Recent shifts in the crustacean zooplankton community of Lake Huron

2009 ◽  
Vol 66 (5) ◽  
pp. 816-828 ◽  
Author(s):  
Richard P. Barbiero ◽  
Mary Balcer ◽  
David C. Rockwell ◽  
Marc L. Tuchman
Keyword(s):  
Primary Production ◽  
Zooplankton Community ◽  
Northern Region ◽  
Lake Huron ◽  
Crustacean Zooplankton ◽  
The South ◽  
Bosmina Longirostris ◽  
Nutrient Levels ◽  
Low Levels

Cladoceran populations in the open waters of Lake Huron declined abruptly in 2003 and have since remained at historically low levels. The two dominant cladocerans, Daphnia mendotae and Bosmina longirostris , have been nearly extirpated from the northern region of the lake and are present in only slightly greater numbers in the south. Average nonpredatory cladoceran biomass in the lake has declined over 90% between 1998–2002 and 2003–2006. In addition, historically unprecedented declines in cyclopoid copepods were seen in the lake in 2005. These changes have occurred against the backdrop of declining nutrient levels in the lake and have coincided closely with declines in the amphipod Diporeia . We speculate that a combination of reduced primary production in the open waters and intensified planktivory due to the continuing disappearance of Diporeia has accounted for the losses in crustacean biomass seen in recent years.

Effects of Low Concentrations of Cadmium on the Crustacean Zooplankton Community of an Artificially Acidified Lake

1987 ◽  
Vol 44 (S1) ◽  
pp. s163-s172 ◽  
Author(s):  
S. G. Lawrence ◽  
M. H. Holoka
Keyword(s):  
Zooplankton Community ◽  
Toxic Effects ◽  
Crustacean Zooplankton ◽  
Individual Species ◽  
Calanoid Copepods ◽  
Bosmina Longirostris ◽  
Low Concentrations ◽  
Total Community

The toxic effects of cadmium to total community and individual species of zooplankton generally decreased as pH of the lake was experimentally lowered over a number of years by additions of acids. The biomass of crustacean zooplankton held in small impoundment systems suspended in the lake for fourteen days was reduced by 60–70% when pH was 6.7–6.8 and concentrations of Cd were maintained at 1 μg∙L−1, and by 70–80% when Cd was at 3 μg∙L−1. At a pH of 5.9, however, biomass was reduced only 20–30% in concentrations of Cd of 1 μg∙L−1, and at pH 5.6, biomass decreased by only 20% when subjected to 3 μg∙L−1 Cd. The cladocerans Bosmina longirostris and Holopedium gibberum were the most sensitive to cadmium. Cladocerans were more sensitive to cadmium than calanoid copepods, and both these groups were more sensitive then cyclopoid copepods. The decrease in toxicity of cadmium with increasing H+ may be analogous to the inhibition of uptake of cadmium by calcium.

scholarly journals Serological evidence of Rift Valley fever virus infection among domestic ruminant herds in Uganda

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Deo B. Ndumu ◽  
Barnabas Bakamutumaho ◽  
Edward Miller ◽  
Jesca Nakayima ◽  
Robert Downing ◽  
...  
Keyword(s):  
Rift Valley ◽  
Rift Valley Fever ◽  
Rift Valley Fever Virus ◽  
Northern Region ◽  
Western Region ◽  
Domestic Ruminant ◽  
The South ◽  
Valley Fever ◽  
Sheep And Goats ◽  
The Western Region

