bluuebunny/crossref_metadata_2025 huggingface dataset:
Picoplankton in Six New Zealand Lakes: Abundance in Relation to Season and Trophic State
Authors: Burns Carolyn W. , Stockner John G.
Published: February 2007

The abundance of picoplankton (0.2‐2 μm) was measured seasonally in the surface waters of six New Zealand lakes that represent a range of trophic states. The lakes were: Wakatipu, Te Anau, Manapouri, Hayes, Mahinerangi and Ross Creek Reservoir. Among the lakes, picoplankton abundance was associated positively with temperature; picoplankton were most abundant in summer and autumn when they attained densities of 108,000‐270,000 cells/ml in the oligotrophic lakes. In these lakes, prokaryotic picoplankton was generally an order of magnitude more abundant than eukaryotic picoplankton. Consistent with the hypothesis that picoplankton are more important in oligotrophic than eutrophic ecosystems, there was a weak negative correlation between the density of prokaryotic picoplankton in the lakes and the level of chlorophyll a. The presence of large numbers of chroococcoid cyanobacteria in the guts of Ceriodaphnia dubia and Bosmina meridionalis implies that prokaryotic picoplankton are collected, but not digested, by these species.
The Seasonal Dynamics and Composition of Photosynthetic Picoplankton Communities in Temperate Lakes in Ontario, Canada
Authors: Pick Frances R. , Agbeti Michael
Published: February 2007

The seasonal abundance and composition of photosynthetic picoplankton (0.2‐2 μm) was compared among five oligotrophic to mesotrophic lakes in Ontario. Epilimnetic picocyanobacteria abundance followed a similar pattern in all lakes; maximum abundance (2‐4 × 105 cells · ml−1) occurred in late summer following a period of rapid, often exponential increase after epilimnetic temperatures reached 20 °C. In half of the lakes picocyanobacteria abundance was significantly correlated with temperature, while in other lakes the presence of a small spring peak resulted in a poor correlation with temperature. In all lakes there was a significant correlation between epilimnetic abundance and day of the year. Correlations with water chemistry parameters (soluble reactive phosphorus, total phosphorus, particulate C: P and C: N) were generally weaker or insignificant. However, in the three lakes with the highest spring nitrate concentrations, a significant negative correlation with nitrate was observed. During summer stratification, picocyanobacteria abundance reached a maximum within the metalimnion and at or above the euphotic zone (1% of incident light) in all lakes. These peaks were not related to nutrient gradients.

The average total phytoplankton biomass ranged from 0.5 g m−3 (wet weight) in the most oligotrophic lake to 1.4 g m−3 for the most mesotrophic with picoplankton biomass ranging from 0.01 g m−3 to 0.3 g m−3. Picocyanobacteria biomass comprised 1 to 9 % of total phytoplankton biomass in late summer, but in one year for one lake represented a maximum of 56%. Other photosynthetic picoplankton (unidentified eukaryotes, Chlorella spp. Nannochloris spp.), although less abundant (103 cells · ml−1) than picocyanobacteria, represented biomass equal or greater than that of the picocyanobacteria in spring and early summer. On average, half of the photosynthetic picoplankton biomass was eukaryotic in the more coloured lakes, while in the clear lakes less than 20% was eukaryotic. Among the lakes there was a significant positive correlation between the average light extinction coefficient and the proportion of eukaryotic biomass of the picoplankton.

In mesotrophic Jack's Lake, the contribution of picoplankton to the maximum photosynthetic rate ranged from 10 to 47% with the highest values in the spring (47%) and late summer (33%), as a result of eukaryotic picoplankton and picocyanobacteria respectively. Picocyanobacteria cell specific growth rates were high during July (0.6‐0.8 day−1) and losses were close to 80% of the growth rate. Thus, despite low biomass, photosynthetic picoplankton populations appeared to turn over rapidly and potentially contributed significantly to planktonic food webs in early spring and late summer.
Autotrophic Picoplankton: Community Composition, Abundance and Distribution across a Gradient of Oligotrophic British Columbia and Yukon Territory Lakes
Authors: Stockner John G. , Shortreed K. S.
Published: February 2007

Autotrophic picoplankton communities were examined in eleven oligotrophic lakes from a broad geographic region of western Canada, representing a variety of physico‐chemical and biological conditions. During our study, several of the lakes were treated with additions of inorganic nitrogen and phosphorus fertilizers. Picoplankton communities in most lakes were dominated (>70%) by unicellular or colonial coccoid cyanobacteria, provisionally identified by morphological and autofluorescence properties as Synechococcus. Also common in some lakes were red‐fluorescing cyanobacteria and Chlorella‐like eucaryotes. Autotrophic picoplankters contributed from 36‐63% to total chlorophyll, from >2‐26% to total phytoplankton carbon, and from 29–53% to total photosynthesis. Average populations ranged from >5‐10,000 cells·ml−1 in winter and early spring to 65‐75,000 cells · ml−1 in summer and fall. Peak densities in most lakes occurred in August‐September and most populations were within the epilimnion or metalimnion/hypolimnion boundary. Subsurface peaks were prevalent only in untreated, strongly stratified lakes. Eucaryotic picoplankters became dominant in acidic (pH < 6.2), humic lakes. Colonial picoplankters were more common in more productive interior lakes in August, and though present, were uncommon in coastal systems. Picoplankton populations exhibited large increases under ice in a Yukon lake, and their abundance and seasonal distribution showed little relation to temperature or to light. Fertilization of lakes resulted in picoplankton population increases (>2x) and the elimination of subsurface peaks. Nutrients were considered to be one of the major factors controlling population abundance in these oligotrophic lakes with average pH < 6.5.
The Nitrogen Budget of a Shallow Lake (Großer Müggelsee, Berlin)
Authors: Dudel Gert , Kohl Johannes‐Günter
Published: February 2007

