Ecological Safety of Coastal and Shelf Zones of Sea Ecological Safety of Coastal and Shelf Zones of Sea 2413-5577 20240303 Research Article Estimation of Carbon Dioxide Fluxes through the Surface of the Black Sea from Numerical Simulation Results Dorofeev V. L.
Russian Federation
viktor.dorofeev@mhi-ras.ru Sukhikh L. I.
Russian Federation
l.sukhikh@gmail.com Marine Hydrophysical Institute of RAS Sevastopol Russia 25 09 2024 2024 3 36 48 25 01 2024 17 06 2024 25 03 2024 Copyright © 2024, V. L. Dorofeev, L. I. Sukhikh 2024 V. L. Dorofeev, L. I. Sukhikh https://creativecommons.org/licenses/by-nc/4.0/ https://ecological-safety.ru/en/repository/issues/2024/03/03/

Based on numerical simulation, the paper studies the spatiotemporal distribution of CO₂ fluxes through the free surface of the Black Sea. The basic equation for solving this problem is the three-dimensional evolutionary transport-diffusion equation for the concentration of dissolved inorganic carbon. The simulation uses hydrodynamic fields resulting from a previous physical reanalysis as input parameters. A model of the lower level of the Black-Sea ecosystem food chain is used to describe the influence of biological factors on the dissolved carbon dioxide distribution. The concentration and equilibrium partial pressure of dissolved carbon dioxide in the surface layer of the Black Sea were calculated from the numerical simulation results. It is shown that the time dependence of these quantities is highly seasonal. The seawater temperature significantly affects the solubility of carbon dioxide and therefore its fluxes. The equilibrium partial pressure of carbon dioxide averaged over the area of the Black Sea is minimal in January-February and maximal in June-July. Accordingly, in the warm season, the flux of carbon dioxide is directed mainly from the sea to the atmosphere; in the cold season, the sea mainly absorbs carbon dioxide. Biological factors also influence the CO₂ content in the sea. Thus, at the beginning of the year, a high concentration of phytoplankton is observed almost throughout the entire Black Sea water area, which is why the absorption of carbon dioxide predominates during photosynthesis. In summer, the release of carbon dioxide predominates due to plankton respiration and oxidation of organic matter. The simulation results are in fairly good agreement with in situ measurements of the partial pressure of dissolved carbon dioxide obtained during scientific cruises.

 carbonate system carbon dioxide partial pressure of carbon dioxide Black Sea marine ecosystem numerical simulation The work was carried out under topic of state assignment of FSBSI FRC MHI FNNN-2023-0001. The authors thank the staff of the Biogeochemistry Department of the FSBSI FRC MHI for providing the results of field data processing.

About the authors:

Viktor L. Dorofeev, Leading Research Associate, Marine Hydrophysical Institute of RAS (2 Kapitanskaya St., Sevastopol, 299011, Russian Federation), PhD (Phys.-Math.), ResearcherID: G-1050-2014, viktor.dorofeev@mhi-ras.ru

Larisa I. Sukhikh, Research Associate, Marine Hydrophysical Institute of RAS (2 Kapitanskaya St., Sevastopol, 299011, Russian Federation), ResearcherID: M-4381-2018, l.sukhikh@gmail.com

Contribution of the authors:

Viktor L. Dorofeev – general scientific supervision of the study, formulation of the goals and objectives of the study, carrying out numerical simulations, analysis of the obtained results and their interpretation

Larisa I. Sukhikh – literature review, numerical simulations, analysis of the results

All the authors have read and approved the final manuscript.

Article text not included.

