The surface water CO2 budget for the Baltic Proper: a new way to determine nitrogen fixation

Schneider, Bernd; Nausch, Günther; Nagel, K.; Wasmund, Norbert

doi:10.1016/s0924-7963(03)00064-2

Cited by 78 publications

(47 citation statements)

References 20 publications

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“…The expected total runoff change to 2100 ranges from −2 to 15 % of the present flow according to the different climate scenarios (Graham, 2004;Graham et al, 2008). Studies performed on Swedish rivers (Smith et al, 2008) indicate that 71-97 % of the carbon load is explained by the water volume. Thus, it is very likely that the change in river runoff to the Baltic Sea will result in a change of terrestrial carbon input.…”

Section: Discussionmentioning

confidence: 99%

“…The biological activity, including the ratio between photosynthesis and respiration in particular, determines the level and dynamics of CO 2 partial pressure (pCO 2 ) in seawater and hence a strength and direction of CO 2 exchange through the seawater/atmosphere interface. These are, most likely, the reasons behind the significant discrepancies in the CO 2 air-sea exchange results reported in the literature (Ohlson, 1990;Thomas and Schneider, 1999;Thomas et al, 2003;Algesten et al, 2004 andKuss et al, 2006;Wesslander et al, 2010;Beldowski et al, 2010;Schneider et al, 2003). On the one hand, low productive and highly influenced by terrestrial organic carbon water of the Gulf of Bothnia is believed to be a CO 2 source to the atmosphere (Algesten et al, 2004 and.…”

Section: Introductionmentioning

confidence: 97%

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The carbon budget of the Baltic Sea

Kuliński

Pempkowiak

2011

Biogeosciences

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Abstract. This paper presents the results of a comprehensive study of the Baltic Sea carbon budget. The Baltic Sea is very much influenced by terrestrial carbon input. Rivers are the largest carbon source, and their input amounts to 10.90 Tg C yr −1 (Tg = 10 12 g) with a 37.5 % contribution of organic carbon. On the other hand, carbon is effectively exported from the Baltic to the North Sea (7.67 Tg C yr −1 ) and is also buried in bottom sediments (2.73 Tg C yr −1 ). The other sources and sinks of carbon are of minor importance. The net CO 2 emission (1.05 Tg C yr −1 ) from the Baltic to the atmosphere was calculated as the closing term of the carbon budget presented here. There is a net loss of organic carbon, which indicates that the Baltic Sea is heterotrophic.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

The carbon budget of the Baltic Sea

Kuliński

Pempkowiak

2011

Biogeosciences

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“…Therefore, we also consider different integrating approaches to determine the annual nitrogen fixation. These are based on (1) the excess PO 4 available for nitrogen fixation after the spring bloom ('nutrient concept ', Rahm et al 2000), (2) a combined surface water carbon/nitrogen budget ('CO 2 concept', Schneider et al 2003) and (3) the temporal increase of total nitrogen compounds in the euphotic zone ('biomass concept . The results of these approaches are compared and their applicability is discussed.…”

Section: Resale or Republication Not Permitted Without Written Consenmentioning

confidence: 99%

Comparison of nitrogen fixation rates determined with different methods: a study in the Baltic Proper

Wasmund

Nausch²,

Schneider³

et al. 2005

Mar. Ecol. Prog. Ser.

