scholarly journals Vertical partitioning of phosphate uptake among picoplankton groups in the low Pi Mediterranean Sea

2015 ◽  
Vol 12 (4) ◽  
pp. 1237-1247 ◽  
Author(s):  
A. Talarmin ◽  
F. Van Wambeke ◽  
P. Lebaron ◽  
T. Moutin
Keyword(s):  
Mediterranean Sea ◽  
Cell Sorting ◽  
Soluble Reactive Phosphorus ◽  
Euphotic Zone ◽  
Western Basin ◽  
Uptake Kinetic ◽  
Pi Turnover ◽  
Uptake Rates ◽  
Heterotrophic Prokaryotes ◽  
Reactive Phosphorus

Abstract. Microbial transformations are key processes in marine phosphorus cycling. In this study, we investigated the contribution of phototrophic and heterotrophic groups to phosphate (Pi) uptake fluxes in the euphotic zone of the low-Pi Mediterranean Sea and estimated Pi uptake kinetic characteristics. Surface soluble reactive phosphorus (SRP) concentrations were in the range of 6–80 nmol L−1 across the transect, and the community Pi turnover times, assessed using radiolabeled orthophosphate incubations, were longer in the western basin, where the highest bulk and cellular rates were measured. Using live cell sorting, four vertical profiles of Pi uptake rates were established for heterotrophic prokaryotes (Hprok), phototrophic picoeukaryotes (Pic) and Prochlorococcus (Proc) and Synechococcus (Syn) cyanobacteria. Hprok cells contributed up to 82% of total Pi uptake fluxes in the superficial euphotic zone, through constantly high abundances (2.7–10.2 × 105 cells mL−1) but variable cellular rates (6.6 ± 9.3 amol P cell−1 h−1). Cyanobacteria achieved most of the Pi uptake (up to 62%) around the deep chlorophyll maximum depth, through high abundances (up to 1.4 × 105 Proc cells mL−1) and high cellular uptake rates (up to 40 and 402 amol P cell−1 h−1, respectively for Proc and Syn cells). At saturating concentrations, maximum cellular rates up to 132 amol P cell−1 h−1 were measured for Syn at station (St.) C, which was 5 and 60 times higher than Proc and Hprok, respectively. Pi uptake capabilities of the different groups likely contribute to their vertical distribution in the low Pi Mediterranean Sea, possibly along with other energy limitations.

scholarly journals Limnological characterisation and phytoplankton seasonal variation in a subtropical shallow lake (Guaiba Lake, Brazil): a long-term study

2014 ◽  
Vol 26 (4) ◽  
pp. 442-456 ◽  
Author(s):  
Rodrigo da Rocha Andrade ◽  
Danilo Giroldo
Keyword(s):  
Shallow Lake ◽  
Soluble Reactive Phosphorus ◽  
Late Summer ◽  
Euphotic Zone ◽  
Subtropical Zone ◽  
Chl A ◽  
Relative Contribution ◽  
Long Term Study ◽  
Reactive Phosphorus

AIM: to provide a long-term limnological characterisation of a subtropical shallow lake in addition to verifying seasonal differences, including phytoplankton variation. METHODS: monthly sampling at sites IP, SJ and MD from 2000 to 2009 to analyse temperature - T; depth - Z; the depth of the euphotic zone - Zeu; Zeu/Z (%); total suspended solids - TSS; dissolved oxygen - DO; pH; electrical conductivity - EC; N-NH3, N-NO2, N-NO3; soluble reactive phosphorus - SRP; chlorophyll a - Chl-a and phytoplankton. RESULTS: low values of Z and Zeu characterised the shallow and turbid conditions of lake and corresponded to the contribution of nano-microflagellates (Chlamydomonas sp., Spermatozopsis sp., Cryptomonas sp. and Rhodomonas sp ) and diatoms (Aulacoseira granulata). Zeu/Z (%), SRP and Chl-a were significantly different at site IP (meso-eutrophic) compared to sites SJ and MD (eutrophic). Phytoplankton density was also significantly higher at sites SJ and MD, and the largest relative contribution of Actinastrum sp., Dictyosphaerium sp., Micractinium sp., Monoraphidium sp., Scenedesmus/Desmodesmus sp. and Euglena sp. corresponded to the most polluted waters at site SJ. The significantly higher T (ºC) in summer corresponded to significantly higher Chl-a as well as a greater richness and density of phytoplankton. Cocconeis sp., Gomphonema sp. and Pinnularia sp. (pennated diatoms) were negatively correlated with temperature and were therefore more representative at the three sites in winter. Asterionella formosa was correlated with SRP and vernal blooms were recorded (2000-2001). Planktothrix isothrix and Planktothricoides raciborskii were expressive in the summer/late summer (2004-2005), and were significantly correlated with Chl-a and low SRP in water column. CONCLUSIONS: The study corroborated the sensitivity of phytoplankton in characterising different stages of eutrophication at different sites and corresponding watersheds as well as in characterising different seasons in a shallow lake in the subtropical zone of Brazil.

