A seasonal study of particulate organic matter composition and quality along an offshore transect in the southern North Sea

Guitton, M. Le; Soetaert, Karline; Damsté, J.S. Sinninghe; Middelburg, Jack J.

doi:10.1016/j.ecss.2017.02.002

Cited by 6 publications

(3 citation statements)

References 54 publications

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“…(3) The aerobic CH 4 production from microbial decomposition of certain organic phosphorus compounds (Karl et al, 2008;Repeta et al, 2016). Recent studies from the study area suggest, that the spring bloom is associated with a predominant degradation of polysaccharides (Teeling et al, 2016;Le Guitton et al, 2017) which could then lead to a methane production.…”

Section: Single Factors (Water Mass Origin Oxygen Turbidity)mentioning

confidence: 99%

Detailed Patterns of Methane Distribution in the German Bight

et al. 2021

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Although methane is a widely studied greenhouse gas, uncertainties remain with respect to the factors controlling its distribution and diffusive flux into the atmosphere, especially in highly dynamic coastal waters. In the southern North Sea, the Elbe and Weser rivers are two major tributaries contributing to the overall methane budget of the southern German Bight. In June 2019, we continuously measured methane and basic hydrographic parameters at a high temporal and spatial resolution (one measurement per minute every 200–300 m) on a transect between Cuxhaven and Helgoland. These measurements revealed that the overall driver of the coastal methane distribution is the dilution of riverine methane-rich water with methane-poor marine water. For both the Elbe and Weser, we determined an input concentration of 40–50 nmol/L compared to only 5 nmol/L in the marine area. Accordingly, we observed a comparatively steady dilution pattern of methane concentration toward the marine realm. Moreover, small-scale anomalous patterns with unexpectedly higher dissolved methane concentrations were discovered at certain sites and times. These patterns were associated with the highly significant correlations of methane with oxygen or turbidity. However, these local anomalies were not consistent over time (days, months). The calculated diffusive methane flux from the water into the atmosphere revealed local values approximately 3.5 times higher than background values (median of 36 and 128 μmol m–2 d–1). We evaluate that this occurred because of a combination of increasing wind speed and increasing methane concentration at those times and locations. Hence, our results demonstrate that improved temporal and spatial resolution of methane measurements can provide a more accurate estimation and, consequently, a more functional understanding of the temporal and spatial dynamics of the coastal methane flux.

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Section: Single Factors (Water Mass Origin Oxygen Turbidity)mentioning

confidence: 99%

Detailed Patterns of Methane Distribution in the German Bight

et al. 2021

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“…A mechanistic understanding of the interaction between benthic fauna and the associated environmental conditions must be derived before a quantitative synthesis can be made (Zhang & Wirtz, 2017). The abundance and community structure of benthic fauna greatly depend on the supply of particulate organic carbon (POC) to the seafloor (Campanyà‐Llovet et al., 2017; Dauwe et al., 1998; Herman et al., 1999; Pearson & Rosenberg, 1987), while on the other hand benthic fauna actively mixes POC into deeper sediments through bioturbation (Kamp & Witte, 2005; Le Guitton et al., 2017). Bioturbation, referred to here as any kind of biological reworking of sediments including particle mixing and burrow ventilation (Meysman, Middelburg, & Heip, 2006), has been found to vary by more than one order of magnitude even at the same site due to seasonal changes in food supply and in the metabolism of benthic organisms (Brown et al., 2004; Teal et al., 2008).…”

Section: Introductionmentioning

confidence: 99%

Quantifying Importance of Macrobenthos for Benthic‐Pelagic Coupling in a Temperate Coastal Shelf Sea

et al. 2021

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The ocean seafloor is the largest carbon reservoir within the surface Earth system, providing a valuable geochemical archive for deciphering variability in global biogeochemical cycling and climate (Ciais et al., 2013;Heinze et al., 2015). Quantification of biogeochemical cycling, especially carbon cycling at the ocean seafloor, is thus a key for understanding the fate of our future Earth (Falkowski et al., 2000;Le Quéré et al., 2018). Of vital importance in this context is the shelf seafloor, which covers less than 10% of the global ocean area (Muller-Karger et al., 2005) but has been estimated to receive ∼50% of the pelagic primary production through sedimentation (Wollast, 1991) and releases regenerated nutrients such as nitrogen, phosphorus, and silica that supply ∼80% of phytoplankton nutrient requirements (Middelburg & Soetaert, 2004). On the other hand, shelf seas constitute the most dynamic part of the surface Earth where intense interactions between geosphere, ecosphere and anthroposphere take place.

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“…River plumes and related near-coastal currents may therefore be underrepresented. Moreover, the identified sensitivity of primary production to tidal forcing could be affected by sediment retention by macrobenthos (Prins et al, 1996;Kamp and Witte, 2005;Le Guitton et al, 2017) and its impact on water column turbidity through reduced POM resuspension. The influence of inorganic suspended particulate matter on tidal impacts on NPP is another source of uncertainty in the presented approach that needs to be addressed in future research.…”

Section: Tidal Impacts On Primary Production On the Nwesmentioning

confidence: 99%

Barotropic and baroclinic tides increase primary production on the Northwest European Shelf

et al. 2023

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High biological productivity and the efficient export of carbon-enriched subsurface waters to the open ocean via the continental shelf pump mechanism make mid-latitude continental shelves like the northwest European shelf (NWES) significant sinks for atmospheric CO2. Tidal forcing, as one of the regionally dominant physical forcing mechanisms, regulates the mixing-stratification status of the water column that acts as a major control for biological productivity on the NWES. Because of the complexity of the shelf system and the spatial heterogeneity of tidal impacts, there still are large knowledge gaps on the role of tides for the magnitude and variability of biological carbon fixation on the NWES. In our study, we utilize the flexible cross-scale modeling capabilities of the novel coupled hydrodynamic–biogeochemical modeling system SCHISM–ECOSMO to quantify the tidal impacts on primary production on the NWES. We assess the impact of both the barotropic tide and the kilometrical-scale internal tide field explicitly resolved in this study by comparing simulated hindcasts with and without tidal forcing. Our results suggest that tidal forcing increases biological productivity on the NWES and that around 16% (14.47 Mt C) of annual mean primary production on the shelf is related to tidal forcing. Vertical mixing of nutrients by the barotropic tide particularly invigorates primary production in tidal frontal regions, whereas resuspension and mixing of particulate organic matter by tides locally hinders primary production in shallow permanently mixed regions. The tidal impact on primary production is generally low in deep central and outer shelf areas except for the southwestern Celtic Sea, where tidal forcing substantially increases annual mean primary production by 25% (1.53 Mt C). Tide-generated vertical mixing of nutrients across the pycnocline, largely attributed to the internal tide field, explains one-fifth of the tidal response of summer NPP in the southwestern Celtic Sea. Our results therefore suggest that the tidal NPP response in the southwestern Celtic Sea is caused by a combination of processes likely including tide-induced lateral on-shelf transport of nutrients. The tidally enhanced turbulent mixing of nutrients fuels new production in the seasonally stratified parts of the NWES, which may impact the air–sea CO2 exchange on the shelf.

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A seasonal study of particulate organic matter composition and quality along an offshore transect in the southern North Sea

Cited by 6 publications

References 54 publications

Detailed Patterns of Methane Distribution in the German Bight

Detailed Patterns of Methane Distribution in the German Bight

Quantifying Importance of Macrobenthos for Benthic‐Pelagic Coupling in a Temperate Coastal Shelf Sea

Barotropic and baroclinic tides increase primary production on the Northwest European Shelf

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