Abstract Background Prior to the first recorded outbreak of Rift Valley fever (RVF) in Uganda, in March 2016, earlier studies done until the 1970’s indicated the presence of the RVF virus (RVFV) in the country, without any recorded outbreaks in either man or animals. While severe outbreaks of RVF occurred in the neighboring countries, none were reported in Uganda despite forecasts that placed some parts of Uganda at similar risk. The Ministry of Agriculture, Animal Industry and Fisheries (MAAIF) undertook studies to determine the RVF sero-prevalence in risk prone areas. Three datasets from cattle sheep and goats were obtained; one from retrospective samples collected in 2010–2011 from the northern region; the second from the western region in 2013 while the third was from a cross-sectional survey done in 2016 in the south-western region. Laboratory analysis involved the use of the Enzyme Linked Immunosorbent Assays (ELISA). Data were subjected to descriptive statistical analyses, including non-parametric chi-square tests for comparisons between districts and species in the regions. Results During the Yellow Fever outbreak investigation of 2010–2011 in the northern region, a total sero-prevalence of 6.7% was obtained for anti RVFV reacting antibodies (IgG and IgM) among the domestic ruminant population. The 2013 sero-survey in the western region showed a prevalence of 18.6% in cattle and 2.3% in small ruminants. The 2016 sero-survey in the districts of Kabale, Kanungu, Kasese, Kisoro and Rubirizi, in the south-western region, had the respective district RVF sero-prevalence of 16.0, 2.1, 0.8, 15.1and 2.7% among the domestic ruminants combined for this region; bovines exhibited the highest cumulative sero-prevalence of 15.2%, compared to 5.3 and 4.0% respectively for sheep and goats per species for the region. Conclusions The absence of apparent outbreaks in Uganda, despite neighboring enzootic areas, having minimal restrictions to the exchange of livestock and their products across borders, suggest an unexpected RVF activity in the study areas that needs to be unraveled. Therefore, more in-depth studies are planned to mitigate the risk of an overt RVF outbreak in humans and animals as has occurred in neighboring countries.

Changes in the crustacean communities of Lakes Michigan, Huron, and Erie following the invasion of the predatory cladoceran Bythotrephes longimanus

2004 ◽  
Vol 61 (11) ◽  
pp. 2111-2125 ◽  
Author(s):  
Richard P Barbiero ◽  
Marc L Tuchman
Keyword(s):  
Zooplankton Community ◽  
Crustacean Zooplankton ◽  
Bythotrephes Longimanus ◽  
Zooplankton Community Structure ◽  
Cladoceran Species ◽  
Invertebrate Predators ◽  
Predatory Cladoceran ◽  
Leptodora Kindti ◽  
Escape Responses ◽  
Zooplankton Communities

The crustacean zooplankton communities in Lakes Michigan and Huron and the central and eastern basins of Lake Erie have shown substantial, persistent changes since the invasion of the predatory cladoceran Bythotrephes in the mid-1980s. A number of cladoceran species have declined dramatically since the invasion, including Eubosmina coregoni, Holopedium gibberum, Daphnia retrocurva, Daphnia pulicaria, and Leptodora kindti, and overall species richness has decreased as a result. Copepods have been relatively unaffected, with the notable exception of Meso cyclops edax, which has virtually disappeared from the lakes. These species shifts have for the most part been consistent and equally pronounced across all three lakes. Responses of crustacean species to the Bythotrephes invasion do not appear to be solely a consequence of size, and it is likely that other factors, e.g., morphology, vertical distribution, or escape responses, are important determinants of vulnerability to predation. Our results indicate that invertebrate predators in general, and invasive ones in particular, can have pronounced, lasting effects on zooplankton community structure.

Crustacean zooplankton community structure in temporary and permanent grassland ponds

Hydrobiologia ◽  
2009 ◽  
Vol 632 (1) ◽  
pp. 225-233 ◽  
Author(s):  
S. Matthew Drenner ◽  
Stanley I. Dodson ◽  
Ray W. Drenner ◽  
John E. Pinder III
Keyword(s):  
Community Structure ◽  
Zooplankton Community ◽  
Crustacean Zooplankton ◽  
Zooplankton Community Structure ◽  
Permanent Grassland

Dynamics of Cadmium-Stressed Plankton Communities

1980 ◽  
Vol 37 (3) ◽  
pp. 403-414 ◽  
Author(s):  
J. S. Marshall ◽  
D. L. Mellinger
Keyword(s):  
Dissolved Oxygen ◽  
Lake Michigan ◽  
Zooplankton Community ◽  
Cadmium Stress ◽  
Crustacean Zooplankton ◽  
Functional Responses ◽  
Experimental Lakes Area ◽  
Individual Values ◽  
Zooplankton Density ◽  
Plankton Communities

