Acidification of the Nordic Seas

Author:

Fransner FilippaORCID,Fröb FriederikeORCID,Tjiputra JerryORCID,Goris NadineORCID,Lauvset Siv K.ORCID,Skjelvan IngunnORCID,Jeansson EmilORCID,Omar Abdirahman,Chierici MelissaORCID,Jones Elizabeth,Fransson AgnetaORCID,Ólafsdóttir Sólveig R.ORCID,Johannessen Truls,Olsen AreORCID

Abstract

Abstract. Due to low calcium carbonate saturation states, and winter mixing that brings anthropogenic carbon to the deep ocean, the Nordic Seas and their cold-water corals are vulnerable to ocean acidification. Here, we present a detailed investigation of the changes in pH and aragonite saturation in the Nordic Seas from preindustrial times to 2100, by using in situ observations, gridded climatological data, and projections for three different future scenarios with the Norwegian Earth System Model (NorESM1-ME). During the period of regular ocean biogeochemistry observations from 1981–2019, the pH decreased with rates of 2–3 × 10−3 yr−1 in the upper 200 m of the Nordic Seas. In some regions, the pH decrease can be detected down to 2000 m depth. This resulted in a decrease in the aragonite saturation state, which is now close to undersaturation in the depth layer of 1000–2000 m. The model simulations suggest that the pH of the Nordic Seas will decrease at an overall faster rate than the global ocean from the preindustrial era to 2100, bringing the Nordic Seas' pH closer to the global average. In the esmRCP8.5 scenario, the whole water column is projected to be undersaturated with respect to aragonite at the end of the 21st century, thereby endangering all cold-water corals of the Nordic Seas. In the esmRCP4.5 scenario, the deepest cold-water coral reefs are projected to be exposed to undersaturation. Exposure of all cold-water corals to corrosive waters can only be avoided with marginal under the esmRCP2.6 scenario. Over all timescales, the main driver of the pH drop is the increase in dissolved inorganic carbon (CT) caused by the raising anthropogenic CO2, followed by the temperature increase. Thermodynamic salinity effects are of secondary importance. We find substantial changes in total alkalinity (AT) and CT as a result of the salinification, or decreased freshwater content, of the Atlantic water during all time periods, and as a result of an increased freshwater export in polar waters in past and future scenarios. However, the net impact of this decrease (increase) in freshwater content on pH is negligible, as the effects of a concentration (dilution) of CT and AT are canceling.

Funder

Norges Forskningsråd

European Commission

Publisher

Copernicus GmbH

Subject

Earth-Surface Processes,Ecology, Evolution, Behavior and Systematics

Reference161 articles.

1. Allison, N., Cohen, I., Finch, A., Erez, J., and Tudhope, A.: Corals concentrate dissolved inorganic carbon to facilitate calcification, Nat. Commun., 5, 5741, https://doi.org/10.1038/ncomms6741, 2014. a

2. Anderson, L. G.: Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the LANCE in the Barents Sea from 1986-07-19 to 1986-07-26 (NCEI Accession 0113910), NOAA National Centers for Environmental Information [data set], https://doi.org/10.3334/cdiac/otg.carina_58la19860719, 2013a. a

3. Anderson, L. G.: Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the ODEN in the Arctic Ocean, Barents Sea and others from 2002-04-20 to 2002-06-06 (NCEI Accession 0113590), NOAA National Centers for Environmental Information [data set], https://doi.org/10.3334/cdiac/otg.carina_77dn20020420, 2013b. a

4. Anderson, L. G. and Olsen, A.: Air–sea flux of anthropogenic carbon dioxide in the North Atlantic, Geophys. Res. Lett., 29, 16-1–16-4, https://doi.org/10.1029/2002GL014820, 2002. a, b, c

5. Anderson, L. G., Blindheim, J., and Rey, F.: Dissolved inorganic carbon, pH, alkalinity, temperature, salinity and other variables collected from discrete sample and profile observations using CTD, bottle and other instruments from the JOHAN HJORT in the North Greenland Sea and Norwegian Sea from 1997-04-14 to 1997-05-22 (NCEI Accession 0113563), NOAA National Centers for Environmental Information [data set], https://doi.org/10.3334/cdiac/otg.carina_58jh19970414, 2013a. a

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3