scholarly journals Do Cross-Latitude and Local Studies Give Similar Predictions of Phytoplankton Responses to Warming? An Analysis of Monitoring Data from 504 Danish Lakes

2021 ◽  
Vol 13 (24) ◽  
pp. 14049
Author(s):  
Erik Jeppesen ◽  
Liselotte S. Johansson ◽  
Sh Tserenpil ◽  
Martin Søndergaard ◽  
Torben L. Lauridsen ◽  
...  
Keyword(s):  
Phytoplankton Biomass ◽  
Monitoring Data ◽  
Minor Importance ◽  
Response Patterns ◽  
Local Response ◽  
Eutrophic Lakes ◽  
Empirical Relationships ◽  
Explanatory Variables ◽  
Total Phytoplankton ◽  
Substantial Concentration

Cross-latitude studies on lakes have a potential to predict how global warming may cause major changes in phytoplankton biomass and composition, e.g., the development of favourable conditions for cyanobacteria dominance. However, results from these studies may be influenced by biogeographical factors, and the conclusions may, therefore, not hold when considering local response patterns. We used monthly monitoring data from 504 lakes in Denmark—a small and homogeneous geographical region—to establish empirical relationships between key phytoplankton groups and a set of explanatory variables including total phosphorus (TP), total nitrogen (TN), lake mean depth (DEP) and water temperature (TEMP). All variables had strong effects on phytoplankton biomass and composition, but their contributions varied over the seasons, with TEMP being particularly important in June–October. We found dominance of cyanobacteria in terms of biomass and also an increase in dinophytes biomass at higher TEMP, while diatoms and chlorophytes became less important. In May, however, the TEMP effect on total phytoplankton biomass was negative, likely reflecting intensified zooplankton grazing. Our results suggest that biogeographical effects are of minor importance for the response patterns of phytoplankton to temperature and that substantial concentration reductions of TN and TP are needed in eutrophic lakes to counteract the effect of the climate change-induced increase in TEMP.

scholarly journals Responses of Phytoplankton Communities in Selected Eutrophic Lakes to Variable Weather Conditions

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1207 ◽  
Author(s):  
Tomasz Lenard ◽  
Wojciech Ejankowski ◽  
Małgorzata Poniewozik
Keyword(s):  
Chlorophyll A ◽  
Air Temperature ◽  
Vegetative Growth ◽  
Phytoplankton Biomass ◽  
Total Precipitation ◽  
Eutrophic Lakes ◽  
Growth Season ◽  
Mild Winter ◽  
Phytoplankton Communities ◽  
Total Phytoplankton

It is well-known that recent climatic changes have strongly affected aquatic ecosystems. In this study, we examined the complex factors determining the development of phytoplankton communities during the vegetative growth season in eutrophic lakes located in a temperate zone in eastern Poland. Our analysis enabled us to divide the data into two different periods: years with a cold winter and low total precipitation, and those with a mild winter and high total precipitation. The analysis showed that the soluble and total nitrogen content, concentration of chlorophyll a, total phytoplankton biomass, and biomasses of Cyanobacteria and Cryptophyceae were significantly higher in the vegetative growth season in the year after a mild winter, whereas the soluble and total phosphorus content and phytoplankton biodiversity were significantly lower in these years. Hence, climate warming indirectly led to the loss of biodiversity in the phytoplankton communities in the studied lakes of temperate zone. During this study, we also tested the effects of increases in air temperature and total precipitation on phytoplankton communities over short time periods (14 and 28 days). The results showed that the total phytoplankton biomass and the chlorophyll a concentration were only positively correlated with the air temperature. All of the features described in this study showed how sensitive lake ecosystems are to climatic fluctuations.

scholarly journals Monitoring antimicrobial resistance trends in commensal Escherichia coli from livestock, the Netherlands, 1998 to 2016

2019 ◽  
Vol 24 (25) ◽  
Author(s):  
Ayla Hesp ◽  
Kees Veldman ◽  
Jeanet van der Goot ◽  
Dik Mevius ◽  
Gerdien van Schaik
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Monitoring Data ◽  
Resistant Isolate ◽  
Similar Data ◽  
Explanatory Variables ◽  
E Coli ◽  
Veal Calves ◽  
Before And After ◽  
Using Data

Background Monitoring of antimicrobial resistance (AMR) in animals is essential for public health surveillance. To enhance interpretation of monitoring data, evaluation and optimisation of AMR trend analysis is needed. Aims To quantify and evaluate trends in AMR in commensal Escherichia coli, using data from the Dutch national AMR monitoring programme in livestock (1998–2016). Methods Faecal samples were collected at slaughter from broilers, pigs and veal calves. Minimum inhibitory concentration values were obtained by broth microdilution for E. coli for 15 antimicrobials of eight antimicrobial classes. A Poisson regression model was applied to resistant isolate counts, with explanatory variables representing time before and after 2009 (reference year); for veal calves, sampling changed from 2012 represented by an extra explanatory variable. Results Resistant counts increased significantly from 1998-2009 in broilers and pigs, except for tetracyclines and sulfamethoxazole in broilers and chloramphenicol and aminoglycosides in pigs. Since 2009, resistant counts decreased for all antimicrobials in broilers and for all but the phenicols in pigs. In veal calves, for most antimicrobials no significant decrease in resistant counts could be determined for 2009–16, except for sulfamethoxazole and nalidixic acid. Within animal species, antimicrobial-specific trends were similar. Conclusions Using Dutch monitoring data from 1998-2016, this study quantified AMR trends in broilers and slaughter pigs and showed significant trend changes in the reference year 2009. We showed that monitoring in commensal E. coli is useful to quantify trends and detect trend changes in AMR. This model is applicable to similar data from other European countries.

