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Henson HC, Holding JM, Meire L, Rysgaard S, Stedmon CA, Stuart-Lee A, Bendtsen J, Sejr M. Coastal freshening drives acidification state in Greenland fjords. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 855:158962. [PMID: 36170921 DOI: 10.1016/j.scitotenv.2022.158962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 09/19/2022] [Indexed: 06/16/2023]
Abstract
Greenland's fjords and coastal waters are highly productive and sustain important fisheries. However, retreating glaciers and increasing meltwater are changing fjord circulation and biogeochemistry, which may threaten future productivity. The freshening of Greenland fjords caused by unprecedented melting of the Greenland Ice Sheet may alter carbonate chemistry in coastal waters, influencing CO2 uptake and causing biological consequences from acidification. However, few studies to date explore the current acidification state in Greenland coastal waters. Here we present the first-ever large-scale measurements of carbonate system parameters in 16 Greenlandic fjords and seek to identify the drivers of acidification state in these freshening ecosystems. Aragonite saturation state (Ω), a proxy for ocean acidification, was calculated from dissolved inorganic carbon (DIC) and total alkalinity from fjords along the east and west coast of Greenland spanning 68-75°N. Aragonite saturation was primarily >1 in the surface mixed layer. However, undersaturated-or corrosive--conditions (Ω < 1) were observed on both coasts (west: Ω = 0.28-3.11, east: Ω = 0.70-3.07), albeit at different depths. West Greenland fjords were largely corrosive at depth while undersaturation in East Greenland fjords was only observed in surface waters. This reflects a difference in the coastal boundary conditions and mechanisms driving acidification state. We suggest that advection of Sub Polar Mode Water and accumulation of DIC from organic matter decomposition drive corrosive conditions in the West, while freshwater alkalinity dilution drives acidification in the East. The presence of marine terminating glaciers also impacted local acidification states by influencing fjord circulation: upwelling driven by subglacial discharge brought corrosive bottom waters to shallower depths. Meanwhile, discharge from land terminating glaciers strengthened stratification and diluted alkalinity. Regardless of the drivers in each system, increasing freshwater discharge will likely lower carbonate saturation states and impact biotic and abiotic carbon uptake in the future.
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Affiliation(s)
| | - Johnna M Holding
- Arctic Research Centre, Aarhus University, Denmark; Department of Ecoscience, Aarhus University, Denmark
| | - Lorenz Meire
- Department of Estuarine and Delta Systems, Royal Netherlands Institute for Sea Research, Yerseke, the Netherlands; Greenland Climate Research Centre, Greenland Institute of Natural Resources, Nuuk, Greenland
| | | | - Colin A Stedmon
- National Institute of Aquatic Resources, Technical University of Denmark, Lyngby, Denmark
| | - Alice Stuart-Lee
- Department of Estuarine and Delta Systems, Royal Netherlands Institute for Sea Research, Yerseke, the Netherlands
| | - Jørgen Bendtsen
- Globe Institute, University of Copenhagen, Copenhagen, Denmark
| | - Mikael Sejr
- Arctic Research Centre, Aarhus University, Denmark; Department of Ecoscience, Aarhus University, Denmark
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Mo A, Kim D, Yang EJ, Jung J, Ko YH, Kang SH, Cho KH, Park K, Kim TW. Factors affecting the subsurface aragonite undersaturation layer in the Pacific Arctic region. MARINE POLLUTION BULLETIN 2022; 183:114060. [PMID: 36027628 DOI: 10.1016/j.marpolbul.2022.114060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 08/08/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
This study evaluated interannual variation in the subsurface aragonite undersaturation zone (ΩAr<1 layer) in the Pacific Arctic Ocean, using data from the 2016-2019 period. The upper boundary (DEPΩ<1UB) of the ΩAr<1 layer generally formed at a depth where the contribution of corrosive Pacific water was approximately 98 %. The intensity of the Beaufort Gyre associated with freshwater accumulation mainly determined interannual variation in DEPΩ<1UB, but the direction of its effect was opposite west and east of ~166°W. The lower boundary (DEPΩ<1LB) of the ΩAr<1 layer was generally found at a depth range where equal contributions of Pacific and Atlantic water were expected. An Atlantic-origin cold saline water intrusion event in 2017 caused by an anomalous atmospheric circulation pattern significantly lifted the DEPΩ<1LB, thus the thickness of the ΩAr<1 layer decreased.
