Plankton Species Composition Research Articles

Vertical profiles of pigments, fatty acids and amino acids: Evidence for undegraded diatomaceous material sedimenting to the deep ocean in the Bellingshausen Sea, Antarctica

The organic carbon content and biochemical composition of suspended particulate material was investigated at five stations in the marginal ice zone of the Bellingshausen Sea during the austral spring of 1992. Stations, each consisting of profiles of between four and eight depths, were sampled along longitude 85°W from fast ice conditions to open water. Samples were collected using large volume in situ filtration systems. The horizontal and vertical distribution of organic carbon, fatty acids, pigments and amino acids reflected strongly the physical environment and planktonic species composition. Concentrations of total hydrolysable amino acids, total fatty acids and photosynthetic pigments all exhibited marked reductions with depth. At an open water station, significant levels of labile fatty acids (16 : 4 n−1 and 20 : 5 n−3) and the xanthophyll fucoxanthin were present at a depth of 3900 m, indicating the sedimentation of undegraded, diatom derived material into the deep ocean. Amino acid, fatty acid and pigment concentrations suggest that degradation rates of particulate material below 500–1000 m were very low. The results show that in some circumstances undegraded material of photosynthetic origin reaches the deep ocean. However, the significance and contribution of this material to the nutrition of deep water pelagic and benthic communities remains to be established. The results are discussed in terms of the transfer of biogenic material from the euphotic zone into the deep ocean and the implications for deep water ecosystems.

Ingestion rates of phytoplankton by copepod size fractions on a bloom associated with an off-shelf front off NW Spain

Herbivory by copepods was studied from the coast towards the ocean, during a bloom in May 1994 off NW Spain.Ingestion rates were estimated by the gut chlorophyll content method in three size fractions. The chlorophyll content displayed significant daily cycles. Three different water bodies were described: coastal, shelf break and oceanic; the latter two zones separated by a thermo haline frontal structure. Marked differences in plankton species composition, vertical distribution and biological rates were found between zones. Theiiighest phytoplankton biomass, dominated by chain- forming diatoms, occurred in the oceanic zone associated with low primary production rates. Copepod feeding had a low effect on oceanic phytoplankton; up to 0.2% of carbon stock and<3% of carbon production was consumed daily. In contrast, medium-sized and large copepods removed 3% of carbon stock and 12% of primary production daily near the coast, where phytoplankton were dominated by small flagellates in active growth. The highest variability in both plankton composition and ingestionrates was found in the shelf-break zone, probably due to displacements of the front. Copepods exerted a moderate predation pressure on phytoplankton in coastal waters. Meanwhile, the impact of copepods on the offshore bloom was negligible and the fate of the accumulated particulate carbon would be mostly determined by sedimentationand water dynamics.

A comparison of sediment trap records of particle fluxes from 19 to 48°N in the northeast Atlantic and their relation to surface water productivity

Sediment trap data from four sites in the northeast Atlantic (48°N 20°W, 28°N 22°W, 24°N 23°W, 19°N 20°W) are presented for fluxes of total mass, organic matter, calcium carbonate, opal and lithogenous material. The results from these sites are compared with other published sediment trap data from this area to consider regional scale variations in the quantity and composition of settling ocean particulate matter along a transect at 20°W from 48°N to 19°N. There are clearly gradients of decreasing mass flux going south from 48°N which reverse around 25–30°N to increase again toward the North Africa upwelling regime. Flux seasonality is greater at the more northern sites. Opal fluxes are high at the more northern sites and the flux of lithogenic material is greater further south. Plankton species composition also changes along the transect. The changes in the mass and composition of sedimenting material along the transect are consistent with known changes in surface water plankton abundance and with fluxes inferred from sediment core results. Carbon fluxes measured by sediment traps and inferred from sediment core data in this area appear to be consistent with one another. These results provide increased confidence in the use of various ocean flux measurement techniques to derive estimates of ocean carbon cycling.

