Effects of nitrogen enrichment on zooplankton biomass and N:P recycling ratios across a DOC gradient in northern-latitude lakes

AbstractWe used data from whole-lake studies to assess how changes in food quantity (phytoplankton biomass) and quality (phytoplankton community composition, seston C:P and N:P) with N fertilization affect zooplankton biomass, community composition and C:N:P stoichiometry, and their N:P recycling ratio along a gradient in lake DOC concentrations. We found that despite major differences in phytoplankton biomass with DOC (unimodal distributions, especially with N fertilization), no major differences in zooplankton biomass were detectable. Instead, phytoplankton to zooplankton biomass ratios were high, especially at intermediate DOC and after N fertilization, implying low trophic transfer efficiencies. An explanation for the observed low phytoplankton resource use, and biomass responses in zooplankton, was dominance of colony forming chlorophytes of reduced edibility at intermediate lake DOC, combined with reduced phytoplankton mineral quality (enhanced seston N:P) with N fertilization. N fertilization, however, increased zooplankton N:P recycling ratios, with largest impact at low DOC where phytoplankton benefitted from light sufficiently to cause enhanced seston N:P. Our results suggest that although N enrichment and increased phytoplankton biomass do not necessarily increase zooplankton biomass, bottom-up effects may still impact zooplankton and their N:P recycling ratio through promotion of phytoplankton species of low edibility and altered mineral quality.

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Biogeochemical versus ecological consequences of modeled ocean physics

Biogeosciences ◽

10.5194/bg-14-2877-2017 ◽

2017 ◽

Vol 14 (11) ◽

pp. 2877-2889 ◽

Cited By ~ 8

Author(s):

Sophie Clayton ◽

Stephanie Dutkiewicz ◽

Oliver Jahn ◽

Christopher Hill ◽

Patrick Heimbach ◽

...

Keyword(s):

Primary Production ◽

Ocean Circulation ◽

Mixed Layer ◽

Phytoplankton Biomass ◽

Phytoplankton Community ◽

Resource Competition ◽

Nutrient Supply ◽

Zooplankton Biomass ◽

Global Ocean ◽

Competition Theory

Abstract. We present a systematic study of the differences generated by coupling the same ecological–biogeochemical model to a 1°, coarse-resolution, and 1∕6°, eddy-permitting, global ocean circulation model to (a) biogeochemistry (e.g., primary production) and (b) phytoplankton community structure. Surprisingly, we find that the modeled phytoplankton community is largely unchanged, with the same phenotypes dominating in both cases. Conversely, there are large regional and seasonal variations in primary production, phytoplankton and zooplankton biomass. In the subtropics, mixed layer depths (MLDs) are, on average, deeper in the eddy-permitting model, resulting in higher nutrient supply driving increases in primary production and phytoplankton biomass. In the higher latitudes, differences in winter mixed layer depths, the timing of the onset of the spring bloom and vertical nutrient supply result in lower primary production in the eddy-permitting model. Counterintuitively, this does not drive a decrease in phytoplankton biomass but results in lower zooplankton biomass. We explain these similarities and differences in the model using the framework of resource competition theory, and find that they are the consequence of changes in the regional and seasonal nutrient supply and light environment, mediated by differences in the modeled mixed layer depths. Although previous work has suggested that complex models may respond chaotically and unpredictably to changes in forcing, we find that our model responds in a predictable way to different ocean circulation forcing, despite its complexity. The use of frameworks, such as resource competition theory, provides a tractable way to explore the differences and similarities that occur. As this model has many similarities to other widely used biogeochemical models that also resolve multiple phytoplankton phenotypes, this study provides important insights into how the results of running these models under different physical conditions might be more easily understood.

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

Earth System Science Data ◽

10.5194/essd-7-261-2015 ◽

2015 ◽

Vol 7 (2) ◽

pp. 261-273 ◽

Cited By ~ 11

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

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Biogeochemical versus ecological consequences of modeled ocean physics

10.5194/bg-2016-337 ◽

2016 ◽

Cited By ~ 2

Author(s):

Sophie Clayton ◽

Stephanie Dutkiewicz ◽

Oliver Jahn ◽

Christopher Hill ◽

Patrick Heimbach ◽

...