The nitrogen budget of Lake Gr. Müggelsee (mean depth 4.85 m, area 7.12 km2) was calculated from weekly measurements of nitrogen transformations from 1978 to 1984. Common mass balances for nitrogen were completed by determination of dinitrogen fixation in order to calculate denitrification as residual budget component and resolved for distinct seasonal periods. N sedimentation was calculated from internal P balance. Influence of flushing rate on loss processes were analysed by comparison of years with very different runoff. Time series analyses and multiple comparison show a relation of hydraulic flow, nitrate load, in‐lake nitrate and N elimination to the seasonal cycle of irradiance. Denitrification is the most important loss process and exceeds the effect of sedimentation. Other in‐ and outputs (precipitation, swimmers, volatilization) are rather stochastic and of lower quantitative importance. Nitrate leaching from the catchment and turbulent mixing within the lake are discussed as determining factors of in‐lake nitrogen fluxes.
Investigation of the Shelf Ecological System on the Basis of Modeling and Field Work
Authors: Belyaev V. I. , Konduforova N. V. , Mikhajlov E. A.
Published: February 2007

Mathematical modelling of the ecosystem of the North‐West shelf of the Black Sea is based on the method of aggregation and averaging with the subsequent hierarchic decomposition (BELYAEV, 1987; BELYAEV and KONDUFOROVA, 1989). This approach includes the step‐by‐step comparison of the modelling results with field observations. The observations have been performed during the integrated oceanographic expedition of the research vessel “Professor Kolesnikov” (1987), for the first time specially organized to verify the modelling results. The comparison of the results of modelling and observation demonstrated that their agreement is satisfactory quantitatively and qualitatively. The efficiency of using models of optical fields for verification is also shown.
Population Dynamics, Growth and Productivity of Abra ovata (Mollusca, Bivalvia) in the Evros Delta (North Aegean Sea)
Authors: Kevrekidis Th. , Koukouras A.
Published: February 2007

Monthly samples of Abra ovata were collected during February 1983‐January 1984 in the Evros Delta (N. Aegean Sea). Population density (mean annual value = 2407.5 ind · m−2) was characterized by seasonal variation. An analysis of the length frequency distributions shows that one annual recruitment of juveniles (> 2 mm) occurred in October‐January; and also that, throughout the year, two age groups existed in the population. One growth ring was formed on the shells of the oldest age group during July‐August.

Mean growth in shell length can be described by Bertalanffy function. A positive correlation existed between shell length and decalcified dry weight.

Secondary production in A. ovata, calculated by the instantaneous growth method, showed a mean biomass of 29.221 g dry weight m−2yr−1, a productivity of 17.086 g dry weight m−2yr−1 and an annual turnover ratio of 0.59.
Seasonal Dynamics of Planktonic Community Metabolism in Newly Constructed Tropical Ponds in a Swampy Area
Authors: Radheyshyam  , Naik D. R.
Published: February 2007

Studies on community metabolism in newly constructed ponds on a swampy area were made over a period of twenty‐four months from November, 1981 to October, 1983. The fluctuations in the gross and net primary productions, photosynthetic efficiency and assimilation efficiency are discussed. The productivity of ponds was apparently influenced by the physico‐chemical and biological environment of the water. pH, secchi disc transparency, phosphate and nitrate‐N were negatively correlated with gross primary productivity, while temperature, conductivity, total alkalinity and ammonium‐N showed positive correlation. The phytoplankton also exhibited positive correlation with primary production. The P/R ratio ranged between 1.79 and 2.91, indicating a high degree of self maintenance of the system. The solar energy conversion efficiency through photosynthesis ranged between 0.17 % and 1.08 % in the first year and 0.09 % and 0.05 % in the second year. Annual average assimilation efficiency ranged between 37.32 % and 56.58 %.
A Study on the Impact of Urban and Industrial Development in the Linggi River Basin, Malaysia. 2. Chemical Environment
Authors: Khan I. S. A. Nather
Published: February 2007

An investigation of the chemical environment of the Linggi River Basin was carried out at 15 main and 27 supplementary stations between January 1983 and January 1984. Spatial and temporal changes in pH, specific conductivity, alkalinity, chloride, ammonia‐nitrogen, nitrite‐nitrogen, nitrate‐nitrogen, orthophosphate, dissolved oxygen, BOD, and diurnal variations were studied in relation to influence of various kinds of pollutants. The chemical composition of natural water analysed at a few undisturbed forest stream stations in the basin can be considered very good. A drastic change in river water quality was noticed in downstream polluted stations. The pH in the basin varied from 4.05 to 10.5 units, conductivity from 23.0–1,500 umhos/cm, alkalinity from 6.0–1,388 mg/l, chloride from 0.9–160.9 mg/l, orthophosphate from 0.5–5.21 mg/l, ammonia‐N from 0.001–53.75 mg/l, nitrite‐N from 0.0–8.2 mg/l, nitrate‐N from 0.03–6.77 mg/l and BOD3, from 0.32–384.0 mg/l and COD from 0.02 to 79.2 unit. Among all the rivers, very high values were recorded at Kundor, Simin and Linggi (sensu stricto).
Population Dynamics of Crustacean Zooplankton in a Mesotrophic Lake, with Emphasis on Boeckella hamata BREHM (Copepoda: Calanoida)
Authors: Burns Carolyn W.
Published: February 2007