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Affiliation(s)
- Ahra Mo
- Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Republic of Korea; Division of Polar Ocean Sciences, Korea Polar Research Institute, Incheon 21990, Republic of Korea
| | - Dongseon Kim
- Marine Environmental Research Center, Korea Institute of Ocean Science & Technology, Busan 49111, Republic of Korea
| | - Eun Jin Yang
- Division of Polar Ocean Sciences, Korea Polar Research Institute, Incheon 21990, Republic of Korea
| | - Jinyoung Jung
- Division of Polar Ocean Sciences, Korea Polar Research Institute, Incheon 21990, Republic of Korea
| | - Young Ho Ko
- OJEong Resilience Institute, Korea University, Seoul 02841, Republic of Korea
| | - Sung-Ho Kang
- Division of Polar Ocean Sciences, Korea Polar Research Institute, Incheon 21990, Republic of Korea
| | - Kyoung-Ho Cho
- Division of Polar Ocean Sciences, Korea Polar Research Institute, Incheon 21990, Republic of Korea
| | - Keyhong Park
- Division of Polar Ocean Sciences, Korea Polar Research Institute, Incheon 21990, Republic of Korea
| | - Tae-Wook Kim
- Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Republic of Korea; OJEong Resilience Institute, Korea University, Seoul 02841, Republic of Korea.
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Ocean Deacidification Technologies for Marine Aquaculture. JOURNAL OF MARINE SCIENCE AND ENGINEERING 2022. [DOI: 10.3390/jmse10040523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
The increase in partial pressure of CO2 in the oceans directly affects the productivity and survival of coastal industries and ecosystems. For marine aquaculture, the decreased alkalinity of seawater results in reduced availability of carbonates for marine organisms to build their shells, leading to decreased aquaculture quality and productivity. The industry has been implementing recirculating aquaculture systems (RASs) to reduce CO2 in feedwaters, but recent interest in ocean-based CO2 capture has led to additional strategies that may be relevant. The new methods in addition to CO2 removal offer capture options for enhanced aquaculture sustainability. Here, we review and compare early-stage and commercially available technologies for deacidification of seawater and their suitability for aquaculture. Most methods considered rely on a voltage-induced pH swing to shift the carbonate/bicarbonate equilibrium toward the release of CO2, with subsequent capture of the released CO2 as a gas or as solid mineral carbonates. The modular design and distributed deployment potential of these systems offers promise, but current demonstrations are limited to bench scale, highlighting the need for sustained research and development before they can be implemented for marine aquaculture.
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Abirami B, Radhakrishnan M, Kumaran S, Wilson A. Impacts of global warming on marine microbial communities. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 791:147905. [PMID: 34126492 DOI: 10.1016/j.scitotenv.2021.147905] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 04/26/2021] [Accepted: 05/16/2021] [Indexed: 06/12/2023]
Abstract
Global warming in ocean ecosystems alters temperature, acidification, oxygen content, circulation, stratification, and nutrient inputs. Microorganisms play a dominant role in global biogeochemical cycles crucial for a planet's sustainability. Since microbial communities are highly dependent on the temperature factor, fluctuations in the same will lead to adverse effects on the microbial community organization. Throughout the Ocean, increase in evaporation rates causes the surface mixed layer to become shallower. This intensified stratification inhibits vertical transport of nutrient supplies. Such density driven processes will decrease oxygen solubility in surface waters leading to significant decrease of oxygen from future Ocean. Metabolism and diversity of microbes along with ocean biogeochemistry will be at great risk due to global warming and its related effects. As a response to the changes in temperature, alteration in the distribution of phytoplankta communities is observed all over the planet, creating changes in the primary production of the ocean causing massive impact on the biosphere. Marine microbial communities try to adapt to the changing ocean environmental conditions by responding with biogeographic range shifts, community structure modifications, and adaptive evolution. Persistence of this climate change on ocean ecosystems, in future, will pose serious threat to the metabolism and distribution of marine microbes leading to fluctuations in the biogeochemical cycles thereby affecting the overall ecosystem functioning. Genomics plays an important role in marine microbial research by providing tools to study the association between environment and organisms. The ecological and genomic perspectives of marine microbes are being investigated to design effective models to understand their physiology and evolution in a changing ocean. Mesocosm/microcosm experimental studies and field studies are in the need of the hour to evaluate the impact of climate shifts on microbial genesis.
