scholarly journals Variations in river input of iron impact sedimentary phosphorus burial in an oligotrophic Baltic Sea estuary

2018 ◽  
Author(s):  
Wytze K. Lenstra ◽  
Matthias Egger ◽  
Niels A. G. M. van Helmond ◽  
Emma Kritzberg ◽  
Daniel J. Conley ◽  
...  
Keyword(s):  
Organic Matter ◽  
Baltic Sea ◽  
Reactive Transport ◽  
Bottom Water ◽  
Coastal Sediments ◽  
Estuarine Sediments ◽  
Water Salinity ◽  
The Baltic Sea ◽  
The Baltic ◽  
Organic Matter Input

Abstract. Estuarine sediments are key sites for removal of phosphorus (P) from rivers and the open sea. Vivianite, an iron (Fe)(II)-P mineral, can act as a major sink for P in Fe-rich coastal sediments. In this study, we investigate the burial of P in the Öre Estuary in the northern Baltic Sea. We find much higher rates of P burial at our five study sites (up to ~ 0.145 mol m−2 yr−1) when compared to more southern coastal areas in the Baltic Sea with similar rates of sedimentation. Detailed study of the sediment P forms at our site with the highest rate of sedimentation reveals a major role for P associated with Fe and the presence of vivianite crystals below the sulfate methane transition zone. By applying a reactive transport model to sediment and porewater profiles for this site, we show that vivianite may account for up to 40 % of total P burial. With the model, we demonstrate that vivianite formation is promoted in sediments with a low bottom water salinity and high rates of sedimentation and Fe oxide input. While high rates of organic matter input are also required, there is an optimum rate above which vivianite formation declines. Distinct enrichments in sediment Fe and sulfur at depth in the sediment are attributed to short periods of enhanced riverine Fe and organic matter input linked to variations in rainfall on land. Most of the P associated with the Fe in the sediment is likely imported from the adjacent eutrophic Baltic Proper. Our work demonstrates that variations in land-to-sea transfer of Fe may act as a key control on burial of P in coastal sediments. Ongoing climate change is expected to lead to a decrease in bottom water salinity and contribute to continued high inputs of Fe oxides from land, further promoting P burial as vivianite in the coastal zone of the northern Baltic Sea. This may enhance the role of this oligotrophic area as a sink for P imported from eutrophic parts of the Baltic Sea.

scholarly journals Large variations in iron input to an oligotrophic Baltic Sea estuary: impact on sedimentary phosphorus burial

2018 ◽  
Vol 15 (22) ◽  
pp. 6979-6996 ◽  
Author(s):  
Wytze K. Lenstra ◽  
Matthias Egger ◽  
Niels A. G. M. van Helmond ◽  
Emma Kritzberg ◽  
Daniel J. Conley ◽  
...  
Keyword(s):  
Organic Matter ◽  
Baltic Sea ◽  
Reactive Transport ◽  
Bottom Water ◽  
Transport Model ◽  
Coastal Sediments ◽  
Estuarine Sediments ◽  
Water Salinity ◽  
The Baltic Sea ◽  
The Baltic

Abstract. Estuarine sediments are key sites for removal of phosphorus (P) from rivers and the open sea. Vivianite, an Fe(II)-P mineral, can act as a major sink for P in Fe-rich coastal sediments. In this study, we investigate the burial of P in the Öre Estuary in the northern Baltic Sea. We find much higher rates of P burial at our five study sites (up to ∼0.145 molm-2yr-1) when compared to more southern coastal areas in the Baltic Sea with similar rates of sedimentation. Detailed study of the sediment P forms at our site with the highest rate of sedimentation reveals a major role for P associated with Fe and the presence of vivianite crystals below the sulfate methane transition zone. By applying a reactive transport model to sediment and porewater profiles for this site, we show that vivianite may account for up to ∼40 % of total P burial. With the model, we demonstrate that vivianite formation is promoted in sediments with a low bottom water salinity and high rates of sedimentation and Fe oxide input. While high rates of organic matter input are also required, there is an optimum rate above which vivianite formation declines. Distinct enrichments in sediment Fe and sulfur at depth in the sediment are attributed to short periods of enhanced input of riverine Fe and organic matter. These periods of enhanced input are linked to variations in rainfall on land and follow dry periods. Most of the P associated with the Fe in the sediment is likely imported from the adjacent eutrophic Baltic Proper. Our work demonstrates that variations in land-to-sea transfer of Fe may act as a key control on burial of P in coastal sediments. Ongoing climate change is expected to lead to a decrease in bottom water salinity and contribute to continued high inputs of Fe oxides from land, further promoting P burial as vivianite in the coastal zone of the northern Baltic Sea. This may enhance the role of this oligotrophic area as a sink for P imported from eutrophic parts of the Baltic Sea.

