A first estimate of the effect of offshore wind farms on sedimentary organic carbon stocks in the Southern North Sea

Offshore wind farms (OWFs) can increase the transfer and stock of organic carbon (OC) in the surrounding sediments during their operational phase, while their construction and decommissioning release carbon. To answer the question whether sediments of OWFs trap more OC than they release, we estimate...

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Main Authors: Knut Heinatz, Maike Iris Esther Scheffold
Format: Article
Language:English
Published: Frontiers Media S.A. 2023-01-01
Series:Frontiers in Marine Science
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fmars.2022.1068967/full
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author Knut Heinatz
Maike Iris Esther Scheffold
author_facet Knut Heinatz
Maike Iris Esther Scheffold
author_sort Knut Heinatz
collection DOAJ
description Offshore wind farms (OWFs) can increase the transfer and stock of organic carbon (OC) in the surrounding sediments during their operational phase, while their construction and decommissioning release carbon. To answer the question whether sediments of OWFs trap more OC than they release, we estimate the net carbon effect over the entire life cycle (construction, operational and decommissioning phases) of OWFs in the Southern North Sea. Based on existing studies we compare the increased OC flux due to the colonization of organisms at the foundations of wind turbines and the OC loss due to sediment-disturbing activities during construction and decommissioning. Our results show that the areal intensity of carbon release in the disturbed areas is about 43.5 times higher than that of carbon trapping in the entire area of the OWFs. However, since the disturbed areas only account for about 0.50 ± 0.06% of the total area of the OWFs, in absolute terms about 4.6 ± 1.4 times more carbon is trapped in the sediment of the OWFs than is released. Due to limited data availability and the resulting need for extensive assumptions, our estimates only represent orders of magnitude. We therefore provide sensitivity estimates that define the limits of our calculations in terms of disturbance depth, remineralisation ratio, scour protection measures and heterogenous OC contents. In addition, we identify shortcomings of our extrapolation. Further research, especially more advanced impact assessments of construction and decommissioning processes must follow to improve the understanding of impacts of OWFs on sedimentary OC.
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spelling doaj.art-98ae282422fc4b16b8a2698bdad5260b2023-01-16T05:49:08ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452023-01-01910.3389/fmars.2022.10689671068967A first estimate of the effect of offshore wind farms on sedimentary organic carbon stocks in the Southern North SeaKnut HeinatzMaike Iris Esther ScheffoldOffshore wind farms (OWFs) can increase the transfer and stock of organic carbon (OC) in the surrounding sediments during their operational phase, while their construction and decommissioning release carbon. To answer the question whether sediments of OWFs trap more OC than they release, we estimate the net carbon effect over the entire life cycle (construction, operational and decommissioning phases) of OWFs in the Southern North Sea. Based on existing studies we compare the increased OC flux due to the colonization of organisms at the foundations of wind turbines and the OC loss due to sediment-disturbing activities during construction and decommissioning. Our results show that the areal intensity of carbon release in the disturbed areas is about 43.5 times higher than that of carbon trapping in the entire area of the OWFs. However, since the disturbed areas only account for about 0.50 ± 0.06% of the total area of the OWFs, in absolute terms about 4.6 ± 1.4 times more carbon is trapped in the sediment of the OWFs than is released. Due to limited data availability and the resulting need for extensive assumptions, our estimates only represent orders of magnitude. We therefore provide sensitivity estimates that define the limits of our calculations in terms of disturbance depth, remineralisation ratio, scour protection measures and heterogenous OC contents. In addition, we identify shortcomings of our extrapolation. Further research, especially more advanced impact assessments of construction and decommissioning processes must follow to improve the understanding of impacts of OWFs on sedimentary OC.https://www.frontiersin.org/articles/10.3389/fmars.2022.1068967/fullconstruction phasedecommissioningoperational phasewind parkoffshore wind turbine (OWT) monopilesediment disturbance
spellingShingle Knut Heinatz
Maike Iris Esther Scheffold
A first estimate of the effect of offshore wind farms on sedimentary organic carbon stocks in the Southern North Sea
Frontiers in Marine Science
construction phase
decommissioning
operational phase
wind park
offshore wind turbine (OWT) monopile
sediment disturbance
title A first estimate of the effect of offshore wind farms on sedimentary organic carbon stocks in the Southern North Sea
title_full A first estimate of the effect of offshore wind farms on sedimentary organic carbon stocks in the Southern North Sea
title_fullStr A first estimate of the effect of offshore wind farms on sedimentary organic carbon stocks in the Southern North Sea
title_full_unstemmed A first estimate of the effect of offshore wind farms on sedimentary organic carbon stocks in the Southern North Sea
title_short A first estimate of the effect of offshore wind farms on sedimentary organic carbon stocks in the Southern North Sea
title_sort first estimate of the effect of offshore wind farms on sedimentary organic carbon stocks in the southern north sea
topic construction phase
decommissioning
operational phase
wind park
offshore wind turbine (OWT) monopile
sediment disturbance
url https://www.frontiersin.org/articles/10.3389/fmars.2022.1068967/full
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