scholarly journals Eutrophication and warming effects on long-term variation of zooplankton in Lake Biwa

2011 ◽  
Vol 8 (5) ◽  
pp. 1383-1399 ◽  
Author(s):  
C. H. Hsieh ◽  
Y. Sakai ◽  
S. Ban ◽  
K. Ishikawa ◽  
T. Ishikawa ◽  
...  
Keyword(s):  
Phytoplankton Biomass ◽  
Phytoplankton Community ◽  
Environmental Changes ◽  
Lake Biwa ◽  
Zooplankton Community ◽  
Trophic Levels ◽  
Environmental Data ◽  
Delayed Response ◽  
Zooplankton Abundance

Abstract. We compiled and analyzed long-term (1961–2005) zooplankton community data in response to environmental variations in Lake Biwa. Environmental data indicate that Lake Biwa had experienced eutrophication (according to the total phosphorus concentration) in the late 1960s and recovered to a normal trophic status around 1985, and then has exhibited warming since 1990. Total zooplankton abundance showed a significant correlation with total phytoplankton biomass. Following a classic pattern, the cladoceran/calanoid and cyclopoid/calanoid abundance ratio was related positively to eutrophication. The zooplankton community exhibited a significant response to the boom and bust of phytoplankton biomass as a consequence of eutrophication-reoligotriphication and warming. Moreover, our analyses suggest that the Lake Biwa ecosystem exhibited a hierarchical response across trophic levels; that is, higher trophic levels may show a more delayed response or no response to eutrophication than lower ones. We tested the hypothesis that the phytoplankton community can better explain the variation of the zooplankton community than bulk environmental variables, considering that the phytoplankton community may directly affect the zooplankton succession through predator-prey interactions. Using a variance partition approach, however, we did not find strong evidence to support this hypothesis. We further aggregated zooplankton according to their feeding types (herbivorous, carnivorous, omnivorous, and parasitic) and taxonomic groups, and analyzed the aggregated data. While the pattern remains similar, the results are less clear comparing the results based on finely resolved data. Our research suggests that zooplankton can be bio-indicators of environmental changes; however, the efficacy depends on data resolution.

scholarly journals Eutrophication and warming effects on long-term variation of zooplankton in Lake Biwa

2011 ◽  
Vol 8 (1) ◽  
pp. 593-629 ◽  
Author(s):  
C. H. Hsieh ◽  
Y. Sakai ◽  
S. Ban ◽  
K. Ishikawa ◽  
T. Ishikawa ◽  
...  
Keyword(s):  
Phytoplankton Biomass ◽  
Phytoplankton Community ◽  
Environmental Changes ◽  
Lake Biwa ◽  
Zooplankton Community ◽  
Trophic Levels ◽  
Environmental Data ◽  
Delayed Response ◽  
Zooplankton Abundance

Abstract. We compiled and analyzed long-term (1961–2005) zooplankton community data in response to environmental variations in Lake Biwa. Environmental data indicate that Lake Biwa had experienced eutrophication (according to total phosphorus concentration) in the late 1960s and recovered to a normal trophic status around 1985, and then exhibited warming since 1990. Total zooplankton abundance showed a significant correlation with total phytoplankton biomass. Following a classic pattern, cladoceran/calanoid and cyclopoid/calanoid abundance ratio was related positively to eutrophication. Zooplankton community exhibited a significant response to the boom and bust of phytoplankton biomass as a consequence of eutrophication-reoligotriphication and warming. Moreover, our analyses suggest that the Lake Biwa ecosystem exhibited a hierarchical response across trophic levels; that is, higher trophic levels may show a more delayed response or no response to eutrophication than lower ones. We tested the hypothesis that phytoplankton community can better explain the variation of zooplankton community than bulk environmental variables, considering that phytoplankton community may directly affects zooplankton succession through predator-prey interactions. Using a variance partition approach, however, we did not find strong evidence to support this hypothesis. We further aggregate zooplankton according to their feeding types (herbivorous, carnivorous, omnivorous, and parasitic) and taxonomic groups, and analyzed the aggregated data. While the pattern remains similar, the results are less clear comparing with the results based on finely resolved data. Our research explored the efficacy of using zooplankton as bio-indicators to environmental changes at various data resolutions.

