ABSTRACT: We tested the sensitivity of the vertical distributions and shell dissolution patterns of thecosome pteropods to spatial gradients associated with an eddy-associated front in the southern California Current System. The aragonite saturation horizon (Ωarag = 1.0) shoaled from >200 to <75 m depth across the front. The vertical distribution of thecosome pteropods tracked these changes, with all 5 species showing reduced occurrence at depths below 100 m where waters were less saturated with respect to aragonite. Shell dissolution patterns of the numerically dominant thecosome Limacina helicina corresponded to the cross-frontal changes in Ωarag saturation state. Severe shell dissolution (categorized here as Type II and Type III) was low in near-surface waters where Ωarag > 1.4, while peak dissolution occurred in depths where Ωarag = 1.0 to 1.4. Vertical habitat compression and increased shell dissolution may be expected to accompany future shoaling of waters that are undersaturated with respect to aragonite.
KEY WORDS: Pteropoda · Ocean fronts · Vertical distribution · Shell dissolution
Full text in pdf format Supplementary material | Cite this article as: Bednaršek N, Ohman MD
(2015) Changes in pteropod distributions and shell dissolution across a frontal system in the California Current System. Mar Ecol Prog Ser 523:93-103. https://doi.org/10.3354/meps11199
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