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Affiliation(s)
- Baskaran Abirami
- Centre for Drug Discovery and Development, Sathyabama Institute of Science and Technology, Chennai 600 119, Tamil Nadu, India
| | - Manikkam Radhakrishnan
- Centre for Drug Discovery and Development, Sathyabama Institute of Science and Technology, Chennai 600 119, Tamil Nadu, India
| | - Subramanian Kumaran
- Centre for Drug Discovery and Development, Sathyabama Institute of Science and Technology, Chennai 600 119, Tamil Nadu, India
| | - Aruni Wilson
- Sathyabama Institute of Science and Technology, Chennai 600119, Tamil Nadu, India; School of Medicine, Loma Linda University, CA, USA; Musculoskeletal Disease Research Laboratory, US Department of Veteran Affairs, Loma Linda, CA, USA.
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Choi Y, Cho S, Kim D. Seasonal variation in aragonite saturation states and the controlling factors in the southeastern Yellow Sea. MARINE POLLUTION BULLETIN 2020; 150:110695. [PMID: 31740181 DOI: 10.1016/j.marpolbul.2019.110695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 10/18/2019] [Accepted: 10/25/2019] [Indexed: 06/10/2023]
Abstract
The aragonite saturation state (Ωarag) was determined to assess its seasonal variations and the major controlling factors in the southeastern Yellow Sea (YS) over four seasons. Ωarag showed large seasonal variation in the surface waters, with dissolved inorganic carbon (DIC) as a major factor controlling the seasonal variation. In the bottom waters, Ωarag exhibited only small seasonal variation compared with the surface waters; DIC and total alkalinity were the main factors contributing to the variation. The bottom water of the southeastern YS was undersaturated with aragonite during the fall, even though the southeastern YS was not typically associated with upwelling, freshwater discharge, or eutrophication processes. Aragonite undersaturation was most likely due to ocean dumping of organic materials. Therefore, ocean pumping should be prohibited in shallow marginal seas to prevent aragonite undersaturation.
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Affiliation(s)
- Yujeong Choi
- Marine Environmental Research Center, Korea Institute of Ocean Science & Technology, Haeyang-ro 385, Yeongdo-gu, Busan, South Korea; Department of Ocean Science, University of Science and Technology, Gajeong-ro 217, Yuseong-gu, Daejeon, South Korea
| | - Sosul Cho
- Marine Environmental Research Center, Korea Institute of Ocean Science & Technology, Haeyang-ro 385, Yeongdo-gu, Busan, South Korea
| | - Dongseon Kim
- Marine Environmental Research Center, Korea Institute of Ocean Science & Technology, Haeyang-ro 385, Yeongdo-gu, Busan, South Korea; Department of Ocean Science, University of Science and Technology, Gajeong-ro 217, Yuseong-gu, Daejeon, South Korea.