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Nitrogen fixation rates were determined at approximately monthly intervals during spring/summer 2001 in the eastern Gotland Sea by means of the 15 N 2 method. Additionally, a comprehensive set of variables were measured in order to apply 3 different budget approaches for the determination of integrated nitrogen fixation: (1) the nutrient concept based on excess PO 4 owing to the low DIN/PO 4 ratios (6.8) in the winter surface water, (2) the CO 2 concept using a combined carbon/nitrogen mass balance and (3) the biomass concept based on the increase in total nitrogen during the cyanobacteria bloom. For the spring season (March to May) the budget approaches gave rise to postulating an additional nitrogen input of about 100 to 200 mmol m -2 . However, this was not attributed to nitrogen fixation because 15 N 2 rate measurements from several years did not show any significant nitrogen fixation during spring. Rate measurements integrated from May to August yielded a nitrogen fixation of 138 mmol m -2 , which was consistent with the estimate based on the biomass concept. The CO 2 concept resulted in a nitrogen input of 268 mmol m -2 from May to August. The nutrient concept was questionable because the excess PO 4 was consumed during spring and not transferred to the summer bloom. High PON/POP ratios in summer indicated that PO 4 release from particulate organic matter provided some of the PO 4 necessary for the primary production based on nitrogen fixation. The estimates obtained from the rate measurements and from the CO 2 concept are considered to represent the lower and upper limit for the nitrogen fixation in the Baltic Proper and correspond to a total nitrogen input of 434 000 and 792 000 t yr -1 respectively. KEY WORDS: Nitrogen fixation · Cyanobacteria bloom · Nutrient · Redfield ratio · Baltic Sea Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 297: [23][24][25][26][27][28][29][30][31] 2005 gen-fixing cyanobacteria are already present in the trophogenic layer in June (Hübel & Hübel 1995, Ohlendieck et al. 2000. Hence, neglecting this period may lead to an underestimation of the annual nitrogen fixation. The purpose of this study was to determine nitrogen fixation rates by the 15 N method with an enhanced temporal resolution of about 1 mo for the period March to October. Since cyanobacteria colonies show a patchy distribution, integration of the rates over time and space involves uncertainties which can hardly be quantified. Therefore, we also consider different integrating approaches to determine the annual nitrogen fixation. These are based on (1) the excess PO 4 available for nitrogen fixation after the spring bloom ('nutrient concept ', Rahm et al. 2000), (2) a combined surface water carbon/nitrogen budget ('CO 2 concept', Schneider et al. 2003) and (3) the temporal increase of total nitrogen compounds in the euphotic zone ('biomass concept . The results of these approaches are compared and their applicability is discussed. MATERIALS AND METHODSInv...

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“…These instruments make quasi-continuous measurements, allowing 3370 G. Parard et al: Remote sensing algorithm for sea surface CO 2 regional analysis of the highly variable spatial and temporal distributions of pCO 2 (e.g. Lefèvre et al, 2004;Lüger et al, 2004;Corbière et al, 2007;Schneider et al, 2003). The Baltic Sea, a semi-enclosed sea in northern Europe, is relatively well monitored and has been studied for several decades (Meier et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Remote sensing the sea surface CO<sub>2</sub> of the Baltic Sea using the SOMLO methodology

2015

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Abstract. Studies of coastal seas in Europe have noted the high variability of the CO 2 system. This high variability, generated by the complex mechanisms driving the CO 2 fluxes, complicates the accurate estimation of these mechanisms. This is particularly pronounced in the Baltic Sea, where the mechanisms driving the fluxes have not been characterized in as much detail as in the open oceans. In addition, the joint availability of in situ measurements of CO 2 and of seasurface satellite data is limited in the area. In this paper, we used the SOMLO (self-organizing multiple linear output; Sasse et al., 2013) methodology, which combines two existing methods (i.e. self-organizing maps and multiple linear regression) to estimate the ocean surface partial pressure of CO 2 (pCO 2 ) in the Baltic Sea from the remotely sensed sea surface temperature, chlorophyll, coloured dissolved organic matter, net primary production, and mixed-layer depth. The outputs of this research have a horizontal resolution of 4 km and cover the 1998-2011 period. These outputs give a monthly map of the Baltic Sea at a very fine spatial resolution. The reconstructed pCO 2 values over the validation data set have a correlation of 0.93 with the in situ measurements and a root mean square error of 36 µatm. Removing any of the satellite parameters degraded this reconstructed CO 2 flux, so we chose to supply any missing data using statistical imputation. The pCO 2 maps produced using this method also provide a confidence level of the reconstruction at each grid point. The results obtained are encouraging given the sparsity of available data, and we expect to be able to produce even more accurate reconstructions in coming years, given the predicted acquisition of new data.

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The surface water CO2 budget for the Baltic Proper: a new way to determine nitrogen fixation

Cited by 78 publications

References 20 publications

The carbon budget of the Baltic Sea

The carbon budget of the Baltic Sea

Comparison of nitrogen fixation rates determined with different methods: a study in the Baltic Proper

Remote sensing the sea surface CO<sub>2</sub> of the Baltic Sea using the SOMLO methodology

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The surface water CO2 budget for the Baltic Proper: a new way to determine nitrogen fixation

Cited by 78 publications

References 20 publications

The carbon budget of the Baltic Sea

The carbon budget of the Baltic Sea

Comparison of nitrogen fixation rates determined with different methods: a study in the Baltic Proper

Remote sensing the sea surface CO&lt;sub&gt;2&lt;/sub&gt; of the Baltic Sea using the SOMLO methodology

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Remote sensing the sea surface CO<sub>2</sub> of the Baltic Sea using the SOMLO methodology