Effects of Experimental Manipulations of Light and Phosphorus Supply on Competition among Picoplankton and Nanoplankton in an Oligotrophic Lake

1993 ◽  
Vol 50 (5) ◽  
pp. 936-945 ◽  
Author(s):  
John D. Wehr
Keyword(s):  
New York ◽  
Nutrient Dynamics ◽  
Size Structure ◽  
Phosphorus Limitation ◽  
Small Cells ◽  
Factorial Experiments ◽  
Community Size ◽  
Low Light ◽  
Multiple Resources ◽  
Phytoplankton Communities

Phytoplankton communities of clear, oligotrophic lakes are often dominated by small cells, especially the cyanobacterium Synechococcus. Experiments in Rye Lake (New York) directly examined effects of light and phosphorus limitation on the growth of small phytoplankters. Factorial experiments compared growth of phytoplankton collected from 1 and 15 m; microcosms were incubated at both depths and treated with a single P pulse (± 2 μM KH2PO4). During stratification, picoplankton (0.2–2 μm; ≈Synechococcus spp.) predominated, but surface nanoplankton (especially Cyclotella stelligera and Chlamydomonas gloeocapsa) were stimulated to equivalent biomass levels following the P pulse. No significant P effect was observed at 15 m. Picoplankton biomass was similar in surface and deepwater communities and independent of P treatment. Depletion of [Formula: see text] was greatest in surface-incubated controls. After turnover, phytoplankton biomass in both size fractions was unaffected by P but decreased when transplanted from 1 to 15 m (−30 to −70%) and increased in transplants from 15 to 1 m (+ 55 to + 140%). Results suggest that (1) Synechococcus is a superior competitor only under low-light, low-P conditions, (2) multiple resources interact to affect community size structure, and (3) resultant size shifts significantly alter ecosystem nutrient dynamics.

scholarly journals Grazing Induced Shifts in Phytoplankton Cell Size Explain the Community Response to Nutrient Supply

2021 ◽  
Vol 9 (12) ◽  
pp. 2440
Author(s):  
Evangelia Charalampous ◽  
Birte Matthiessen ◽  
Ulrich Sommer
Keyword(s):  
Cell Size ◽  
Environmental Changes ◽  
Size Structure ◽  
Community Response ◽  
Community Level ◽  
Small Cells ◽  
Community Size ◽  
Nutrient Pulse ◽  
Phytoplankton Cell ◽  
Community Growth

Phytoplankton cell size is important for a multitude of functional traits such as growth rates, storage capabilities, and resistance to grazing. Because these response traits are correlated, selective effects on mean community cell size of one environmental factor should impact the ability of phytoplankton to cope with other factors. Here, we experimentally apply expectations on the functional importance of phytoplankton cell size to the community level. We used a natural marine plankton community, and first altered the community’s cell size structure by exposing it to six different grazer densities. The size-shifted communities were then treated with a saturated nutrient pulse to test how the changes in community size structure influenced the mean community growth rate in the short-term (day 1–3) and nutrient storage capacity in the postbloom phase. Copepod grazing reduced the medium-sized phytoplankton and increased the share of the smallest (<10 µm3) and the largest (>100,000 µm3). Communities composed of on average small cells grew faster in response to the nutrient pulse, and thus confirmed the previously suggested growth advantage of small cells for the community level. In contrast, larger phytoplankton showed better storage capabilities, reflected in a slower post-bloom decline of communities that were on average composed of larger cells. Our findings underline that the easily measurable mean cell size of a taxonomically complex phytoplankton community can be used as an indicator trait to predict phytoplankton responses to sequential environmental changes.

scholarly journals Quantifying heterogeneous responses of fish community size structure using novel combined statistical techniques

2016 ◽  
Vol 22 (5) ◽  
pp. 1755-1768 ◽  
Author(s):  
Abigail M. Marshall ◽  
Grant R. Bigg ◽  
Sonja M. van Leeuwen ◽  
John K. Pinnegar ◽  
Hua-Liang Wei ◽  
...  
Keyword(s):  
Fish Community ◽  
Size Structure ◽  
Statistical Techniques ◽  
Community Size

scholarly journals Redundancy in metrics describing the composition, structure, and functioning of the North Sea demersal fish community

2012 ◽  
Vol 69 (1) ◽  
pp. 8-22 ◽  
Author(s):  
Simon P. R. Greenstreet ◽  
Helen M. Fraser ◽  
Stuart I. Rogers ◽  
Verena M. Trenkel ◽  
Stephen D. Simpson ◽  
...  
Keyword(s):  
North Sea ◽  
Fish Community ◽  
Size Structure ◽  
Demersal Fish ◽  
Community Size ◽  
The North ◽  
Management Objectives ◽  
The North Sea ◽  
Composition Structure ◽  
And Function

