scholarly journals Winter decrease of zooplankton abundance and biomass in subalpine oligotrophic Lake Atnsjøen (SE Norway)

2019 ◽  
Vol 78 (3) ◽  
Author(s):  
Thomas C. Jensen
Keyword(s):  
Water Temperature ◽  
Phytoplankton Biomass ◽  
Phytoplankton Bloom ◽  
Zooplankton Biomass ◽  
Zooplankton Abundance ◽  
Total Biomass ◽  
Total Zooplankton ◽  
Additional Food ◽  
Lake Ecosystems ◽  
Lake Atnsjøen

Despite the rapidly changing winter conditions in temperate ecosystems, little attention has been devoted to the effects of these changes on lake ecology. Few studies on the seasonal changes in abundance and biomass of the major groups of the metazooplankton community (i.e. rotifers, cladocerans and copepods) in northern oligotrophic lakes include data from the ice-covered winter months. This study reports monthly variation in zooplankton abundance and biomass from June 2010 to October 2011, including winter, in an oligotrophic, subalpine lake in southeastern Norway (Lake Atnsjøen). Changes in rotifer, cladoceran, copepod, and total zooplankton abundances and biomass were related to seasonal variation in water temperature and phytoplankton biomass by means of ordination analysis. The zooplankton abundance and biomass were much lower in winter than during the open water season. However, an under-ice phytoplankton bloom occurred during the final winter months, when snow cover and ice thickness were reduced and (presumably) light penetration increased, leading to an increase in abundance of copepod nauplii. Winter zooplankton abundance was dominated by copepods and rotifers, while winter zooplankton biomass was dominated by copepods and cladocerans. Both phytoplankton and zooplankton had two biomass peaks in 2010 and one peak in 2011. Rotifers dominated zooplankton abundance with a peak in August and total zooplankton abundance followed a similar pattern. In contrast, cladocerans dominated zooplankton biomass with a peak in July and total zooplankton biomass also peaked at this time. Rotifer and total zooplankton abundance and rotifer biomass were most closely correlated to water temperature. However, cladoceran biomass and total biomass were most closely correlated with phytoplankton biomass, but also appeared to be dependent on other carbon sources. Estimates of non-phytoplankton particulate organic carbon indicated that this part of the carbon pool could be an additional food source for zooplankton particularly in early and mid-winter. The longer growing season in 2011 than in 2010, owing to earlier ice-off in 2011, may have contributed to higher phytoplankton and zooplankton biomass in 2011. With climate warming, this is an expected change in temperate lake ecosystems.

scholarly journals Zooplankton Distribution and Community Structure in the Pacific and Atlantic Sectors of the Southern Ocean during Austral Summer 2017–18: A Pilot Study Conducted from Ukrainian Long-Liners

2020 ◽  
Vol 8 (7) ◽  
pp. 488
Author(s):  
Evgeny A. Pakhomov ◽  
Leonid K. Pshenichnov ◽  
Anatoly Krot ◽  
Valery Paramonov ◽  
Ilia Slypko ◽  
...  
Keyword(s):  
Pilot Study ◽  
Southern Ocean ◽  
Ross Sea ◽  
Austral Summer ◽  
Water Layer ◽  
Zooplankton Biomass ◽  
Zooplankton Abundance ◽  
Total Biomass ◽  
Total Zooplankton ◽  
Zooplankton Dynamics

