Long-term simulation of the eutrophication of the North Sea: temporal development of nutrients, chlorophyll and primary production in comparison to observations

Controls of the surface water partial pressure of CO<sub>2</sub> in the North Sea

“…This finding is in good agreement with the results of the sophisticated DIC mass balance approach by Bozec et al (2005b) 1 . Gazeau et al (2004) reported a mean gross primary production (GPP) in the North Sea of approximately 18 mol C m −2 yr −1 , which appears to be on a similar order of magnitude as the values given by Pätsch and Radach (1997). The reverse spatial gradient of the GGP data by Pätsch and Radach (1997) and our NCP data can be explained by the different bottom topographical settings, discussed above.…”

“…Gazeau et al (2004) reported a mean gross primary production (GPP) in the North Sea of approximately 18 mol C m −2 yr −1 , which appears to be on a similar order of magnitude as the values given by Pätsch and Radach (1997). The reverse spatial gradient of the GGP data by Pätsch and Radach (1997) and our NCP data can be explained by the different bottom topographical settings, discussed above. The separation of production and respiration processes into upper and lower water column permits higher net carbon fixation in the surface layer of the northern region, while the shallower mixed water column prevents higher NCP values despite of higher GGP.…”

“…Although it is generally assumed that the southern North Sea reveals higher gross primary productivity (see for example Joint and Pomroy, 1993;Pätsch and Radach, 1997), net community production is lower here than in the central and northern areas because of the competing gross primary production and community respiration in the annually well mixed water column of the south. This finding is in good agreement with the results of the sophisticated DIC mass balance approach by Bozec et al (2005b) 1 .…”

The carbon budget of the North Sea

“…In order to overcome this problem, our carbon budget calculations rely on the water budget of Eisma and Kalf (1987), which describes reliably the influx from the Baltic Sea (Stigebrandt, 2001;Thomas et al, 2003b) as well as the magnitude of the riverine inputs (OSPARCOM, 2000). There is notable evidence that the water transport across the northern boundaries can be subdivided into transports in the upper and lower parts of the water column Pätsch and Radach, 1997). The relative information has been used (Table 1), since it enables us to consider the high resolution DIC and dissolved organic carbon (DOC) data recently obtained.…”

Modeling the nitrogen fluxes in the Black Sea using a 3D coupledhydrodynamical-biogeochemical model: transport versus biogeochemicalprocesses, exchanges across the shelf break and comparison of the shelf anddeep sea ecodynamics

“…Dippner, 1993;Yanagi et al, 1995;Patsch and Radach, 1997;Tagushi and Nakata, 1998;Lancelot et al, 2002). Indeed, ecosystem models are necessary to assess the ecosystem's vulnerability to contaminants of anthropogenic origin and to calculate the transfer and accumulation of toxic substances from one level of the foodweb to the next.…”