Interannual variability of carbon fluxes in the North Sea from 1970 to 2006 – Competing effects of abiotic and biotic drivers on the gas-exchange of CO2

Lorkowski, Ina; Pätsch, Johannes; Moll, A.; Kühn, Wilfried

doi:10.1016/j.ecss.2011.11.037

Cited by 49 publications

(97 citation statements)

References 69 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, ECOHAM applies constant C:N:P ratios to phytoplankton, zooplankton and bacteria (Lorkowski et al, 2012;Große et al, 2016). Though, it is known that elemental ratios vary between different phytoplankton species (e.g., Geider and La Roche, 2002;Quigg et al, 2003;Malzahn et al, 2010) as well as under varying environmental conditions (e.g., Rhee, 1978;Goldman et al, 1979).…”

Section: Limitations Of the Model Intrinsics And The Tbnt Methodsmentioning

confidence: 99%

“…The present version of ECOHAM is identical to that used by Große et al (2016). Lorkowski et al (2012) provide a full description of the ECOHAM model equations and parameter settings. Here, we will only summarize the relevant features of the O 2 cycle.…”

Section: The Hamsom-ecoham Modelmentioning

confidence: 99%

“…In addition, the "microbial loop" (Azam et al, 1983) is represented. ECOHAM simulates the cycles of carbon (C), N, P, silicon (Si) and O 2 (Pätsch and Kühn, 2008;Lorkowski et al, 2012). The present version of ECOHAM is identical to that used by Große et al (2016).…”

Section: The Hamsom-ecoham Modelmentioning

confidence: 99%

“…We use a three-dimensional (3D) model consisting of the physical model HAMSOM (HAMburg Shelf Ocean Model; Backhaus, 1985;Pohlmann, 1991Pohlmann, , 1996 and the biogeochemical model ECOHAM (ECOsystem model, HAMburg; Pätsch and Kühn, 2008;Kühn et al, 2010;Lorkowski et al, 2012;Große et al, 2016). HAMSOM is a baroclinic, primitive equation model using the hydrostatic and Boussinesq approximations (Pohlmann, 1991).…”

Section: The Hamsom-ecoham Modelmentioning

confidence: 99%

“…provided for dissolved inorganic carbon (DIC; Lorkowski et al, 2012). A daily climatology of suspended particulate matter was derived from results of Pohlmann and Puls (1994) to include its effect on the light climate.…”

Section: Model Setupmentioning

confidence: 99%

See 4 more Smart Citations

A Novel Modeling Approach to Quantify the Influence of Nitrogen Inputs on the Oxygen Dynamics of the North Sea

et al. 2017

Self Cite

View full text Add to dashboard Cite

Oxygen (O 2 ) deficiency, i.e., dissolved O 2 concentrations below 6 mg O 2 L −1 , is a common feature in the southern North Sea. Its evolution is governed mainly by the presence of seasonal stratification and production of organic matter, which is subsequently degraded under O 2 consumption. The latter is strongly influenced by riverine nutrient loads, i.e., nitrogen (N) and phosphorus (P). As riverine P loads have been reduced significantly over the past decades, this study aims for the quantification of the influence of riverine and non-riverine N inputs on the O 2 dynamics in the southern North Sea. For this purpose, we present an approach to expand a nutrient-tagging technique for physical-biogeochemical models -often referred to as 'trans-boundary nutrient transports' (TBNT) -by introducing a direct link to the O 2 dynamics. We apply the expanded TBNT to the physical-biogeochemical model system HAMSOM-ECOHAM and focus our analysis on N-related O 2 consumption in the southern North Sea during 2000-2014. The analysis reveals that near-bottom O 2 consumption in the southern North Sea is strongly influenced by the N supply from the North Atlantic across the northern shelf edge. However, riverine N sources -especially the Dutch, German and British rivers -as well as the atmosphere also play an important role. In the region with lowest simulated O 2 concentrations (around 56 • N, 6.5 • E), riverine N on average contributes 39% to overall near-bottom O 2 consumption during seasonal stratification. Here, the German and the large Dutch rivers constitute the highest riverine contributions (11% and 10%, respectively). At a site in the Oyster Grounds (around 54.5 • N, 4 • E), the average riverine contribution adds up to 41%, even exceeding that of the North Atlantic. Here, highest riverine contributions can be attributed to the Dutch and British rivers adding up to almost 28% on average. The atmospheric contribution results in 13%. Our results emphasize the importance of anthropogenic N inputs and seasonal stratification for the O 2 conditions in the southern North Sea. They further suggest that reductions in the riverine and atmospheric N inputs may have a relevant positive effect on the O 2 levels in this region.