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Lowe AT, Bos J, Ruesink J. Ecosystem metabolism drives pH variability and modulates long-term ocean acidification in the Northeast Pacific coastal ocean. Sci Rep 2019; 9:963. [PMID: 30700764 PMCID: PMC6353961 DOI: 10.1038/s41598-018-37764-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 12/12/2018] [Indexed: 11/24/2022] Open
Abstract
Ocean acidification poses serious threats to coastal ecosystem services, yet few empirical studies have investigated how local ecological processes may modulate global changes of pH from rising atmospheric CO2. We quantified patterns of pH variability as a function of atmospheric CO2 and local physical and biological processes at 83 sites over 25 years in the Salish Sea and two NE Pacific estuaries. Mean seawater pH decreased significantly at −0.009 ± 0.0005 pH yr−1 (0.22 pH over 25 years), with spatially variable rates ranging up to 10 times greater than atmospheric CO2-driven ocean acidification. Dissolved oxygen saturation (%DO) decreased by −0.24 ± 0.036% yr−1, with site-specific trends similar to pH. Mean pH shifted from <7.6 in winter to >8.0 in summer concomitant to the seasonal shift from heterotrophy (%DO < 100) to autotrophy (%DO > 100) and dramatic shifts in aragonite saturation state critical to shell-forming organisms (probability of undersaturation was >80% in winter, but <20% in summer). %DO overwhelmed the influence of atmospheric CO2, temperature and salinity on pH across scales. Collectively, these observations provide evidence that local ecosystem processes modulate ocean acidification, and support the adoption of an ecosystem perspective to ocean acidification and multiple stressors in productive aquatic habitats.
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Affiliation(s)
- Alexander T Lowe
- Tennenbaum Marine Observatories Network, Smithsonian Institution, 647 Contees Wharf Road, Edgewater, MD, 21307, USA. .,Department of Biology, University of Washington, 24 Kincaid Hall, Seattle, WA, 98195, USA.
| | - Julia Bos
- Washington Department of Ecology, 300 Desmond Dr. SE, Lacey, WA, 98503, USA
| | - Jennifer Ruesink
- Department of Biology, University of Washington, 24 Kincaid Hall, Seattle, WA, 98195, USA
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Kim D, Park GH, Baek SH, Choi Y, Kim TW. Physical and biological control of aragonite saturation in the coastal waters of southern South Korea under the influence of freshwater. MARINE POLLUTION BULLETIN 2018; 129:318-328. [PMID: 29680554 DOI: 10.1016/j.marpolbul.2018.02.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 02/08/2018] [Accepted: 02/21/2018] [Indexed: 06/08/2023]
Abstract
We investigated the aragonite saturation state (Ωarag) during all four seasons in a coastal region of southern Korea that receives considerable freshwater input. The surface Ωarag values were higher during productive seasons with enhanced freshwater influences, likely due to an increased net removal of dissolved inorganic carbon (DIC) from the water column (i.e., biological control). In addition, during the productive seasons, enhancement of Ωarag was observed with decreasing salinity within a linear mixing zone present between river-influenced surface and saltier bottom waters. DIC appeared to be effectively sequestered from the warmer, less salty surface water by downward flux of organic matter, but not significantly affected by the relatively DIC-rich, cooler and saltier bottom waters under strong stratification conditions during these seasons (i.e., physical control). Low phytoplankton productivity and seasonal breakdown of the stratification caused reduced saturation in other seasons and made the study area a weak sink for atmospheric CO2.
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Affiliation(s)
- Dongseon Kim
- Marine Chemistry & Geochemistry Research Center, Korea Institute of Ocean Science & Technology, Ansan, South Korea
| | - Geun-Ha Park
- Marine Chemistry & Geochemistry Research Center, Korea Institute of Ocean Science & Technology, Ansan, South Korea
| | - Seung Ho Baek
- South Sea Institute, Korea Institute of Ocean Science & Technology, Geoje, South Korea
| | - Yujeong Choi
- Marine Chemistry & Geochemistry Research Center, Korea Institute of Ocean Science & Technology, Ansan, South Korea
| | - Tae-Wook Kim
- Department of Marine Science, Incheon National University, Incheon, South Korea; Division of Environmental Science and Ecological Engineering, Korea University, Seoul, South Korea.