The crustacean zooplankton in Lake Mahinerangi, a polymictic, mesotrophic reservoir, were studied for 19 months. The cladocerans, Bosmina meridionalis and Ceriodaphnia dubia, had unimodal patterns of abundance with peak densities in summer; cyclopoids had a single peak of maximum abundance in autumn and Daphnia carinata showed a bimodal pattern with peak densities in early summer and early winter. The strong seasonality in abundance of zooplankton in Lake Mahinerangi distinguishes this lake from other temperate lakes in New Zealand and may reflect its cool winter temperatures (< 5 °C for 2 months). A calanoid, Boeckella hamata, bred throughout the year and was the dominant species numerically. Instar analysis indicated that there were at least three, and possibly four, generations per year. Instantaneous birth and death rates were low with annual mean values (0.036 and 0.057, respectively) that were 2‐3.5 times less than those recorded in a population of the same species in Lake Pounui, but within the range of those recorded in calanoid populations elsewhere in New Zealand. The Boeckella population in Lake Mahinerangi appears to be controlled largely by temperature, parasitism and food, with predation having no, or a negligible, effect.
The Concept of Seasonal Succession Theory Applied to Phytoplankton Through the Coupling Use of Diversity Index and Rank‐Frequencies Diagrams in a Eutrophic Ecosystem
Authors: Aleya Lotfi , Devaux Jean
Published: February 2007

Seasonal succession of phytoplankton was studied in a eutrophic lake (Lake Aydat, Massif Central, France), from March to November 1985.

An attempt is made to check the succession stages of the concept of ecological succession theory using either the H‐diversity index of SHANNON and WEAVER or the FRONTIER'S rank‐frequencies diagrams. A description of a stage 3 community was only possible through the use of the latter diagrams.
Development, Reproduction and Growth Pattern of two Coexisting, Pond Dwelling Cladocerans
Authors: Maier Gerhard
Published: February 2007

Laboratory investigations on life history parameters of 2 coexisting cladocerans (Daphnia obtusa. Moina brachiata) from a nearly temporary pond in South Germany revealed that the species have different temperature tolerances and temperature optima. D. obtusa experienced the highest reproductive success at 15 and 20 °C and was able to survive and to reproduce at 2 °C but died at 30 °C. The reproductive success of M. brachiata was highest at 25 and 30 °C and the species could not withstand temperatures <15 °C and ≥35 °C. At temperatures between approximately 20 and 25 °C, where both cladocerans coexisted in nature, M. brachiata showed a faster population growth due to its approximately twofold higher egg production rates (10–12 eggs female−1 day−1 compared to approximately 5 eggs female−1 day−1 in D. obtusa) and its shorter juvenile development (3.3 and 2.4 days compared to 6.3 and 5.3 days in D. obtusa); M. brachiata needs generally only 3 molts to reach maturity while D. obtusa requires 5–6 molts.
Dispersions‐, Abundanz‐ und Dominanzdaten von koexistierenden Hydroporus‐Imagines (Coleoptera; Dytiscidae) aus sekundären Moorgewässern
Authors: Behr Hauke
Published: February 2007

The population dynamic of coexisting Hydroporus‐species (adults) living in 2 secondary bog pools is described. Both pools are charakterized by a typical community structure, persisting over a period of 4 years. They also differ in physical and chemical properties. None of the 5 coexisting populations in a shaded pool is dispersed equally. Most individuals were kept in an area of 0–20 cm water depth. On an average 42–100 individuals/m2 were recorded from a pool lying in a secondary birch swamp (Betuletum pubescentis).
Unterschiede in Eibiologie und Habitatbindung zwischen Prosimulium tomosvaryi (Prosimuliini) und verschiedenen Simuliini (Diptera, Simuliidae)
Authors: Timm Tobias
Published: February 2007

Differences in Egg‐biology and Habitat Binding between Prosimulium tomosvaryi (Prosimuliini) and Simuliini (Diptera, Simuliidae)

Oviposition of the mountain black fly Prosimulium tomosvaryi (Enderlein, 1921) (tribe Prosimuliini) takes place in May in the „Niederbergisch‐Märkisches Hügelland”︁ (North Rhine‐Westphalia). The eggs aestivate until late November. They differ in morphology, egg‐layers and germ band‐formation from tribe Simuliini. The development is negatively correlated with temperature: the embryo develops slowly, but without a pause at low temperatures (<10°C), while high temperatures (>12°C) prevent development (temperature controlled dormancy). It is explained that distribution of Prosimulium species in Central Europe is limited by the potency of the terrestrial egg stage.
Phytoplankton Staining Using Coomassie Brilliant Blue G
Authors: Lohner‐Schurig Sigrun , Stelzer Ralf , Schmidt Ahlert
Published: February 2007

A method is introduced to a) distinguish phytoplankton organisms from organic matter and b) ease its determination by staining protein structures with Coomassie Brilliant Blue G.
Seasonal and Spatial Distribution of Vitamin B12 in a Coastal Area of Eastern Mediterranean Sea
Authors: Moschopoulou N. , Ignatiades L.
Published: February 2007