Annual cycle of the production and fate of DMS and DMSP in a marine coastal system

The production of DMSP by phytoplankton and the fate through the marine system of both DMSP and DMS were followed for a period of 21 mo in the natural environment by studying a Wadden Sea tidal inlet. The major production and emission of DMS appeared to be Limited to a period of only 2 mo, which was closely linked to the presence of phytoplankton blooms. The production of DMS in the water column was not well correlated with chlorophyll a concentrations or plankton species composition. It was however, found to be closely related to the start of a Phaeocystis bloom early in spring. Contrary to our expectations, the senescence phase of this Phaeocystis bloom did not result in high DMS accumulation. It is postulated that this phenomenon could be the result of a bacterial consumption which increased with time in combination with a decreasing DMSP-lyase activity of Phaeocystis. A simple model, into which the overall DMSP consumption could be introduced, could very well imitate the measured concentrations of DMS in the water column of the natural system studied.

Microbial utilization of lipids in lake water

This report evaluates the importance of lipids as a source of substrates for metabolism of heterotrophic bacteria based on measurements of uptake of [ 3H]palmitic acid and lipase activity in lakes of differing degrees of eutrophication. The highest rates of utilization of lipids by bacteria (i.e. specific and actual rates of uptake of [ 3H]palmitic acid and specific lipase activity) were observed in pelagic water of mesotrophic lake where the highest concentration and the shortest turnover time of natural pool of palmitic acid was found. Lipids in highly eutrophicated lakes were less important for metabolism of aquatic bacterial communities. Lipid content in lake water depended on species composition of plankton in the studied lakes.

The role of phytoplankton cells on the control of heavy metal concentration in seawater

An overview is presented of the ability of phytoplankton to passively adsorb and actively assimilate heavy metals from their aqueous environment and to release into the environment organic ligands capable of complexing metals. The uptake of all necessary trace metals by phytoplankton occurs via binding to a surface ligand and subsequent transfer across the cell membrane. This sorptive process can be explained by using surface complex formation equilibria; due to the heterogeneity of the algal surface, multi-site binding models must be developed. The production of extracellular organic matter with metal complexing properties plays an important role in decreasing the concentration of free metal ions and thus mitigating the potential toxic effects on organisms. However, while much research has been carried out on the uptake of single species of metal ions, little attention seems to have been given to the study of multimetal ion systems. Synergistic and antagonistic interactions between multiple trace metals are expected and could be very important in the oceans. These types of behaviours are extremely complex, influencing uptake and release of natural ligands and limiting plankton production and plankton species composition in the oceans. Future investigations should be carried out in order to gain understanding how the combinations of metal ions affect the physiological, biochemical and ecological processes of phytoplankton in seawater.

Results of an International Plankton Investigation on the River Rhine

Quantitative plankton observations have been carried out in the River Rhine from Lake Constance to the North Sea as part of an ecological monitoring programme, initiated to provide a baseline for evaluating measures taken under the “Rhine Action Programme”. The phyto- and Zooplankton monitoring, carried out in 1990 is the first concerted programme covering the 1000 km long reach of the river below Lake Constance. Seasonal observations at 20 fixed stations along the river were carried out by different institutes; this required calibration of methods. In the upper Rhine the sparse population of phyto-plankton (&amp;lt; 5 µg chlorophyll-a l-1) was dominated by various groups of algae, i.e. Cryptop-hyceae, Bacillariophyceae, Chlorophyceae and Cyanophyceae. Downstream, the phyto-plankton density increased gradually, while Bacillariophyceae tended to dominate. The high densities found in the lower R. Rhine represented only a few species of centric Bacillariophyceae and Chlorophyceae. The dense blooms of phytoplankton in the lower R. Rhine are triggered by the input of phytoplankton from the upper reaches and tributaries, and are stimulated by large inputs of nutrients. These blooms are accompanied by blooms of Zooplankton, especially rotifers, Dreissena polymorpha larvae and, in the lower Rhine, nauplii larvae. The species composition and biomass of plankton in the R. Rhine vary strongly during the year but also between years, as indicated for the period 1980-1990. However, the information at the species level needs further elaboration to allow interpretation of long-term trends. Notably, the input by tributaries should be included. To assess these long-term trends we recommend supplementing the large-scale biological inventory, as planned for the years 1995 and 2000, with plankton observations in the years between and investigating the relationship between the benthic and pelagic communities of the river.