Environmental drivers of a decline in a coastal zooplankton community

2021 ◽  
Author(s):  
Seòna R Wells ◽  
Eileen Bresnan ◽  
Kathryn Cook ◽  
Dafne Eerkes-Medrano ◽  
Margarita Machairopoulou ◽  
...  
Keyword(s):  
Zooplankton Community ◽  
Water Masses ◽  
Environmental Drivers ◽  
High Temporal Resolution ◽  
Monitoring Site ◽  
Zooplankton Abundance ◽  
Offshore Water ◽  
Additive Mixed Models ◽  
Zooplankton Communities

Abstract Major changes in North Atlantic zooplankton communities in recent decades have been linked to climate change but the roles of environmental drivers are often complex. High temporal resolution data is required to disentangle the natural seasonal drivers from additional sources of variability in highly heterogeneous marine systems. Here, physical and plankton abundance data spanning 2003–2017 from a weekly long-term monitoring site on the west coast of Scotland were used to investigate the cause of an increasing decline to approximately -80± 5% in annual average total zooplankton abundance from 2011 to 2017. Generalized additive mixed models (GAMMs), with an autoregressive correlation structure, were used to examine seasonal and inter-annual trends in zooplankton abundance and their relationship with environmental variables. Substantial declines were detected across all dominant taxa, with ∼ 30–70% of the declines in abundance explained by a concurrent negative trend in salinity, alongside the seasonal cycle, with the additional significance of food availability found for some taxa. Temperature was found to drive seasonal variation but not the long-term trends in the zooplankton community. The reduction in salinity had the largest effect on several important taxa. Salinity changes could partly be explained by locally higher freshwater run-off driven by precipitation as well as potential links to changes in offshore water masses. The results highlight that changes in salinity, caused by either freshwater input (expected from climate predictions) or fresher offshore water masses, may adversely impact coastal zooplankton communities and the predators that depend on them.

scholarly journals Long-term, predation-based control of a central-west North Sea zooplankton community

2003 ◽  
Vol 60 (2) ◽  
pp. 187-197 ◽  
Author(s):  
Robin A Clark ◽  
Chris L.J Frid ◽  
Kirsty R Nicholas
Keyword(s):  
North Sea ◽  
Inverse Relationship ◽  
Climatic Factors ◽  
Zooplankton Community ◽  
Positive Association ◽  
Zooplankton Abundance ◽  
Total Zooplankton ◽  
Population Growth Rates ◽  
North Wall

Abstract Long-term monitoring of the zooplankton community at a station 5.5 miles from the English coast in the central-west North Sea has been performed since 1968. Analyses of these data have revealed an inverse relationship between annual total zooplankton abundance and the position of the Gulf Stream North Wall (GSNW). This long-term relationship is opposite to the long-term positive association observed between the GSNW and total zooplankton abundances throughout most of the oceanic NE Atlantic region and the northern and central North Sea using Continuous Plankton Recorder data. This study investigates the mechanism behind the inverse relationship with the GSNW, focussing on the importance of zooplankton predators in influencing long-term changes in the zooplankton community of the central-west North Sea. The results suggest that the dominant zooplankton predator Sagitta elegans plays a key role in mediating spring copepod population growth rates and thus their maximum and overall productivity during any one particular year. In turn, the abundance of Sagitta during the spring appears to be related to climatic factors. The implications of this on the zooplankton community are discussed.