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8
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Overwintering individuals of the Arctic krill Thysanoessa inermis appear tolerant to short-term exposure to low pH conditions. Polar Biol 2017. [DOI: 10.1007/s00300-017-2194-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Abstract
The large diversity of marine microorganisms harboured by oceans plays an important role in planet sustainability by driving globally important biogeochemical cycles; all primary and most secondary production in the oceans is performed by microorganisms. The largest part of the planet is covered by cold environments; consequently, cold-adapted microorganisms have crucial functional roles in globally important environmental processes and biogeochemical cycles cold-adapted extremophiles are a remarkable model to shed light on the molecular basis of survival at low temperature. The indigenous populations of Antarctic and Arctic microorganisms are endowed with genetic and physiological traits that allow them to live and effectively compete at the temperatures prevailing in polar regions. Some genes, e.g. glycosyltransferases and glycosylsynthetases involved in the architecture of the cell wall, may have been acquired/retained during evolution of polar strains or lost in tropical strains. This present work focusses on temperature and its role in shaping microbial adaptations; however, in assessing the impacts of climate changes on microbial diversity and biogeochemical cycles in polar oceans, it should not be forgotten that physiological studies need to include the interaction of temperature with other abiotic and biotic factors.
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10
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Chen Y, Zhang L, Xu C, Vaidyanathan S. Dissolved inorganic carbon speciation in aquatic environments and its application to monitor algal carbon uptake. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 541:1282-1295. [PMID: 26476067 DOI: 10.1016/j.scitotenv.2015.10.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 10/06/2015] [Accepted: 10/06/2015] [Indexed: 06/05/2023]
Abstract
Dissolved inorganic carbon (DIC) speciation is an important parameter that enables chemical and ecological changes in aquatic environments, such as the aquatic environmental impact of increasing atmospheric CO2 levels, to be monitored. We have examined and developed a sensitive and cost-effective 'back-titration' method to determine the DIC species and abundance in aqueous environments that is more accurate and reproducible than existing methods and is applicable in a range of fresh, brackish and sea waters. We propose the use of pHHCO3 (bicarbonate-dominant pH) and pH3.5 as the titration end points in the back-titration technique to accurately determine carbonate alkalinity. The proposed method has a higher accuracy and precision than other modified Gran's methods that are currently in use. The detection limit was found to be ~5 μmol kg(-1) with an accuracy within 1% and a precision (CV) within 0.2% and 0.5% at high and low level of carbonates, respectively. This method was successfully applied to monitor DIC in the aqueous medium of Nannochlopsis salina cultivation separately carried out with NaHCO3 and CO2 as the respective inorganic carbon source. The cells were able to grow in the NaHCO3 medium with a similar growth curve to cells with 0.039% CO2 (air). Increases in CO2 level stimulated lipid accumulation by diverting the fixed carbon from protein to lipids. The increased concentration of gaseous CO2 and the accompanying lower pH appears to significantly inhibit the growth of algae despite the presence of HCO3(-) when 20% CO2 was employed.
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Affiliation(s)
- Yimin Chen
- Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, People's Republic of China; ChELSI Institute, Advanced Biomanufacturing Centre, Department of Chemical and Biological Engineering, The University of Sheffield, Sheffield S1 3JD, UK; School of Environmental Science and Engineering, Liaoning Technical University, No. 47, Zhong Hua Rd, Fuxin City, Liaoning Province 123000, People's Republic of China.
| | - Liang Zhang
- School of Environmental Science and Engineering, Liaoning Technical University, No. 47, Zhong Hua Rd, Fuxin City, Liaoning Province 123000, People's Republic of China
| | - Changan Xu
- Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, People's Republic of China.
| | - Seetharaman Vaidyanathan
- ChELSI Institute, Advanced Biomanufacturing Centre, Department of Chemical and Biological Engineering, The University of Sheffield, Sheffield S1 3JD, UK.
