluctuations in river dischargewith a 1–2 year lag. River discharge was in turn regulatedby variations in atmospheric pressure and precipitation, whichoscillated on 3–5 year cycles. Shorter-term variationsin salinity and temperature were related to changes in the dominatmgwind directions. The seasonally adjusted residuals of totalmesozooplankton biomass, cladoceran biomass and those of manyof the dominant mesozooplankton species were significantly negativelycorrelated with salinity. The annual peaks of the most abundaiitcladoceran species and one of the most abundant calanoid speciesco-varied with the seasonal fluctuation of surface water temperature.Canonical correspondence analysis identified the mesozooplanktonspecies by their relationship to water stability: rotifers andcladocerans had their optima in warm and stabile conditions,while the nentic calanoid copepods were more abundant in relativelysaline and mixed conditions.     

Egg Size and Formation of the Geographical Range in <Emphasis Type="Italic">Thysanoessa inermis</Emphasis> (Kroyer, 1846) (Crustacea: Euphausiacea) in the Norwegian and Barents Seas

Using materials on the euphausiacean Thysanoessa inermis collected in the Norwegian and Barents seas (from 60°N to 73°N) we studied the variability of size characteristics in the eggs (diameter of embryos and egg capsules and the width of the perivitelline space) and their correlations with water temperature and salinity. The size of embryos showed almost no variability irrespective of the location of the sampling site and the water temperature and salinity; the perivitelline space performs a protective function, and its width showed a tendency to decrease with increasing water temperature and salinity. The similarities in the size of embryos in T. inermis populations thousands of kilometers away from each other might be explained, first, by the relatively small age of the populations (the age of the population from the Barents Sea did not exceed 6000–7000 years) and second, by movement of the crustaceans with currents from the Norwegian Sea to the Barents Sea.     

Zooplankton feeding on seston in the Rhone River plume area (NW Mediterranean Sea) in May 1988

In the Rhone delta area the seston concentration was maximum in the plume waters where small-sized particles dominated, while marine waters were characterized by large particles. The food conditions were optimal for grazers in the interface layer, where the high chlorophyll concentration contrasted with the low values found under the plume.The mesozooplankton specific composition did not show marked difference in and outside the plume. No special pattern for particle size selection by grazers appeared in the plume, contrary to marine waters, where largest particles were the most intensively grazed. The calculations of specific ingestion and filtration rates show that the plume waters (particularly at the salinity interface) were more favourable to zooplankton feeding than the marine ones (outside and under the plume). Nevertheless, taking into account the high level of seston biomass in the whole area studied, the daily grazing pressure of mesozooplankton was very low.     

The synthesis and deposition of the prolamin storage proteins (secalins) of rye

The synthesis and deposition of the endosperm storage proteins of rye, usually termed secalins, has been studied. The rate of accumulation of secalin in developing rye grain was at a maximum between 3 and 5 weeks after anthesis. Some changes in the proportions of the four major groups of secalin polypeptides were observed during maturation, notably an increase in γ-secalins of M_r 75k and a decrease in ω-secalins. In-vitro translation of mRNA fractions prepared from 4-week-old endosperms showed that secalin polypeptides were synthesised on membrane-bound polysomes. The secalin products were identified by their mobilities on SDS-PAGE and their relative incorporation of radioactive lysine, glycine, proline, leucine and methionine. Protein bodies prepared by sucrose density ultracentrifugation contained reduced amounts of γ-secalins of M_r 40k and ω-secalins compared with the total secalin fraction, but these components were present in the expected amounts when 1.0 M NaCl was added to the buffers. Treatment of the protein bodies with proteinase-k resulted in the digestion of their contents regardless of the presence of NaCl, indicating that the surrounding membrane was incomplete. It was concluded that the NaCl reduced the loss of secalins from the protein bodies by decreasing secalin solubility rather than by affecting the integrity of the protein body membrane. The results reported for the synthesis and deposition of secalins are consistent with the results of previous studies on the prolamins of wheat and barley.     

