Showing papers in "International Review of Hydrobiology in 1983"

Selective Predation in Freshwater Zooplankton Communities

Abstract: The impact of selective predation in freshwater zooplankton communities is examined with special emphasis on the ecological and evolutionary consequences for the prey. The behavioral interactions between predators and prey are reviewed, and the general patterns in age- and size-selective predation are derived in a semi-quantitative model. The final section explores the life history adaptations that zooplankton have evolved in response to these different patterns of selective predation.

Qualitative and quantitative interactions between microphytobenthos and herbivorous meiofauna on a brackish intertidal mudflat

Abstract: Micro- and meiofauna are the predominant consumers of diatoms on a brackish intertidal mudflat. The impact of grazing on the benthic diatom populations was studied by field observations and feeding experiments on a few abundant members of the community. Only small fractions of the microphytobenthic biomass and production are converted by herbivores. A hypothesis is presented explaining the growth kinetics and productivity of diatom populations and the inefficient transfer of carbon into herbivore foodchains. Data on feeding rate and population dynamics of the nematode species, Eudiplogaster pararmatus, are discussed in view of the seasonal succession of edible diatom species.

Subsurface chlorophyll maximum and associated Cyclotella pulse in Lake Superior

Abstract: An investigation of the subsurface chlorophyll layer (SCL) in Lake Superior was conducted from 1 May through 15 October. During spring unstratified conditions (1 May–17 July), chlorophyll a and phytoplankton biomass were vertically and temporally uniform. Phytoflagellates such as Rhodomonas minuta, Cryptomonas spp., and Ochromonas spp. were dominant at this time. The photosynthetic maximum was associated with the depth receiving 10% of surface irradiance, ca. 15–25 m. Once thermal stratification occurred, a SCL developed around 20 m. Although epilimnetic chlorophyll concentrations remained similar to spring mixing levels, concentrations in the SCL increased 3-fold. In situ production was the principal process associated with the development of the SCL. The upper portion of the SCL was dominated by Cyclotella species; C. stelligera, C. comensis, and C. ocellata. The increased abundance of Cyclotella appeared to be related to stable irradiance fields produced during thermal stratification.

Size Structure of Deep‐Sea Meio‐ and Macrobenthos in the Western Pacific

Abstract: The size structure of deep-sea meio- and macrobenthos was studied using 12 USNEL box corer samples collected in the Western Pacific. Both macro- and meiobenthos decreased in abundance with increasing water depth, as expected, but contrary to previous findings, the rate of decrease did not differ significantly between the two size classes of organisms. The median size index of total meiobenthos decreased with increasing water depth, while when the vertical distribution of organisms in the sediment was considered, such a trend was restricted to the organisms found in the upper 1 cm layer. In contrast, the median size of the nematodes increased with increasing water depth, and a possible cause for this correlation is discussed.

Revision of the Genus BosminaBAIRD, 1845 (Crustacea, Cladocera)

Abstract: The genus Bosmina can be differentiated into four subgenera: 1. Bosmina s. str. BAIRD, 1845, 2. EubosminaSELIGO, 1900, 3. NeobosminaLIEDER, 1957, and 4. SinobosminaLIEDER, 1957. Subgeneric discrimination is based upon several features of the females (postabdominal claw, serration of the mucro, patterns of the lateral head pores) and, mainly, upon certain differences in the morphology of the male (postabdomen and, according to LILLJEBORG 1900, BURCKHARDT 1924 and KOŘINEK 1971, the first leg). The distribution of the Bosmina subgenera throughout the world varies: Bosmina s. str. is distributed worldwide (except for Australia?), Eubosmina is holarctic, Neobosmina has been found in Africa, the neotropical zone, Australia and Oceania, and Sinobosmina occurs in East and South-East Asia.