REFERENCES ZhorovV.A. AbakumovaT.N. SovgaE.E. LyashenkoS.V. On CO₂ Exchange between the Sea and the Atmosphere in Some Regions of the Black Sea Okeanologiya 1981 21 1 55 62 (in Russian) KhoruzhiyD.S. KonovalovS.K. Diurnal Variation and Inter-Diurnal Changes of Carbonic Acid and Dissolved Inorganic Carbon Content in the Black Sea Coastal Waters Morskyy Gidrofizicheskiy Zhurnal 2014 1 28 43 (in Russian) KonovalovS.K. KondratevS.I. KhoruzhiyD.S. MedvedevE.V. MoiseenkoO.G. Total Inorganic Carbon, Carbonate System and Carbon Dioxide Fluxes in the Coastal Zone of the Southern Coast of Crimea: Monitoring, Characteristics, Dynamics Monitoring of the Coastal Zone in the Black Sea Experimental Sub-Satellite Testing Area 2014 250 271 (in Russian) KhoruzhiiD.S. Variability of Equilibrium Partial Pressure of Carbon Dioxide (pCO₂) and Concentration of Dissolved Inorganic Carbon (TCO₂) in the Black Sea Coastal Waters in 2010–2014 Physical Oceanography 2016 4 34 46 10.22449/1573-160X-2016-4-34-46 OrekhovaN.A. KonovalovS.K. MedvedevE.V. Features of Inorganic Carbon Regional Balance in Marine Ecosystems under Anthropogenic Pressure Physical Oceanography 2019 26 3 225 235 10.22449/1573-160X-2019-3-225-235 SilkinV.A. PodymovO.I. LifanchukA.V. Biological Carbon Pump in the Black Sea Hydrosphere Ecology 2022 2 69 92 10.33624/2587-9367-2022-2(8)-69-92 (in Russian) VarenikA.V. KondratyevS.I. MedvedevE.V. KhoruzhiiD.S. OrekhovaN.A. Characteristics of State and Evolution of the Black Sea Hydrochemical Structure Physical Oceanography 2023 30 6 826 850 GrégoireM. SoetaertK. NezlinN. KostianoyA. Modeling the Nitrogen Cycling and Plankton Productivity in an Enclosed Environment (The Black Sea) Using a Three-Dimensional Coupled Hydrodynamical-Ecosystem Model Journal of Geophysical Research: Oceans 2004 109 C5 C05007 10.1029/2001JC001014 TsiarasK.P. KourafalouV.H. DavidovA. StanevaJ. A Three-Dimensional Coupled Model of the Western Black Sea Plankton Dynamics: Seasonal Variability and Comparison to SeaWiFS Data Journal of Geophysical Research: Oceans 2008 113 C7 C07007 10.1029/2006JC003959 DorofeevV.L. Modeling of Decadal Variations in the Black-Sea Ecosystem Physical Oceanography 2009 19 6 400 409 10.1007/s11110-010-9062-6 CapetA. MeysmanF.J.R. AkoumaniakI. SoetaertK. GrégoireM. Integrating Sediment Biogeochemistry into 3D Oceanic Models: A Study of Benthic-Pelagic Coupling in the Black Sea Ocean Modelling 2016 101 83 100 10.1016/j.ocemod.2016.03.006 AumontO. EthéC. TagliabueA. BoppL. GehlenM. PISCES-v2: An Ocean Biogeochemical Model for Carbon and Ecosystem Studies Geoscientific Model Development 2015 8 8 2465 2513 10.5194/gmd-8-2465-2015 Van den MeerscheK. MiddelburgJ.J. SoetaertK. Van RijswijkP. BoschkerH.T.S. HeipC.H.R. Carbon Nitrogen Coupling and Algal-Bacterial Interactions during an Experimental Bloom: Modeling a ¹³C Tracer Experiment Limnology and Oceanography 2004 49 3 862 878 10.4319/lo.2004.49.3.0862 DorofeyevV. SukhikhL. A Model for Monitoring the Evolution of the Black Sea Ecosystem on the Basis of Remote Sensing Data Assimilation International Journal of Remote Sensing 2018 39 24 9339 9355 10.1080/01431161.2018.1523589 DorofeevV.L. SukhikhL.I. Studying Long-Term Variations in Black-Sea Ecosystem Based on the Assimilation of Remote Sensing Data in a Numerical Model Water Resources 2019 46 1 65 75 10.1134/S0097807819010032 GrégoireM. RaickC. SoetaertK. Numerical Modeling of the Central Black Sea Ecosystem Functioning During the Eutrophication Phase Progress in Oceanography 2008 76 3 286 333 10.1016/j.pocean.2008.01.002 DorofeevV.L. SukhikhL.I. Analysis of Long-Term Variability of Hydrodynamic Fields in the Upper 200-Meter Layer of the Black Sea Based on the Reanalysis Results Physical Oceanography 2023 30 5 581 593 MilleroF.J. The Marine Inorganic Carbon Cycle Chemical Reviews 2007 107 2 308 341 10.1021/cr0503557 TakahashiT. SutherlandS.C. WanninkhofR. SweeneyC. FeelyR.A. ChipmanD.W. HalesB. FriederichG. ChavezF. Climatological Mean and Decadal Changes in Surface Ocean pCO₂ and Net Sea-Air CO₂ Flux over the Global Oceans Deep-Sea Research II: Topical Studies in Oceanography 2009 56 8-10 554 577 10.1016/j.dsr2.2008.12.009 ZabegaevI.A. MedvedevE.V. Equilibrium Partial Pressure of Carbon Dioxide in the Surface Water Layer of the Northern Black Sea Based on Direct Observations in 2017 Seas of Russia: Fundamental and Applied Studies. Proceedings of the All-Russian Scientific Conference 2019 76 78 (in Russian)