Preliminary results of the pilot study of the zooplankton in the region between the Ross and Scotia Seas from November 2017 to April 2018 are presented. In total, 53 zooplankton samples were collected in the top 100 m water layer using vertical tows of a 0.1 m2 Juday net from four Ukrainian longliners operating during the Antarctic toothfish fishery. Total zooplankton abundance ranged from 3 to 2836 ind m−3 with a global mean of 360 ± 550 (±1 SD) ind m−3. The highest abundances were recorded at the northeastern Ross Sea. At those stations, small copepods (mainly Oithona spp., Oncaea spp., Ctenocalanus spp. and copepod nauplii) numerically dominated the samples. Total biomass ranged from 0.3 to 85 mg DW m−3 with a mean of 10.9 ± 14.5 mg DW m−3. The highest biomasses were recorded at the eastern Ross Sea, where pelagic tunicates Salpa thompsoni, siphonophores and ctenophora Callianira sp. accounted for >90% of total zooplankton biomass. At other stations, zooplankton biomass generally ranged from 5 to 20 mg DW m−3 with no clear pattern in distribution. The community composition was driven by the sampling latitude and/or season rather than longitudinally. This pilot study emphasized the unique opportunity to investigate zooplankton dynamics in the regions traditionally not sampled during the oceanographic surveys. It also created unprecedented opportunities to increase the seasonal and geographical zooplankton sampling coverage using ships of opportunity at a fraction of a dedicated oceanographic survey costs. The potential of such surveys are enormous in both providing invaluable information, contributing to existing long-term databases and enhancing an international collaboration in the Southern Ocean, particularly in light of recent modeling initiatives of the whole Antarctic system undertaken by the Commission for the Conservation of Antarctic Marine Living Resources.

scholarly journals Seasonal variation in copepod abundance in relation to other zooplanktonic groups in the northwestern Mediterranean

1993 ◽  
Vol 62 (4) ◽  
pp. 215-226 ◽  
Author(s):  
Juliana H.M. Kouwenberg
Keyword(s):  
Seasonal Variation ◽  
Coastal Region ◽  
Zooplankton Biomass ◽  
High Abundance ◽  
Total Biomass ◽  
Total Zooplankton ◽  
Copepod Abundance ◽  
Bottom Depth ◽  
Total Zooplankton Biomass ◽  
Northwestern Mediterranean

Abundance of adult copepods and late copepodid stages from the upper 50 m in the Golfe du Lion (N.W. Mediterranean) was studied by the author in 1986, 1987, and 1988 for each season. Altogether 87 stations at 22 fixed locations were sampled in the frame of the multidisciplinary French/Spanish programme Pélagolion/Leopel in the near-coastal region (≤ 25 m bottom depth), the Rhone dilution zone, the neritic region (≤ 200 m bottom depth), and the oceanic region (200–2000 m bottom depth). Abundance of other zooplanktonic groups was estimated and total zooplankton biomass was determined for the upper 50 m. Copepod abundance was highest during September 1986 (all regions) and July 1987 (neritic). Total biomass was highest during July 1987 and May/June 1988, caused by high abundance of many other zooplankters.

scholarly journals Mesozooplankton structure and functioning during the onset of the Kerguelen phytoplankton bloom during the KEOPS2 survey

2015 ◽  
Vol 12 (14) ◽  
pp. 4543-4563 ◽  
Author(s):  
F. Carlotti ◽  
M.-P. Jouandet ◽  
A. Nowaczyk ◽  
M. Harmelin-Vivien ◽  
D. Lefèvre ◽  
...  
Keyword(s):  
Spring Bloom ◽  
Phytoplankton Bloom ◽  
Size Structure ◽  
Early Stage ◽  
Distribution Patterns ◽  
Zooplankton Biomass ◽  
Zooplankton Abundance ◽  
Mesozooplankton Community ◽  
Remarkable Feature ◽  
Kerguelen Islands