scholarly journals Dynamics of Cyanobacteria and Related Environmental Drivers in Freshwater Bodies Affected by Mitten Crab Culturing: A Study of Lake Guchenghu, China

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2468
Author(s):  
Hongmin Li ◽  
Huihui Chen ◽  
Xiaohong Gu ◽  
Zhigang Mao ◽  
Qingfei Zeng ◽  
...  
Keyword(s):  
Environmental Variables ◽  
Phytoplankton Biomass ◽  
Dominant Species ◽  
N:P Ratio ◽  
Water Bodies ◽  
Environmental Drivers ◽  
Mitten Crab ◽  
Total Phytoplankton ◽  
Freshwater Bodies ◽  
Harmful Species

Mitten crab aquaculture is prevalent in China, however, knowledge about the threat of cyanobacteria in mitten crab aquaculture-impacted water bodies is limited. Here, seasonal variations of cyanobacteria and their relationships with environmental factors were investigated for Lake Guchenghu area. Results suggested the changes of cyanobacteria community in crab ponds distinguished from the adjacent lake. In the lake, cyanobacterial biomass (3.86 mg/L, 34.6% of the total phytoplankton) was the highest in autumn with the dominance of Oscillatoria, Aphanocapsa and Pesudanabaena. By contrast, in crab ponds, cyanobacteria (46.80 mg/L, 97.2% of the total phytoplankton biomass) were the most abundant in summer when Pesudanabaena and Raphidiopsis were the dominant species. Of particular note was that obviously higher abundance of filamentous and potentially harmful species (e.g., Raphidiopsis raciborskii and Dolichospermum circinale) were observed in ponds compared to the lake. Specifically, water depth (WD), permanganate index (CODMn), total phosphorus (TP), N:P ratio, and NO 2 −-N were the key environmental variables affected cyanobacteria composition. For crab ponds, N:P ratio, water temperature (WT) and TP were the potential environmental drivers of cyanobacteria development. This study highlighted the fact that mitten crab culture had non-negligible influences on the cyanobacteria community and additional attention should be paid to the cyanobacteria dynamics in mitten crab culture-impacted water bodies, especially for those potentially harmful species.

Effects of zooplankton and nutrients on phytoplankton: an experimental analysis in a eutrophic tropical reservoir

2017 ◽  
Vol 68 (6) ◽  
pp. 1061 ◽  
Author(s):  
Juliana dos Santos Severiano ◽  
Viviane Lúcia dos Santos Almeida-Melo ◽  
Enaide Marinho de Melo-Magalhães ◽  
Maria do Carmo Bittencourt-Oliveira ◽  
Ariadne do Nascimento Moura
Keyword(s):  
Experimental Analysis ◽  
Phytoplankton Biomass ◽  
Phytoplankton Community ◽  
N:P Ratio ◽  
Molar Ratio ◽  
Zooplankton Species ◽  
Tropical Reservoir ◽  
Total Phytoplankton Biomass ◽  
Taxonomic Class ◽  
Total Phytoplankton

Experiments were conducted to evaluate the N:P ratio, as well as the effects of the interaction between this ratio and zooplankton, on phytoplankton in a tropical reservoir. Three experiments were performed in the presence (+Z) or absence (–Z) of zooplankton and the addition of N and P in different ratios (N:P molar ratio of 5, 16 and 60).In Experiment I, the total phytoplankton biomass and biomass by taxonomic class and species of the N:P 16–Z treatment did not differ significantly from that of the control, whereas for N:P 16+Z, there was a reduction in total phytoplankton. In Experiment II, there was a significant increase in Bacillariophyceae and the biomass of two species in the N:P 60–Z treatment. For the N:P 60+Z treatment, a significant reduction was observed in the total phytoplankton biomass and the biomass of three phytoplankton classes and three species. In Experiment III, there was an increase in the biomass of Dinophyceae with the N:P 5–Z treatment. In the N:P 5+Z treatment, there was a significant reduction in total phytoplankton biomass and the biomass of the phytoplankton class and five species. The findings of the present study reveal that zooplankton species native to a tropical reservoir can change the structure of the phytoplankton community and the response of these organisms to variations in nutrients.

