scholarly journals Variability in nitrogen and phosphorus limitation for Baltic Sea phytoplankton during nitrogen-fixing cyanobacterial blooms

2003 ◽  
Vol 262 ◽  
pp. 81-95 ◽  
Author(s):  
PH Moisander ◽  
TF Steppe ◽  
NS Hall ◽  
J Kuparinen ◽  
HW Paerl
Keyword(s):  
Baltic Sea ◽  
Phosphorus Limitation ◽  
Cyanobacterial Blooms ◽  
Nitrogen Fixing ◽  
Nitrogen And Phosphorus

scholarly journals Quantitative Proteomic and Microcystin Production Response of Microcystis aeruginosa to Phosphorus Depletion

2021 ◽  
Vol 9 (6) ◽  
pp. 1183
Author(s):  
Nian Wei ◽  
Lirong Song ◽  
Nanqin Gan
Keyword(s):  
Microcystis Aeruginosa ◽  
Molecular Mechanisms ◽  
Phosphorus Limitation ◽  
Cyanobacterial Blooms ◽  
Metabolic Processes ◽  
Absolute Quantitation ◽  
Nitrogen And Phosphorus ◽  
Microcystis Blooms ◽  
Isobaric Tags ◽  
Phosphorus Depletion

Microcystis blooms are the most widely distributed and frequently occurring cyanobacterial blooms in freshwater. Reducing phosphorus is suggested to be effective in mitigating cyanobacterial blooms, while the underlying molecular mechanisms are yet to be elucidated. In the present study, isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomics was employed to study the effects of phosphorus depletion on Microcystis aeruginosa FACHB-905. The production of microcystins (MCs), a severe hazard of Microcystis blooms, was also analyzed. In total, 230 proteins were found to be differentially abundant, with 136 downregulated proteins. The results revealed that, upon phosphorus limitation stress, Microcystis aeruginosa FACHB-905 raised the availability of phosphorus primarily by upregulating the expression of orthophosphate transport system proteins, with no alkaline phosphatase producing ability. Phosphorus depletion remarkably inhibited cell growth and the primary metabolic processes of Microcystis, including transcription, translation and photosynthesis, with structures of photosystems remaining intact. Moreover, expression of nitrogen assimilation proteins was downregulated, while proteins involved in carbon catabolism were significantly upregulated, which was considered beneficial for the intracellular balance among carbon, nitrogen and phosphorus. The expression of MC synthetase was not significantly different upon phosphorus depletion, while MC content was significantly suppressed. It is assumed that phosphorus depletion indirectly regulates the production of MC by the inhibition of metabolic processes and energy production. These results contribute to further understanding of the influence mechanisms of phosphorus depletion on both biological processes and MC production in Microcystis cells.

scholarly journals Deposition of nitrogen and phosphorus on the Baltic Sea: seasonal patterns and nitrogen isotope composition

2008 ◽  
Vol 5 (6) ◽  
pp. 1657-1667 ◽  
Author(s):  
C. Rolff ◽  
R. Elmgren ◽  
M. Voss
Keyword(s):  
Baltic Sea ◽  
Isotope Composition ◽  
Seasonal Pattern ◽  
Nitrogen Isotope ◽  
Cyanobacterial Blooms ◽  
Organic N ◽  
Nitrogen And Phosphorus ◽  
Clear Seasonal Pattern ◽  
Upper Mixed Layer ◽  
The Baltic

Abstract. Atmospheric deposition of nitrogen and phosphorus on the central Baltic Sea (Baltic Proper) was estimated monthly at two coastal stations and two isolated islands in 2001 and 2002. Yearly nitrogen deposition ranged between 387 and 727 mg N m−2 yr−1 (average 617) and was composed of ~10% organic N and approximately equal amounts of ammonium and nitrate. Winter nitrate peaks at the isolated islands possibly indicated ship emissions. Load weighted δ15N of deposited N was 3.7‰ and 0.35‰ at the coastal stations and the isolated islands respectively. Winter δ15N was ~3‰ lighter than in summer, reflecting winter dominance of nitrate. The light isotopic composition of deposited nitrogen may cause overestimates of nitrogen fixation in basin-wide isotopic budgeting, whereas relatively heavy deposition of ammonium during summer instead may cause underestimates of fixation in budgets of the upper mixed layer. δ15N in atmospherically deposited nitrate and ammonium was estimated by regression to −7.9 and 13.5‰ respectively. Phosphorus deposition showed no clear seasonal pattern and was considerably lower at the isolated islands. Organic P constituted 20–40% of annual P deposition. P deposition is unlikely to be a major source for cyanobacterial blooms but may potentially prolong an ongoing bloom.