Assessment of recent environmental changes in New Brunswick (Canada) lakes based on paleolimnological shifts in diatom species assemblages

2006 ◽  
Vol 84 (1) ◽  
pp. 151-163 ◽  
Author(s):  
M. Anne Harris ◽  
Brian F. Cumming ◽  
John P. Smol
Keyword(s):  
Climate Change ◽  
New Brunswick ◽  
Environmental Changes ◽  
Environmental Data ◽  
Species Assemblages ◽  
Past Century ◽  
Diatom Species ◽  
Long Term Effects ◽  
Recent Climate

New Brunswick lakes are subjected to multiple environmental stressors, such as atmospheric acid deposition and climate change. In the absence of long-term environmental data, the impacts of these stressors are not well understood. Long-term effects of environmental change on diatom species assemblages were assessed in the sediments of 16 New Brunswick lakes using paleolimnological approaches. A regional trend of increasing Cyclotella stelligera Cleve & Gunrow and decreasing Aulacoseira species complex was recorded in most lakes. Detailed paleolimnological analyses of Wolfe, Cundy, and West Long lakes revealed varying degrees of species change, with assemblage shifts beginning ca. 1900 CE (common era). These species trends are not consistent with acidification. However, linear regression of mean July temperature with time for two New Brunswick historical instrumental temperature records revealed statistically significant warming over the past century. The shift from heavily silicified tychoplanktonic Aulacoseira species to small planktonic diatom species, such as C. stelligera, is consistent with paleolimnological inferences of warming trends recorded in several other lake regions of the Northern Hemisphere. These assemblage shifts are likely due to recent climate change and may be mediated by reduced ice cover and (or) increased thermal stability (decreased lake mixing) during the open water period.

scholarly journals Vertical distribution of chlorophyll <I>a</I> concentration and phytoplankton community composition from in situ fluorescence profiles: a first database for the global ocean

2015 ◽  
Vol 7 (2) ◽  
pp. 261-273 ◽  
Author(s):  
R. Sauzède ◽  
H. Lavigne ◽  
H. Claustre ◽  
J. Uitz ◽  
C. Schmechtig ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Chlorophyll A ◽  
Community Composition ◽  
Phytoplankton Biomass ◽  
Phytoplankton Community ◽  
Environmental Data ◽  
Global Ocean ◽  
Control Procedure ◽  
Chlorophyll A Concentration ◽  
Phytoplankton Community Composition

Abstract. In vivo chlorophyll a fluorescence is a proxy of chlorophyll a concentration, and is one of the most frequently measured biogeochemical properties in the ocean. Thousands of profiles are available from historical databases and the integration of fluorescence sensors to autonomous platforms has led to a significant increase of chlorophyll fluorescence profile acquisition. To our knowledge, this important source of environmental data has not yet been included in global analyses. A total of 268 127 chlorophyll fluorescence profiles from several databases as well as published and unpublished individual sources were compiled. Following a robust quality control procedure detailed in the present paper, about 49 000 chlorophyll fluorescence profiles were converted into phytoplankton biomass (i.e., chlorophyll a concentration) and size-based community composition (i.e., microphytoplankton, nanophytoplankton and picophytoplankton), using a method specifically developed to harmonize fluorescence profiles from diverse sources. The data span over 5 decades from 1958 to 2015, including observations from all major oceanic basins and all seasons, and depths ranging from the surface to a median maximum sampling depth of around 700 m. Global maps of chlorophyll a concentration and phytoplankton community composition are presented here for the first time. Monthly climatologies were computed for three of Longhurst's ecological provinces in order to exemplify the potential use of the data product. Original data sets (raw fluorescence profiles) as well as calibrated profiles of phytoplankton biomass and community composition are available on open access at PANGAEA, Data Publisher for Earth and Environmental Science. Raw fluorescence profiles: http://doi.pangaea.de/10.1594/PANGAEA.844212 and Phytoplankton biomass and community composition: http://doi.pangaea.de/10.1594/PANGAEA.844485

scholarly journals Meso- and macro-zooplankton community structure of the Amundsen Sea Polynya, Antarctica (Summer 2010–2011)

Elem Sci Anth ◽  
2015 ◽  
Vol 3 ◽  
Author(s):  
Stephanie E. Wilson ◽  
Rasmus Swalethorp ◽  
Sanne Kjellerup ◽  
Megan A. Wolverton ◽  
Hugh W. Ducklow ◽  
...  
Keyword(s):  
Community Structure ◽  
Trophic Position ◽  
Mixed Layer Depth ◽  
Zooplankton Community ◽  
Thick Layer ◽  
Trophic Levels ◽  
Zooplankton Abundance ◽  
Amundsen Sea ◽  
Zooplankton Community Structure ◽  
Pigment Ratios