The seasonal and spatial distribution of vitamin B12 was investigated in Eastern Mediterranean (Saronicos Gulf, Aegean Sea). Vitamin B12 concentration had an annual range 0.12–7.93 ng. 1−1 and an annual mean 1.88 ng. 1−1. The statistical analysis of data indicated significant seasonal and regional variations of vitamin B12 in this area and an inverse relationship of this vitamin with chl a. The results showed that the Eastern Mediterranean Sea contains less vitamin B12 than the Western Mediterranean Sea.
Addition to Water‐borne Fungal Spora of Western Ghat Streams, India
Authors: Sridhar K. R. , Kaveriappa K. M.
Published: February 2007

Conidial propagules encountered in foam samples of three lotic sources in Western Ghat forests of India are reported. Nine species can be assigned to known genera of water‐borne hyphomycetes. Five kinds of conidia could not be assigned to known genera. Some of the conidia resemble spore types reported from Africa, Thailand and Malaysia.
Thermal Regime and Stability of Jurumirim Reservoir (Paranapanema River, São Paulo, Brazil)
Authors: Henry Raoul
Published: February 2007

Thermal regime and stability in Jurumirim Reservoir (São Paulo, Brazil) were studied for a year. Isothermy and thermal stratification were observed from June to September and from October to March, respectively. The annual heat budget was 14.0 Kcal · cm−2 and average heat gain per day was 67.2 cal · cm−2 · day−1. Maximum stability and wind work reached 324.2 and 3,037.5 g · cm · cm−2, respectively. According to thermal structure and heat content, Jurumirim Reservoir was classified as a warm tropical monomictic lake.
The Seasonal Dynamics and Trophic Relations of the Plankton Components in Lake Peipsi (Peipus)
Authors: Nõges Tiina , Haberman Juta , Timm Malle , Nõges Peeter
Published: February 2007

The seasonal dynamics of the biomass and production of phyto‐, zoo‐ and bacterioplankton was investigated during the vegetation periods (from May to November) in 1985 and 1986 in the pelagial of the large eutrophic lake Peipsi (Estonia). The average values of productions per vegetation period for the investigation years were as follows: phytoplanktion − 203.5 gC · m−2; bacterioplankton − 37.9 gC · m−2; filter‐feeding zooplankton − 20.6 gC · m−2 and predatory zooplankton − 1.5 gC · m−2. The herbivorous zooplankton production constituted 10.1% of primary production. This ratio indicates a direct relationship between zoo‐ and phytoplankton in the food chain — filtrators are feeding mostly on living algae and the detrital food chain seems of little importance. The dominance of large forms (Melosira sp., Aphanothece saxicola), in the phytoplankton during the major part of the vegetation period is assumed to be a result of high grazing pressure on small algae. Zooplankton grazing was investigated in situ in a specially constructed twin bathometer. Experimental measurements revealed, that zooplanktion presence in the experimental vessel actually stimulated the phytoplankton growth in many cases — the negative grazing values have been registered. That could be caused by the stimulation effect of nutrients (N, P), excreted by the concentrated zooplankton in the grazing chamber, which led to an increase of the nongrazed phytoplankton production. Bacteria have satisfied the zooplankton food requirements on average by 11%. Grazing on bacteria increased, when grazing on phytoplankton was somehow disturbed.
Long‐Term Temporal and Spatial Fluctuations of Soft Bottom Infaunal Invertebrates Associated with an Ocean Outfall from the San Pedro Shelf, California
Authors: Maurer Don , Robertson George , Gerlinger Thomas
Published: February 2007

Temporal (annual) and spatial fluctuations of soft‐bottom invertebrates from 1977 to 1988 were reviewed and analyzed from an ocean outfall area on the San Pedro Shelf, California. Several dominant species which occurred throughout the monitoring period provide continuity between early sampling efforts and recent ones. Annual fluctuations in the mean number of species, abundance, diversity and biomass were generally conservative compared to spatial fluctuations. Temporal changes of note include a marked reduction in abundance and biomass between 1981 and 1984 and another decline in biomass in 1988. The former was associated with conditions of the 1982–1983 El Niño, and the latter with a shift in population dominance from a bivalve to a polychaete.

Mean abundance and biomass were enhanced by the outfall without a significant reduction in number of species. The response of the biota to the outfall extended further upcoast (northwest) than downcoast.

Several hypotheses were posed and briefly examined. These include the effects of total suspended solids generated from the outfall, and the role of the “Three Little Pigs” (bivalve‐Parvilucina tenuisculpta CARPENTER, ostracod‐Euphilomedes carcharodonta (SMITH), polychaete‐Capitella capitata (FABRICIUS)) in influencing benthic community structure. Finally, measures of infauna from the San Pedro Shelf were, except for abundance, very similar to those reported from other California shelf areas. Through time and space the outfall has had limited negative effect on infaunal community structure.
Time Compatibility of Water Chemical Lake Variables
Authors: Håkanson Lars
Published: February 2007

