Numerical modelling of the benthic-pelagic coupling in coastal marine ecosystems at contrasting sites

2020 ◽  
Author(s):  
Carolina Amadio ◽  
Marco Zavatarelli ◽  
Tomas Lovato ◽  
Momme Butenschoen
Keyword(s):  
Organic Matter ◽  
Inorganic Compounds ◽  
Marine Ecosystem ◽  
Ecosystem Dynamics ◽  
Shortwave Radiation ◽  
Global Ocean ◽  
In Situ Data ◽  
Benthic Pelagic Coupling ◽  
Diffusive Fluxes ◽  
St Helena

<p>Continental shelves cover less than 5% of the global ocean surface, but play a crucial role in the marine global biogeochemical cycling. Coastal ecosystem dynamics are governed and constrained to a wide extent by the biogeochemical processes occurring in the benthic domain. Such processes define the so called benthic-pelagic coupling (hereafter BPC), i.e. two-way exchange of organic matter (particulate and dissolved) and inorganic compounds. The physically mediated exchanges structuring the BPC are constituted by the sinking and resuspension fluxes of particulate organic matter and by the diffusion of inorganic nutrients. Despite its importance and the continuous enhancement of model resolution, the BPC in global marine ecosystem models is generally roughly approximated. Moreover, observational data focusing on the BPC dynamics are fairly scanty in time and space, thereby hampering model parameterization and validation. The main objectives of this study are to develop and test a numerical model addressing BPC processes and to evaluate ecosystem dynamics in marine areas with different climatic and ecological characteristics. In particular, we here focused on two key interaction processes: the sinking velocity of particulate matter and the diffusive fluxes of inorganic dissolved nutrients at the benthic-pelagic interface. The benthic sub-model has been calibrated accounting for the complex pelagic food web and for the main ecological and physical characteristics of continental shelf areas in different sites: Gulf of Trieste (Italy), St. Helena Bay (South Africa), Svinoy Fyr (Norway). At each study area, the one-dimensional coupled BFM-NEMO modelling system was setup by prescribing temperature and salinity vertical profiles in NEMO, while the shortwave radiation acts as a primary forcing of BFM. Model results have been validated with available in situ data.</p><p>Sensitivity tests has been performed to investigate the role of the BPC exchanges in determining the pelagic biogeochemical cycles and to carry out a comparative analysis accounting for each site characteristics.</p>

scholarly journals ERSEM 15.06: a generic model for marine biogeochemistry and the ecosystem dynamics of the lower trophic levels

2016 ◽  
Vol 9 (4) ◽  
pp. 1293-1339 ◽  
Author(s):  
Momme Butenschön ◽  
James Clark ◽  
John N. Aldridge ◽  
Julian Icarus Allen ◽  
Yuri Artioli ◽  
...  
Keyword(s):  
Food Web ◽  
Current Model ◽  
Marine Ecosystem ◽  
Ecosystem Model ◽  
Essential Elements ◽  
Ecosystem Dynamics ◽  
Trophic Levels ◽  
Global Ocean ◽  
Generic Model ◽  
The North

Abstract. The European Regional Seas Ecosystem Model (ERSEM) is one of the most established ecosystem models for the lower trophic levels of the marine food web in the scientific literature. Since its original development in the early nineties it has evolved significantly from a coastal ecosystem model for the North Sea to a generic tool for ecosystem simulations from shelf seas to the global ocean. The current model release contains all essential elements for the pelagic and benthic parts of the marine ecosystem, including the microbial food web, the carbonate system, and calcification. Its distribution is accompanied by a testing framework enabling the analysis of individual parts of the model. Here we provide a detailed mathematical description of all ERSEM components along with case studies of mesocosm-type simulations, water column implementations, and a brief example of a full-scale application for the north-western European shelf. Validation against in situ data demonstrates the capability of the model to represent the marine ecosystem in contrasting environments.

scholarly journals ERSEM 15.06: a generic model for marine biogeochemistry and the ecosystem dynamics of the lower trophic levels

2015 ◽  
Vol 8 (8) ◽  
pp. 7063-7187 ◽  
Author(s):  
M. Butenschön ◽  
J. Clark ◽  
J. N. Aldridge ◽  
J. I. Allen ◽  
Y. Artioli ◽  
...  
Keyword(s):  
Food Web ◽  
Current Model ◽  
Marine Ecosystem ◽  
Essential Elements ◽  
Ecosystem Dynamics ◽  
Trophic Levels ◽  
Global Ocean ◽  
Generic Model ◽  
North West ◽  
The North