Abstract The Amundsen Sea Polynya (ASP) has, on average, the highest productivity per unit area in Antarctic waters. To investigate community structure and the role that zooplankton may play in utilizing this productivity, animals were collected at six stations inside and outside the ASP using paired “day-night” tows with a 1 m2 MOCNESS. Stations were selected according to productivity based on satellite imagery, distance from the ice edge, and depth of the water column. Depths sampled were stratified from the surface to ∼ 50–100 m above the seafloor. Macrozooplankton were also collected at four stations located in different parts of the ASP using a 2 m2 Metro Net for krill surface trawls (0–120 m). The most abundant groups of zooplankton were copepods, ostracods, and euphausiids. Zooplankton biovolume (0.001 to 1.22 ml m-3) and abundance (0.21 to 97.5 individuals m-3) varied throughout all depth levels, with a midsurface maximum trend at ∼ 60–100 m. A segregation of increasing zooplankton trophic position with depth was observed in the MOCNESS tows. In general, zooplankton abundance was low above the mixed layer depth, a result attributed to a thick layer of the unpalatable colonial haptophyte, Phaeocystis antarctica. Abundances of the ice krill, Euphausia crystallarophias, however, were highest near the edge of the ice sheet within the ASP and larvae:adult ratios correlated with temperature above a depth of 60 m. Total zooplankton abundance correlated positively with chlorophyll a above 150 m, but negative correlations observed for biovolume vs. the proportion of P. antarctica in the phytoplankton estimated from pigment ratios (19’hexanoyloxyfucoxanthin:fucoxanthin) again pointed to avoidance of P. antarctica. Quantifying zooplankton community structure, abundance, and biovolume (biomass) in this highly productive polynya helps shed light on how carbon may be transferred to higher trophic levels and to depth in a region undergoing rapid warming.

scholarly journals Challenges in Assembling and Managing Environmental Data Sets

Eos ◽  
2016 ◽  
Vol 97 ◽  
Author(s):  
Catherine O'Reilly ◽  
Stephanie Hampton ◽  
Sapna Sharma ◽  
Derek Gray ◽  
Jordan Read ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Environmental Data ◽  
Data Sets ◽  
Term Data

Pulling together long-term data is increasingly important in assessing environmental changes, whether regionally or globally.

Effect of an invasive filter-feeder on the zooplankton assemblage in a coastal lagoon

2015 ◽  
Vol 96 (6) ◽  
pp. 1201-1210 ◽  
Author(s):  
Martin Bruschetti ◽  
Tomas Luppi ◽  
Oscar Iribarne
Keyword(s):  
Phytoplankton Biomass ◽  
Food Resource ◽  
Zooplankton Community ◽  
Grazing Intensity ◽  
Trophic Levels ◽  
Grazing Impact ◽  
Filter Feeder ◽  
Cascading Effects ◽  
Mesocosm Experiments ◽  
The Impact

Depletion of phytoplankton biomass by the introduced reef-forming polychaete Ficopomatus enigmaticus has previously been observed in the Mar Chiquita lagoon (37°40′S 57°23′W; Argentina), but the effect of polychaetes on the higher trophic levels is still unknown. To evaluate the effect of this polychaete on the zooplankton assemblage, replicated mesocosm experiments (N = 10) were performed during spring, summer and winter. Mesocosms with reefs and without reefs were installed and grazing intensity and the effect on the zooplankton assemblage by the polychaetes were assessed. Our results show that the reefs of F. enigmaticus generate minor changes in overall composition of zooplankton assemblage. Although the structure of the zooplankton assemblage was different between seasons, the impact of the reefs was not significant in any of them. There was no relationship between the decline of food resource by grazing and changes in the structure of the zooplankton assemblage. Thus, contrary to our hypothesis, the grazing impact of the invasive polychaete on the biomass of primary producers did not generate cascading effects to higher trophic levels. However, changes in some components of the zooplankton assemblage (e.g. cladocerans) clearly show that the reefs of F. enigmaticus have the potential to affect the structure of the zooplankton community. The lack of data of community composition and abundance of zooplankton before the invasion limits the understanding of how this polychaete might have affected the structure and abundance of the zooplankton of this lagoon. Nevertheless this work suggests that these changes may not be so significant.

