Nitrogen and phosphorous loading by aquatic avifauna in a shallow eutrophic freshwater lake

Author(s):  
Sagar Adhurya ◽  
Suvendu Das ◽  
Santanu Ray
Keyword(s):  
2020 ◽  
Vol 85 ◽  
pp. 131-139
Author(s):  
S Shen ◽  
Y Shimizu

Despite the importance of bacterial cell volume in microbial ecology in aquatic environments, literature regarding the effects of seasonal and spatial variations on bacterial cell volume remains scarce. We used transmission electron microscopy to examine seasonal and spatial variations in bacterial cell size for 18 mo in 2 layers (epilimnion 0.5 m and hypolimnion 60 m) of Lake Biwa, Japan, a large and deep freshwater lake. During the stratified period, we found that the bacterial cell volume in the hypolimnion ranged from 0.017 to 0.12 µm3 (median), whereas that in the epilimnion was less variable (0.016 to 0.033 µm3, median) and much lower than that in the hypolimnion. Additionally, in the hypolimnion, cell volume during the stratified period was greater than that during the mixing period (up to 5.7-fold). These differences in cell volume resulted in comparable bacterial biomass in the hypolimnion and epilimnion, despite the fact that there was lower bacterial abundance in the hypolimnion than in the epilimnion. We also found that the biomass of larger bacteria, which are not likely to be grazed by heterotrophic nanoflagellates, increased in the hypolimnion during the stratified period. Our data suggest that estimation of carbon flux (e.g. bacterial productivity) needs to be interpreted cautiously when cell volume is used as a constant parametric value. In deep freshwater lakes, a difference in cell volume with seasonal and spatial variation may largely affect estimations.


1984 ◽  
Vol 16 (1-2) ◽  
pp. 51-77 ◽  
Author(s):  
M Knoester ◽  
J Visser ◽  
B A Bannink ◽  
C J Colijn ◽  
W P A Broeders

In the planning of the Delta-works, carried out in the Southwestern Netherlands, the Eastern Scheldt was the largest and therefore last tidal basin to be fully closed mainly to protect the area from floods. Increased recognition for the natural value of estuaries and a strong lobby from nature conservationists and shellfish producers led to a reconsideration of original plans, confirmed by a series of governmental decisions. Per consequence execution of the present plans will result in a storm-surge barrier at the entrance of the tidal basin together with two partitioning dams, separating the (reduced) tidal Eastern Scheldt from a new freshwater lake. Attention is paid to the present values in the Eastern Scheldt and briefly to changes involved by the project. The decisionmaking process is described and discussed: In the course of the project the majority of decisions taken were prepared by teams of ecologists, civil engineers, hydrologists and financial experts using policy-analysis methods. For guidance of developments in the influenced area the local government accepted a policy plan, in which human uses are regulated. Operations of the barrier are designed such that safety from flooding is guaranteed, while adverse effects for the tidal ecosystems are minimized.


Author(s):  
Fabian Gräßle ◽  
Caroline Plugge ◽  
Paolo Franchini ◽  
Bernhard Schink ◽  
David Schleheck ◽  
...  

Harmful Algae ◽  
2021 ◽  
Vol 101 ◽  
pp. 101967
Author(s):  
Megumu Fujibayashi ◽  
Seiko Furuta ◽  
Eiso Inoue ◽  
Satoshi Ichise ◽  
Naoko Takei

2017 ◽  
Vol 9 (5) ◽  
pp. 522-527 ◽  
Author(s):  
Tomohiro Watanabe ◽  
Aya Miura ◽  
Tomoya Iwata ◽  
Hisaya Kojima ◽  
Manabu Fukui

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