Phytoplankton specimen bank for assessing ecological state of NPP cooling ponds

The data bank for species composition and seasonal dynamics of phytoplankton in the cooling pond of the Leningrad nuclear power plant (NPP), in the Finland Gulf, Kopor Bay, was developed over several years of complex monitoring. Regular observations were carried out, beginning in 1978. The inflow of warm waters from NPP (200 m3/s and industrial-municipal discharges resulted in rapid reservoir eutrophication. Phytoplankton vegetation is now observed practically for the whole year; the species composition of plankton has gradually changed and blue-green algae now predominate. Mean and maximum indices of phytoplankton concentrations increased significantly. Features of anthropogenic succession are discussed relative to the action of thermal and biogenic loads. Results of correlation analysis of phytoplankton time series and hydrochemical parameters are shown. A mathematical model is developed for describing phytoplankton seasonal dynamics in cooling ponds.

Crustacean Plankton in Lake Winnipeg: Variation in Space and Time as a Function of Lake Morphology, Geology, and Climate

Rivers draining different geological basins have the most important impact on the formation of the planktonic community in Lake Winnipeg. Very diverse patterns of distribution of individual species reflected the complexity of the water masses structured by lake morphology and the configuration of river inflows. Of the 34 species identified (15 copepods and 19 cladocerans), 12 were found exclusively in the South Basin, 7 exclusively in the North Basin, and 15 were common to both basins. A "core" group of 12 species was distributed over the whole lake, but the remaining 22 species ("unsuccessful invaders") were present only in restricted areas, mostly adjacent to river inflows. Plankton species composition has not exhibited major changes after 40 yr, but abundance has at least doubled, probably due to eutrophication. Several times more planktonic crustaceans were found in the western part of the lake, affected by sedimentary drainage, than in the eastern part, influenced by the Precambrian Shield. The plankton community in a lake as large as Lake Winnipeg can be affected by differences in climate within its shores. Midsummer epilimnion temperature was the single best parameter predicting crustacean abundance in Lake Winnipeg and other North American great lakes and, combined with phosphorus loading, explained 97% of variance.

Planktonic food chains of a highly humic lake

The development and metabolism of epilimnetic plankton from a highly humic lake was followed in late summer, when the predominant zooplankton species, Daphnia longispina, was very abundant (ca. 200 ind. l -1 ). The experiment was made in two tanks: one with an unaltered plankton assemblage and one with larger zooplankton removed. The scarce phytoplankton community was also simple, consisting mainly of one Cryptomonas two Mallomonas species. The abundance and species composition of smaller plankton was heavily influenced by grazing of Daphnia

Interactive influences of bioactive trace metals on biological production in oceanic waters

We present an overview of the oceanic chemistries of the bioactive trace metals, Mn, Fe, Co, Ni, Cu, and Zn; we combine field data with results from laboratory phytoplankton culture-trace metal studies and speculate on the potential influences of these trace metals on oceanic plankton production and species composition. Most field studies have focused on the effects of single metals. However, we propose that synergistic and antagonistic interactions between multiple trace metals could be very important in the oceans. Trace metal antagonisms that may prove particularly important are those between Cu and the potential biolimiting metals Fe, Mn, and Zn. These antagonistic interactions could have the greatest influence on biological productivity in areas of the open ocean isolated from terrestrial inputs, such as the remote high nutrient regions of the Pacific and Antarctic Oceans. The emerging picture of trace metal-biota interactions in these oceanic areas is one in which biology strongly influences distribution and chemical speciation of all these bioactive trace metals. It also seems likely that many of these bioactive trace metals and their speciation may influence levels of primary productivity, species composition, and trophic structure. Future investigations should give more complete consideration to the interactive effects of biologically important trace metals.

Metal enrichment experiments in the Weddell-Scotia Seas: Effects of iron and manganese on various plankton communities

During the European Polarstern Study (EPOS 1988/1989) in the Weddell and Scotia Seas, five series of metal enrichment experiments were carried out with natural plankton communities under ultraclean conditions. Despite a clear stimulation of growth by the addition of Fe, control bottles (no additions) also showed rapid buildup of Chl a and complete utilization of a major nutrient within 2 weeks, indicating nonlimiting ambient Fe levels. Effects of Mn additions were less pronounced or absent, whereas extra additions of Zn and Cu in one experiment showed little or no effect. The species composition of the plankton community, monitored by HPLC pigment analysis and microscopic observations, changed in favor of diatoms when Fe was added. The addition of Fe also caused an increase in microzooplankton densities and concentrations of pigment breakdown products. However, metal-mediated shifts in the plankton community were minor compared to major changes resulting from incubation. Changes were most pronounced in experiments where microzooplankton was strongly developed, presumably as a result of excluding mesozooplankton from the bottles. Fe had an impact on plankton growth and species composition, but other factors seem to be responsible for keeping phytoplankton productivity far from its potential in these Antarctic waters.