Keyword(s):

Primary Production ◽

Ocean Circulation ◽

Mixed Layer ◽

Phytoplankton Biomass ◽

Phytoplankton Community ◽

Nutrient Supply ◽

Zooplankton Biomass ◽

Global Ocean ◽

Biogeochemical Model ◽

Biogeochemical Models

Abstract. Regional and idealized modeling studies have shown that increasing the physical resolution of biogeochemical models to include mesoscale and submesoscale dynamics can result in both increases and decreases in phytoplankton biomass and primary production, as well as changes in phytoplankton community structure. Here we present a systematic study of the differences generated by coupling the same ecological-biogeochemical model to a 1°, coarse-resolution, and 1/6°, eddy-permitting, global ocean circulation model. Surprisingly, we find that the modeled phytoplankton community is largely unchanged, with the same phenotypes dominating in both cases. Conversely, there are large regional variations in integrated primary production, phytoplankton and zooplankton biomass. In the subtropics, mixed layer depths are, on average, deeper in the eddy-permitting model, resulting in higher nutrient supply driving increases in primary production and phytoplankton biomass. In the higher latitudes, deeper spring mixed layer depths in the eddy-permitting model result in increased light limitation during the spring bloom. Counter-intuitively, this does not drive a decrease in phytoplankton biomass, but is reflected in decreased primary production and zooplankton biomass. We explain these similarities and differences in the model using the framework of resource competition theory, and find that they are the consequence of changes in the regional and seasonal nutrient supply and light environment, mediated by differences in the modeled mixed layer depths. Although previous work has suggested that complex models may respond chaotically and unpredictably to changes in forcing, we find that our model responds in a predictable way to different ocean circulation forcing, despite its complexity.

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

Earth System Science Data Discussions ◽

10.5194/essdd-8-365-2015 ◽

2015 ◽

Vol 8 (1) ◽

pp. 365-399

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 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 in 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 five decades from 1958 to 2015, including observations from all major oceanic basins and all seasons, and depths ranging from 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 in open access at PANGAEA, Data Publisher for Earth and Environmental Science. Raw fluorescence profiles: http://doi.pangaea.de/10.1594/PANGAEA.844485.

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Empirical Relationships Between Phytoplankton and Zooplankton Biomass in Lakes

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f81-063 ◽

1981 ◽

Vol 38 (4) ◽

pp. 458-463 ◽

Cited By ~ 154

Author(s):

Edward McCauley ◽

Jaap Kalff

Keyword(s):

Regression Analysis ◽

Phytoplankton Biomass ◽

Food Source ◽

Phytoplankton Community ◽

Zooplankton Biomass ◽

Empirical Models ◽

Crustacean Zooplankton ◽

Functional Regression ◽

Regression Equations ◽

Empirical Relationships

Empirical models based on regression analysis were derived using published values of phytoplankton and crustacean zooplankton biomass from lakes. Equations presented predict crustacean zooplankton biomass from measures of phytoplankton biomass. Zooplankton biomass was shown to be positively related to phytoplankton biomass based on an inter-lake comparison. Analyses of functional regression equations suggest that the ratio of zooplankton to phytoplankton biomass decreases as phytoplankton biomass increases among lakes. It is hypothesized that variation in the biomass of nannoplankton, representing the principal food source for crustaceans present in the phytoplankton community, can account for the variation in the biomass of the crustacean zooplankton community.Key words: phytoplankton, zooplankton, biomass, nannoplankton

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Differences between Nearshore and Offshore Phytoplankton Communities in Lake Ontario

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f87-264 ◽

1987 ◽

Vol 44 (12) ◽

pp. 2155-2163 ◽

Cited By ~ 33

Author(s):

I. M. Gray

Keyword(s):