Structural and functional responses of plankton communities to cadmium stress were studied during 1977 in Lake Michigan using small-volume (8 L) completely sealed enclosures, and in Canada's Experimental Lakes Area (ELA) Lake 223 using large-volume (1.5 × 105 L) open-surface enclosures. In Lake Michigan, reductions of the average abundance of micro-crustaceans by cadmium were significantly greater in "light" or shallow epilimnetic incubations than they were in "dark" or deep epilimnetic incubations. Measurements of dissolved oxygen indicated that this interaction with light (depth) was an indirect effect due to a reduction of photosynthesis and primary production. Zooplankton density and species diversity were not significantly affected within 21 d by cadmium concentrations [Formula: see text] and [Formula: see text] Cd/L, respectively, whereas final dissolved oxygen concentration and percentage similarity (PS) of the crustacean zooplankton community were significantly reduced by [Formula: see text] Cd/L. In the ELA Lake 223 experiment, the reducing effect of cadmium on zooplankton density increased up to 31 d after Cd enrichment and then decreased, probably due to decreasing Cd concentrations in the water. Values of PS on day 24 for the ELA enclosures enriched with 1 and 3 μg Cd/L were within the 95% confidence limits for individual values predicted from a regression of PS on cadmium for the 21-d Lake Michigan experiments.Key words: plankton communities, zooplankton, phytoplankton, cadmium stress, Lake Michigan, Canadian Shield lakes

Estimations of primary production and export production in the South China Sea based on sediment trap experiments

1998 ◽  
Vol 43 (7) ◽  
pp. 583-586 ◽  
Author(s):  
Jianfang Chen ◽  
Lianfu Zheng ◽  
M. G. Wiesner ◽  
Ronghua Chen ◽  
Yulong Zheng ◽  
...  
Keyword(s):  
South China Sea ◽  
Primary Production ◽  
South China ◽  
Sediment Trap ◽  
The South China Sea ◽  
The South ◽  
Export Production ◽  
China Sea

Vanilla ribeiroi Hoehne (Orchidaceae: Vanilloideae): notes on taxonomy and geographical distribution

Phytotaxa ◽  
2021 ◽  
Vol 490 (1) ◽  
pp. 99-106
Author(s):  
MATHIAS ERICH ENGELS ◽  
ANA KELLY KOCH
Keyword(s):  
20Th Century ◽  
Geographical Distribution ◽  
Northern Region ◽  
The South ◽  
Mato Grosso ◽  
Elusive Species

Vanilla materials collected during botanical explorations in the Northern region of the Mato Grosso State and the South of Pará State, Brazil were identified as V. ribeiroi. An elusive species that was originally described at the beginning of the 20th century, as part of the Rondon Commission. Vanilla ribeiroi is recircumbscribed on the basis of the original and fresh materials, an epitype is designed, and the distribution of the species is extended.

scholarly journals Population dynamics and net primary production of the aquatic macrophite Nymphaea rudgeana C. F. Mey in a lotic environment of the Itanhaém River basin (SP, Brazil)

2000 ◽  
Vol 60 (1) ◽  
pp. 83-92 ◽  
Author(s):  
A. F. M. CAMARGO ◽  
E. R. FLORENTINO
Keyword(s):  
Population Dynamics ◽  
Primary Production ◽  
Aquatic Macrophytes ◽  
Aquatic Macrophyte ◽  
Net Primary Production ◽  
Growth Period ◽  
Pistia Stratiotes ◽  
Annual Productivity ◽  
Lotic Environment ◽  
Low Levels

In this paper we evaluated the population dynamics and obtained estimates of the net primary production of the aquatic macrophyte Nymphaea rudgeana in an arm of the Itanhaém River (São Paulo State, Brazil). This species presents, in the studied area, a broad seasonal variation of biomass. As from November (13.1 g DW/m²) we observed a gradual increase of biomass that reached a maximum in February (163.1 g DW/m²). Then, the biomass decreased, maintaining low levels until a new growth period. The reduction of biomass is associated to the development of floating aquatic macrophytes (Pistia stratiotes and Salvinia molesta) and, subsequently to environmental factors (higher salinity values) that are unfavorable to their development. The net primary production of N. rudgeana was estimated from the biomass data, and the annual productivity value was estimated between 3.02 and 3.82 t/ha/year.