Abstract. The ERSEM model is one of the most established ecosystem models for the lower trophic levels of the marine food-web in the scientific literature. Since its original development in the early nineties it has evolved significantly from a coastal ecosystem model for the North-Sea to a generic tool for ecosystem simulations from shelf seas to the global ocean. The current model release contains all essential elements for the pelagic and benthic part of the marine ecosystem, including the microbial food-web, the carbonate system and calcification. Its distribution is accompanied by a testing framework enabling the analysis of individual parts of the model. Here we provide a detailed mathematical description of all ERSEM components along with case-studies of mesocosm type simulations, water column implementations and a brief example of a full-scale application for the North-West European shelf. Validation against in situ data demonstrates the capability of the model to represent the marine ecosystem in contrasting environments.

scholarly journals Double-diffusive mixing makes a small contribution to the global ocean circulation

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Carine G. van der Boog ◽  
Henk A. Dijkstra ◽  
Julie D. Pietrzak ◽  
Caroline A. Katsman
Keyword(s):  
Ocean Circulation ◽  
Mechanical Energy ◽  
Global Ocean ◽  
Small Contribution ◽  
Global Ocean Circulation ◽  
Diffusive Fluxes ◽  
Diffusive Mixing ◽  
Diffusive Processes ◽  
Flowing Waters ◽  
Double Diffusive

AbstractDouble-diffusive processes enhance diapycnal mixing of heat and salt in the open ocean. However, observationally based evidence of the effects of double-diffusive mixing on the global ocean circulation is lacking. Here we analyze the occurrence of double-diffusive thermohaline staircases in a dataset containing over 480,000 temperature and salinity profiles from Argo floats and Ice-Tethered Profilers. We show that about 14% of all profiles contains thermohaline staircases that appear clustered in specific regions, with one hitherto unknown cluster overlying the westward flowing waters of the Tasman Leakage. We estimate the combined contribution of double-diffusive fluxes in all thermohaline staircases to the global ocean’s mechanical energy budget as 7.5 GW [0.1 GW; 32.8 GW]. This is small compared to the estimated energy required to maintain the observed ocean stratification of roughly 2 TW. Nevertheless, we suggest that the regional effects, for example near Australia, could be pronounced.

scholarly journals Trends and Evolution in the Concept of Marine Ecosystem Services: An Overview

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2060
Author(s):  
Elvira Buonocore ◽  
Umberto Grande ◽  
Pier Paolo Franzese ◽  
Giovanni F. Russo
Keyword(s):  
Ecosystem Services ◽  
Alternative Assessment ◽  
Natural Capital ◽  
Marine Ecosystem ◽  
Management Strategies ◽  
Marine Ecosystems ◽  
Global Ocean ◽  
Coastal Protection ◽  
Policy Dialogue ◽  
Marine Ecosystem Services

The biotic and abiotic assets of the marine environment form the “marine natural capital” embedded in the global ocean. Marine natural capital provides the flow of “marine ecosystem services” that are directly used or enjoyed by people providing benefits to human well-being. They include provisioning services (e.g., food), regulation and maintenance services (e.g., carbon sequestration and storage, and coastal protection), and cultural services (e.g., tourism and recreational benefits). In recent decades, human activities have increased the pressures on marine ecosystems, often leading to ecosystem degradation and biodiversity loss and, in turn, affecting their ability to provide benefits to humans. Therefore, effective management strategies are crucial to the conservation of healthy and diverse marine ecosystems and to ensuring their long-term generation of goods and services. Biophysical, economic, and sociocultural assessments of marine ecosystem services are much needed to convey the importance of natural resources to managers and policy makers supporting the development and implementation of policies oriented for the sustainable management of marine resources. In addition, the accounting of marine ecosystem service values can be usefully complemented by their mapping to enable the identification of priority areas and management strategies and to facilitate science–policy dialogue. Given this premise, this study aims to review trends and evolution in the concept of marine ecosystem services. In particular, the global scientific literature on marine ecosystem services is explored by focusing on the following main aspects: the definition and classification of marine ecosystem services; their loss due to anthropogenic pressures, alternative assessment, and mapping approaches; and the inclusion of marine ecosystem services into policy and decision-making processes.

