scholarly journals Water Column Turbidity Not Sediment Nutrient Enrichment Moderates Microphytobenthic Primary Production

2020 ◽  
Vol 8 (10) ◽  
pp. 732
Author(s):  
Stephanie Mangan ◽  
Andrew M. Lohrer ◽  
Simon F. Thrush ◽  
Conrad A. Pilditch
Keyword(s):  
Primary Production ◽  
Water Column ◽  
Nutrient Enrichment ◽  
Net Primary Production ◽  
High Water ◽  
Detectable Effect ◽  
Anthropogenic Pressure ◽  
Benthic Primary Production ◽  
Cascading Effects ◽  
Sediment Porewaters

Soft sediment intertidal habitats are under intense anthropogenic pressure resulting from increased land derived sediment and nutrient delivery. Long term, this can cause high water column turbidity and nutrient enrichment of sediment porewaters, which has cascading effects on coastal ecosystem functionality. However, how these stressors may interact and influence benthic productivity over alternating periods of submergence and emergence is largely unknown. This study investigates the effects of sediment nutrient enrichment (at three levels for 20 months) on benthic primary production at six sites in four New Zealand estuaries that spanned a gradient in water column turbidity. While nutrient enrichment had no detectable effect on microphytobenthic primary production, water column turbidity had a significant influence, explaining up to 40% of variability during tidal submergence, followed by temperature and sediment characteristics. In addition, negative net primary production (NPP) estimates and therefore net heterotrophy for the most turbid estuaries during tidal submergence resulted in an increased reliance on production during emerged periods, where NPP was positive across all sites. This study highlights the prominent role of water column turbidity over nutrient enrichment in moderating microphytobenthic production, and the increasing importance of emerged periods to maintain the health and functioning of coastal habitats.

Benthic primary production in emerged intertidal habitats provides resilience to high water column turbidity

2018 ◽  
Vol 142 ◽  
pp. 101-112 ◽  
Author(s):  
Tarn P. Drylie ◽  
Andrew M. Lohrer ◽  
Hazel R. Needham ◽  
Richard H. Bulmer ◽  
Conrad A. Pilditch
Keyword(s):  
Primary Production ◽  
Water Column ◽  
High Water ◽  
Benthic Primary Production ◽  
Intertidal Habitats

scholarly journals Spring–summer net community production, new production, particle export and related water column biogeochemical processes in the marginal sea ice zone of the Western Antarctic Peninsula 2012–2014

2018 ◽  
Vol 376 (2122) ◽  
pp. 20170177 ◽  
Author(s):  
Hugh W. Ducklow ◽  
Michael R. Stukel ◽  
Rachel Eveleth ◽  
Scott C. Doney ◽  
Tim Jickells ◽  
...  
Keyword(s):  
Sea Ice ◽  
Primary Production ◽  
Water Column ◽  
Antarctic Peninsula ◽  
Net Primary Production ◽  
Western Antarctic Peninsula ◽  
New Production ◽  
Net Community Production ◽  
Particle Export ◽  
Community Production

New production (New P, the rate of net primary production (NPP) supported by exogenously supplied limiting nutrients) and net community production (NCP, gross primary production not consumed by community respiration) are closely related but mechanistically distinct processes. They set the carbon balance in the upper ocean and define an upper limit for export from the system. The relationships, relative magnitudes and variability of New P (from 15 NO 3 – uptake), O 2  : argon-based NCP and sinking particle export (based on the 238 U :  234 Th disequilibrium) are increasingly well documented but still not clearly understood. This is especially true in remote regions such as polar marginal ice zones. Here we present a 3-year dataset of simultaneous measurements made at approximately 50 stations along the Western Antarctic Peninsula (WAP) continental shelf in midsummer (January) 2012–2014. Net seasonal-scale changes in water column inventories (0–150 m) of nitrate and iodide were also estimated at the same stations. The average daily rates based on inventory changes exceeded the shorter-term rate measurements. A major uncertainty in the relative magnitude of the inventory estimates is specifying the start of the growing season following sea-ice retreat. New P and NCP(O 2 ) did not differ significantly. New P and NCP(O 2 ) were significantly greater than sinking particle export from thorium-234. We suggest this is a persistent and systematic imbalance and that other processes such as vertical mixing and advection of suspended particles are important export pathways. This article is part of the theme issue ‘The marine system of the west Antarctic Peninsula: status and strategy for progress in a region of rapid change’.