scholarly journals Lack of P-limitation of phytoplankton and heterotrophic prokaryotes in surface waters of three anticyclonic eddies in the stratified Mediterranean Sea

2011 ◽  
Vol 8 (2) ◽  
pp. 525-538 ◽  
Author(s):  
T. Tanaka ◽  
T. F. Thingstad ◽  
U. Christaki ◽  
J. Colombet ◽  
V. Cornet-Barthaux ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Surface Waters ◽  
Ammonium Phosphate ◽  
Turnover Time ◽  
General Notion ◽  
Western Basin ◽  
P Limitation ◽  
Levantine Basin ◽  
Heterotrophic Prokaryotes ◽  
Anticyclonic Eddies

Abstract. We investigated the identity of the limiting nutrient of the pelagic microbial food web in the Mediterranean Sea using nutrient manipulated microcosms during summer 2008. Experiments were carried out with surface waters at the center of anticyclonic eddies in the Western Basin, the Ionian Basin, and the Levantine Basin. In situ, the ratio of N to P was always higher in both dissolved and particulate organic fractions compared to the Redfield ratio, suggesting a relative P-starvation. In each experiment, four different treatments in triplicates (addition of ammonium, phosphate, a combination of both, and the unamended control) were employed and chemical and biological parameters monitored throughout a 3–4 day incubation. Temporal changes of turnover time of phosphate and ATP, and alkaline phosphatase activity during the incubation suggested that the phytoplankton and heterotrophic prokaryotes (Hprok) communities were not P-limited at the sites. Furthermore, statistical comparison among treatments at the end of the incubation did not support a hypothesis of P-limitation at the three study sites. In contrast, primary production was consistently limited by N, and Hprok growth was not limited by N nor P in the Western Basin, but N-limited in the Ionian Basin, and N and P co-limited in the Levantine Basin. Our results demonstrated the gap between biogeochemical features (an apparent P-starved status) and biological responses (no apparent P-limitation). We question the general notion that Mediterranean surface waters are limited by P alone during the stratified period.

scholarly journals Vertical partitioning of phosphate uptake among picoplankton groups in the P-depleted Mediterranean Sea

2014 ◽  
Vol 11 (10) ◽  
pp. 14639-14665 ◽  
Author(s):  
A. Talarmin ◽  
F. Van Wambeke ◽  
P. Lebaron ◽  
T. Moutin
Keyword(s):  
Mediterranean Sea ◽  
Cellular Level ◽  
Uptake Kinetic ◽  
Natural Concentration ◽  
Half Saturation Constant ◽  
Low Concentrations ◽  
Uptake Rates ◽  
Maximum Cell ◽  
The Mediterranean ◽  
Low K

Abstract. Radiolabeled orthophosphate (Pi) incubations coupled with cell sorting were conducted in the Mediterranean Sea to assess the contribution of picoplanktonic groups to total Pi uptake and to potentially explain their spatial distribution. Under natural Pi concentrations (P-deficient and stratified conditions during the survey), total Pi uptake was dominated in the surface by heterotrophic prokaryotes (Hprok; up to 82%) and shifted to a cyanobacterial dominance around the deep chlorophyll maximum depth. These experiments were completed with concentration bioassays at 4 stations to determine Pi uptake kinetic constants (maximum cell-normalized uptake rates Vmax and the half-saturation constant plus natural concentration K +Sn) in picophytoeukaryotes (Pic), Synechococcus (Syn), Prochlorococcus (Proc) and Hprok. Syn cells were the most efficient in the uptake of Pi at the cellular level at saturating concentration (100 nmol L-1). Indeed, Syn displayed the highest Vmax (up to 132 amol P cell−1 h-1) compared to other groups like Hprok (Vmax up to 2 amol P cell−1 h-1), and the lowest K + Sn. This suggests that they could be quickly reactive to a pulsed supply of Pi. Hprok and Proc cells seemed more adapted to take up Pi at low concentrations, with low K + Sn values (2.9 to 22.7 nmol P L-1), conferring them a nutritional advantage under P-deficient conditions. Such characteristics may explain the successful year-long coexistence of osmotrophic autotrophs and heterotrophs in the Mediterranean Sea and their vertical distribution in the photic zone.