Oxygen Consumption and Dissolved Inorganic Nutrient Production in Marine Coastal and Shelf Sediments of the Middle Atlantic Bight

Abstract: The benthic oxygen demand and inorganic nutrient release have been investigated in the coastal zone of the Mid-Atlantic Bight of the United States using in situ and ship-board incubations to estimate fluxes across the sediment-water interface. Oxygen demand ranged from ca. 70 ml m−2 hr−1 nearshore in warm (25°C) muddy sediments to ca. 4 ml m−2 hr−1 in cold (6°C), coarse-grained sediments offshore. Ammonium ion flux was out of the sediments in all but 4 of 29 incubations, while nitrate was often found to be utilized within or on the sediments, decreasing in 10 of 29 incubations. Those locations with fluxes of nitrate out of the sediment had concentrations in the pore water that were generally high, sometimes up to several mM l−1. Nitrate fluxes were always well below those of ammonia, even where high almost equivalent concentrations of both NH4 and NO3 were found at the same locale. On George's Bank only 13 % of total N demand by the phytoplankton was estimated to be supplied by the benthos, whereas in New York Bight the supply amounted to 42 % of the demand. This difference can be attributed to higher pelagic biological and advective (mixing and upwelling) inputs to George's Bank compared to the relatively well stratified New York Bight in late summer and autumn.

Introgression as a Factor in the Evolution of Polytypical Plankton Cladocera

Abstract: The genera Bosmina and Daphnia offer considerable taxonomical difficulties due to the existence of a very great number of different races. An attempt has been made to understand this phenomenon mainly as the result of introgressive processes.

Growth Kinetics of Microcystis aeruginosa (KÜTZ) KÜTZ as a Basis for Modelling its Population Dynamics

Abstract: The dependence of the specific growth rate of Microcystis aeruginosa (KUTZ); KUTZ f. aeruginosa upon temperature and light intensity was determined under continuous illumination in batch cultures. The result can be well described by the function: where μmax = 3.44.d−1, Topt = 33.2°C, Tmin = 18.3°C and KI = 71.4 Wm−2. The validity of this function is limited to the range of 10–28 °C and light intensities from 5–25 Wm−2. The dependence of the specific growth rate on the nutrient concentration was investigated a t 25°C and 24 Wm−2 light intensity by means of chemostat cultures. The half saturation constants related to the maximum specific growth rate of 1.1 d−1 measured under these conditions were 0.44 μmol.I−1, 4.3 μmol.I−1 and 26.5 μmol.−1 for orthophosphate, nitrate, and ammonium, respectively.

Estimating competition in cladocerans using data on dynamics of clutch size and population density

Abstract: L'existence d'une correlation negative entre la taille de la ponte et la densite de la population est proposee comme preuve de competition intra- et interspecifique chez les cladoceres du lac mesotrophe Glubokoye (region de Moscou). Un chevauchement important de la niche ecologique a ete trouvee pour les diverses populations etudiees

The Natural History of a Nearctic Temporary Pond in Ontario with Remarks on Continental Variation in such Habitats

Abstract: The seasonal succession of members of the invertebrate community of a temporary vernal pond in southern Ontario is described. Although succession was essentially continuous, 5 faunal groups are suggested, based on time of appearance and duration of active forms in the pond. Some species were found during virtually the entire aquatic phase, while others completed their life cycles in only 2-3 weeks. Analysis of growth rates revealed many different patterns between species and groups. Analysis of community structure in terms of trophic status indicated shifts which coincided with the seasonal occurrence of the pond's potential food resources. Comparison of this fauna with that of a similar pond on Vancouver Island, British Columbia (some 2,400 km to the west) showed many similarities in niche occupancy, including 6 species in common. The biological characteristics leading to the success of these cosmopolitan species in temporary aquatic habitats is discussed.

Degradation of macromolecular organic compounds in a tropical lagoon (Ciénaga grande, Colombia) and its ecological significance

Abstract: Primary production and decomposition of organic substances were investigated in a tropical lagoon during the rainy season. Production and mineralization were measured using the oxygen method. Total bacteria numbers and biomasses were estimated with epifluorescence microscopy, and the enzymatic degradation capacity of model substrates was determined photometrically. These parameters were measured in the water and sediment of the lagoon itself and also in its effluents and incoming waters. The aim of the study was to determine the sites of highest microbial activity in the lagoon and to compare its activity with other coastal water bodies. Since the shallow water lagoon contains a large amount of particulate matter, it was of special interest to study the degradation of this material and its influence on the microbial population. It was found that up to 14 % of the bacteria colonized the particles and that 62 % of the respiration originated in the particle fraction >8 μm. Highest exoenzymatic activities were measured in the sediment and water of the mangrove belt. It is concluded that decomposition and conditioning of particulate organic matter play dominant roles in the recycling of organic carbon in the lagoon.