scholarly journals Phosphorus limitation and diel control of nitrogen-fixing cyanobacteria in the Baltic Sea

2007 ◽  
Vol 345 ◽  
pp. 41-50 ◽  
Author(s):  
PH Moisander ◽  
HW Paerl ◽  
J Dyble ◽  
K Sivonen
Keyword(s):  
Baltic Sea ◽  
Phosphorus Limitation ◽  
Nitrogen Fixing ◽  
The Baltic Sea ◽  
The Baltic

scholarly journals Exploring the distance between nitrogen and phosphorus limitation in mesotrophic surface waters using a sensitive bioassay

2017 ◽  
Vol 14 (2) ◽  
pp. 379-387 ◽  
Author(s):  
Enis Hrustić ◽  
Risto Lignell ◽  
Ulf Riebesell ◽  
Tron Frede Thingstad
Keyword(s):  
Baltic Sea ◽  
Incubation Time ◽  
Phosphorus Limitation ◽  
Early Summer ◽  
Parameter Estimates ◽  
Nitrogen And Phosphorus ◽  
Field Station ◽  
N Limitation ◽  
P Limitation ◽  
Two Samples

Abstract. The balance in microbial net consumption of nitrogen and phosphorus was investigated in samples collected in two mesotrophic coastal environments: the Baltic Sea (Tvärminne field station) and the North Sea (Espegrend field station). For this, we have refined a bioassay based on the response in alkaline phosphatase activity (APA) over a matrix of combinations in nitrogen and phosphorus additions. This assay not only provides information on which element (N or P) is the primary limiting nutrient, but also gives a quantitative estimate for the excess of the secondary limiting element (P+ or N+, respectively), as well as the ratio of balanced net consumption of added N and P over short timescales (days). As expected for a Baltic Sea late spring–early summer situation, the Tvärminne assays (n =  5) indicated N limitation with an average P+ =  0.30 ± 0.10 µM-P, when incubated for 4 days. For short incubations (1–2 days), the Espegrend assays indicated P limitation, but the shape of the response surface changed with incubation time, resulting in a drift in parameter estimates toward N limitation. Extrapolating back to zero incubation time gave P limitation with N+ ≈  0.9 µM-N. The N : P ratio (molar) of nutrient net consumption varied considerably between investigated locations: from 2.3 ± 0.4 in the Tvärminne samples to 13 ± 5 and 32 ± 3 in two samples from Espegrend. Our assays included samples from mesocosm acidification experiments, but statistically significant effects of ocean acidification were not found by this method.

scholarly journals Alterations in microbial community composition with increasing <i>f</i>CO<sub>2</sub>: a mesocosm study in the eastern Baltic Sea

2017 ◽  
Vol 14 (16) ◽  
pp. 3831-3849 ◽  
Author(s):  
Katharine J. Crawfurd ◽  
Santiago Alvarez-Fernandez ◽  
Kristina D. A. Mojica ◽  
Ulf Riebesell ◽  
Corina P. D. Brussaard
Keyword(s):  
Microbial Community ◽  
Ocean Acidification ◽  
Baltic Sea ◽  
Community Dynamics ◽  
Inorganic Nitrogen ◽  
Microbial Community Composition ◽  
Cell Diameter ◽  
Viral Lysis ◽  
Nitrogen And Phosphorus ◽  
Eastern Baltic