Abstract. This paper presents results on the spatial and temporal distribution patterns of mesozooplankton in the naturally fertilized region to the east of the Kerguelen Islands (Southern Ocean) visited at early bloom stage during the KEOPS2 survey (15 October to 20 November 2011). The aim of this study was to compare the zooplankton response in contrasted environments localized over the Kerguelen Plateau in waters of the east shelf and shelf edge and in productive oceanic deep waters characterized by conditions of complex circulation and rapidly changing phytoplankton biomass. The mesozooplankton community responded to the spring bloom earlier on the plateau than in the oceanic waters, where complex mesoscale circulation stimulated initial more or less ephemeral blooms before a broader bloom extension. Taxonomic compositions showed a high degree of similarity across the whole region, and the populations initially responded to spring bloom with a large production of larval forms increasing abundances, without biomass changes. Taxonomic composition and stable isotope ratios of size-fractionated zooplankton indicated the strong domination of herbivores, and the total zooplankton biomass values over the survey presented a significant correlation with the integrated chlorophyll concentrations in the mixed layer. The biomass stocks observed at the beginning of the KEOPS2 cruise were around 1.7 g C m−2 above the plateau and 1.2 g C m−2 in oceanic waters. Zooplankton biomass in oceanic waters remained on average below 2 g C m−2 over the study period, except for one station in the Polar Front zone (F-L), whereas zooplankton biomasses were around 4 g C m−2 on the plateau at the end of the survey. The most remarkable feature during the sampling period was the stronger increase in abundance in the oceanic waters (25 × 103 to 160 × 103 ind m−2) than on the plateau (25 × 103 to 90 × 103 ind m−2). The size structure and taxonomic distribution patterns revealed a cumulative contribution of various larval stages of dominant copepods and euphausiids particularly in the oceanic waters, with clearly identifiable stages of progress during a Lagrangian time series survey. The reproduction and early stage development of dominant species were sustained by mesoscale-related initial ephemeral blooms in oceanic waters, but growth was still food-limited and zooplankton biomass stagnated. In contrast, zooplankton abundance and biomass on the shelf were both in a growing phase, at slightly different rates, due to growth under sub-optimal conditions. Combined with our observations during the KEOPS1 survey (January–February 2005), the present results deliver a consistent understanding of patterns in mesozooplankton abundance and biomass from early spring to summer in the poorly documented oceanic region east of the Kerguelen Islands.

scholarly journals Interannual dynamics of zooplankton in the Kola Section of the Barents Sea during the recent warming period

2019 ◽  
Vol 76 (Supplement_1) ◽  
pp. i10-i23
Author(s):  
Irina P Prokopchuk ◽  
Alexander G Trofimov
Keyword(s):  
Barents Sea ◽  
Zooplankton Community ◽  
Zooplankton Biomass ◽  
Calanus Finmarchicus ◽  
The Arctic ◽  
Zooplankton Abundance ◽  
Total Zooplankton ◽  
The Barents Sea ◽  
Warming Period ◽  
Total Zooplankton Biomass

Abstract Our research focused on the analysis of interannual variability of zooplankton in the Kola Section (the Barents Sea) in the period of current warming in the Arctic basing on previously unpublished data. The zooplankton community was investigated based on the analysis of 240 plankton samples, collected in late May–early June 2009–2017. A total of 74 zooplankton taxa of nine phyla were identified in the plankton samples, but copepods were the most diverse and numerous taxonomic group. The biodiversity index varied considerably from year to year, but a stable tendency for the index to increase since the beginning of the period studied was observed. Copepods dominated in terms of abundance and biomass, comprising on average 73–96% of the total zooplankton abundance and 81–96% of the total zooplankton biomass. Calanus finmarchicus was the main zooplankton species utterly dominated by abundance and biomass (on average 92 and 97% respectively). Considerable differences in zooplankton abundance and biomass at different stations of the section were observed. Although the investigations were carried out during a warming period, interannual differences in zooplankton abundance and biomass were observed. Zooplankton biomasses were higher in the years with higher temperatures and stronger water inflow.

A VARIABILIDADE AMBIENTAL INFLUENCIA A COMPOSIÇÃO E BIOMASSA FITOPLANCTÔNICA DE UM RESERVATÓRIO NEOTROPICAL

2021 ◽  
Vol 25 (01) ◽  
pp. 90-102
Author(s):  
Bárbara Marques dos Santos ◽  
◽  
Silvia Moreira dos Santos ◽  
Cláudia Alves de Souza ◽  
Carlos Roberto Alves dos Santos ◽  
...  
Keyword(s):  
Water Temperature ◽  
Phytoplankton Biomass ◽  
Phytoplankton Community ◽  
Environmental Variability ◽  
Total Biomass ◽  
Dry Period ◽  
Rainy Period ◽  
Biomass Structure ◽  
Health Relevance ◽  
Spatio Temporal