scholarly journals A global satellite environmental data record derived from AMSR-E and AMSR2 microwave earth observations

2017 ◽  
Author(s):  
Jinyang Du ◽  
John S. Kimball ◽  
Lucas A. Jones ◽  
Youngwook Kim ◽  
Joseph Glassy ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Global Climate ◽  
Grid Cell ◽  
Microwave Remote Sensing ◽  
Environmental Data ◽  
Daily Maximum ◽  
Data Set ◽  
Vegetation Activity ◽  
Data Record

Abstract. Space-borne microwave remote sensing is widely used to monitor global environmental changes for understanding hydrological, ecological and climate processes. A new global land parameter data record (LPDR) was generated using similar calibrated, multi-frequency brightness temperature (Tb) retrievals from the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) and the Advanced Microwave Scanning Radiometer 2 (AMSR2). The resulting LPDR provides a long-term (Jun. 2002 – Dec. 2015) global record of key environmental observations at 25-km grid cell resolution, including surface fractional open water (fw) cover, atmosphere precipitable water vapor (PWV), daily maximum and minimum surface air temperatures (Tmx and Tmn), vegetation optical depth (VOD) and surface volumetric soil moisture (vsm). Global mapping of the land parameter climatology means and seasonal variability over the full-year records from AMSR-E (2003–2010) and AMSR2 (2013–2015) observation periods is consistent with characteristic global climate and vegetation patterns. Quantitative comparisons with independent observations indicated favorable LPDR performance for fw (R ≥ 0.75; RMSE ≤ 0.06), PWV (R ≥ 0.91; RMSE ≤ 4.99 mm), Tmx and Tmn (R ≥ 0.90; RMSE ≤ 3.48 ºC), and vsm (0.63 ≤ R ≤ 0.84; bias corrected RMSE ≤ 0.06 cm3/cm3). The LPDR derived global VOD record is also proportional to satellite observed NDVI (GIMMS3g) seasonality (R ≥ 0.88) due to synergy between canopy biomass structure and photosynthetic greenness. Statistical analysis shows overall LPDR consistency, but with small biases between AMSR-E and AMSR2 retrievals that should be considered when evaluating long-term environmental trends. The resulting LPDR and potential updates from continuing AMSR2 operations provide for effective global monitoring of environmental parameters related to vegetation activity, terrestrial water storage and mobility; and are suitable for climate and ecosystem studies. The LPDR data set is publicly available at http://files.ntsg.umt.edu/data/LPDR_v2.

Hydrology of the Ythan Estuary With Reference to Distribution of Major Nutrients and Detritus

1971 ◽  
Vol 51 (1) ◽  
pp. 137-157 ◽  
Author(s):  
J. H. Leach
Keyword(s):  
Ecological Study ◽  
Trophic Levels ◽  
Environmental Data ◽  
North Eastern ◽  
Energy Relationships ◽  
Algal Productivity ◽  
Major Nutrients ◽  
Physical And Chemical ◽  
Shallow Estuaries

INTRODUCTIONA long-term ecological study is being carried out in the Ythan Estuary in north-eastern Scotland. An understanding of the hydrology of the estuary is a prerequisite for future studies into energy relationships in lower trophic levels of the food web. Much of current research into the estuarine environment is concerned with large coastal-plain systems where physical and chemical characteristics are so different from those of shallow estuaries, such as the Ythan, that comparisons of environmental data are untenable. The present investigation reports information collected between October 1966 and September 1968 on major environmental factors and their effect on the distribution of nutrients and detritus in the ecosystem. Results of a concomitant study of algal productivity in a mudflat of the estuary are reported in Leach (1970).

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