Spatial and Temporal Water Quality Trends in Severn Sound, Georgian Bay, since the Introduction of Phosphorus Control Guidelines: Nutrients and Phytoplankton, 1973 to 1991

1995 ◽  
Vol 30 (4) ◽  
pp. 565-592 ◽  
Author(s):  
A.F. Gemza
Keyword(s):  
Total Phosphorus ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Soluble Reactive Phosphorus ◽  
Euphotic Zone ◽  
Water Clarity ◽  
Sewage Treatment Plants ◽  
Order Of Magnitude ◽  
Phosphorus Levels

Abstract Severn Sound continues to exhibit signs of eutrophication despite initial identification of the problem in 1969 and the construction of several sewage treatment plants since then. In general, improvements in trophic state indicators have been marginal, suggesting that the sewage treatment plants have had limited success in controlling phosphorus concentrations. These discharges likely contributed to the increased total phosphorus levels and consequently the higher phytoplankton densities of the nearshore waters. Phytoplankton biovolumes were on average one order of magnitude higher than in the open waters of Lake Huron with mean summer biovolumes as high as 8.0 mm/L. Algal biovolumes were most dense in Penetang Bay, which experienced limited exchange with the main waters of the sound. No significant long-term trends were observed. Water clarity was declining significantly, however, at a rate of -0.60 to -0.78 m/year throughout the sound except in Sturgeon Bay. Total phosphorus levels were highly variable from year to year; however, concentrations from a 20-year perspective were declining in the open waters at a rate of 0.70 µg/L/year, but response was limited in nearshore areas. In Sturgeon Bay, mean annual euphotic zone total phosphorus as well as soluble reactive phosphorus levels declined by as much as 50% following the construction of a sewage treatment plant with tertiary treatment. Phytoplankton genera typical of eutrophic waters continued to dominate the algal assemblage but members indicative of mesotrophic conditions have become apparent in some areas of the sound.

scholarly journals Effects of Lanthanum Modified Bentonite and Polyaluminium Chloride on the Environmental Variables in the Water and Sediment Phosphorus Form in Lake Yanglan, China

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1947
Author(s):  
Ling Su ◽  
Chen Zhong ◽  
Lei Gan ◽  
Xiaolin He ◽  
Jinlei Yu ◽  
...  
Keyword(s):  
Suspended Solids ◽  
Soluble Reactive Phosphorus ◽  
Particulate Phosphorus ◽  
Modified Bentonite ◽  
Combined Application ◽  
Water And Sediment ◽  
Phosphorus Form ◽  
Labile P ◽  
Reactive Phosphorus ◽  
Polyaluminium Chloride

The application of lanthanum modified bentonite (Phoslock®) and polyaluminium chloride (PAC) is popular in the restoration of European temperate lakes; however, the effects of the application on the concentrations of phosphorus (P) in both the water and the sediments have been poorly evaluated to date. We studied the effects of the application of Phoslock® + PAC on the concentrations of total phosphorus (TP), particulate phosphorus (PP), soluble reactive phosphorus (SRP), total suspended solids (TSS) and chlorophyll a (Chla) in the water, and different P forms in the sediments, in an isolated part of Lake Yanglan. The results showed that the concentrations of TP, PP, SRP, TSS and Chla decreased significantly after the addition of Phoslock® + PAC. Moreover, the concentrations of labile-P, reductant-soluble-P and organic-P in the sediments were also significantly decreased after the Phoslock® + PAC application. However, the concentrations of both the stable apatite-P and residual-P in the sediments after application of Phoslock® + PAC were much higher than the pre-addition values, while the concentrations of metal-oxide-P did not differ significantly between the pre- and post- application conditions. Our findings imply that the combined application of Phoslock® and PAC can be used in the restoration of subtropical shallow lakes, to reduce the concentrations of P in the water and suppress the release of P from the sediments.

scholarly journals Seasonal Variations of Phosphorus Species in the Overlying and Pore Waters of the Tuohe River, China

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Qing Xu ◽  
Xiaoping Yu ◽  
Yafei Guo ◽  
Tianlong Deng ◽  
Yu-Wei Chen ◽  
...  
Keyword(s):  
Seasonal Variations ◽  
Yangtze River ◽  
Algal Bloom ◽  
Soluble Reactive Phosphorus ◽  
Pore Waters ◽  
Phosphorus Species ◽  
Dissolved Phosphorus ◽  
Vertical Distributions ◽  
Reactive Phosphorus ◽  
Main Factor