scholarly journals Cell-free extracellular enzymatic activity is linked to seasonal temperature changes: a case study in the Baltic Sea

2016 ◽  
Vol 13 (9) ◽  
pp. 2815-2821 ◽  
Author(s):  
Federico Baltar ◽  
Catherine Legrand ◽  
Jarone Pinhassi
Keyword(s):  
Organic Matter ◽  
Baltic Sea ◽  
Extracellular Enzymes ◽  
Seasonal Pattern ◽  
Critical Factor ◽  
Hydrolytic Activity ◽  
Seasonal Temperature ◽  
The Baltic Sea ◽  
The Baltic ◽  
Hydrolysis Of

Abstract. Extracellular enzymatic activities (EEAs) are a crucial step in the degradation of organic matter. Dissolved (cell-free) extracellular enzymes in seawater can make up a significant contribution of the bulk EEA. However, the factors controlling the proportion of dissolved EEA in the marine environment remain unknown. Here we studied the seasonal changes in the proportion of dissolved relative to total EEA (of alkaline phosphatase (APase), β-glucosidase (BGase), and leucine aminopeptidase (LAPase)), in the Baltic Sea for 18 months. The proportion of dissolved EEA ranged between 37 and 100, 0 and 100, and 34 and 100 % for APase, BGase, and LAPase, respectively. A consistent seasonal pattern in the proportion of dissolved EEA was found among all the studied enzymes, with values up to 100 % during winter and  <  40 % during summer. A significant negative relation was found between the proportion of dissolved EEA and temperature, indicating that temperature might be a critical factor controlling the proportion of dissolved relative to total EEA in marine environments. Our results suggest a strong decoupling of hydrolysis rates from microbial dynamics in cold waters. This implies that under cold conditions, cell-free enzymes can contribute to substrate availability at large distances from the producing cell, increasing the dissociation between the hydrolysis of organic compounds and the actual microbes producing the enzymes. This might also suggest a potential effect of global warming on the hydrolysis of organic matter via a reduction of the contribution of cell-free enzymes to the bulk hydrolytic activity.

scholarly journals Pectenotoxin-2 and dinophysistoxin-1 in suspended and sedimenting organic matter in the Baltic Sea

2006 ◽  
Vol 51 (5) ◽  
pp. 2300-2307 ◽  
Author(s):  
Pirjo Kuuppo ◽  
Pauliina Uronen ◽  
Anika Petermann ◽  
Timo Tamminen ◽  
Edna Granéli
Keyword(s):  
Organic Matter ◽  
Baltic Sea ◽  
The Baltic Sea ◽  
The Baltic ◽  
Pectenotoxin 2

The influence of dissolved organic matter on the acid–base system of the Baltic Sea

2014 ◽  
Vol 132 ◽  
pp. 106-115 ◽  
Author(s):  
Karol Kuliński ◽  
Bernd Schneider ◽  
Karoline Hammer ◽  
Ulrike Machulik ◽  
Detlef Schulz-Bull
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Baltic Sea ◽  
Base System ◽  
The Baltic Sea ◽  
Acid Base ◽  
The Baltic

scholarly journals Study on organic matter fractions in the surface micro layer in the Baltic Sea by spectrophotometric and spectrofluorometric methods

2017 ◽  
Author(s):  
Violetta Drozdowska ◽  
Iwona Wróbel ◽  
Piotr Markuszewski ◽  
Przemyslaw Makuch ◽  
Anna Raczkowska ◽  
...  
Keyword(s):  
Organic Matter ◽  
Baltic Sea ◽  
Subsurface Layer ◽  
Molecular Size ◽  
Surface Microlayer ◽  
The Baltic Sea ◽  
Vistula River ◽  
Meteorological Observations ◽  
Organic Matter Fractions ◽  
The Baltic