Abstract Greenstreet, S. P. R., Fraser, H. M., Rogers, S. I., Trenkel, V. M., Simpson, S. D., and Pinnegar, J. K. 2012. Redundancy in metrics describing the composition, structure, and functioning of the North Sea demersal fish community. – ICES Journal of Marine Science, 69: 8–22. Broader ecosystem management objectives for North Sea demersal fish currently focus on restoring community size structure. However, most policy drivers explicitly concentrate on restoring and conserving biodiversity, and it has not yet been established that simply restoring demersal fish size composition will be sufficient to reverse declines in biodiversity and ensure a generally healthy community. If different aspects of community composition, structure, and function vary independently, then to monitor all aspects of community general health will require application of a suite of metrics. This assumes low redundancy among the metrics used in any such suite and implies that addressing biodiversity issues specifically will require explicit management objectives for particular biodiversity metrics. This issue of metric redundancy is addressed, and 15 metrics covering five main attributes of community composition, structure, and function are applied to groundfish survey data. Factor analysis suggested a new interpretation of the metric information and indicated that a minimum suite of seven metrics was necessary to ensure that all changes in the general health of the North Sea demersal fish community were monitored properly. Covariance among size-based and species-diversity metrics was low, implying that restoration of community size structure would not necessarily reverse declines in species diversity.

Effect of phytoplankton community size structure on remote-sensing reflectance and chlorophyll a products

2020 ◽  
Vol 211 ◽  
pp. 103400 ◽  
Author(s):  
Monika Soja-Woźniak ◽  
Leonardo Laiolo ◽  
Mark E. Baird ◽  
Richard Matear ◽  
Lesley Clementson ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Chlorophyll A ◽  
Phytoplankton Community ◽  
Size Structure ◽  
Community Size ◽  
Remote Sensing Reflectance

Global patterns in phytoplankton biomass and community size structure in relation to macronutrients in the open ocean

2018 ◽  
Vol 63 (3) ◽  
pp. 1298-1312 ◽  
Author(s):  
Erik Askov Mousing ◽  
Katherine Richardson ◽  
Marianne Ellegaard
Keyword(s):  
Phytoplankton Biomass ◽  
Size Structure ◽  
Open Ocean ◽  
Community Size ◽  
Global Patterns

scholarly journals Linking community size structure and ecosystem functioning using metabolic theory

2012 ◽  
Vol 367 (1605) ◽  
pp. 2998-3007 ◽  
Author(s):  
Gabriel Yvon-Durocher ◽  
Andrew P. Allen
Keyword(s):  
Ecosystem Functioning ◽  
Size Structure ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Research Question ◽  
Biogeochemical Cycles ◽  
Ecosystem Functions ◽  
Central Research ◽  
Metabolic Theory ◽  
Community Size

Understanding how biogeochemical cycles relate to the structure of ecological communities is a central research question in ecology. Here we approach this problem by focusing on body size, which is an easily measured species trait that has a pervasive influence on multiple aspects of community structure and ecosystem functioning. We test the predictions of a model derived from metabolic theory using data on ecosystem metabolism and community size structure. These data were collected as part of an aquatic mesocosm experiment that was designed to simulate future environmental warming. Our analyses demonstrate significant linkages between community size structure and ecosystem functioning, and the effects of warming on these links. Specifically, we show that carbon fluxes were significantly influenced by seasonal variation in temperature, and yielded activation energies remarkably similar to those predicted based on the temperature dependencies of individual-level photosynthesis and respiration. We also show that community size structure significantly influenced fluxes of ecosystem respiration and gross primary production, particularly at the annual time-scale. Assessing size structure and the factors that control it, both empirically and theoretically, therefore promises to aid in understanding links between individual organisms and biogeochemical cycles, and in predicting the responses of key ecosystem functions to future environmental change.

Phosphorus Kinetics in Lake Superior: Light Intensity and Phosphate Uptake in Algae

1981 ◽  
Vol 38 (2) ◽  
pp. 224-232 ◽  
Author(s):  
C. Nalewajko ◽  
K. Lee ◽  
H. Shear
Keyword(s):  
Management Strategy ◽  
Phosphorus Content ◽  
Lake Superior ◽  
Chlorella Pyrenoidosa ◽  
Phosphorus Limitation ◽  
P Uptake ◽  
Uptake Kinetics ◽  
Low Light ◽  
Light Levels ◽  
Uptake Rates

Epilimnetic phytoplankton in Lake Superior in September, 1979, had low Ik values (75–190 μE∙m−2∙s−1), low N/P ratios (8 to 13:1) and 32PO4–P uptake kinetics that were not consistent with a state of extreme phosphorus limitation. Parallel laboratory experiments with Chlorella pyrenoidosa indicated that phosphorus content per cell was higher and uptake rates of phosphate were lower in cells grown under low light (57 μE∙m−2∙s−1) than those under high light (340 μE∙m−2∙s−1). Maximum 32PO4 uptake occurred at about 50–60 μE∙m−2∙s−1 in both cultures indicating 32PO4 uptake kinetics are light dependent at very low light levels, below or close to their Ik values. It appears that light and not phosphorus limited phytoplankton growth in Lake Superior at the time of our experiments. Antecedent solar radiation prior to our experiments coupled with complete mixing of the top 20–25 m of the Lake possibly resulted in a low light-adapted phytoplankton population. We suggest that phosphorus control need not be the correct management strategy to maintain oligotrophy in Lake Superior. Key words: phosphorus, kinetics, light, primary production, mixing, management

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