scholarly journals MAREDAT: towards a World Ocean Atlas of MARine Ecosystem DATa

2012 ◽  
Vol 5 (2) ◽  
pp. 1077-1106 ◽  
Author(s):  
E. T. Buitenhuis ◽  
M. Vogt ◽  
R. Moriarty ◽  
N. Bednaršek ◽  
S. C. Doney ◽  
...  
Keyword(s):  
Marine Ecosystem ◽  
World Ocean ◽  
Zooplankton Biomass ◽  
Global Ocean ◽  
Special Issue ◽  
Biomass Distribution ◽  
Phytoplankton Pigment ◽  
Autotrophic Biomass ◽  
Ocean Ecosystem ◽  
World Ocean Atlas

Abstract. We present a summary of biomass data for 11 Plankton Functional Types (PFTs) plus phytoplankton pigment data, compiled as part of the MARine Ecosystem biomass DATa (MAREDAT) initiative. The goal of the MAREDAT initiative is to provide global gridded data products with coverage of all biological components of the global ocean ecosystem. This special issue is the first step towards achieving this. The PFTs presented here include picophytoplankton, diazotrophs, coccolithophores, Phaeocystis, diatoms, picoheterotrophs, microzooplankton, foraminifers, mesozooplankton, pteropods and macrozooplankton. All variables have been gridded onto a World Ocean Atlas (WOA) grid (1° × 1° × 33 vertical levels × monthly climatologies). The data show that (1) the global total heterotrophic biomass (2.0–6.4 Pg C) is at least as high as the total autotrophic biomass (0.5–2.6 Pg C excluding nanophytoplankton and autotrophic dinoflagellates), (2) the biomass of zooplankton calcifiers (0.9–2.3 Pg C) is substantially higher than that of coccolithophores (0.01–0.14 Pg C), (3) patchiness of biomass distribution increases with organism size, and (4) although zooplankton biomass measurements below 200 m are rare, the limited measurements available suggest that Bacteria and Archaea are not the only heterotrophs in the deep sea. More data will be needed to characterize ocean ecosystem functioning and associated biogeochemistry in the Southern Hemisphere and below 200 m. Microzooplankton database: doi:10.1594/PANGAEA.779970.

Detecting Climate Fingerprints in Southern Ocean Carbon using a Biogeochemical Ocean Model

2021 ◽  
Author(s):  
Rebecca Wright ◽  
Corinne Le Quéré ◽  
Erik Buitenhuis ◽  
Dorothee Bakker
Keyword(s):  
Climate Change ◽  
Climate Variability ◽  
Southern Ocean ◽  
Observational Data ◽  
Ecosystem Dynamics ◽  
Global Ocean ◽  
Subsurface Waters ◽  
Climatic Drivers ◽  
Ocean Carbon ◽  
And Storage

<p>The Southern Ocean plays an important role in the uptake, transport and storage of carbon by the global oceans. These properties are dominated by the response to the rise in anthropogenic CO<sub>2</sub> in the atmosphere, but they are modulated by climate variability and climate change. Here we explore the effect of climate variability and climate change on ocean carbon uptake and storage in the Southern Ocean. We assess the extent to which climate change may be distinguishable from the anthropogenic CO<sub>2</sub> signal and from the natural background variability. We use a combination of biogeochemical ocean modelling and observations from the GLODAPv2020 database to detect climate fingerprints in dissolved inorganic carbon (DIC).</p><p>We conduct an ensemble of hindcast model simulations of the period 1920-2019, using a global ocean biogeochemical model which incorporates plankton ecosystem dynamics based on twelve plankton functional types. We use the model ensemble to isolate the changes in DIC due to rising anthropogenic CO<sub>2</sub> alone and the changes due to climatic drivers (both climate variability and climate change), to determine their relative roles in the emerging total DIC trends and patterns. We analyse these DIC trends for a climate fingerprint over the past four decades, across spatial scales from the Southern Ocean, to basin level and down to regional ship transects. Highly sampled ship transects were extracted from GLODAPv2020 to obtain locations with the maximum spatiotemporal coverage, to reduce the inherent biases in patchy observational data. Model results were sampled to the ship transects to compare the climate fingerprints directly to the observational data.</p><p>Model results show a substantial change in DIC over a 35-year period, with a range of more than +/- 30 µmol/L. In the surface ocean, both anthropogenic CO<sub>2</sub> and climatic drivers act to increase DIC concentration, with the influence of anthropogenic CO<sub>2</sub> dominating at lower latitudes and the influence of climatic drivers dominating at higher latitudes. In the deep ocean, the anthropogenic CO<sub>2</sub> generally acts to increase DIC except in the subsurface waters at lower latitudes, while climatic drivers act to decrease DIC concentration. The combined fingerprint of anthropogenic CO<sub>2</sub> and climatic drivers on DIC concentration is for an increasing trend at the surface and decreasing trends in low latitude subsurface waters. Preliminary comparison of the model fingerprints to observational ship transects will also be presented.</p>

scholarly journals PhytoSFDM version 1.0.0: Phytoplankton Size and Functional Diversity Model