A Comparative Study of Respiration Rates of Some Aquatic Oligochaetes in Relation to Sublethal Stress

Abstract: Aquatic oligochaete species selected on the basis of pollution tolerance or intolerance as determined from field studies were used to determine respiration rates under standard conditions, after exposure to sublethal levels of environmental variables (pH, salinity, temperature) or toxicants (Cd, Hg, NaPCP) alone or in pairs. Respiration rates, critical oxygen levels and degree of regulation were not correlated with field-determined tolerance to organic pollution. Stress factors caused increased or lowered respiration rate, loss of regulation (partial or total) and sometimes shifts in critical oxygen level. Regulation was improved in the face of some stresses. Combined stresses produced additional changes in respiration rates and regulation. These responses were complex, which makes them useful indicators of specific stress factors but also indicate complex mechanisms behind the observed changes.

Production and Ecology of Benthic Chironomid Larvae (Diptera) in Lake Hayes, New Zealand, a Warm‐monomictic Eutrophic Lake

Abstract: The distribution and abundance of larval chironomids in Lake Hayes were studied from December 1973 to March 1975. The mean annual production of the two dominant species, Chironomus zealandicus and Chironomus sp. a, was 29.2 g m−2 dry weight which is approximately 4.3 % of the average annual phytoplankton production in the lake. A high annual P/B ratio of 18.5 is consistent with the multivoltine life cycle of C. zealandicus. Larval chironomid production in the second summer when Anabaena blooms were absent was only one quarter of that in the first summer and is consistent with the hypothesis that the production of benthic chironomids in Lake Hayes is closely linked to that of the phytoplankton through the sedimentation of autochthonous organic matter.

Theory of the upper limit to phytoplankton production per unit area in natural waters

Abstract: Using the maximum quantum yield of photosynthesis, the maximum daily integral of photosynthetically active radiation (PAR) and the euphotic zone depth as a basis, general formulae for the upper limits to gross and net carbon fixation in natural waters are derived by theoretical considerations. The results are compared with a set of extremely high production data published by independently working authors, including data from algal mass cultures, oxidation ponds, freshwater and salt lakes, reservoirs, rivers and canals, coastal and other marine waters, including upwelling areas. The comparison reveals a quite surprising degree of agreement and suggests that the derived formulae represent a new, theoretically sound general approach to phytoplankton production. In particular, it can be shown that the upper limit to phytoplankton production in natural waters is about three times higher than earlier estimates in the literature. The maximum energy efficiency is of the same order of magnitude as in terrestrial plant communities.

Sediment Composition, Mud-water Interchanges and the Role of Macrophytes in Dal Lake, Kashmir

Abstract: The particulate phase of lake sediments showed a marked reduction in the concentration of N, P, K and C during late spring and summer. Larger amounts of these elements were found towards the autumn, and these higher levels were maintained through winter until early spring. The reduction in the concentration of these mineral nutrients was greatest during the growing season of the macrophytes.

Comparative Morphology of Arthropod Exterior Surfaces with the Capability of Binding a Film of Air Underwater

Abstract: The air-binding surfaces of aquatic and semi-aquatic insects and spiders were examined under a scanning electron microscope. The bristles that are instrumental in binding the film of air show distinctive characteristics within each phylogenetic group. Very small species can often maintain themselves in a bubble of air underwater although they lack the dense bristle coat characteristic of larger plastron breathers. Relatively large insects generally require a morphologically adapted chamber in which to carry their air supplies. The ecological advantages of an underwater respiration employing portable air are discussed.