show abstract

Section: Limitations Of the Model Intrinsics And The Tbnt Methodsmentioning

confidence: 99%

Section: The Hamsom-ecoham Modelmentioning

confidence: 99%

Section: The Hamsom-ecoham Modelmentioning

confidence: 99%

Section: The Hamsom-ecoham Modelmentioning

confidence: 99%

Section: Model Setupmentioning

confidence: 99%

See 3 more Smart Citations

A Novel Modeling Approach to Quantify the Influence of Nitrogen Inputs on the Oxygen Dynamics of the North Sea

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

Variability of North Sea pH and CO₂ in response to North Atlantic Oscillation forcing

et al. 2013

View full text Add to dashboard Cite

[1] High biological activity causes a distinct seasonality of surface water pH in the North Sea, which is a strong sink for atmospheric CO 2 via an effective shelf pump. The intimate connection between the North Sea and the North Atlantic Ocean suggests that the variability of the CO 2 system of the North Atlantic Ocean may, in part, be responsible for the observed variability of pH and CO 2 in the North Sea. In this work, we demonstrate the role of the North Atlantic Oscillation (NAO), the dominant climate mode for the North Atlantic, in governing this variability. Based on three extensive observational records covering the relevant levels of the NAO index, we provide evidence that the North Sea pH and CO 2 system strongly responds to external and internal expressions of the NAO. Under positive NAO, the higher rates of inflow of water from the North Atlantic Ocean and the Baltic outflow lead to a strengthened north-south biogeochemical divide. The limited mixing between the north and south leads to a steeper gradient in pH and partial pressure of CO 2 (pCO 2 ) between the two regions in the productive period. This is exacerbated further when coinciding with higher sea surface temperature, which concentrates the net community production in the north through shallower stratification. These effects can be obscured by changing properties of the constituent North Sea water masses, which are also influenced by NAO. Our results highlight the importance of examining interannual trends in the North Sea CO 2 system with consideration of the NAO state.Citation: Salt, L. A

show abstract

Carbon sources in the North Sea evaluated by means of radium and stable carbon isotope tracers

et al. 2016

View full text Add to dashboard Cite

A multitracer approach is applied to assess the impact of boundary fluxes (e.g., benthic input from sediments or lateral inputs from the coastline) on the acid-base buffering capacity, and overall biogeochemistry, of the North Sea. Analyses of both basin-wide observations in the North Sea and transects through tidal basins at the North-Frisian coastline, reveal that surface distributions of the d 13 C signature of dissolved inorganic carbon (DIC) are predominantly controlled by a balance between biological production and respiration.In particular, variability in metabolic DIC throughout stations in the well-mixed southern North Sea indicates the presence of an external carbon source, which is traced to the European continental coastline using naturally occurring radium isotopes ( 224 Ra and 228 Ra). 228 Ra is also shown to be a highly effective tracer of North Sea total alkalinity (AT) compared to the more conventional use of salinity. Coastal inputs of metabolic DIC and AT are calculated on a basin-wide scale, and ratios of these inputs suggest denitrification as a primary metabolic pathway for their formation. The AT input paralleling the metabolic DIC release prevents a significant decline in pH as compared to aerobic (i.e., unbuffered) release of metabolic DIC. Finally, longterm pH trends mimic those of riverine nitrate loading, highlighting the importance of coastal AT production via denitrification in regulating pH in the southern North Sea.

show abstract

Interannual variability of carbon fluxes in the North Sea from 1970 to 2006 – Competing effects of abiotic and biotic drivers on the gas-exchange of CO2

Cited by 49 publications

References 69 publications

A Novel Modeling Approach to Quantify the Influence of Nitrogen Inputs on the Oxygen Dynamics of the North Sea

A Novel Modeling Approach to Quantify the Influence of Nitrogen Inputs on the Oxygen Dynamics of the North Sea

Variability of North Sea pH and CO₂ in response to North Atlantic Oscillation forcing

Carbon sources in the North Sea evaluated by means of radium and stable carbon isotope tracers

Contact Info

Product

Resources

About

Interannual variability of carbon fluxes in the North Sea from 1970 to 2006 – Competing effects of abiotic and biotic drivers on the gas-exchange of CO2

Cited by 49 publications

References 69 publications

A Novel Modeling Approach to Quantify the Influence of Nitrogen Inputs on the Oxygen Dynamics of the North Sea

A Novel Modeling Approach to Quantify the Influence of Nitrogen Inputs on the Oxygen Dynamics of the North Sea

Variability of North Sea pH and CO2 in response to North Atlantic Oscillation forcing

Carbon sources in the North Sea evaluated by means of radium and stable carbon isotope tracers

Contact Info

Product

Resources

About

Variability of North Sea pH and CO₂ in response to North Atlantic Oscillation forcing