scholarly journals Effects of large-scale floating (solar photovoltaic) platforms on hydrodynamics and primary production in a coastal sea from a water column model

Ocean Science ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 195-208
Author(s):  
Thodoris Karpouzoglou ◽  
Brigitte Vlaswinkel ◽  
Johan van der Molen
Keyword(s):  
Primary Production ◽  
Water Column ◽  
Large Scale ◽  
Net Primary Production ◽  
Biogeochemical Model ◽  
Solar Photovoltaic ◽  
Column Model ◽  
Coastal Sea ◽  
Floating Platforms ◽  
The Impact

Abstract. An improved understanding of the effects of floating solar platforms on the ecosystem is necessary to define acceptable and responsible real-world field implementations of this new marine technology. This study examines a number of potential effects of offshore floating solar photovoltaic (PV) platforms on the hydrodynamics and net primary production in a coastal sea for the first time. Three contrasting locations within the North Sea (a shallow and deeper location with well-mixed conditions and a seasonally stratifying location) have been analysed using a water column physical–biogeochemical model: the General Ocean Turbulence Model coupled with the European Regional Seas Ecosystem Model – Biogeochemical Flux Model (GOTM-ERSEM-BFM). The results show strong dependence on the characteristics of the location (e.g. mixing and stratification) and on the density of coverage with floating platforms. The overall response of the system was separated into contributions by platform-induced light deficit, shielding by the platforms of the sea surface from wind and friction induced by the platforms on the currents. For all three locations, light deficit was the dominant effect on the net primary production. For the two well-mixed locations, the other effects of the platforms resulted in partial compensation for the impact of light deficit, while for the stratified location, they enhanced the effects of light deficit. For up to 20 % coverage of the model surface with platforms, the spread in the results between locations was relatively small, and the changes in net primary production were less than 10 %. For higher percentages of coverage, primary production decreased substantially, with an increased spread in response between the sites. The water column model assumes horizontal homogeneity in all forcings and simulated variables, also for coverage with floating platforms, and hence the results are applicable to very-large-scale implementations of offshore floating platforms that are evenly distributed over areas of at least several hundreds of square kilometres, such that phytoplankton remain underneath a farm throughout several tidal cycles. To confirm these results, and to investigate more realistic cases of floating platforms distributed unevenly over much smaller areas with horizontally varying hydrodynamic conditions, in which phytoplankton can be expected to spend only part of the time underneath a farm and effects are likely to be smaller, spatial detail and additional processes need to be included. To do so, further work is required to advance the water column model towards a three-dimensional modelling approach.

scholarly journals Effects of floating (solar PV) platforms on hydrodynamics and primary production in a coastal sea

2019 ◽  
Author(s):  
Thodoris Karpouzoglou ◽  
Brigitte Vlaswinkel ◽  
Johan van der Molen
Keyword(s):  
Primary Production ◽  
Water Column ◽  
Net Primary Production ◽  
Strong Dependence ◽  
Biogeochemical Model ◽  
Solar Pv ◽  
Column Model ◽  
Coastal Sea ◽  
Floating Platforms ◽  
The Impact

