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1

Characteristics of the spring/summer production in the Mecklenburg Bight (Baltic Sea) as revealed by long-term pCO2data

Schneider B., Buecker S., Kaitala S., Maunula P., Wasmund N.

Oceanologia

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2015

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No. 57 (4)

375--385

EN

Automated CO2 partial pressure, pCO2, measurements were performed on a cargo ship that commutes between the Gulf of Finland and the Mecklenburg Bight in the southwest of the Baltic Sea. The data from 2004 to 2014 along a sub-transect in the Mecklenburg Bight are used to analyze the timing and intensity of the net community production (NCP). The start of the spring bloom, identified by the first continuous drop of the pCO2 below the atmospheric level, spanned from mid-February to mid-March. Converting the pCO2 decrease during spring to changes in the total CO2 concentration and taking into account air-sea gas exchange, the spring NCP was determined. The NCP increased by about 80% during 2004–2014, the mean amounted to 40 μmol L-1. In two years a distinct second pCO2 minimum in mid-summer succeeded the minimum in spring. This was attributed to production fuelled by nitrogen fixation since the nitrate concentrations were virtually zero and since the atmospheric deposition could not satisfy the NCP nitrogen demand. Furthermore, investigations of the plankton composition revealed a cyanobacteria biomass peak in the year with the highest mid-summer NCP. Based on the calculation of the mid-summer NCP in the two particular years and on the C/N ratio of particulate organic matter, the corresponding nitrogen fixation activity was calculated. These values and the analysis of the relationship between the integrated NCP and temperature indicated that the nitrogen fixation activity in the Mecklenburg Bight was by a factor 3–4 lower than in the central Baltic Sea.

2

Processes regulating pCO2 in the surface waters of the central eastern Gotland Sea: a model study

Kuznetsov I., Neumann T., Schneider B., Yakushev E.

Oceanologia

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2011

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No. 53 (3)

745-770

EN

This work presents a one-dimensional simulation of the seasonal changes in CO2 partial pressure (pCO2). The results of the model were constrained using data from observations, which improved the model's ability to estimate nitrogen fixation in the central Baltic Sea and allowed the impact of nitrogen fixation on the ecological state of the Baltic Sea to be studied. The model used here is the public domain water-column model GOTM (General Ocean Turbulence Model), which in this study was coupled with a modifed Baltic Sea ecosystem model, ERGOM (The Baltic Sea Research Institute's ecosystem model). To estimate nitrogen fixation rates in the Gotland Sea, the ERGOM model was modified by including an additional cyanobacteria group able to fix nitrogen from March to June. Furthermore, the model was extended by a simple CO2 cycle. Variable C:P and N:P ratios, controlled by phosphate concentrations in ambient water, were used to represent cyanobacteria, detritus and sediment detritus. This approach improved the model's ability to reproduce sea-surface phosphate and pCO2 dynamics. The resulting nitrogen fixation rates in 2005 for the two simulations, with and without the additional cyanobacteria group, were 259 and 278 mmol N m-2 year-1respectively.

3

PO4 release at the sediment surface under anoxic conditions: a contribution to the eutrophication of the Baltic Sea?

Schneider B.

Oceanologia

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2011

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No. 53 (1-TI)

415-429

EN

The vertical profiles of phosphate, total CO2 and oxygen/hydrogen sulphide were determined in the deep water of the Gotland Sea during March 2003 to July 2006 with a temporal resolution of 2-3 months. This time span included the shift from anoxic to oxic conditions resulting from a water renewal event, as well as the transition back to anoxic waters during the subsequent two-year stagnation period. The data from depths below 150 m were used to identify and quantify phosphate release and removal processes. The relationship between the total CO_2 generated by mineralization (CT, min) and the PO_4 concentrations indicated that the initial decrease in the phosphate concentrations after the inflow of oxygen-rich water was mainly a dilution effect. Only about one third of the PO_4 removal was a consequence of the precipitation of insoluble iron-3-hydroxo-phosphates (Fe-P), which occurred slowly at the sediment surface under oxic conditions. From the CT, min/PO4 ratios it was also concluded that the formation of Fe-P was reversed during the later phase of the stagnation, when the redoxcline approached a depth of 150 m. A phosphate mass balance was performed for four deep water sub-layers in order to quantify the dissolution of Fe-P during the stagnation period and thus to estimate the amount of Fe-P deposited during the last inflow of oxygen-rich water. A value of about 50 mmol-P m-2 was found, which refers to the specific biogeochemical conditions during the change from anoxic to oxic conditions that preceded the stagnation period.

4

Analysis of 50-year wind data of the southern Baltic Sea for modelling coastal morphological evolution - a case study from the Darss-Zingst Peninsula

Zhang W., Harff J., Schneider B.

Oceanologia

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2011

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No. 53 (1-TI)

489-518

EN

High-resolution wind series in the southern Baltic Sea for the period of 1958-2007 are analysed to generate representative climate input conditions for a multi-scale morphodynamic model to simulate decadal-to-centennial coastline change. Four seasonal wind classes, each characterized by a predominant distribution of wind direction and speed, are derived from statistical analysis. Further calibration of this statistical description is done by sensitivity studies of the model to generate similar coastline changes of the Darss-Zingst peninsula as the measured data for the last century. The coastline change of this area is then projected for the next 300 years based on four different climate scenarios, through which impacts of accelerated sea level rise and storm frequency on the long-term coastline change are quantified.

5

Profilowanie metabolitów prób moczu noworodków

Schneider B., Zurek G., Baessmann C., Schaefer H., Godejohann M., Keller S., Spraul M., Fusch G., Nauck M., Fusch Ch., Rucińska M., Karpiński A.

Laboratorium - Przegląd Ogólnopolski

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2009

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nr 7-8

40--41

PL

Wrodzonym wadom metabolizmu poświęca się sporo uwagi nie tylko ze względu na ich znaczenie, ale również dlatego, że reprezentują one uniwersalny system pozwalający zademonstrować korzyści profilowania metabolitów. W niniejszym opracowaniu do analizy próbek moczu noworodków użyto systemu profilowania metabolitów opartego na technikach LC-MS oraz MR. Identyfikacji związków chemicznych w próbkach moczu noworodków dokonano bez żadnej wiedzy a priori o leczeniu, w podwójnie ślepej próbie.

EN

In born errors of metabolism receive much attention due to their clinical relevance, but they also represent a versatile system to demonstrate the benefits of metabolic profiling. A metabolic profiling system based on LC-MS and MR has been developed and applied to child urine samples. The identification of chemical compounds from the baby urine samples was achieved without any prior knowledge of treatment in a double blind experiment.

6

Sources of particulate selenium in the Baltic Sea atmosphere

Dudzińska-Huczuk B., Schneider B., Bolałek J.

Oceanologia

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2000

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No. 42 (3)

305-313

EN

To determine the atmospheric concentrations and size distributions of particulate selenium (Se), aerosols were collected by air filtration and impactor sampling at the Kap Arkona coastal weather station on the Island of Rügen. Total reflection X-ray fluorescence analysis was used to determine Se and numerous other elements as well. The dependence of the Se concentration on the wind direction and the results of a regression analysis indicated that Se associated with sub-micron particles is mainly derived from anthropogenic sources. The pronounced relationship between Se and Cu indicated that copper smelting is a major source of atmospheric selenium. A marine Se contribution was identified for particles larger than 2 žm.