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Monier A, Findlay HS, Charvet S, Lovejoy C. Late winter under ice pelagic microbial communities in the high Arctic Ocean and the impact of short-term exposure to elevated CO2 levels. Front Microbiol 2014; 5:490. [PMID: 25324832 PMCID: PMC4179612 DOI: 10.3389/fmicb.2014.00490] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 09/01/2014] [Indexed: 11/13/2022] Open
Abstract
Polar Oceans are natural CO2 sinks because of the enhanced solubility of CO2 in cold water. The Arctic Ocean is at additional risk of accelerated ocean acidification (OA) because of freshwater inputs from sea ice and rivers, which influence the carbonate system. Winter conditions in the Arctic are of interest because of both cold temperatures and limited CO2 venting to the atmosphere when sea ice is present. Earlier OA experiments on Arctic microbial communities conducted in the absence of ice cover, hinted at shifts in taxa dominance and diversity under lowered pH. The Catlin Arctic Survey provided an opportunity to conduct in situ, under-ice, OA experiments during late Arctic winter. Seawater was collected from under the sea ice off Ellef Ringnes Island, and communities were exposed to three CO2 levels for 6 days. Phylogenetic diversity was greater in the attached fraction compared to the free-living fraction in situ, in the controls and in the treatments. The dominant taxa in all cases were Gammaproteobacteria but acidification had little effect compared to the effects of containment. Phylogenetic net relatedness indices suggested that acidification may have decreased the diversity within some bacterial orders, but overall there was no clear trend. Within the experimental communities, alkalinity best explained the variance among samples and replicates, suggesting subtle changes in the carbonate system need to be considered in such experiments. We conclude that under ice communities have the capacity to respond either by selection or phenotypic plasticity to heightened CO2 levels over the short term.
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Affiliation(s)
- Adam Monier
- Département de Biologie, Québec Océan and Institut de Biologie Intégrative et des Systèmes, Université Laval Québec, QC, Canada ; Takuvik Joint International Laboratory (CNRS UMI-3376), Université Laval Québec, QC, Canada
| | | | - Sophie Charvet
- Département de Biologie, Québec Océan and Institut de Biologie Intégrative et des Systèmes, Université Laval Québec, QC, Canada
| | - Connie Lovejoy
- Département de Biologie, Québec Océan and Institut de Biologie Intégrative et des Systèmes, Université Laval Québec, QC, Canada ; Takuvik Joint International Laboratory (CNRS UMI-3376), Université Laval Québec, QC, Canada
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Gazeau F, van Rijswijk P, Pozzato L, Middelburg JJ. Impacts of ocean acidification on sediment processes in shallow waters of the Arctic Ocean. PLoS One 2014; 9:e94068. [PMID: 24718610 PMCID: PMC3981760 DOI: 10.1371/journal.pone.0094068] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 03/10/2014] [Indexed: 11/18/2022] Open
Abstract
Despite the important roles of shallow-water sediments in global biogeochemical cycling, the effects of ocean acidification on sedimentary processes have received relatively little attention. As high-latitude cold waters can absorb more CO2 and usually have a lower buffering capacity than warmer waters, acidification rates in these areas are faster than those in sub-tropical regions. The present study investigates the effects of ocean acidification on sediment composition, processes and sediment-water fluxes in an Arctic coastal system. Undisturbed sediment cores, exempt of large dwelling organisms, were collected, incubated for a period of 14 days, and subject to a gradient of pCO2 covering the range of values projected for the end of the century. On five occasions during the experimental period, the sediment cores were isolated for flux measurements (oxygen, alkalinity, dissolved inorganic carbon, ammonium, nitrate, nitrite, phosphate and silicate). At the end of the experimental period, denitrification rates were measured and sediment samples were taken at several depth intervals for solid-phase analyses. Most of the parameters and processes (i.e. mineralization, denitrification) investigated showed no relationship with the overlying seawater pH, suggesting that ocean acidification will have limited impacts on the microbial activity and associated sediment-water fluxes on Arctic shelves, in the absence of active bio-irrigating organisms. Only following a pH decrease of 1 pH unit, not foreseen in the coming 300 years, significant enhancements of calcium carbonate dissolution and anammox rates were observed. Longer-term experiments on different sediment types are still required to confirm the limited impact of ocean acidification on shallow Arctic sediment processes as observed in this study.