This paper summarizes results from extensive field work in 95 Swedish lakes. The focus is on methodological aspects of importance when establishing the time compatibility of traditional water variables (monthly data on pH, Secchi depth, temperature, alkalinity, total‐P, conductivity, Fe, Ca, hardness and colour from 4 years, 1986 to 1989). From most textbooks in limnology, it is evident that there exist patterns, in terms of how the concentrations and the variability of the concentrations of these standard variables vary in lakes. Then it would be interesting to see if there exists patterns also for the time compatibility between different lake variables and different variants of the same variable, i.e., mean values from different periods. This issue is discussed in a systematic way in this paper with statistical methods. These results are of importance in ecosystem analyses, monitoring and modelling. These parameters generally vary in a lake, both temporally and areally, the focus here is on such variations and how to express lake‐typical, time compatible values for longer periods of time. Selected results: High correlations (r2‐values) exist between (1) mean annual pH and all the variants of alkalinity and lake colour for different periods of time. (2) between mean (3 year) total‐P and most of the variants of total‐P, especially those from the winter period (months 10 to 12; r2 ≈ 0.95), but not for the variants from the spring and the summer periods, when the variability is great for total‐P, (3) between mean (3 year) lake colour and most of the variants of Fe and pH, especially those from the first half of the year for pH and those from the second half of the year for Fe. Quite high r2‐values, about 0.5, exist between colour and different variants from the winter period for total‐P and Secchi depth.
Long‐Term Trends in the Nutrient Input and In‐Lake Concentrations of a Drinking Water Reservoir in a Dense Populated Catchment Area (Erzgebirge, Germany)
Authors: Horn W. , Horn H. , Paul L.
Published: February 2007

The concentrations of soluble reactive and total phosphate, silicate, and nitrate in the tributaries and in the watercolumn of the meso/eutrophic reservoir Saidenbach were investigated at weekly or fortnightly intervals. The results are presented as annual averages over 16 years (from 1975 till 1990) and show a gradual increase of the N‐ and P‐concentration in the inlets caused by an intensification of the agriculture in the drainage basin and high domestic sewage releases from the settlements having no waste water treatment. The silicate concentration of the inlets remained constant. Consequently, also a rise of the in‐lake concentrations of the two P‐fractions was observed. The nitrate concentration of the reservoir Saidenbach increased till 1978, but showed no significant trend over the whole investigation period. The drop of the in‐lake silicate concentration during the eighties has to be explained by diminished discharges and, most of all, a higher biological activity as a consequence of the increased P‐loading.

Intra‐annual concentrations calculated as winter, spring, summer (epi‐ and hypolimnion) and autumn means show the distinct seasonal periodicity of the phosphorus and silicon cycles. Therefore, annual average in‐lake concentrations of these nutrients are not quite good measures reflecting changes of the trophic conditions, but rather the winter and early spring values are. No correlations were detected between the annual mean concentrations and the loads. On the other hand, no remarkable seasonal cycling of the nitrate concentrations could be observed and, in this case, a clear dependence exists between annual mean concentrations and loads.

The results found for the tributaries of the meso/eutrophic reservoir Saidenbach were compared with those observed in the inlets of the neighbouring oligotrophic reservoir Neunzehnhain. Here the phosphorus concentrations remained almost constant during the time of investigation, but the nitrate concentrations increased too. This must be attributed to agriculture, air pollution and forest management.
Spring‐Summer Succession of Planktonic Rotifers in a South Andes Lake
Authors: Modenutti Beatriz E.
Published: February 2007

The dynamics of planktonic rotifer in Laguna Ezquerra (Rio Negro, Argentina) was studied from October 1988 to March 1989, in relation to food resources and cladoceran populations. During the spring and summer period, total rotifer density differed markedly. In spring rotifer populations remained at low density and an inverse relationship with cladoceran biomass was found. In contrast, in summer, the rotifer densities increased greatly and a positive relationship with cladoceran biomass was observed. Food resources decreased during mid January and this seemed to give rotifers a competitive advantage over cladocerans. Bosmina longirostris and Ceriodaphnia dubia were both present during the spring, but only Bosmina prevailed in summer. The composition of cladoceran assemblages together with food resources seem to be an important factor in rotifer dynamics.
Allochthonous Input of Coarse Particulate Organic Matter (CPOM) in a First to Fourth Order Austrian Forest Stream
Authors: Weigelhofer G. , Waringer J. A.
Published: February 2007

The allochthonous input of coarse particulate organic matter (CPOM) at the Mauerbach, a low order Austrian forest brook, was investigated from October 1990 to November 1991. Annual input rates ranged from 361.5 to 716.2 g dry weight m−2 for the direct input and 46.6 to 594.9 g m−1 for the lateral input. Input rates were influenced by the composition and density of the riparian vegetation and the bank inclination. The temporal distribution of the direct input showed an autumnal maximum (50–70% of the total), whereas for the lateral input an autumn (30–50%) and a spring (19%) peak were observed. Along the course of the stream, the proportion of the lateral input increased with decreasing stream width. Total annual input for the Mauerbach was 21.8 t CPOM, with 73.4% due to direct and 26.6% due to lateral input.
Polymorphism and Food Limitation in Three Daphnia carinata Populations
Authors: Chapman M. A. , Burns Carolyn W.
Published: February 2007

The annual cycles of Daphnia carinata in three fish‐free ponds in southern New Zealand (Quarry, Taieri and Raupo Ponds) are described. Although breeding was continuous, the populations were frequently dominated by distinct cohorts and there was a sexual phase in spring. Growth rates, particularly in Quarry Pond, were often slow, and clutch sizes generally small. Egg and neonate sizes changed seasonally, but changes were not closely related to clutch sizes and body lengths. In Taieri Pond and Raupo Pond some D. carinata grew to 6.14 mm and carried clutches of up to 154 eggs. The potentially high fecundity associated with large size makes D. carinata a good coloniser, but our studies showed that it also survives well in poor food conditions by growing slowly and producing only 1–2 eggs per clutch.