Phytoplankton is an important model of the aquatic environments functioning, responding directly to environmental variability in space and time. Therefore, represents an excellent tool for the monitoring of reservoirs, which comprise highly heterogeneous ecosystems longitudinally, influencing the structure and distribution of phytoplankton species. The objective of this study was to investigate the variation in the composition and biomass of the phytoplankton in a reservoir in the Goiás state, Brazil, and how these organisms respond to environmental variability along the reservoir spatial extent in dry and rainy periods. The phytoplankton and environmental variables were collected during one dry period and other rainy, over seven sampling sites, distributed in the regions downstream of the dam, lacustrine, intermediate and lotic of the reservoir. The composition and biomass of the phytoplankton community were measured as a response to the spatial and temporal environmental variability. We recorded a spatio-temporal variation in water temperature, light, nutrients, and phytoplankton biomass. Cyanobacteria had the highest biomass in the lacustrine and intermediate regions, while diatoms in the lotic region, in both periods. The highest phytoplankton total biomass was recorded in rainy period. We recorded a clear relation between the phytoplankton biomass and the environmental variability, being that water temperature, turbidity and soluble iron the ones that showed the biggest influence on the biomass structure. Thus, the composition and biomass of the phytoplankton community can be important metrics of reservoirs functioning and, therefore, the phytoplankton study in these ecosystems it's of interest in their monitoring, since reservoirs have great ecological, economic or public health relevance

Crustacean Zooplankton Communities of Acidic, Metal-Contaminated Lakes Near Sudbury, Ontario

1980 ◽  
Vol 37 (12) ◽  
pp. 2282-2293 ◽  
Author(s):  
N. D. Yan ◽  
R. Strus
Keyword(s):  
Phytoplankton Biomass ◽  
Quantitative Data ◽  
Zooplankton Biomass ◽  
Crustacean Zooplankton ◽  
Total Biomass ◽  
Metal Levels ◽  
Total Phytoplankton ◽  
Average Biomass ◽  
Average Size ◽  
Zooplankton Communities

Crustacean zooplankton data for 1973 to 1978 from Clearwater Lake, an acidic, metal-contaminated lake near Sudbury, Ontario, are presented and compared with data from four other contaminated lakes near Sudbury and six uncontaminated lakes in the Muskoka–Haliburton Region of Ontario. Species richness and community biomass were reduced in the contaminated lakes, the latter because of reductions in numbers and average size of community dominants. The greatest reductions were observed in the lake with the highest metal levels, Hannah Lake. Cladocera were much more important contributors to total biomass in the contaminated lakes, forming, for example, 80–96% of the average biomass for the ice-free period in Clearwater Lake. An average of 89% of all adult Crustacea observed in Clearwater Lake were Bosmina longirostris (O. F. Müller). Zooplankton biomass in the contaminated lakes, excluding Hannah Lake, was not significantly correlated with pH, with Cu, Ni, or TP concentrations, or with total phytoplankton biomass. While similarities existed, community structure was different from that of acidic lakes in the La Cloche Mountains that were not contaminated with Cu or Ni. Hypotheses relating to how acidification alters typical phytoplankton–zooplankton interactions were constructed. The scarcity of quantitative data required to test such hypotheses is emphasized.

scholarly journals Zooplankton productivity in the coastal area of the southern Barents Sea in spring

2020 ◽  
Vol 5 (4) ◽  
pp. 3-14
Author(s):  
V. G. Dvoretsky ◽  
A. G. Dvoretsky
Keyword(s):  
Coastal Water ◽  
Barents Sea ◽  
Dry Mass ◽  
Zooplankton Biomass ◽  
Calanus Finmarchicus ◽  
Zooplankton Abundance ◽  
Total Zooplankton ◽  
Dominant Group ◽  
Hydrological Conditions ◽  
Oithona Similis