Abstract. An improved understanding of the effects of floating solar platforms on the ecosystem is necessary to define acceptable and responsible real-world field implementations of this new marine technology. This study examines a number of potential effects of offshore floating solar PV platforms on the hydrodynamics and net primary production in a coastal sea for the first time. Three contrasting locations within the North Sea (a shallow and deeper location with well-mixed conditions and a summer-stratifying location) have been analysed using a water column physical-biogeochemical model (GOTM-ERSEM-BFM). The results show strong dependence on the characteristics of the location (e.g. mixing and stratification) and on the density of coverage with floating platforms. The overall response of the system was separated into contributions by platform shadow, shielding by the platforms of the sea surface from wind, and friction induced by the platforms on the currents. For all three locations, platform shadow was the dominant effect on the net primary production. For the two well-mixed locations, the other effects of the platforms resulted in partial compensation for the impact of platform shadow, while for the stratified location, they enhanced the effects of platform shadow. For up to 20 % coverage of the model surface with platforms, the spread in the results between locations was relatively small, and the changes in net primary production were less than 10 %. For higher percentages of coverage, primary production decreased substantially, with an increased spread in response between the sites. The water-column model assumes horizontal homogeneity in all forcings and simulated variables, also for coverage with floating platforms, and hence the results are applicable to very large-scale implementations of offshore floating platforms that are evenly distributed over areas of at least several hundreds of square kilometres. To confirm these results, and to investigate more realistic cases of floating platforms distributed unevenly over much smaller areas with horizontally varying hydrodynamic conditions, in which phytoplankton can be expected to spend only part of the time underneath a farm, spatial detail and additional processes need to be included. To do so, further work is required to advance the water-column model towards a 3D modelling approach.

scholarly journals Link or sink: a modelling interpretation of the open Baltic biogeochemistry

2004 ◽  
Vol 1 (1) ◽  
pp. 219-274 ◽  
Author(s):  
M. Vichi ◽  
P. Ruardij ◽  
J. W. Baretta
Keyword(s):  
Organic Matter ◽  
Primary Production ◽  
Water Column ◽  
Nutrient Dynamics ◽  
Net Primary Production ◽  
Meteorological Data ◽  
Euphotic Zone ◽  
Nutrient Loads ◽  
Intermediate Waters ◽  
The Baltic

Abstract. A 1-D model system, consisting of the 1-D version of the Princeton Ocean Model (POM) coupled with the European Regional Seas Ecosystem Model (ERSEM) has been applied to a sub-basin of the Baltic Proper, the Bornholm basin. The model has been forced with 3h meteorological data for the period 1979-1990, producing a 12-year hindcast validated with datasets from the Baltic Environmental Database for the same period. The model results demonstrate the model to hindcast the time-evolution of the physical structure very well, confirming the view of the open Baltic water column as a three layer system of surface, intermediate and bottom waters. Comparative analyses of modelled hydrochemical components with respect to the independent data have shown that the long-term system behaviour of the model is within the observed ranges. Also primary production processes, deduced from oxygen (over)saturation are hindcast correctly over the entire period and the annual net primary production is within the observed range. The largest mismatch with observations is found in simulating the biogeochemistry of the Baltic intermediate waters. Modifications in the structure of the model (addition of fast-sinking detritus and polysaccharide dynamics) have shown that the nutrient dynamics is linked to the quality and dimensions of the organic matter produced in the euphotic zone, highlighting the importance of the residence time of the organic matter within the microbial foodweb in the intermediate waters. Experiments with different scenarios of riverine nutrient loads, assessed in the limits of a 1-D setup, have shown that the external input of organic matter makes the open Baltic model more heterotrophic. The characteristics of the inputs also drive the dynamics of nitrogen in the bottom layers leading either to nitrate accumulation (when the external sources are inorganic), or to coupled nitrification-denitrification (under strong organic inputs). The model indicates the permanent stratification to be the main feature of the system as regulator of carbon and nutrient budgets. The model predicts that most of the carbon produced in the euphotic zone is also consumed in the water column and this enhances the importance of heterotrophic benthic processes as final closures of carbon and nutrient cycles in the open Baltic.

scholarly journals Link or sink: a modelling interpretation of the open Baltic biogeochemistry