D. carinata showed marked seasonal polymorphism in tailspine length and development of head crests. In winter, crests were absent and tailspines were short and varied little with body length. Crests were first apparent, and tailspines began to elongate, in early spring, before the first appearance of a notonectid, Anisops wakefieldi. By midsummer, tailspines had increased markedly with body length but the slope of the relationship declined in autumn. Laboratory trials showed that both tailspine length and crest development increased in the presence of Anisops. These increases may be due to water‐soluble factor(s) produced by Anisops.
Feeding Rate of Brachionus plicatilis O. F. Müller on Two Types of Food Depending on Ambient Temperature and Salinity
Authors: Lebedeva L. I. , Orlenko O. N.
Published: February 2007

Feeding rates of Brachionus plicatilis were studied for two types of food — algae Monochrysis lutheri and baker's yeast Saccharomyces cerevisae. The main regularities of changes in filtration rate and ration were studied in small culture volumes (1 ml) for adult amictic females depending on food concentration (1, 2, 4, 8 and 16 · 106 cells · ml−1), ambient temperature (16 and 26 °C), and salinity (5, 10, 15, 20, 25 and 30 ppt). B. plicatilis ration did not depend on the salinity, but was largely determined by temperature and food concentration. It was found that at 16 and 26 °C the dependence of the ingestion rate (ration) on food concentration differed greatly. A hypothesis was suggested to explain this phenomenon. A critical concentration of both types of food at which the increase in the rotifer ration ceased is 4 · 106 cells · ml−1. This is the minimum “background” food concentration for B. plicatilis mass cultivation.

The average rations measured at the concentration of M. lutheri and S. cerevisae of 4 · 106 cells · ml−1 where 1.3 ± 0.1 and 4.8 ± 1.3 μg dry weight. · ind−1 · day−1 at 26 °C and 0.54 ± 0.1 and 1.9 μg d. w. · ind−1 · day−1 at 16 °C, respectively. The rations obtained in the laboratory were corrected for the conditions of rotifer commercial production in the open field in summer time. The correct values were 0.86 and 0.72 μg d. w. · ind−1 · day−1 for algae and yeast, respectively.
A Quantitative Photographic Survey of ‘Spoke‐Burrow’ Type Lebensspuren on the Cape Verde Abyssal Plain
Authors: Bett Brian J. , Rice Anthony L. , Thurston Michael H.
Published: February 2007

A photographic survey of the seafloor was conducted during RRS Discovery cruise 204 in September/October 1993 at the oligotrophic site of the French EUMELI programme at c. 21° N: 31° W (4650 m) on the Cape Verde Abyssal Plain. Two systems were used, a wide angle system (WASP) obtaining usable photographs covering 10 to 30m2, and an epibenthic sledge mounted system obtaining photographs of about 2 m2.

A total of more than 3000 usable frames were obtained, covering about 64000 m2 of seafloor. The photographs indicated an epibenthic invertebrate megafaunal density of 5.2 hectare−1 and a demersal fish density of 1.8 hectare −1. In contrast, the photographs were dominated by lebensspuren, particularly of the ‘spoke‐burrow’ type usually attributed to echiurans. Spoke‐burrow density, where related burrows and other features such as sediment mounds are considered unitary, is estimated at 871 hectare −1. We describe and quantify the five principal types of spoke burrow encountered in this study and, on the basis of these observations and some morphometric studies of the lebensspuren, discuss the possible behaviour of their producers.

We have no direct knowledge of the production rate of, or longevity of, lebensspuren in the study area. However, based on a number of assumptions and limited data from other areas we suggest that trace producer (mainly echiurans) density is on the order of tens of individuals per hectare. These trace producers probably greatly outnumber the rest of the invertebrate megabenthos, and we can only guess at the role this potential large population of hidden benthos might have in the overall structure and function of the deep‐sea floor ecosystem.
Observations on the Diet of Some Slope Dwelling Fishes of Southern Portugal
Authors: Saldanha Luiz , Almeida Armando J. , Andrade Francisco , Guerreiro José
Published: February 2007

The diets of 33 fish species from the southern Portuguese slope, at depths between 498 and 740 m were studied through the examination of stomach contents. Species of scyliorhinids, squalids, rajids, chimaerids, anguilliforms, notacanthids, macrourids, gadids and merluccids, with pelagic, benthope‐lagic and benthic modes of life were examined. Nezumia sclerorhynchus feeding habits were studied in detail. Its diet its dominated by amphipods. No differences of prey preferences were recorded corresponding to predator size classes. The studied predators can exploit a wide range of prey, but they feed mainly on benthopelagic and epibenthic material. Consequently it is difficult to establish distinct feeding guilds, so confirming a generalist type of feeding for most of the upper slope dwelling fishes.
Biogenic Sediment Compounds in Relation to Marine Meiofaunal Abundances
Authors: Soltwedel Thomas , Thiel Hjalmar
Published: February 2007