The Prediction of Lacustrine Phytoplankton Diversity

1981 ◽  
Vol 38 (5) ◽  
pp. 524-534 ◽  
Author(s):  
Bruce D. LaZerte ◽  
Susan Watson
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Good Predictor ◽  
Phytoplankton Biomass ◽  
Phytoplankton Community ◽  
Taxonomic Composition ◽  
Phytoplankton Community Structure ◽  
Trophic Gradient ◽  
Phytoplankton Diversity ◽  
Total Phytoplankton

We tested the hypothesis that total phytoplankton biomass can predict phytoplankton community structure independent of its taxonomic composition. From a 2-yr study on Lake Memphremagog, Quebec, which exhibits a marked axial trophic gradient, 133 samples were rarefied to uniform count sizes and a range of diversity numbers, based on proportional biomass, was calculated for each. Biomass is a good predictor of evenness (0.7 < R < 0.9), but not species richness (0.1 < R < 0.3), and this prediction is independent of changes in taxonomic composition. Species richness is more directly related to season and changes in taxonomic composition.Key words: diversity, evenness, species richness, phytoplankton

Sedimentary Cladoceran remains and their relationship to nutrients and other limnological variables in 53 lakes from British Columbia, Canada

2003 ◽  
Vol 60 (10) ◽  
pp. 1177-1189 ◽  
Author(s):  
Darren G Bos ◽  
Brian F Cumming
Keyword(s):  
British Columbia ◽  
Sediment Cores ◽  
Species Abundance ◽  
Environmental Variable ◽  
Weighted Averaging ◽  
Eutrophic Lakes ◽  
Inference Models ◽  
Cladoceran Remains ◽  
Explanatory Variables ◽  
Averaging Techniques

To develop models to predict past lake-water nutrient levels, the sedimentary remains of Cladocera were sampled from 53 lakes in central British Columbia, Canada. At the same time, the lakes were sampled for a suite of chemical variables. In addition, a host of physical and spatial explanatory variables were collected from each site. Canonical correspondence analysis showed that total phosphorus (TP), which ranged from 5 to 146 µg·L–1, was the measured environmental variable that best described the differences in species composition among the lakes. Additionally, lake depth and surface water temperature were also important in explaining the distribution of cladoceran taxa. Chydorus brevilabris, Daphnia ambigua, Daphnia cf. pulex, and Graptoleberis testudinaria had a preference for eutrophic lakes, whereas Acroperus harpae, Alonella nana, Alonella excisa, Chydorus piger, Daphnia cf. dentifera, and Eubosmina spp. were found in the less productive lakes. Predictive models to estimate TP from species abundance data were developed using weighted averaging techniques. This research has produced strong and significant inference models, which can now be used to reconstruct past changes in lake trophic status from remains of Cladocera in sediment cores.

scholarly journals Patterns of CO2 concentration and inorganic carbon limitation of phytoplankton biomass in agriculturally eutrophic lakes

2021 ◽  
Vol 190 ◽  
pp. 116715
Author(s):  
Horacio E. Zagarese ◽  
María de los Ángeles González Sagrario ◽  
Dieter Wolf-Gladrow ◽  
Peeter Nõges ◽  
Tiina Nõges ◽  
...  
Keyword(s):  
Phytoplankton Biomass ◽  
Inorganic Carbon ◽  
Co2 Concentration ◽  
Carbon Limitation ◽  
Eutrophic Lakes ◽  
Inorganic Carbon Limitation

Effect of phytoplankton adaptation on the distribution of its biomass and chlorophyll a concentration in the surface layer of the Black Sea

2019 ◽  
Vol 48 (4) ◽  
pp. 404-414 ◽  
Author(s):  
Liudmila Stelmakh ◽  
Tatiana Gorbunova
Keyword(s):  
Surface Layer ◽  
Spatial Variability ◽  
Black Sea ◽  
Phytoplankton Biomass ◽  
Abiotic Factors ◽  
Nitrogen Concentration ◽  
The Black Sea ◽  
Total Phytoplankton ◽  
Upper Mixed Layer ◽  
Effect Of Light

Abstract Using the field data collected in the Black Sea in September 2005–May 2013, the authors studied the spatial variability of the ratio of organic carbon to chlorophyll a (C:Chl a) in the sea surface layer (0–1 m). The C:Chl a ratio is an important parameter that reflects the phytoplankton adaptation to abiotic factors. Its maximum variations occurred in September–October 2005 and October 2010 when the highest spatial variability of average light intensity and nitrogen concentration was observed in the upper mixed layer. As a result, the maps of phytoplankton biomass differed from chlorophyll maps. In August 2011, no effect of light or nitrogen on the spatial variability of the C:Chl a ratio was found. Changes in the contribution of dinoflagellates to the total phytoplankton biomass affected the C:Chl a ratio variability, which was two times lower compared to September–October 2005 and October 2010. Also, the spatial distribution of phytoplankton biomass differed from the distribution of chlorophyll a concentration only in some areas of the sea. In May 2013, environmental factors slightly varied across the study area and the spatial variability of the C:Chl a ratio was insignificant. Therefore, the map of phytoplankton biomass indicated similarities with the chlorophyll map.

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