Abstract. Ocean acidification resulting from the uptake of anthropogenic carbon dioxide (CO2) by the ocean is considered a major threat to marine ecosystems. Here we examined the effects of ocean acidification on microbial community dynamics in the eastern Baltic Sea during the summer of 2012 when inorganic nitrogen and phosphorus were strongly depleted. Large-volume in situ mesocosms were employed to mimic present, future and far future CO2 scenarios. All six groups of phytoplankton enumerated by flow cytometry ( <  20 µm cell diameter) showed distinct trends in net growth and abundance with CO2 enrichment. The picoeukaryotic phytoplankton groups Pico-I and Pico-II displayed enhanced abundances, whilst Pico-III, Synechococcus and the nanoeukaryotic phytoplankton groups were negatively affected by elevated fugacity of CO2 (fCO2). Specifically, the numerically dominant eukaryote, Pico-I, demonstrated increases in gross growth rate with increasing fCO2 sufficient to double its abundance. The dynamics of the prokaryote community closely followed trends in total algal biomass despite differential effects of fCO2 on algal groups. Similarly, viral abundances corresponded to prokaryotic host population dynamics. Viral lysis and grazing were both important in controlling microbial abundances. Overall our results point to a shift, with increasing fCO2, towards a more regenerative system with production dominated by small picoeukaryotic phytoplankton.

The History of Cyanobacterial Blooms in the Baltic Sea

AMBIO ◽  
2001 ◽  
Vol 30 (4) ◽  
pp. 172-178 ◽  
Author(s):  
Terttu Finni ◽  
Kaisa Kononen ◽  
Riitta Olsonen ◽  
Kerstin Wallström
Keyword(s):  
Baltic Sea ◽  
Cyanobacterial Blooms ◽  
The Baltic Sea ◽  
History Of ◽  
The Baltic

scholarly journals Photosynthetic response to nitrogen source and different ratios of nitrogen and phosphorus in toxic cyanobacteria, Microcystis aeruginosa FACHB-905

2016 ◽  
Author(s):  
Guotao Peng ◽  
Zhengqiu Fan ◽  
Xiangrong Wang ◽  
Chen Chen
Keyword(s):  
Chlorophyll Fluorescence ◽  
Algal Blooms ◽  
Freshwater Ecosystems ◽  
Cyanobacterial Blooms ◽  
Photosynthetic Response ◽  
Nitrogen And Phosphorus ◽  
Ammonium Toxicity ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters ◽  
N Assimilation

<p>The frequent outbreak of cyanobacterial blooms has become a worldwide phenomenon in freshwater ecosystems. Studies have elucidated the close relationship between harmful algal blooms and nutrient contents, including the loading of nitrogen and the ratios of nitrogen (N) and phosphorus (P). In this study, the effect of inorganic (nitrate and ammonium) and organic (urea) nitrogen at varied N/P ratios on the <em>Microcystis</em> <em>aeruginosa</em> FACHB-905 accumulation and photosynthesis was investigated.  The optimal NO<sub>3</sub>/P in this study were 30~50 indicated by the cell abundance (4.1×10<sup>6</sup>/mL), pigment concentration (chlorophyll a 3.1 mg/L,  phycocyanin 8.3mg/L), and chlorophyll fluorescence parameters (<em>rETR</em>, <em>E<sub>k</sub>, α, φPSII</em> and <em>F<sub>v</sub>/F<sub>m</sub> </em>values), while too high NO<sub>3</sub>-N (N/P=100:1) would cause an intracellular nitrate inhibition, leading to a decrease of photosynthetic activity. In addition, low concentration of NH<sub>4</sub>-N (N/P=4:1) would favor the <em>M. aeruginosa </em>growth and photosynthesis, and high NH<sub>4</sub>/P ratio (&gt;16) would rise the ammonium toxicity of algal cells and affect the N assimilation. In urea treatments, <em>M. aeruginosa </em>responded similarly to the NH<sub>4</sub>-N treatments both in growth curves and pigment contents, and the favorable N/P ratio was between 16~30, suggested by the chlorophyll fluorescence parameters. The results demonstrated that the various chemical forms of N and N/P ratios have a significant impact on <em>Microcystis</em> abundance and photosynthesis. More work is needed to figure out the mechanism of nitrogen utilization by <em>Microcystis</em> and  the photosynthetic response to nutrient stress at the molecular level.</p>

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