Correlations between a series of biogenic sediment compounds, commonly used in ecological studies, and a major component of the benthic infauna, the meiofauna, were studied on the continental margin off Southwest Africa (Angola) and in a central oceanic region of the Atlantic Ocean (Mid Oceanic Ridge). Biogenic sediment compounds chosen for this investigation (electron‐transport‐system activity, total adenylates and energy charge, particulate proteins, chloroplastic pigments) are obviously not suitable for a quick and rough estimation of meiofaunal abundances. Nevertheless, biogenic sediment compounds might reflect quite well the activity and biomass of the total benthic infauna, including all size classes (from bacteria to macrofaunal organisms) and/or the total particulate organic matter within the sediments. Furthermore, analyzing biogenic sediment compounds leads to a better understanding of environmental conditions and biological activities of benthic organisms. Consequently, despite their limitations, biochemical sediment parameters may be very useful in benthic ecological studies to obtain rapid information on the eco‐status of the benthic system.
Comparison of the Vertical Distribution of Nematodes from Two Contrasting Abyssal Sites in the Northeast Atlantic Subject to Different Seasonal Inputs of Phytodetritus
Authors: Lambshead P. John D. , Ferrero Timothy J. , Wollf George A.
Published: February 2007

The vertical distribution of nematodes in the sediments of three cores from the phytodetritus‐influenced Porcupine Abyssal Plain station is compared with three cores from the Madeira Abyssal Plain station in the DEEPSEAS programme. Nematode vertical distributions are compared with sediment organic chemistry data sampled at the same time from the same sites. The results support the two hypotheses erected by Thiel (1983) that the penetration of meiofauna into deep‐sea sediments might be correlated with the input of organic matter and that a greater biological activity of larger organisms would increase the penetration of nematodes into the sediment through increase downward transport of food material.
Extraction of Prokaryotic Genomic DNA from Marine Microbial Communities Suitable for Amplification Using the Polymerase Chain Reaction
Authors: McInerney James O. , Paskins Lynn , Eardly Donal , Patching John W. , Powell Richard
Published: February 2007

We present a method for extraction of DNA from marine microbial communities and amplification of the small subunit ribosomal RNA gene from the prokaryotic organisms contained therein. Results of cloning, sequencing and phylogenetic analyses are also presented. This DNA extraction technique is specifically designed to be used in conjunction with the Polymerase Chain Reaction (PCR). Emphasis was placed on producing a technique which results in total cell lysis yielding DNA of sufficient purity to facilitate amplification using PCR. Minimisation of surface contamination and procedure suitability for a multi‐sample study were considered to be of prime importance throughout this investigation. As a demonstration of the suitability of the technique, a preliminary analysis of the small subunit ribosomal RNA (SSU rRNA) gene from marine microbial communities was investigated. The amplification reactions are designed to specifically target the SSU rRNA gene from the two primary prokaryotic domains: Bacteria and Archaea sensu Woese (Woese et al., 1990). The primers were designed to amplify a sequence exceeding 1 Kb in length which is sufficient for use in taxonomic and phylogenetic analyses of marine communities (Murray and Schleifer, 1994). The samples used represent spatially and temporally distinct regimes, from the North East Atlantic. These include water samples from open ocean sites and gut contents from a deep sea deposit feeder, Oneirophanta mutabilis (Holothuria: Elasipodida). The analysis shows the identification of a group of unusual Archaea. as‐yet uncultured, in the samples analysed.
Brachionus calyciflorus Pallas (Rotatoria) in Inland Waters of Tropical Latitudes Brachionus calyciflorus Tropical in Waters
Authors: Kutikova L. A. , Fernando C. H.
Published: February 2007

The widely distributed Brachionus calyciflorus was studied for morphological variation based on material from all tropical areas. The subspecies B. calyciflorus borgerti Apstein is redescribed and its subspecific status affirmed. Various forms with local distributions were noted and described and the morphological differences are attributed to a variety of possible factors. From the distribution patterns it is clear that rotifers are governed by the general principles that apply to other invertebrates and are not cosmopolitan. There are evidently dispersal centres for Brachionus calyciflorus and its subspecies borgerti.
Habitats and Distribution Patterns of Marine Luminous Bacteria in the Western Baltic Sea
Authors: Schulz Claus‐Jürgen , Rheinheimer Gerhard
Published: February 2007

Numbers of luminous bacteria were counted at three stations of the brackish water ecosystem of the western Baltic Sea from July 1985 to July 1986. Additional samples were taken during three cruises from stations at the North Atlantic Ocean, the Norwegian Sea and adjacent marine areas. — In Kiel Bight (western Baltic) values varied between 0 and 68,000 luminous cfu 1−1. With exception of the coastal station a distinct seasonal distribution pattern was shown in a water depth of 20 m: high numbers found in summer were opposed to low numbers in winter, the peaks being rather high in comparison to those of other areas. Statistical analysis showed that the results of 20 m were significantly different from those of 0 and 10 m depth; however, there was no correlation with temperature and salinity. Taxonomic studies revealed that the population consisted primarily of the genus Photobacterium. — The optimum of salinity was not a brackish but a marine one and was about 30% for the majority of the strains tested. A smaller number of strains grew best at a salinity between 10 and 15%. Optima of temperature ranged from 15 to 20 °C for most of the test strains. — Taxonomic analysis was also performed with luminous strains from marine areas adjacent to the western Baltic Sea, Photobacterium being the dominant genus here, too. Luminous bacteria were also enriched from the external surface and the gut contents of whitings (Merlangius merlangus) and cods (Gadus morhua). A model is proposed which explains the distribution pattern found. According to this, the gut‐dwelling luminous bacteria are transported by their hosts from the North Sea into the western Baltic Sea. Here they are released into the environment, thus inhabiting another niche.
Defensive Reactions of Stream Ecosystems in the Early Stages of Pollution. Ecological Importance and Possibilities of Ecosystem‐Adequate Restoration Methods
Authors: Schönborn Wilfried
Published: February 2007