Chlorophyll A ◽

Phytoplankton Biomass ◽

Algal Biomass ◽

Phytoplankton Community ◽

Seasonal Pattern ◽

Principal Component ◽

Lake Ontario ◽

Dominant Group ◽

Phytoplankton Communities ◽

Eutrophic Species

Differences between nearshore and offshore phytoplankton biomass and composition were evident in Lake Ontario in 1982. Phytoplankton biomass was characterized by multiple peaks which ranged over three orders of magnitude. Perhaps as a consequence of the three times higher current velocities at the northshore station, phytoplankton biomass ranged from 0.09 to 9.00 g∙m−3 compared with 0.10 to 2.40 g∙m−3 for the midlake station. Bacillariophyceae was the dominant group at the northshore station until September when Cyanophyta contributed most to the biomass (83%). Although Bacillariophyceae was the principal component of the spring phytoplankton community at the midlake station, phytoflagellates (49%) and Chlorophyceae (25%) were responsible for summer biomass, with the Chlorophyceae expanding to 80% in the fall. The seasonal pattern of epilimnetic chlorophyll a correlated with temperature. While chlorophyll a concentrations were similar to values from 1970 and 1972, algal biomass had declined and a number of eutrophic species (Melosira binderana, Stephanodiscus tenuis, S. hantzschii var. pusilla, and S. alpinus) previously found were absent in 1982.

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Response of ocean phytoplankton community structure to climate change over the 21st century: partitioning the effects of nutrients, temperature and light

Biogeosciences ◽

10.5194/bg-7-3941-2010 ◽

2010 ◽

Vol 7 (12) ◽

pp. 3941-3959 ◽

Cited By ~ 96

Author(s):

I. Marinov ◽

S. C. Doney ◽

I. D. Lima

Keyword(s):

Climate Change ◽

Community Structure ◽

Sea Ice ◽

Phytoplankton Biomass ◽

Phytoplankton Community ◽

Vertical Mixing ◽

Phytoplankton Community Structure ◽

Marginal Sea ◽

Small Phytoplankton ◽

The Impact

Abstract. The response of ocean phytoplankton community structure to climate change depends, among other factors, upon species competition for nutrients and light, as well as the increase in surface ocean temperature. We propose an analytical framework linking changes in nutrients, temperature and light with changes in phytoplankton growth rates, and we assess our theoretical considerations against model projections (1980–2100) from a global Earth System model. Our proposed "critical nutrient hypothesis" stipulates the existence of a critical nutrient threshold below (above) which a nutrient change will affect small phytoplankton biomass more (less) than diatom biomass, i.e. the phytoplankton with lower half-saturation coefficient K are influenced more strongly in low nutrient environments. This nutrient threshold broadly corresponds to 45° S and 45° N, poleward of which high vertical mixing and inefficient biology maintain higher surface nutrient concentrations and equatorward of which reduced vertical mixing and more efficient biology maintain lower surface nutrients. In the 45° S–45° N low nutrient region, decreases in limiting nutrients – associated with increased stratification under climate change – are predicted analytically to decrease more strongly the specific growth of small phytoplankton than the growth of diatoms. In high latitudes, the impact of nutrient decrease on phytoplankton biomass is more significant for diatoms than small phytoplankton, and contributes to diatom declines in the northern marginal sea ice and subpolar biomes. In the context of our model, climate driven increases in surface temperature and changes in light are predicted to have a stronger impact on small phytoplankton than on diatom biomass in all ocean domains. Our analytical predictions explain reasonably well the shifts in community structure under a modeled climate-warming scenario. Climate driven changes in nutrients, temperature and light have regionally varying and sometimes counterbalancing impacts on phytoplankton biomass and structure, with nutrients and temperature dominant in the 45° S–45° N band and light-temperature effects dominant in the marginal sea-ice and subpolar regions. As predicted, decreases in nutrients inside the 45° S–45° N "critical nutrient" band result in diatom biomass decreasing more than small phytoplankton biomass. Further stratification from global warming could result in geographical shifts in the "critical nutrient" threshold and additional changes in ecology.