Evaluation of Succession in an Estuarine Macrobenthic Soft‐Bottom Community near Tampa, Florida

Abstract: A subtidal macrobenthic infaunal community was quantitatively sampled monthly from February 1975 to July 1978 (42 months). During that period, complete defaunation (presumably due to hypoxia) occurred three times at approximately annual intervals. The recovery of the community was examined for successional patterns by quantitative and qualitative normal and inverse classification analyses and by rank-order analysis of the dominant species. There was no consistent pattern of succession from recovery to recovery. Samples taken just after defaunation were not similar to each other and no consistent suites of species were detected. Classical succession in which suites of species are successively replaced by other suites until a persisting suite of species occurs (faciliation model) was not found. Other models of succession are discussed.

The Natural Feeding and Resource Partitioning of Erpobdella octoculata L. and Erpobdella testacea SAV. in Lake Esrom, Denmark

Abstract: The natural feeding and competitive interactions between populations of Erpobdella ostoculata and Erpobdella testacea were investigated in Lake Esrom, Denmark, during 1979/80. Statistical analysis revealed that the size of the leeches was the main factor involved in resource utilization. Size-specific feeding included differences in the numerical composition of diets and the size of individual prey. Five weight classes of Erpobdella spp. were distinguished. The number of prey per leech increased from 1.63-2.84 for the first to the fifth weight class, whereas diversity in feeding averaged 1.71 prey per leech. Quantification of competitive interactions indicated that the temporal differences in weight class composition of the two species were sufficient to explain coexistence, although both species have an annual life cycle, and neither species showed taxonomic food refuges.

Effect of Filter‐feeding Zooplankton on Phytoplankton in Fish Ponds

Abstract: The effect of filter-feeding zooplankton on phytoplankton was investigated in two fish ponds near Blatna (southwestern Bohemia, Czechoslovakia) using enclosures of 50 liters volume. Filter-feeding activity had a positive effect on the growth of individual net phytoplankton (> 40 μm) species except for Aphanizomenon flos-aquae and Melosira granulata. Except for Schroederia setigera nanoplankton species (< 40 μm) were suppressed by the filter-feeding zooplankton. In bags without zooplankton the addition of nutrients induced growth of nanophytoplankton species, but no significant differences were noted in bags with zooplankton.

Macrobenthic Communities of the Lower Chesapeake Bay. II. Lynn‐haven Roads, Lynnhaven Bay, Broad Bay, and Linkhorn Bay

Abstract: Based on 96 grab samples at 16 sites the composition and distribution of macrobenthic fauna were examined in a small coastal basin of lower Chesapeake Bay. Normal classification analysis of dominant species produced five site groups. Site groups were divided into clean sand sites, fine sand sites with varying amounts of silt-clay, and mud sites. Dominant species of the clean group were primarily restricted to this sediment type, while the dominant species of the other groups were widespread in the study area.

The Possible Importance of Primary Amino Nitrogen in Nitrogen Regeneration by Coastal Marine Sediments in Buzzards Bay, Massachusetts

Abstract: To investigate the role of primary amino nitrogen (PAN) in nitrogen regeneration by marine sediments, the distribution and fluxes of PAN in organic-rich coastal sediments off Massachusetts (USA) were investigated. Decreases with depth in the sediment of total organic carbon, organic nitrogen, and PAN contents indicate that organics with C to N ratios of about 6, such as primary amines, are selectively consumed. Near the sediment surface, dissolved PAN (DPAN) accumulates and supports a large DPAN flux into the water column and this flux greatly exceeds the inorganic nitrogen flux. Consumption of C, N, and PAN was investigated using diagenetic equations describing their exponentially decreasing distributions with depth and which included the effects of sediment mixing, sediment accumulation, and consumption, considered to be a first-order reaction rate. Calculations showed that the reaction rate constant for PAN was between 5.1 and 26.1 times faster than that for the utilizable organic N and the depth-integrated consumption of PAN accounted for between 8.6 and 43.9% of the N disappearance rate. These ranges are estimated when sediment accumulation dominates over sediment mixing (the lower values) and when mixing dominates over accumulation (the upper values). Although the magnitude of D is unknown, these calculations indicate that PAN, which comprises less than 2% of the organic N, has an important role in sedimentary nutrient dynamics because of its enhanced reactivity.