Defensive reactions of rhithron and epipotamon against low and early organic pollution are described. Hitherto two reactions could be found in streams: transformation of the epilithic energy flow to intensify microbial decomposition, and the mass production of Cladophora for elimination of biomass, nutrients, heavy metals and other noxious agents. The Cladophora production reaction leads to a centralization of the ecosystem, but functions incompletely. This can be compensated by an ecosystem‐adequate restoration method. Similarly the “whiting” (i.e. biogenic decalcification) during in pelagials Cladophora mass production happens at the expense of the benthic communities and may be called “dysoecism”.
The Seasonal Succession of Biotic Communities in Wetlands of the Tropical Wet‐and‐Dry Climatic Zone: III. The Algal Communities in the Pantanal of Mato Grosso, Brazil, with a Comprehensive List of the Known Species and Revision of two Desmid Taxa
Authors: De‐Lamonica‐Freire Ermelinda Maria , Heckman Charles W.
Published: February 2007

Studies conducted over a period of about 14 years in the northern part of the Pantanal of Mato Grosso revealed that there is a pronounced seasonal succession of algal communities resulting from periodic flooding and desiccation. Generally, during the high water period, the microflora is very sparse but species‐rich and dominated by the Desmidiales, which are notably inhabitants of mineral‐poor waters. During the dry season, the rapidly evaporating pools of water in the Pantanal often support extremely large concentrations of algae belonging mainly to other orders of Chlorophyta and to Euglenophyta. The seasons of rising and falling water levels are characterized by a mixed flora containing elements typical of both the high water and dry seasons, according to the local conditions that prevail. Dense beds of filamentous algae in the family Zygnemataceae are generally encountered only where there is inflow of nutrient‐rich water or another source of local eutrophication. The algae present belong overwhelmingly to cosmopolitan or circumtropical species. Their presence and relative abundance seem to be determined primarily by the concentrations of inorganic nutrients in the water. Of the 337 species observed, most are reported for the first time from the Pantanal, and the list of species provides the only comprehensive catalog of autotrophic microorganisms yet compiled for this vast wetland. The physical and chemical characteristics of the habitats in which the various algae occur and their relationships with the macrophyte communities are discussed. One variety of desmid is redescribed and given a valid name: Staurodesmus convergens (Ehrenberg ex Ralfs) Lillieroth var. teilingii DE‐Lamonica‐Freire nom. nov., and the taxonomic status of Cosmarium galiciense (Gutwinski) DE‐Lamonica‐Freire comb. nov. is revised.
Modelling of the Genetic Composition of Water Masses in Two Valley Reservoirs in the Volga Basin
Authors: Yershova M. G.
Published: February 2007

The theoretical basis, assumptions and algorithms of the one‐dimensional model CWMVR (Composition of Water Masses in Valley Reservoirs) are given. This model is intended for a diagnosis and forecast of the genetic composition of the river water masses and the main water mass of a reservoir in different seasons of wet or dry years. The results of the calculations of the water masses regime in the Mozhayskoye and Cheboksarskoye reservoirs are given using the hydrometric and chemical investigation in 1984. The errors of the model are estimated by comparison of the computed and measured values of conservative parameters of water quality in the quasi‐synchronous surveys of these reservoirs in 1972 and in 1983‐1985. A satisfactory graphical and statistical similarity (0.55 ≤ S/σ ≤ 0.66) among them is shown. The reasons of the largest errors of modelling and the ways of development of this model are discussed.
Taxonomic Characterization of Pseudohaplocaulus infravacuolatus nov. spec. and Vorticella chlorellata Stiller 1940, Epiplanktonic Peritrichs (Ciliophora, Peritrichia) Attached to Coenobia of Anabaena (Cyanophyta), Including a Redescription of V chlorostigma (Ehrenberg, 1831)
Authors: Foissner Wilhelm , Brozek Susanne
Published: February 2007

Pseudohaplocaulus infravacuolatus nov. spec. and Vorticella chlorellata Stiller, 1940. two peritrich ciliates attached to planktonic coenobia of Anabaena sp. (Cyanophyta). were investigated using live observation, silver impregnation, and scanning electron microscopy. Pseudohaplocaulus infravacuolatus differs from its nearest relative, P. anabaenae (Stiller, 1940). mainly by the location of the anterior contractile vacuole. Vorticella chlorellata has symbiotic green algae. a J‐shaped macronucleus. and a single, ventral contractile vacuole. The number of silverlines is very close to that of V. picta, but distinctly different from that of V. chlorostigma (Ehrenberg, 1931), an other green Vorticella, redescribed for the first time. Vorticella rhabdostyloides Kellicott, 1885 is recognized as a distinct species, but transferred to Haplocaulus: H. rhabdostyloides (Kellicott, 1885) nov. comb. Likewise, Vorticella fasciculuta Müller, 1773 is considered a distinct species and transferred to Pseudovorticella: P.fasciculata (Müller, 1773) nov. comb.
Hyphomycetes in Twenty Springs of the Knyszyn‐Bialystok Forest in Various Seasons
Authors: Czeczuga Bazyli , Orlowska Miroslawa
Published: February 2007

The aquatic mycoflora and environmental factors in 20 springs were analysed at monthly intervals for one year. At total of 102 Hyphomycete species was noted. 16 species are new records for Poland. The highest number of species was found in spring and autumn. the lowest number in winter.