Abstract. The fluorescence and absorption measurements of the samples collected from a surface microlayer (SML) and a subsurface layer (SS), a depth of 1 m were studied during three research cruises in the Baltic Sea along with hydrophysical studies and meteorological observations. Several absorption (E2 : E3, S, SR) and fluorescence (fluorescence intensities at peaks: A, C, M, T, the ratio (M + T) / (A + C), HIX) indices of colored and fluorescent organic matter (CDOM and FDOM) helped to describe the changes in molecular size and weight as well as in composition of organic matter. The investigation allow to assess a decrease in the contribution of two terrestrial components (A and C) with increasing salinity (~ 1.64 % and ~ 1.89 % in SML and ~ 0.78 % and ~ 0.71 % in SS, respectively) and an increase of in-situ produced components (M and T) with salinity (~ 0.52 % and ~ 2.83 % in SML and ~ 0.98 % and ~ 1.87 % in SS, respectively). Hence, a component T reveals the biggest relative changes along the transect from the Vistula River outlet to Gdansk Deep, both in SML and SS, however an increase was higher in SML than in SS (~ 18.5 % and ~ 12.3 %, respectively). The ratio E2 : E3

scholarly journals Parameterization of the light absorption properties of chromophoric dissolved organic matter in the Baltic Sea and Pomeranian lakes

Ocean Science ◽  
2016 ◽  
Vol 12 (4) ◽  
pp. 1013-1032 ◽  
Author(s):  
Justyna Meler ◽  
Piotr Kowalczuk ◽  
Mirosława Ostrowska ◽  
Dariusz Ficek ◽  
Monika Zabłocka ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Absorption Coefficient ◽  
Baltic Sea ◽  
Chlorophyll A ◽  
Chromophoric Dissolved Organic Matter ◽  
The Baltic Sea ◽  
Absorption Properties ◽  
Chlorophyll A Concentration ◽  
The Baltic

Abstract. This study presents three alternative models for estimating the absorption properties of chromophoric dissolved organic matter aCDOM(λ). For this analysis we used a database containing 556 absorption spectra measured in 2006–2009 in different regions of the Baltic Sea (open and coastal waters, the Gulf of Gdańsk and the Pomeranian Bay), at river mouths, in the Szczecin Lagoon and also in three lakes in Pomerania (Poland) – Obłęskie, Łebsko and Chotkowskie. The variability range of the chromophoric dissolved organic matter (CDOM) absorption coefficient at 400 nm, aCDOM(400), lay within 0.15–8.85 m−1. The variability in aCDOM(λ) was parameterized with respect to the variability over 3 orders of magnitude in the chlorophyll a concentration Chl a (0.7–119 mg m−3). The chlorophyll a concentration and aCDOM(400) were correlated, and a statistically significant, nonlinear empirical relationship between these parameters was derived (R2 =  0.83). On the basis of the covariance between these parameters, we derived two empirical mathematical models that enabled us to design the CDOM absorption coefficient dynamics in natural waters and reconstruct the complete CDOM absorption spectrum in the UV and visible spectral domains. The input variable in the first model was the chlorophyll a concentration, and in the second one it was aCDOM(400). Both models were fitted to a power function, and a second-order polynomial function was used as the exponent. Regression coefficients for these formulas were determined for wavelengths from 240 to 700 nm at 5 nm intervals. Both approximations reflected the real shape of the absorption spectra with a low level of uncertainty. Comparison of these approximations with other models of light absorption by CDOM demonstrated that our parameterizations were superior (bias from −1.45 to 62 %, RSME from 22 to 220 %) for estimating CDOM absorption in the optically complex waters of the Baltic Sea and Pomeranian lakes.

scholarly journals Response of <i>Nodularia spumigena</i> to <i>p</i>CO<sub>2</sub> – Part 1: Growth, production and nitrogen cycling

2012 ◽  
Vol 9 (8) ◽  
pp. 2973-2988 ◽  
Author(s):  
N. Wannicke ◽  
S. Endres ◽  
A. Engel ◽  
H.-P. Grossart ◽  
M. Nausch ◽  
...  
Keyword(s):  
Organic Matter ◽  
Baltic Sea ◽  
N2 Fixation ◽  
Inorganic Nitrogen ◽  
High Pco2 ◽  
The Baltic Sea ◽  
Nodularia Spumigena ◽  
Co2 Concentrations ◽  
Elemental Stoichiometry ◽  
The Baltic

