Importance of Picoplankton in Lake Superior

1986 ◽  
Vol 43 (1) ◽  
pp. 235-240 ◽  
Author(s):  
Gary L. Fahnenstiel ◽  
Linda Sicko-Goad ◽  
Donald Scavia ◽  
Eugene F. Stoermer
Keyword(s):  
Primary Production ◽  
Lake Superior ◽  
Size Class ◽  
Eukaryotic Cells ◽  
Size Fractionation ◽  
Mean Size ◽  
Total Primary Production ◽  
Chroococcoid Cyanobacteria ◽  
Pass Through ◽  
Track Autoradiography

In Lake Superior, approximately 50% of total primary production is attributable to phytoplankton that pass through a 3-μm screen. The <3-μm size class is dominated by eukaryotic flagellates, nonmotile eukaryotic cells (1 μm), and chroococcoid cyanobacteria. Approximately 20% of total primary production is attributable to orange autofluorescent chroococcoid cyanobacteria (mean size = 0.7 μm) as determined by size fractionation and track autoradiography. These small prokaryotes exhibited abundances of 42 000 and 56 000 cells∙ml−1, maximum photosynthetic rates of 7 and 6 fg∙cell−1∙h−1, and growth rates of 1.5 and 0.8∙d−1 in the epilimnion and hypolimnion, respectively. A significant portion of this picoplankton (<1 μm) production may be consumed by heterotrophic protozoans in a "microbial loop."

Emergence of Chironomidae (Diptera) in Fertilized and Natural Lakes at Saqvaqjuac, N.W.T.

1988 ◽  
Vol 45 (4) ◽  
pp. 731-737 ◽  
Author(s):  
Harold E. Welch ◽  
John K. Jorgenson ◽  
Martin F. Curtis
Keyword(s):  
Primary Production ◽  
Phytoplankton Production ◽  
Experimental Lakes Area ◽  
Natural Lakes ◽  
Before And After ◽  
Mean Size ◽  
Apparent Reason ◽  
Total Primary Production ◽  
Latitudinal Range ◽  
Lake Fertilization

Chironomid emergence was quantified in four small lakes at Saqvaqjuac, N.W.T. (63°39′N), before and after lake fertilization. Emerging biomass responded immediately to increased phytoplankton production, reaching equilibrium the following year. Emergence from the reference lake was extremely variable, for no apparent reason. The emergence – phytoplankton production relationships found by Davies for the Experimental Lakes Area (~49°N) were generally valid for Saqvaqjuac lakes and Char Lake (74°42′), except that (1) biomass was better correlated than numbers because of increased mean size with increasing latitude and (2) total primary production was a better predictor than phytoplankton production alone because benthic photosynthesis increases with increasing latitude. Chironomid production seems to be a predictable function of total primary production throughout the latitudinal range of the small Canadian lakes examined.

scholarly journals Soil Pollution from Micro- and Nanoplastic Debris: A Hidden and Unknown Biohazard

2020 ◽  
Vol 12 (18) ◽  
pp. 7255 ◽  
Author(s):  
Shamina Imran Pathan ◽  
Paola Arfaioli ◽  
Tommaso Bardelli ◽  
Maria Teresa Ceccherini ◽  
Paolo Nannipieri ◽  
...  
Keyword(s):  
Physical Properties ◽  
Molecular Techniques ◽  
Ecological Effect ◽  
Eukaryotic Cells ◽  
Ecological Functions ◽  
Plastic Debris ◽  
Chemical Structures ◽  
Pass Through ◽  
Nano Size

The fate, properties and determination of microplastics (MPs) and nanoplastics (NPs) in soil are poorly known. In fact, most of the 300 million tons of plastics produced each year ends up in the environment and the soil acts as a log-term sink for these plastic debris. Therefore, the aim of this review is to discuss MP and NP pollution in soil as well as highlighting the knowledge gaps that are mainly related to the complexity of the soil ecosystem. The fate of MPs and NPs in soil is strongly determined by physical properties of plastics, whereas negligible effect is exerted by their chemical structures. The degradative processes of plastic, termed ageing, besides generating micro-and nano-size debris, can induce marked changes in their chemical and physical properties with relevant effects on their reactivity. Further, these processes could cause the release of toxic oligomeric and monomeric constituents from plastics, as well as toxic additives, which may enter in the food chain, representing a possible hazard to human health and potentially affecting the fauna and flora in the environment. In relation to their persistence in soil, the list of soil-inhabiting, plastic-eating bacteria, fungi and insect is increasing daily. One of the main ecological functions attributable to MPs is related to their function as vectors for microorganisms through the soil. However, the main ecological effect of NPs (limited to the fraction size < than 50 nm) is their capacity to pass through the membrane of both prokaryotic and eukaryotic cells. Soil biota, particularly earthworms and collembola, can be both MPs and NPs carriers through soil profile. The use of molecular techniques, especially omics approaches, can gain insights into the effects of MPs and NPs on composition and activity of microbial communities inhabiting the soil and into those living on MPs surface and in the gut of the soil plastic-ingesting fauna.

scholarly journals The Regulation of Autophagy in Eukaryotic Cells: Do All Roads Pass through Atg1?

Autophagy ◽  
2006 ◽  
Vol 2 (2) ◽  
pp. 146-148 ◽  
Author(s):  
Joseph S. Stephan ◽  
Paul K. Herman
Keyword(s):  
Eukaryotic Cells ◽  
Pass Through

New and regenerated primary production in a productive reservoir ecosystem

2010 ◽  
Vol 67 (2) ◽  
pp. 278-287 ◽  
Author(s):  
Leah M. Domine ◽  
Michael J. Vanni ◽  
William H. Renwick
Keyword(s):  
Primary Production ◽  
Euphotic Zone ◽  
Gizzard Shad ◽  
Phytoplankton Production ◽  
Total Production ◽  
Relative Importance ◽  
Dorosoma Cepedianum ◽  
New Production ◽  
Total Primary Production ◽  
The Difference

The concept of new and regenerated production has been used extensively in marine ecosystems but rarely in freshwaters. We assessed the relative importance of new and regenerated phosphorus (P) in sustaining phytoplankton production in Acton Lake, a eutrophic reservoir located in southwestern Ohio, USA. Sources of nutrients to the euphotic zone, including watershed loading, fluxes from sediments, and excretion by sediment-feeding fish (gizzard shad, Dorosoma cepedianum ), were considered sources of new P input that support new primary production and were quantified over the course of a growing season. Regenerated production was estimated by the difference between new and total primary production. New production represented 32%–53% of total primary production, whereas regenerated production represented 47%–68% of total primary production. P excretion by gizzard shad supplied 45%–74% of new P and 24% of P required for total production. In summary, fluxes of P from the watershed and those from sediment-feeding fish need to be considered in strategies to reduce eutrophication in reservoir ecosystems.

Seasonal Variations in the Small Phytoplankton Contribution to the Total Primary Production in the Amundsen Sea, Antarctica

2019 ◽  
Vol 124 (11) ◽  
pp. 8324-8341 ◽  
Author(s):  
Yu Jeong Lim ◽  
Tae‐Wan Kim ◽  
SangHoon Lee ◽  
Dabin Lee ◽  
Jisoo Park ◽  
...  
Keyword(s):  
Primary Production ◽  
Seasonal Variations ◽  
Amundsen Sea ◽  
Small Phytoplankton ◽  
Total Primary Production
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