The results of the analysis of zooplankton assemblage state of the southern Barents Sea are presented. Zooplankton samples were collected during the cruise of the RV “Dalnie Zelentsy” in May 2016. Hydrological conditions were typical for Murmansk coastal water this season. A total of 47 zooplankton taxa were identified. Taxa number varied between stations, ranging 18–29, with copepods being a dominant group in zooplankton. The most frequent ones were Calanus finmarchicus, Metridia longa, Metridia lucens, Microcalanus spp., Oithona atlantica, Oithona similis, Pseudocalanus spp., copepod nauplii and ova, as well as cladoceran Evadne nordmanni, larvae of Echinodermata and Polychaeta, chaetognath Parasagitta elegans, and early stages of the euphausiids of the genus Thysanoessa. In populations of common copepod species Pseudocalanus spp. and Oithona similis, early age stages dominated, which indicated their continued reproduction. Total zooplankton abundance ranged from 748 to 6576 ind.·m−3, averaging 3012. Total zooplankton biomass varied from 17 to 157 mg of dry mass per m³, with a mean value of 83. The data obtained were comparable to those registered in Murmansk coastal water in July 2008 and were higher than those in August 2007. The authors suggest that it might be related to the differences in sampling seasons and hydrological conditions. Daily zooplankton production was estimated to be 0.49–4.04 mg of dry mass per m³, averaging (2.17 ± 0.17). These estimates were about twice as high as mean values, registered in Murmansk coastal water during summer period. This seems to be due to higher phytoplankton concentrations in spring. Total zooplankton stock for water area studied (25.8 thousand km²) was estimated to be 425,000 thousand tons of dry mass. Cluster analysis revealed four groups of stations that differ in relative abundance of Calanus finmarchicus, Copepoda nauplii, Oithona similis, larvae of Echinodermata, and appendicularian Fritillaria borealis. Spatial variation of zooplankton abundance was closely related to station location (latitude, longitude, and sampling depth), as well as bottom layer temperature and mean salinity at the station.

scholarly journals LONG-TERM CHANGES OF COPEPODA (CRUSTACEA) ABUNDANCE AND BIOMASS IN THE DANUBE AND ODESA REGIONS OF THE BLACK SEA AS INDICATOR OF WATER QUALITY

2021 ◽  
Author(s):  
Yuliia Kharytonova ◽  
◽  
Vasil Dyadichko ◽  
Keyword(s):  
Black Sea ◽  
Fish Larvae ◽  
Ecological Status ◽  
Zooplankton Biomass ◽  
The Black Sea ◽  
Total Biomass ◽  
Ecological State ◽  
Total Zooplankton ◽  
Main Components ◽  
Total Zooplankton Biomass

Copepoda are the most important zooplanktonic group constituting the primary food for fish larvae and some fishes. Copepoda have the longest life cycles among the Black Sea mesozooplankton, so their biomass and percentage of total zooplankton biomass is greatly reduced by eutrophication. The percentage of Copepoda from the total biomass of zooplankton is a reliable indicator of the ecological status of the water bodies. For the Black Sea marine waters the indicator of “good” ecological status (GES) is the average annual biomass of Copepoda, which exceeds 45% of the total biomass of zooplankton. Changes of total biomass of zooplankton, biomass of Copepoda, the abundance and biomass of dominant species – Oithona davisae Ferrari F. D. & Orsi, 1984, Acartia (Acartiura) clausi Giesbrecht, 1889 and A. (Acanthacartia) tonsa Dana, 1849 in the Danube and Odesa marine regions from 1970 to 2019 were analysed. Also the ecological quality class in the Nort-Western part of Black sea by Copepoda indicators from 2004 to 2017 were established according to Water Framework Directive US. The total zooplankton biomass had been decreasing in Ukrainian waters and % of Copepoda from total zooplankton biomass was increasing. These tendencies shown a positive change in the forage base of commercial planktophagous fishes and ecological class status of the investigated aquatories. The abundance and biomass of O. davisae, A. clausi and A. tonsa were decreased from 2016 to 2019. The highest values of their metrics were in 2016 and the lowest rates observed in 2019. O. davisae, A. clausi and A. tonsa were the main components of copepods number and biomass. The Acartia species formed higher part of Copepoda biomass than O. davisae. The ecological state was “good” (GES) only in Danube-Dnieper coastal waters and Danube delta in 2004–2017 where Copepoda formed more than 45 % of total zooplankton biomass. In waters of Northwester Black Sea bays, shallow and deepwater shelfs the ecological state was “Bad” (notGES), the part of Copepoda was lower than 45 %.

