Seasonal controls of aragonite saturation states in the Gulf of Maine
Wang, Zhaohui Aleck
Lawson, Gareth L.
Pilskaln, Cynthia H.
Maas, Amy E.
MetadataShow full item record
KeywordOcean acidification; Carbonate chemistry; Aragonite saturation; Pteropod; Gulf of Maine; Wilkinson Basin
The Gulf of Maine (GoME) is a shelf region especially vulnerable to ocean acidification (OA) due to natural conditions of low pH and aragonite saturation states (Ω-Ar). This study is the first to assess the major oceanic processes controlling seasonal variability of the carbonate system and its linkages with pteropod abundance in Wilkinson Basin in the GoME. Two years of seasonal sampling cruises suggest that water-column carbonate chemistry in the region undergoes a seasonal cycle, wherein the annual cycle of stratification-overturn, primary production, respiration-remineralization and mixing all play important roles, at distinct spatiotemporal scales. Surface production was tightly coupled with remineralization in the benthic nepheloid layer during high production seasons, which results in occasional aragonite undersaturation. From spring to summer, carbonate chemistry in the surface across Wilkinson Basin reflects a transition from a production-respiration balanced system to a net autotropic system. Mean water-column Ω-Ar and abundance of large thecosomatous pteropods show some correlation, although patchiness and discrete cohort reproductive success likely also influence their abundance. Overall, photosynthesis-respiration is the primary driving force controlling Ω-Ar variability during the spring-to-summer transition as well as over the seasonal cycle. However, calcium carbonate (CaCO3) dissolution appears to occur near bottom in fall and winter when bottom water Ω-Ar is generally low but slightly above 1. This is accompanied by a decrease in pteropod abundance that is consistent with previous CaCO3 flux trap measurements. The region might experience persistent subsurface aragonite undersaturation in 30–40 years under continued ocean acidification.
Author Posting. © American Geophysical Union, 2017. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 122 (2017): 372–389, doi:10.1002/2016JC012373.
Suggested CitationArticle: Wang, Zhaohui Aleck, Lawson, Gareth L., Pilskaln, Cynthia H., Maas, Amy E., "Seasonal controls of aragonite saturation states in the Gulf of Maine", Journal of Geophysical Research: Oceans 122 (2017): 372–389, DOI:10.1002/2016JC012373, https://hdl.handle.net/1912/8874
Showing items related by title, author, creator and subject.
Variations in coral reef net community calcification and aragonite saturation state on local and global scales Bernstein, Whitney N. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2013-09)Predicting the response of net community calcification (NCC) to ocean acidification (OA) and declining aragonite saturation state (Ωa) requires a thorough understanding of controls on NCC. The diurnal control of light ...
Cook, Ann E.; Waite, William F. (John Wiley & Sons, 2018-02-17)Accurately quantifying the amount of naturally occurring gas hydrate in marine and permafrost environments is important for assessing its resource potential and understanding the role of gas hydrate in the global carbon ...
The impact of seawater saturation state and bicarbonate ion concentration on calcification by new recruits of two Atlantic corals de Putron, Samantha J.; McCorkle, Daniel C.; Cohen, Anne L.; Dillon, A. B. (2010-11-05)Rising concentrations of atmospheric CO2 are changing the carbonate chemistry of the oceans, a process known as ocean acidification (OA). Absorption of this CO2 by the surface oceans is increasing the amount of total ...