Salinity as a regulator of DMSP degradation in Ruegeria pomeroyi DSS-3

Dimethylsulfoniopropionate (DMSP) is an important carbon and sulfur source to marine bacterial communities and the main precursor of dimethylsulfide (DMS), a gas that influences atmospheric chemistry and potentially the global climate. In nature, bacterial DMSP catabolism can yield different proportions of DMS and methanethiol (MeSH), but relatively little is known about the factors controlling the pathways of bacterial degradation that select between their formation (cleavage vs. demethiolation). In this study, we carried out experiments to evaluate the influence of salinity on the routes of DMSP catabolism in Ruegeria pomeroyi DSS-3. We monitored DMS and MeSH accumulation in cell suspensions grown in a range of salinities (10, 20, 30 ppt) and with different DMSP amendments (0, 50, 500 µM). Significantly higher concentrations of DMS accumulated in low salinity treatments (10 ppt; P < 0.001), in both Marine Basal Medium (MBM) and half-strength Yeast Tryptone Sea Salts (1/2 YTSS) media. Results showed a 47.1% and 87.5% decrease of DMS accumulation, from salinity 10 to 20 ppt, in MBM and 1/2 YTSS media, respectively. On the other hand, MeSH showed enhanced accumulations at higher salinities (20, 30 ppt), with a 90.6% increase of MeSH accumulation from the 20 ppt to the 30 ppt salinity treatments. Our results with R. pomeroyi DSS-3 in culture are in agreement with previous results from estuarine sediments and demonstrate that salinity can modulate selection of the DMSP enzymatic degradation routes, with a consequent potential impact on DMS and MeSH liberation into the atmosphere.     

Eine “red tide” in der südlichen Nordsee und ihre Beziehungen zur Umwelt

Phytoplankton blooms have attracted attention since times of old, especially the red tides caused by peridinians. Observed in all regions of the world, red tides occur predominantly in the warmer seas (e. g. West Coast of Florida). An opportunity to study a bloom, caused by the non-toxic dinoflagellateCeratium furca, was provided in North Sea coastal waters of an area ranging from Belgium to Sweden. Its development could be followed from July to October 1981 with the aid of samples taken 5 days a week near the island of Helgoland. A decline in the bloom coincided with a drop in water temperature (increasing turbulence). This condition and the presence, right up to the end, of relatively high amounts of nutrients indicate that nutrient deficiency did not terminate the bloom. Similarly, there was no evidence for a dependence on micronutrients by freshwater input or by the preceding diatom bloom. Longterm investigations indicate that climatic changes coincide with an increase in the phytoplankton stock during all seasons (especially noticeable from July to September) and with a decrease in salinity (there was a minimum in 1981). The stratification of the sea water causes the peridinians to move to depths optimal for their growth which may bring about an aggregation at the surface. There are numerous indications in literature of similar changes of environmental conditions in the North Sea. One example from the Western Baltic Sea demonstrates that the presence of a high vertical density gradient in the sea leads to oxygen deficiency in deeper zones, which, however, is not directly correlated to the coincident phytoplanktonic bloom in the upper layers. It is probable that, under appropriate hydrographical conditions, “red tides” can occur repeatedly in the southern North Sea, produced by non-toxic as well as toxic species.     

{delta}15N signatures of marine mesozooplankton and seston size fractions in Kiel Fjord, Baltic Sea

The ¹⁵N of marine mesozooplankton species was measured on fouroccasions. Significant differences were found between copepodsand meroplanktonic larvae, yet not between holoplanktonic species.On average, mesozooplankton was enriched by 3.4 ± 0.9relative to selected seston size fractions. Despite suggestingsmall differences (0.5 to 1) in the ¹⁵N of different phytoplanktontaxa on one occasion, the size fractionation procedure generallyproved inadequate in separating major taxonomic groups composingseston. This circumstance, and phase-shifts in the transmissionof rapid changes (>2) in seston ¹⁵N to mesozooplankton complicatethe calculation of mesozooplankton trophic levels.     

Analysis of benthic macroinvertebrate communities from the Lower sections of Large river in relation to different environmental factors

The aim of this study was to make a comparative analysis of macrozoobenthos composition at different sites at selected sections of lower the Odra River with relation to different physicochemical factors. The observations were made on the lower section of Odra River at five study sites: two of them were localized in the main channel, one in the left branch of river, another one in the channel carrying post-cooling water from Dolna Odra power plant, and the last one was in the channel connecting both branches of Odra River. At all sites, 26 taxa were found representing by: Bivalvia, Gastropoda, Oligochaeta, Hirudinea, Malacostraca and Insecta. The greatest biodiversity and the highest abundance of zoobenthos organisms were noted in the channel joining the two branches of the river, site 5, characterised by the lowest water flow rates and the densest coverage of the macrophytes at the bottom. Temperature was the sole parameter to be studied that affected the composition of benthic invertebrates. A clearly negative impact of temperature on the diversity of invertebrates was observed only in the channel with post-cooling water discharged from the power plant.     

