Using B isotopes and B/Ca in corals from low saturation springs to constrain calcification mechanisms.

ABSTRACT: Ocean acidification is expected to negatively impact calcifying organisms, yet we lack understanding of their acclimation potential in the natural environment. Here we measured geochemical proxies (?¹¹B and B/Ca) in Porites astreoides corals that have been growing for their entire life under low aragonite saturation (?_sw: 0.77-1.85). This allowed us to assess the ability of these corals to manipulate the chemical conditions at the site of calcification (?_cf), and hence their potential to acclimate to changing ?_sw. We show that lifelong exposure to low ?_sw did not enable the corals to acclimate and reach similar ?_cf as corals grown under ambient conditions. The lower ?_cf at the site of calcification can explain a large proportion of the decreasing P. astreoides calcification rates at low ?_sw. The naturally elevated seawater dissolved inorganic carbon concentration at this study site shed light on how different carbonate chemistry parameters affect calcification conditions in corals.

SUBMITTER: Wall M 

PROVIDER: S-EPMC6687739 | biostudies-literature | 2019 Aug

REPOSITORIES: biostudies-literature