Particulate organic matter delta 13C variations across the Drake Passage.

A 7 % gradient in the delta 13C of suspended particulate organic matter (POM) was observed in samples taken during two transects across the Drake Passage during March 1986. This POM delta 13C transition from -23.2 % at 53.3 degrees S to values as low as -30.3 % at > 62 degrees S does not track previously reported abrupt changes in water chemistry and plankton species composition associated with the Polar Front Zone that resides at approximately 58 degrees S in this region. Also, the north-south isotopic trend is not accompanied by significant changes in POM carbon or nitrogen concentrations, or in POM C/N. Differences in plankton standing crop or biochemistry (e.g., lipid content) therefore do not appear responsible for the isotopic trends observed. The latitudinal change in POM delta 13C is, however, highly correlated with water temperature and with the calculated concentration of CO2 (aq) at equilibrium with atmospheric CO2. These observations are consistent with the hypothesis that [CO2 (aq)] significantly influences POM delta 13C in ocean surface waters.

Phosphatase activity in relation to phytoplankton composition and pH in Swedish lakes

SUMMARY. 1. Potential phosphatase activity and phytoplankton from several lakes of different character were compared in order to evaluate the importance of lake water pH and phytoplankton composition for the activity and pH optimum of lake water phosphatases.2. In oligotrophic lakes, in which phytoplankton biomass was most often dominated by Ochromonadaceae spp., optimum phosphate activity was found at pH values &lt;6. In eutrophic lakes, where species of Cyanophyceae and Bacillariophyceae dominated the phytoplankton biomass, optimum phosphatase activity was found at pH 7.5 or 8.5.3. The pH optimum of phosphatase activity often differed from the corresponding lake water pH.4. Experimental variation in phosphorus availability resulted in predictable changes in phosphatase activity. However, specific phosphatase activity, calculated per biomass of phytoplankton, was dependent on plankton species composition.

Influence of a Thermal Electric Generating Station on Water Chemistry and Distribution of Plankton

Thirty-one locations within a 3- by 6-km area, bordering Lennox Generating Station (Bay of Qunite, Lake Ontario), were sampled during the summer thermal stratification period. Distributions of crustacean zooplankton, rotifers, phytoplankton, and selected chemical parameters in near-surface waters were determined prior to, during, and following capacity pumping of the station, over a 2-week period. Effects of station operation on species composition or abundance of plankton occurred primarily in the immediate discharge area, affecting a region of approximately 1 km 2. Similarly, reduced levels of turbidity and pH, and an increase in concentration of dissolved silica, occurred in the discharge area. These changes were attributed to relocation of cooling water, which was drawn from the hypolimnion and returned to the lake surface.

Time scales and mechanisms of estuarine variability, a synthesis from studies of San Francisco Bay

This review of the preceding papers suggests that temporal variability in San Francisco Bay can be characterized by four time scales (hours, days-weeks, months, years) and associated with at least four mechanisms (variations in freshwater inflow, tides, wind, and exchange with coastal waters). The best understood component of temporal variability is the annual cycle, which is most obviously influenced by seasonal variations in freshwater inflow. The winter season of high river discharge is characterized by: large-scale redistribution of the salinity field (e.g. the upper estuary becomes a riverine system); enhanced density stratification and gravitational circulation with shortened residence times in the bay; decreased tissue concentrations of some contaminants (e.g. copper) in resident bivalves; increased estuarine inputs of river-borne materials such as dissolved inorganic nutrients (N, P, Si), suspended sediments, and humic materials; radical redistributions of pelagic organisms such as copepods and fish; low phytoplankton biomass and primary productivity in the upper estuary; and elimination of freshwater-intolerant species of macroalgae and benthic infauna from the upper estuary. Other mechanisms modulate this river-driven annual cycle: (1) wind speed is highly seasonal (strongest in summer) and causes seasonal variations in atmosphere-water column exchange of dissolved gases, resuspension, and the texture of surficial sediments; (2) seasonal variations in the coastal ocean (e.g. the spring-summer upwelling season) influence species composition of plankton and nutrient concentrations that are advected into the bay; and (3) the annual temperature cycle influences a few selected features (e.g. production and hatching of copepod resting eggs). Much of the interannual variability in San Francisco Bay is also correlated with freshwater inflow: wet years with persistently high river discharge are characterized by persistent winter-type conditions.