On the Occurrence of “Arctic” Cladocera with Special Reference to those along the Strait of Belle Isle (Quebec, Labrador, Newfoundland)

Abstract: In September, 1978, ten ponds inhabited by Cladocera were sampled along the coasts of the Strait of Belle Isle. Fourteen out of nineteen species that were found there also occur in Greenland. On the other hand, a comparison with faunal lists for the island of Newfoundland and several faunal regions of Western Europe, and the ecological distribution of all European Cladocera reveals that the Arctic is settled exclusively by euryecious species, so that the relatively strong “arctic” element within the cladoceran fauna along the Strait of Belle Isle indicates simply the extreme conditions. Macrothrix hirsuticornis NORMAN & BRADY and Daphnia pulex LEYDIG are new for the island of Newfoundland.

Trace Metal and PCB Content of Mussels (Mytilus edulis) from the Southwestern Baltic Sea

Abstract: The concentrations of polychlorinated biphenyls and 28 metals were determined in mussels from 32 stations in the southwestern Baltic Sea. Elevated levels of PCBs (up to 28 mg/kg lipids) were found in harbour areas. Increased amounts of some metal contaminants were found in three large areas. The discharge from a sewage plant is responsible for high residues at stations in the outlet of Kiel Fjord. Increased levels of heavy metals in the outer Flensburg Fjord and in the vicinity of Fehmarn Sound seem to be due to natural geological formations, as indicated by the occurrence of elements that usually are not found at high concentrations in anthropogenic wastewaters.

Macrobenthic Communities of the Lower Chesapeake Bay. III. Southern Branch of the Elizabeth River

Abstract: Macrobenthic invertebrates of an industrialized seaport ecosystem were studied seasonally from October, 1977 through July, 1978. Five stations were selected along the Southern Branch of the Elizabeth River, Virginia. The benthic community was dominated by eurytopic species that were not affected by minor to moderate stresses induced by man's activities in the seaport. Caution is required when benthic communities of the lower polyhaline to mesohaline zones of an estuary are used to indicate the effects of anthropomorphic alterations.

Study of Domestic Sewage Waste Treatment by the Polychaetes, Neanthes japonica and Perinereis nuntia var. vallata, on an Artificial Tidal Flat

Abstract: In order to establish a new biological method of treating sewage waste, mass cultures of the polychaete annelids, Neanthes japonica and Perinereis nuntia var. vallata, were employed. These species are known to ingest a large quantity of sewage sludge extracted from domestic sewage treatment plants. During this study, laboratory experiments were carried out to determine the effects of changes in various environmental factors on sludge consumption and growth. A pilot plant with an artificial tidal flat simulating natural estuarine tidal flat conditions was constructed and operated as a habitat for the polychaetes. The suitability of this artificial tidal flat for the treatment of sewage waste was discussed.

Ingestion Rates of Some Daphnia Species in a Shallow Lake (Lake Balaton, Hungary)

Abstract: Filtering rates of three species of Daphnia were studied in situ by the 14C technique during the summer in a lake with a water temperature of 20-25°C (Lake Balaton, Hungary). The renewal time of gut contents proved to be 3-5 min in each of the three species whether fed on natural or artificial food. From May to September, filtering rates of D. cucullata, D. hyalina and D. galeata averaged 7.8, 10.3 and 9.2 ml ind.−1 day−1, respectively. Identically long individuals of all three species had almost the same filtering rates in spring, whereas in summer animals of identical weights had similar filtering rates regardless of species because of the length variability of the helmets. The grazing rate of adult filter-feeding crustaceans is suggested to be approximately 7 % per day.

Biological Studies of the Pearl Spot Etroplus suratensis (Pisces, Cichlidae) from three Different Habitats in Sri Lanka

Abstract: The morphometry, feeding habits and reproductive biology of Etroplus suratensis, an indigenous cichlid food fish, were studied for a period of one year on specimens from three different habitats in Sri Lanka. The morphometric studies implied that the length weight relationships are curvilinear. Macrophytic fragments formed the most important component of food, although detritus, diatoms, and animal matter are also ingested. First sexual maturity is attained in the length ranges 8.0-9.0 cm in females from brackish water habitats. Fecundity ranged from 700-3900 eggs in mature specimens. The wide range of the gonadosomatic index suggests that spawning occurs several times during the year.