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Affiliation(s)
- Frédéric Gazeau
- Sorbonne Universités, Université Pierre et Marie Curie-Paris 06, Laboratoire d'Océanographie de Villefranche, Observatoire océanologique, Villefranche/mer, France
- Centre National de la Recherche Scientifique-Institut National des Sciences de l'Univers, Laboratoire d'Océanographie de Villefranche, Observatoire océanologique, Villefranche/mer, France
- * E-mail:
| | - Pieter van Rijswijk
- Department of Ecosystem Studies, Royal Netherlands Institute for Sea Research, Yerseke, The Netherlands
| | - Lara Pozzato
- Department of Ecosystem Studies, Royal Netherlands Institute for Sea Research, Yerseke, The Netherlands
| | - Jack J. Middelburg
- Department of Ecosystem Studies, Royal Netherlands Institute for Sea Research, Yerseke, The Netherlands
- Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands
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Robbins LL, Wynn JG, Lisle JT, Yates KK, Knorr PO, Byrne RH, Liu X, Patsavas MC, Azetsu-Scott K, Takahashi T. Baseline monitoring of the western Arctic Ocean estimates 20% of Canadian basin surface waters are undersaturated with respect to aragonite. PLoS One 2013; 8:e73796. [PMID: 24040074 PMCID: PMC3770696 DOI: 10.1371/journal.pone.0073796] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 07/25/2013] [Indexed: 11/18/2022] Open
Abstract
Marine surface waters are being acidified due to uptake of anthropogenic carbon dioxide, resulting in surface ocean areas of undersaturation with respect to carbonate minerals, including aragonite. In the Arctic Ocean, acidification is expected to occur at an accelerated rate with respect to the global oceans, but a paucity of baseline data has limited our understanding of the extent of Arctic undersaturation and of regional variations in rates and causes. The lack of data has also hindered refinement of models aimed at projecting future trends of ocean acidification. Here, based on more than 34,000 data records collected in 2010 and 2011, we establish a baseline of inorganic carbon data (pH, total alkalinity, dissolved inorganic carbon, partial pressure of carbon dioxide, and aragonite saturation index) for the western Arctic Ocean. This data set documents aragonite undersaturation in ∼20% of the surface waters of the combined Canada and Makarov basins, an area characterized by recent acceleration of sea ice loss. Conservative tracer studies using stable oxygen isotopic data from 307 sites show that while the entire surface of this area receives abundant freshwater from meteoric sources, freshwater from sea ice melt is most closely linked to the areas of carbonate mineral undersaturation. These data link the Arctic Ocean’s largest area of aragonite undersaturation to sea ice melt and atmospheric CO2 absorption in areas of low buffering capacity. Some relatively supersaturated areas can be linked to localized biological activity. Collectively, these observations can be used to project trends of ocean acidification in higher latitude marine surface waters where inorganic carbon chemistry is largely influenced by sea ice meltwater.
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Affiliation(s)
- Lisa L. Robbins
- St. Petersburg Coastal and Marine Science Center, United States Geological Survey, St. Petersburg, Florida, United States of America
- * E-mail:
| | - Jonathan G. Wynn
- Department of Geology, University of South Florida, Tampa, Florida, United States of America
| | - John T. Lisle
- St. Petersburg Coastal and Marine Science Center, United States Geological Survey, St. Petersburg, Florida, United States of America
| | - Kimberly K. Yates
- St. Petersburg Coastal and Marine Science Center, United States Geological Survey, St. Petersburg, Florida, United States of America
| | - Paul O. Knorr
- St. Petersburg Coastal and Marine Science Center, United States Geological Survey, St. Petersburg, Florida, United States of America
| | - Robert H. Byrne
- College of Marine Science, University of South Florida, St. Petersburg, Florida, United States of America
| | - Xuewu Liu
- College of Marine Science, University of South Florida, St. Petersburg, Florida, United States of America
| | - Mark C. Patsavas
- College of Marine Science, University of South Florida, St. Petersburg, Florida, United States of America
| | - Kumiko Azetsu-Scott
- Ocean Sciences Division, Department of Fisheries and Oceans, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada
| | - Taro Takahashi
- Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York, United States of America
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Mathis JT, Cross JN, Bates NR. Coupling primary production and terrestrial runoff to ocean acidification and carbonate mineral suppression in the eastern Bering Sea. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jc006453] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Azetsu-Scott K, Clarke A, Falkner K, Hamilton J, Jones EP, Lee C, Petrie B, Prinsenberg S, Starr M, Yeats P. Calcium carbonate saturation states in the waters of the Canadian Arctic Archipelago and the Labrador Sea. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009jc005917] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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