2004 ◽  
Vol 1 (1) ◽  
pp. 79-100 ◽  
Author(s):  
M. Vichi ◽  
P. Ruardij ◽  
J. W. Baretta
Keyword(s):  
Organic Matter ◽  
Primary Production ◽  
Water Column ◽  
Nutrient Dynamics ◽  
Net Primary Production ◽  
Meteorological Data ◽  
Euphotic Zone ◽  
Nutrient Loads ◽  
Intermediate Waters ◽  
The Baltic

Abstract. A 1-D model system, consisting of the 1-D version of the Princeton Ocean Model (POM) coupled with the European Regional Seas Ecosystem Model (ERSEM) has been applied to a sub-basin of the Baltic Proper, the Bornholm basin. The model has been forced with 3h meteorological data for the period 1979-1990, producing a 12-year hindcast validated with datasets from the Baltic Environmental Database for the same period. The model results demonstrate the model to hindcast the time-evolution of the physical structure very well, confirming the view of the open Baltic water column as a three layer system of surface, intermediate and bottom waters. Comparative analyses of modelled hydrochemical components with respect to the independent data have shown that the long-term system behaviour of the model is within the observed ranges. Also primary production processes, deduced from oxygen (over)saturation are hindcast correctly over the entire period and the annual net primary production is within the observed range. The largest mismatch with observations is found in simulating the biogeochemistry of the Baltic intermediate waters. Modifications in the structure of the model (addition of fast-sinking detritus and polysaccharide dynamics) have shown that the nutrient dynamics are linked to the quality and dimensions of the organic matter produced in the euphotic zone, highlighting the importance of the residence time of the organic matter within the microbial foodweb in the intermediate waters. Experiments with different scenarios of riverine nutrient loads, assessed in the limits of a 1-D setup, have shown that the external input of organic matter makes the open Baltic model more heterotrophic. The characteristics of the inputs also drive the dynamics of nitrogen in the bottom layers leading either to nitrate accumulation (when the external sources are inorganic), or to coupled nitrification-denitrification (under strong organic inputs). The model indicates the permanent stratification to be the main feature of the system as regulator of carbon and nutrient budgets. The model predicts that most of the carbon produced in the euphotic zone is also consumed in the water column and this enhances the importance of heterotrophic benthic processes as final closure of carbon and nutrient cycles in the open Baltic.

scholarly journals Acidification, deoxygenation, nutrient and biomasses decline in a warming Mediterranean Sea

2021 ◽  
Author(s):  
Marco Reale ◽  
Gianpiero Cossarini ◽  
Paolo Lazzari ◽  
Tomas Lovato ◽  
Giorgio Bolzon ◽  
...  
Keyword(s):  
Primary Production ◽  
Mediterranean Sea ◽  
Water Column ◽  
21St Century ◽  
Dissolved Inorganic Carbon ◽  
Net Primary Production ◽  
Eastern Mediterranean ◽  
Marine Ecosystems ◽  
Global Ocean ◽  
Co2 Absorption

Abstract. The projected warming, nutrient decline, changes in net primary production, deoxygenation and acidification of the global ocean will dramatically affect marine ecosystems during the 21st century. Here we assess the climate change-related impacts in the marine ecosystems of the Mediterranean Sea in the middle and at the end of the 21st century using high-resolution projections of the physical and biogeochemical state of the basin under the Representative Concentration Pathways (RCPs) 4.5 and 8.5. The analysis shows significant changes in the dissolved nutrient content of the euphotic and intermediate layers of the basin, net primary production, phytoplankton respiration and carbon stock (including phytoplankton, zooplankton, bacterial biomass and particulate organic matter). The projections also show a uniform surface and subsurface reduction in the oxygen concentration driven by the warming of the water column and by the increase in respiration. Moreover, we observe an acidification in the upper water column, linked to the increase in the dissolved inorganic carbon content of the water column due to CO2 absorption from the atmosphere and the increase in respiration. The projected changes are stronger in the eastern Mediterranean due to the limited influence, in that part of the basin, of the exchanges in the Strait of Gibraltar.

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