Planktivory by the predacious cladoceran Bythotrephes longimanus: effects on zooplankton size structure and abundance

1999 ◽  
Vol 56 (10) ◽  
pp. 1865-1872 ◽  
Author(s):  
Eva Wahlström ◽  
Erika Westman
Keyword(s):  
Size Structure ◽  
Zooplankton Community ◽  
Zooplankton Biomass ◽  
Zooplankton Abundance ◽  
Large Species ◽  
Bythotrephes Longimanus ◽  
Total Zooplankton ◽  
Natural Systems ◽  
Phytoplankton Communities ◽  
Zooplankton Communities

In order to study density-dependent effects of invertebrate planktivory, four different densities of Bythotrephes longimanus were inoculated into mesocosm enclosures with a mixed zooplankton community. Changes in size structure and abundance of zooplankton and phytoplankton communities were recorded over a period of 3 weeks. High densities of Bythotrephes were able to reduce total zooplankton abundance, which was mainly due to a decrease in the density of the relatively large species Holopedium gibberum. The density of the smaller species Bosmina longirostris was also reduced with increasing densities of Bythotrephes, whereas rotifer abundance remained largely unaffected. The mean size of Holopedium increased with increasing densities of Bythotrephes. Despite the decrease in total zooplankton biomass in high-Bythotrephes treatments, no effect of Bythotrephes density on primary producers was observed. Our experiment shows that predacious cladocerans may reduce macrozooplankton biomass, large as well as small species. Predation from invertebrate planktivores results in a zooplankton community consisting of larger individuals. Comparing our experimental densities with densities of Bythotrephes found in natural systems suggests that invertebrate planktivores may influence size structure and abundance of zooplankton communities even in lakes with planktivorous fish.

scholarly journals Mesozooplankton structure and functioning during the onset of the Kerguelen phytoplankton bloom during the Keops2 survey

2015 ◽  
Vol 12 (3) ◽  
pp. 2381-2427 ◽  
Author(s):  
F. Carlotti ◽  
M.-P. Jouandet ◽  
A. Nowaczyk ◽  
M. Harmelin-Vivien ◽  
D. Lefèvre ◽  
...  
Keyword(s):  
Phytoplankton Bloom ◽  
Size Structure ◽  
Early Stage ◽  
Zooplankton Community ◽  
Polar Front ◽  
Zooplankton Biomass ◽  
Individual Growth ◽  
Zooplankton Abundance ◽  
Remarkable Feature ◽  
Mesozooplankton Biomass

Abstract. This study presents results on the zooplankton response to the early phase of the northeastern Kerguelen bloom during the KEOPS2 survey (15 October–20 November 2011). The campaign combined a large coverage of the eastern part of the shelf and the adjacent oceanic regions with 2 quasi-perpendicular transects oriented south to north (between 49°08' and 46°50' S) and west to east (between 69°50' and 74°60' E) aiming to document the spatial extension of the bloom and its coastal-off shore gradient, and a pseudo-lagrangian survey located in a complex recirculation zone in a stationary meander of the Polar front nearly centered at the crossing of the 2 initial transects. In addition, 8 stations were performed for 24 h observations, distributed in key areas and some of them common with the KEOPS1 cruise (January–February 2005). The mesozooplankton biomass stocks observed at the beginning of the KEOPS2 cruise were around 2 g C m−2 both above the plateau and in oceanic waters. Zooplankton biomasses in oceanic waters were maintained in average below 2 g C m−2 over the study period, except for one station in the Polar Front Zone (FL), whereas zooplankton biomasses were around 4 g C m−2 on the plateau at the end of the cruise. Taxonomic composition and stable isotope ratios of size-fractionated zooplankton indicated the strong domination of herbivores. The most remarkable feature during the sampling period was the stronger increase in the integrated 0–250 m abundances in the oceanic waters (25 × 103 to 160 × 103 ind m−2) than on the plateau (25 × 103 to 90 × 103 ind m−2). The size structure and taxonomic distributions revealed a cumulative contribution of various larval stages of dominant copepods and euphausiids particularly in the oceanic waters, with clearly identifiable stages of progress during the Lagrangian survey. These different results during KEOPS2 suggested that the zooplankton community was able to respond to the growing phytoplankton blooms earlier on the plateau than in the oceanic waters. The reproduction and early stage development of dominant species were sustained by mesoscale-related initial ephemeral blooms in oceanic waters but individual growth was still food-limited and zooplankton biomass stagnated. On the contrary, zooplankton abundances and biomasses on the shelf were both in a growing phase, with slightly different rates, due to sub-optimal conditions of growth and reproduction conditions. Combined with the KEOPS1, the present results deliver a consistent understanding of the spring changes in zooplankton abundance and biomass in the Kerguelen area.

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