Importance of coastal primary production in the northern Baltic Sea

Ask, Jenny; Rowe, Owen; Brügel, Sonia; Strömgren, Mårten; Byström, Pär; Andersson, Agneta

doi:10.1007/s13280-016-0778-5

Cited by 32 publications

(25 citation statements)

References 71 publications

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“…The difference between production that falls onto sediment and a production that takes place directly on illuminated seafloor is uncertain. Benthic microalgae do play an important role for total primary production capacity, e.g., in the northern Baltic Sea (Ask et al, 2016). According to Sundbäck et al (2004) microphytobenthic (MPB) nitrogen assimilation often exceeds nitrogen removal by denitrification, partly because MPB activity suppresses denitrification and benthic production by MPB, and thus affects nutrient pathways in the sediment.…”

Section: Uncertainty Of Biogeochemical Processesmentioning

confidence: 99%

Nutrient Retention in the Swedish Coastal Zone

et al. 2018

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In this study, the average nutrient filter efficiency of the entire Swedish coastline is estimated to be about 54 and 70% for nitrogen and phosphorus, respectively. Hence, significantly less than half of the nutrient input from land (defined as river discharge and point sources) can be assumed to be exported from coastal waters to the open sea. However, some coastal areas retained more than 100% of the land load and thus, also filter the open Baltic Sea water. These areas with effective filtering of nutrients have low land load per unit coastal area. The filter efficiency was calculated from a 30-years model simulation (1985-2014) of water exchanges and nutrient cycling within the Swedish coastal zone. The average model skill was evaluated to be good or acceptable compared to observations. In addition to the entire Swedish coast, the retention of total nutrient loads in seven larger coastal sub-regions and selected key sites representing different coastal types was also estimated. The modeled long term nutrient retention was found to be associated with the physical characteristics of a water body, such as the surface area, but also the mean depth and residence time of water. In addition, high retention efficiency is associated with high ratio of sediment nutrient content to pelagic nutrient concentrations. On interannual timescales temporal changes in the coastal nutrient pool can have a large influence on perceived nutrient retention. At one site, the phosphorus filter efficiency was actually negative, i.e., the coastal zone transported more phosphorus to the open Baltic Sea than it received from land. The nutrient removal is most efficient close to land, where the area specific retention efficiency is the highest. The variability of both the filter and retention efficiency between coastal regions was found to be large, with a range of approximately 4-1,200% and 0.1-8.5%, respectively.

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Section: Uncertainty Of Biogeochemical Processesmentioning

confidence: 99%

Nutrient Retention in the Swedish Coastal Zone

et al. 2018

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“…Estuaries are the primary recipients of the riverine N load, and intense biogeochemical cycling establishes them as "filters" of land-derived N on its way to the open sea (Nedwell et al, 1999;Soetaert et al, 2006). The N filter function consists of retention and removal, with N retention defined as the cycling of bioavailable N within a system for longer than its mean fresh water residence time, and N removal as the permanent removal of N from a system via burial and the production of gaseous forms (Asmala et al, 2017). Microbial processes that contribute to N retention include uptake into biomass, ammonification, nitrification, and dissimilatory nitrate reduction to ammonia (DNRA), while denitrification and anaerobic ammonium oxidation (anammox) lead to N removal.…”

Section: Introductionmentioning

confidence: 99%

“…Baltic Sea estuaries are highly variable in terms of their riverine N load, stratification, water residence time, and sediment type (Asmala et al, 2017;Conley et al, 2011;Stepanauskas et al, 2002). All these environmental settings can impact the estuarine filter function.…”

Section: Introductionmentioning

confidence: 99%

“…Based on a compilation of denitrification rates across different coastal types in the Baltic Sea, Asmala et al (2017) estimated that the entire Baltic coastal zone removes ∼ 16 % of annual land-derived TN loads via denitrification, while the remaining 84 % is probably retained within the coastal zone or exported to the open sea. Model results indicate, however, that the export of riverine N to the open Baltic Sea accounts for only a minor share of the TN load (Radtke et al, 2012), suggesting that most N remains within the coastal zone.…”

Section: Introductionmentioning

confidence: 99%

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Particulate organic matter controls benthic microbial N retention and N removal in contrasting estuaries of the Baltic Sea

et al. 2019

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Abstract. Estuaries worldwide act as “filters” of land-derived nitrogen (N) loads, yet differences in coastal environmental settings can affect the N filter function. We investigated microbial N retention (nitrification, ammonium assimilation) and N removal (denitrification, anammox) processes in the aphotic benthic system (bottom boundary layer (BBL) and sediment) of two Baltic Sea estuaries differing in riverine N loads, trophic state, geomorphology, and sediment type. In the BBL, rates of nitrification (5–227 nmol N L−1 d−1) and ammonium assimilation (9–704 nmol N L−1 d−1) were not enhanced in the eutrophied Vistula Estuary compared to the oligotrophic Öre Estuary. No anammox was detected in the sediment of either estuary, while denitrification rates were twice as high in the eutrophied (352±123 µmol N m−2 d−1) as in the oligotrophic estuary. Particulate organic matter (POM) was mainly of phytoplankton origin in the benthic systems of both estuaries. It seemed to control heterotrophic denitrification and ammonium assimilation as well as autotrophic nitrification by functioning as a substrate source of N and organic carbon. Our data suggest that in stratified estuaries, POM is an essential link between riverine N loads and benthic N turnover and may furthermore function as a temporary N reservoir. During long particle residence times or alongshore transport pathways, increased time is available for the recycling of N until its eventual removal, allowing effective coastal filtering even at low process rates. Understanding the key controls and microbial N processes in the coastal N filter therefore requires to also consider the effects of geomorphological and hydrological features.

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“…Recent research shows that the primary production in shallow, vegetated bays and inlets is considerably higher than previously known. Ask et al (2016) found that benthic habitats, especially benthic microalgae but also microalgae and submerged rooted plants, contributed to 31% of the total primary production of the Bothnian Bay, which is three times higher than past estimates. Primary production rates of vegetation in Baltic bays and inlets vary among species; Potamogeton filiformis, P. perfoliatus, and Myriophyllum spicatum have maximum production rates of 1-5 mg carbon (C) per g dry weight per hour, while Stuckenia pectinata, Ruppia sp., Zannichellia sp.…”

Section: Primary Production Food Webs and Nutrient Cyclingmentioning

confidence: 65%