Calibration of the zooplankton community size spectrum as an indicator of change in Canadian Shield lakes

2019 ◽  
Vol 76 (12) ◽  
pp. 2268-2287
Author(s):  
Lauren Emily Barth ◽  
Brian John Shuter ◽  
William Gary Sprules ◽  
Charles Kenneth Minns ◽  
James Anthony Rusak
Keyword(s):  
Zooplankton Community ◽  
Canadian Shield ◽  
Rate Of Change ◽  
Crustacean Zooplankton ◽  
Size Spectrum ◽  
Community Size ◽  
Mean Values ◽  
Sampling Protocols ◽  
Stable Characteristic ◽  
Shield Lakes

Developing the crustacean zooplankton community size spectrum into an indicator of change in lakes requires quantification of the natural variability in the size spectrum related to broad-scale seasonal, annual, and spatial factors. Characterizing seasonal patterns of variation in the size spectrum is necessary so that monitoring programs can be designed to minimize the masking effects that seasonal processes can have on detecting longer-term temporal change. We used a random effects model to measure monthly, annual, and interlake variability in the slope (i.e., relative abundance of small and large organisms) and centered height (i.e., total abundance) of the crustacean zooplankton normalized abundance size spectrum from 1981 to 2011 among eight Canadian Shield lakes. Consistent with theoretical predictions, the slope was a relatively stable characteristic of the zooplankton community compared with the height, which varied significantly among lakes. We identified a seasonal signal in height and slope and used a mixed effects model to characterize the linear rate of change from May to October; there was an overall decline in height and an overall increase in slope. Seasonal variance was greater than annual variance for both the height and the slope, suggesting that long-term monitoring of lakes and interlake comparisons using zooplankton size spectra should be based on temporally standardized sampling protocols that minimize the effects of seasonal processes. We recommend sampling the zooplankton community in midsummer because this results in size spectrum estimates close to seasonal mean values.

scholarly journals Zooplankton Community Response to Seasonal Hypoxia: A Test of Three Hypotheses

Diversity ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 21 ◽  
Author(s):  
Julie E. Keister ◽  
Amanda K. Winans ◽  
BethElLee Herrmann
Keyword(s):  
Community Structure ◽  
Puget Sound ◽  
Temporal Stability ◽  
Zooplankton Community ◽  
Community Response ◽  
Crustacean Zooplankton ◽  
Zooplankton Abundance ◽  
Calanoid Copepods ◽  
Low Oxygen ◽  
Seasonal Hypoxia

Several hypotheses of how zooplankton communities respond to coastal hypoxia have been put forward in the literature over the past few decades. We explored three of those that are focused on how zooplankton composition or biomass is affected by seasonal hypoxia using data collected over two summers in Hood Canal, a seasonally-hypoxic sub-basin of Puget Sound, Washington. We conducted hydrographic profiles and zooplankton net tows at four stations, from a region in the south that annually experiences moderate hypoxia to a region in the north where oxygen remains above hypoxic levels. The specific hypotheses tested were that low oxygen leads to: (1) increased dominance of gelatinous relative to crustacean zooplankton, (2) increased dominance of cyclopoid copepods relative to calanoid copepods, and (3) overall decreased zooplankton abundance and biomass at hypoxic sites compared to where oxygen levels are high. Additionally, we examined whether the temporal stability of community structure was decreased by hypoxia. We found evidence of a shift toward more gelatinous zooplankton and lower total zooplankton abundance and biomass at hypoxic sites, but no clear increase in the dominance of cyclopoid relative to calanoid copepods. We also found the lowest variance in community structure at the most hypoxic site, in contrast to our prediction. Hypoxia can fundamentally alter marine ecosystems, but the impacts differ among systems.

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