Abstract. Heterocystous cyanobacteria of the genus Nodularia form extensive blooms in the Baltic Sea and contribute substantially to the total annual primary production. Moreover, they dispense a large fraction of new nitrogen to the ecosystem when inorganic nitrogen concentration in summer is low. Thus, it is of ecological importance to know how Nodularia will react to future environmental changes, in particular to increasing carbon dioxide (CO2) concentrations and what consequences there might arise for cycling of organic matter in the Baltic Sea. Here, we determined carbon (C) and dinitrogen (N2) fixation rates, growth, elemental stoichiometry of particulate organic matter and nitrogen turnover in batch cultures of the heterocystous cyanobacterium Nodularia spumigena under low (median 315 μatm), mid (median 353 μatm), and high (median 548 μatm) CO2 concentrations. Our results demonstrate an overall stimulating effect of rising pCO2 on C and N2 fixation, as well as on cell growth. An increase in pCO2 during incubation days 0 to 9 resulted in an elevation in growth rate by 84 ± 38% (low vs. high pCO2) and 40 ± 25% (mid vs. high pCO2), as well as in N2 fixation by 93 ± 35% and 38 ± 1%, respectively. C uptake rates showed high standard deviations within treatments and in between sampling days. Nevertheless, C fixation in the high pCO2 treatment was elevated compared to the other two treatments by 97% (high vs. low) and 44% (high vs. mid) at day 0 and day 3, but this effect diminished afterwards. Additionally, elevation in carbon to nitrogen and nitrogen to phosphorus ratios of the particulate biomass formed (POC : POP and PON : POP) was observed at high pCO2. Our findings suggest that rising pCO2 stimulates the growth of heterocystous diazotrophic cyanobacteria, in a similar way as reported for the non-heterocystous diazotroph Trichodesmium. Implications for biogeochemical cycling and food web dynamics, as well as ecological and socio-economical aspects in the Baltic Sea are discussed.

Soil organic matter characteristics as indicator of Chernozem genesis in the Baltic Sea region

2016 ◽  
Vol 7 (2) ◽  
pp. 187-200 ◽  
Author(s):  
Andre Acksel ◽  
Wulf Amelung ◽  
Peter Kühn ◽  
Ernst Gehrt ◽  
Tom Regier ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Baltic Sea ◽  
The Baltic Sea ◽  
Baltic Sea Region ◽  
The Baltic

Environmental factors affecting recent benthic foraminiferal distribution in the south-eastern Baltic Sea

Baltica ◽  
2020 ◽  
Vol 33 (1) ◽  
pp. 58-70
Author(s):  
Ekaterina Ponomarenko ◽  
Viktor Krechik ◽  
Evgenia Dorokhova
Keyword(s):  
Organic Carbon ◽  
Baltic Sea ◽  
Benthic Foraminifera ◽  
Bottom Water ◽  
Environmental Parameters ◽  
Organic Carbon Content ◽  
The South ◽  
The Baltic Sea ◽  
South Eastern ◽  
The Baltic

The Baltic Sea is characterized by a restricted exchange of deep waters due to permanent stratification of the water column. The aim of the present study is to investigate the distribution of benthic foraminifera in the south-eastern part of the Baltic Sea in relation to environmental parameters. The distribution of benthic foraminifera was analyzed in 26 surface sediment samples collected in the south-eastern part of the Baltic Sea and in the Bornholm Basin during springtime and wintertime 2016. Foraminiferal diversity in the studied region was extremely low. Agglutinated specimens dominated the assemblages and were represented by small-sized individuals which belong to Psammosphaera, Pseudothurammina, Saccammina, and Reophax genera. Calcareous foraminifera were dominated by Cribroelphidium genus. Micropaleontological data were compared to the environmental parameters characterizing bottom water (temperature, salinity, and dissolved oxygen content) and substrate conditions (grain size composition and total organic carbon content). Higher foraminiferal concentrations and diversity were found in deeper parts of the study region where fine-grained sediments with a higher total organic carbon content were accumulated under stable hydrographical conditions. Calcareous tests were found only at the stations with elevated salinity, indicating that bottom water salinity is the main factor limiting the distribution of calcareous foraminifera. On the other hand, substrate parameters and hydrodynamic conditions appear to play a major role in the distribution of agglutinated foraminifera.

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