2016 ◽  
Vol 9 (11) ◽  
pp. 4071-4085 ◽  
Author(s):  
Esteban Acevedo-Trejos ◽  
Gunnar Brandt ◽  
S. Lan Smith ◽  
Agostino Merico
Keyword(s):  
Open Source ◽  
Open Source Software ◽  
Marine Ecosystem ◽  
Three Dimensional ◽  
Functional Trait ◽  
Global Ocean ◽  
Total Biomass ◽  
Spatially Resolved ◽  
Phytoplankton Communities ◽  
Natural Complexity

Abstract. Biodiversity is one of the key mechanisms that facilitate the adaptive response of planktonic communities to a fluctuating environment. How to allow for such a flexible response in marine ecosystem models is, however, not entirely clear. One particular way is to resolve the natural complexity of phytoplankton communities by explicitly incorporating a large number of species or plankton functional types. Alternatively, models of aggregate community properties focus on macroecological quantities such as total biomass, mean trait, and trait variance (or functional trait diversity), thus reducing the observed natural complexity to a few mathematical expressions. We developed the PhytoSFDM modelling tool, which can resolve species discretely and can capture aggregate community properties. The tool also provides a set of methods for treating diversity under realistic oceanographic settings. This model is coded in Python and is distributed as open-source software. PhytoSFDM is implemented in a zero-dimensional physical scheme and can be applied to any location of the global ocean. We show that aggregate community models reduce computational complexity while preserving relevant macroecological features of phytoplankton communities. Compared to species-explicit models, aggregate models are more manageable in terms of number of equations and have faster computational times. Further developments of this tool should address the caveats associated with the assumptions of aggregate community models and about implementations into spatially resolved physical settings (one-dimensional and three-dimensional). With PhytoSFDM we embrace the idea of promoting open-source software and encourage scientists to build on this modelling tool to further improve our understanding of the role that biodiversity plays in shaping marine ecosystems.

scholarly journals Coastal hypoxia and sediment biogeochemistry

2009 ◽  
Vol 6 (7) ◽  
pp. 1273-1293 ◽  
Author(s):  
J. J. Middelburg ◽  
L. A. Levin
Keyword(s):  
Organic Matter ◽  
Bottom Water ◽  
Water Exchange ◽  
Transport Processes ◽  
Ecosystem Dynamics ◽  
Ecosystem Functions ◽  
Oxygen Levels ◽  
Concise Review ◽  
Water Oxygen ◽  
Sediment Biogeochemistry

Abstract. The intensity, duration and frequency of coastal hypoxia (oxygen concentration <63 μM) are increasing due to human alteration of coastal ecosystems and changes in oceanographic conditions due to global warming. Here we provide a concise review of the consequences of coastal hypoxia for sediment biogeochemistry. Changes in bottom-water oxygen levels have consequences for early diagenetic pathways (more anaerobic at expense of aerobic pathways), the efficiency of re-oxidation of reduced metabolites and the nature, direction and magnitude of sediment-water exchange fluxes. Hypoxia may also lead to more organic matter accumulation and burial and the organic matter eventually buried is also of higher quality, i.e. less degraded. Bottom-water oxygen levels also affect the organisms involved in organic matter processing with the contribution of metazoans decreasing as oxygen levels drop. Hypoxia has a significant effect on benthic animals with the consequences that ecosystem functions related to macrofauna such as bio-irrigation and bioturbation are significantly affected by hypoxia as well. Since many microbes and microbial-mediated biogeochemical processes depend on animal-induced transport processes (e.g. re-oxidation of particulate reduced sulphur and denitrification), there are indirect hypoxia effects on biogeochemistry via the benthos. Severe long-lasting hypoxia and anoxia may result in the accumulation of reduced compounds in sediments and elimination of macrobenthic communities with the consequences that biogeochemical properties during trajectories of decreasing and increasing oxygen may be different (hysteresis) with consequences for coastal ecosystem dynamics.

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