Overlying sediment and pore waters were collected in summer and winter at upstream (Jintang) and downstream (Neijiang) sites of the Tuohe River, which is one of the five largest tributaries of the Yangtze River in China. Phosphorus species, including soluble reactive phosphorus (SRP), soluble unreactive phosphorus (SUP), and total dissolved phosphorus (TDP), and some diagenetic constituents including dissolved Fe(II), Mn(II), and sulfide in overlying and pore waters, were measured systematically. The seasonal variations and vertical distributions of phosphorus species in overlying and pore waters at both sampling sites were obtained to elucidate some aspects of the transport and transformations of phosphorus. Based on the profiles of pore and overlying waters as well as the TDN/TDP data during an algal bloom in 2007, it was clearly demonstrated that phosphorus was the main factor limiting the phytoplankton growth in the Tuohe River.

Impact of hydro-sedimentary processes on the dynamics of soluble reactive phosphorus in the Seine River

2014 ◽  
Vol 122 (2-3) ◽  
pp. 229-251 ◽  
Author(s):  
Lauriane Vilmin ◽  
Najla Aissa-Grouz ◽  
Josette Garnier ◽  
Gilles Billen ◽  
Jean-Marie Mouchel ◽  
...  
Keyword(s):  
Soluble Reactive Phosphorus ◽  
Sedimentary Processes ◽  
Seine River ◽  
Reactive Phosphorus

Changes in Nutrient Levels of Lake Water Stored at 4 °C

1984 ◽  
Vol 41 (6) ◽  
pp. 985-988 ◽  
Author(s):  
A. H. El-Shaarawi ◽  
M. A. Neilson
Keyword(s):  
Statistical Analysis ◽  
Lake Water ◽  
Water Samples ◽  
Soluble Reactive Phosphorus ◽  
Lake Ontario ◽  
The Other ◽  
Nutrient Levels ◽  
Glass Bottles ◽  
Reactive Phosphorus

Water samples were collected on Lake Ontario during April and November, filtered (0.45 μm), and immediately analyzed onboard ship for the nutrients soluble reactive phosphorus, nitrate-plus-nitrite, and ammonia. Replicates were stored in glass bottles at 4 °C and reanalyzed within 8 d. Statistical analysis showed that soluble reactive phosphorus decreased by 11 and 13% and nitrate-plus-nitrite by 7 and 6%, whereas ammonia increased by 75% on one cruise and decreased by 37% on the other.

scholarly journals Periphytic algae dynamics in lentic ecosystems in the Brazilian semiarid

2016 ◽  
Vol 77 (3) ◽  
pp. 495-505 ◽  
Author(s):  
R. S. Cordeiro ◽  
J. E. L. Barbosa ◽  
G. Q. Lima Filho ◽  
L. G. Barbosa
Keyword(s):  
Aquatic Macrophytes ◽  
Soluble Reactive Phosphorus ◽  
Algal Community ◽  
Aquatic Communities ◽  
Dry Period ◽  
Rainy Period ◽  
Brazilian Semiarid ◽  
High Concentrations ◽  
Reactive Phosphorus ◽  
Reduced Density

Abstract The hydrological periods drive the structure and organization of aquatic communities in semiarid regions. We hypothesize that a decrease of the precipitation during the dry period will favor the development of the periphytic algal community, leading to higher richness and density in this period. To test this hypothesis, we investigated the changes in the periphytic algal community structure in three shallow and eutrophic ecosystems of the Brazilian semiarid. The sampling was performed between 2007 and 2010 at two-mensal intervals. The sampling of periphytic algal was performed in aquatic macrophytes and rocks. The abiotic variables were analyzed simultaneously. Dominance in diatoms, cyanobacteria and chlorophytes, respectively, was observed in two periods. In the dry period, waters were alkaline and had high concentrations of nitrate and total phosphorus associated with the highest densities of Bacillariophyceae. In the rainy period the water was warmer, oxygenated and high concentrations of ammonia and soluble reactive phosphorus with diatoms remained dominant but with reduced density, while cyanobacteria and chlorophytes increased. Overall, periphytic algal community composition no responded to changes in the hydrological periods. However, the hydrological periods altered the dynamics of periphytic algal community, supported by the alternation of the most representative classes (diatoms and cyanobacteria) between the hydrologic periods. Our data suggest that the morphometric and chemical and physical characteristics of lentic aquatic ecosystems studied were more important in the dynamics of periphytic algal community than the hydrological periods and types of substrates.

Sign in / Sign up

Export Citation Format

Share Document