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Are Bacterio- and Phytoplankton Community Compositions Related in Lakes Differing in Their Cyanobacteria Contribution and Physico-Chemical Properties?

Genes ◽

10.3390/genes12060855 ◽

2021 ◽

Vol 12 (6) ◽

pp. 855

Author(s):

Mikołaj Kokociński ◽

Dariusz Dziga ◽

Adam Antosiak ◽

Janne Soininen

Keyword(s):

Environmental Factors ◽

Community Composition ◽

Phytoplankton Community ◽

Heterotrophic Bacteria ◽

Bacterial Community Composition ◽

Physical Factors ◽

Research Attention ◽

Phytoplankton Community Composition ◽

The Impact ◽

Bacteria Communities

Bacterioplankton community composition has become the center of research attention in recent years. Bacteria associated with toxic cyanobacteria blooms have attracted considerable interest. However, little is known about the environmental factors driving the bacteria community, including the impact of invasive cyanobacteria. Therefore, our aim has been to determine the relationships between heterotrophic bacteria and phytoplankton community composition across 24 Polish lakes with different contributions of cyanobacteria including the invasive species Raphidiopsis raciborskii. This analysis revealed that cyanobacteria were present in 16 lakes, while R. raciborskii occurred in 14 lakes. Our results show that bacteria communities differed between lakes dominated by cyanobacteria and lakes with minor contributions of cyanobacteria but did not differ between lakes with R. raciborskii and other lakes. Physical factors, including water and Secchi depth, were the major drivers of bacteria and phytoplankton community composition. However, in lakes dominated by cyanobacteria, bacterial community composition was also influenced by biotic factors such as the amount of R. raciborskii, chlorophyll-a and total phytoplankton biomass. Thus, our study provides novel evidence on the influence of environmental factors and R. raciborskii on lake bacteria communities.

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Divergent Accumulation of Microbial Residues and Amino Sugars in Loess Soil after Six Years of Different Inorganic Nitrogen Enrichment Scenarios

Applied Sciences ◽

10.3390/app11135788 ◽

2021 ◽

Vol 11 (13) ◽

pp. 5788

Author(s):

Dominic Kwadwo Anning ◽

Zhilong Li ◽

Huizhen Qiu ◽

Delei Deng ◽

Chunhong Zhang ◽

...

Keyword(s):

Plant Biomass ◽

Inorganic Nitrogen ◽

Amino Sugar ◽

N Fertilization ◽

Biochemical Properties ◽

Sugar Accumulation ◽

Amino Sugars ◽

N Enrichment ◽

Over Time ◽

Microbial Residues

Amino sugars are key microbial biomarkers for determining the contribution of microbial residues in soil organic matter (SOM). However, it remains largely unclear as to what extent inorganic nitrogen (N) fertilization can lead to the significant degradation of SOM in alkaline agricultural soils. A six-year field experiment was conducted from 2013 to 2018 to evaluate the effects of chronic N enrichment on microbial residues, amino sugars, and soil biochemical properties under four nitrogen (urea, 46% N) fertilization scenarios: 0 (no-N, control), 75 (low-N), 225 (medium-N), and 375 (high-N) kg N ha−1. The results showed that chronic N enrichment stimulated microbial residues and amino sugar accumulation over time. The medium-N treatment increased the concentration of muramic acid (15.77%), glucosamine (13.55%), galactosamine (18.84%), bacterial residues (16.88%), fungal residues (11.31%), and total microbial residues (12.57%) compared to the control in 2018; however, these concentrations were comparable to the high-N treatment concentrations. The ratio of glucosamine to galactosamine and of glucosamine to muramic acid decreased over time due to a larger increase in bacterial residues as compared to fungal residues. Microbial biomass, soil organic carbon, and aboveground plant biomass positively correlated with microbial residues and amino sugar components. Chronic N enrichment improved the soil biochemical properties and aboveground plant biomass, which stimulated microbial residues and amino sugar accumulation over time.

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