Kurzzeitige Veränderungen hydrographischer Faktoren und der Sestonkomponenten in driftenden Wassermassen in der Helgoländer Bucht

Zusammenfassung 1. In der Helgoländer Bucht wurden vor der Elbe- und Eidermündung sowie bei Helgoland driftende Wassermassen 4–8 Stunden lang untersucht. Dabei wurden in etwa halbstündigen Zeitabständen Vertikalserien von Wasserproben entnommen und Salzgehalt, Temperatur, Trübung und Sestongewicht bestimmt sowie Phytoplankton gezählt (Abb. 2–4).2. Lediglich das auflaufende Wasser bei der Driftstation Außeneider blieb hydrographisch unverändert; nur hier waren die Voraussetzungen für die Messung kurzzeitiger Veränderungen des Partikelgehalts gegeben. Das unbewegliche Plankton (Diatomeen) zeigte nicht den raschen Abfall der Konzentration mit dem Nachlassen des Gezeitenstroms wie das Sestongewicht und die Trübung.3. Die Verfolgung driftenden Wassers bei Helgoland ließ erkennen, daß durch die besonderen Gezeitenstromverhältnisse Wassermassen mehrmals um die Insel kreisen und die Helgoland-Reede passieren können.4. Diese Untersuchungen wie auch veröffentlichte Ergebnisse von Messungen der horizontalen Diffusion im Meerze zeigen, daß Untersuchungen der Veränderungen innerhalb einer einzelnen Planktonpopulation im Laufe von mehreren Tagen in der Helgoländer Bucht eine aufwendige Gemeinschaftsarbeit erfordern.

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Short-term variations of hydrographical factors and seston components in drifting water masses in Helgoland Bight

In Helgoland Bight (Inner German Bight, North Sea) drifting water masses were investigetad at 3 stations for 4–8 hours during August and November, 1968. Measurements of salinity, temperature, turbidity and seston weight were made and phytoplankton was counted in vertical series of water samples taken at about 30 — minute intervals. Only the water at drifting station Außeneider remained hydrographically unchanged during the investigation. The concentration of non-motile phytoplankton (diatoms) did not decrease with the slowing down of tidal current, whereas seston weight and turbidity decreased rapidly. Drift-cross tracking of the water at Helgoland Roads revealed that the water masses may circle around the island several times. Published results on horizontal diffusion and the present data indicate that measurements of changes within a plankton population over several days in Helgoland Bight require elaborate teamwork.

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Herrn Prof. Dr.J. Krey zum 60. Geburtstag in Verehrung gewidmet.     

Summer mesozooplankton distribution near Novaya Zemlya (eastern Barents Sea)

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.     

Long-term dynamics of main mesozooplankton species in the central Baltic Sea

Long-term dynamics (1959–1997) of the copepod speciesPseudocalanus elongatus, Temora longicornis, Acartia spp. andCentropages hamatus, as well as the taxonomic group of cladocerans,are described for the open sea areas of the central Baltic Sea.Differences between areas, i.e. Bornholm Basin, Gdansk Deepand Gotland Basin, as well as between 5 year periods, were investigatedby means of Analysis of Variance (ANOVA). No significant differencesin mesozooplankton biomass between areas were found. On theother hand, clear time-trends could be demonstrated and relatedto salinity and temperature, with P.elongatus biomass mainlydependent on salinity and T.longicornis, Acartia spp. and cladoceransbiomasses dependent, to a large extent, on thermal conditions.Decreasing salinities since the early 1980s due to a lack ofmajor inflows of highly saline water from the North Sea andincreased river run-off, both triggered by meteorological conditions,obviously caused a decrease in biomass of P.elongatus. Contrarily,the standing stocks of the other abundant copepod species andcladocerans followed, to a large degree, the temperature developmentand showed, in general, an increase. The shift in species compositionduring this period is considered to be a reason for decreasinggrowth rates of Baltic herring (Clupea harengus) since the early1980s, and for sprat (Sprattus sprattus) since the early 1990s.Generally, it is suggested that low mesozooplankton biomassesin the 1990s were caused, at least partially, by amplified predationby clupeid fish stocks.