Vertical distribution and isotopic fractionation of living planktonic foraminifera from the Panama Basin

A model1,2, which explains the vertical and seasonal distribution of planktonic foraminifera was developed using data from the western North Atlantic and is comprised of three tenets: (1) The conditions in the photic zone (upper 80–100 m) exclusively dictate planktonic foraminifera species composition and abundance throughout the water column. (2) Species are vertically stratified within the photic zone according to their temperature preference. Depth distribution according to temperature preference has been proposed by several authors3 based on isotope analyses of sediments. Due to seasonal temperature variations, seasonal variations in the δ18O composition of seawater, and species-specific isotope fractionation, rigorous proof of this hypothesis cannot be provided from sediment analyses alone. (3) The chlorophyll maximum is a major food source zone, which is preferentially exploited by foraminifera. Our data from the Panama Basin, which are presented here, are confirmation of this model. The Panama Basin in the eastern equatorial Pacific, which has a shallow and steep thermocline, was sampled for living planktonic foraminifera. A multiple opening–closing net and environmental sensing system (MOCNESS)4 was used to collect 13 sets of eight vertically stratified oblique samples. We report here the quantitative distribution and stable isotopic composition of planktonic foraminifera from four MOCNESS tows taken over 5 days, during August 1979 (RV Knorr cruise 73) at 5°20′ N, 8°50′ W. Each tow consisted of eight samples which integrated ∼12.5-m intervals from 0 to 100 m for MOC 126, 25-m intervals from 0 to 200 m for MOC 127, 100–150-m intervals from 0 to 1,000 m on MOC 128 and 250-m intervals from 0 to 2,000 m on MOC 131.

Limnological Studies on Fukuji Reservoir at Higashi-son, Okinawa Island

The physicochemical conditions and the species composition of plankton in Fukuji Reservoir on Okinawa Island, which has a subtropical climate, were investigated for about a year-long period covering the main seasons from June 1980 to February 1981. In the summer thermal stratification was markedly developed, but was not observed in winter. The water temperature was considered to form the various limnological characteristics in the reservoir. With respect to plankton, 17 genera and 38 taxa were recorded from the fixed station. Green algae were the most abundant plankton in the summer, and diatoms developed profusely in the winter. The zooplankton were surprisingly few in both number and species during the winter. The development of plankton in the summer was found to he associated with the abundance of inorganic nutrients such as NH4+ and PO43-. According to Hutchinson's classification, the Fukuji Reservoir seems to fall into the plankton group X (mesotrophic or eutrophic desmids).

Some aspects of the chemical composition of plankton from the North-Western Mediterranean Sea

Plankton samples were collected from different parts of the Liguro-Provencal Basin during 1979 and 1980 (nearshore and open waters, respectively). Carbon, nitrogen, phosphorus, silicium, aluminium, iron, manganese, zinc, copper, cadmium and mercury concentrations have been determined in these samples. The species composition of plankton has been studies. The results indicated that species composition as well as sampling dates and location are factors of great importance when considering the chemical composition of plankton. Carbon, nitrogen and phosphorus concentrations display variations, but their ratios appear to be almost constant in the various samples. The other elements, except zinc, seem to be less concentrated in plankton from open waters than from coastal waters. The concentrations found are in good agreement with those reported in the literature by various authors.

Phytoplankton and cooling systems: Temperature effects using different intake and discharge depths

The effect of depth of intake and controlled discharge of heated waters ( Δ T—10°C) on a natural phytoplankton community in a cold water lake was studied using polyethylene enclosures. Changes in plankton species composition and cell concentrations were used as indicators of temperature effects. Of three intake-discharge arrangements studied (surface intake-surface discharge; deep intake-deep discharge; deep intake-surface discharge) only the first design produced statistically significant increases in plankton numbers. A deep intake-surface discharge resulted in the least biological and physical changes in the lake water. Phytoplankton species succession in the heated water was similar to patterns observed in the open lake.