Changes in pteropod distributions and shell dissolution across a frontal system in the California Current System

• Main Authors: Bednaršek, N, Ohman, MD
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: eScholarship, University of California 2015
• Subjects: Pteropoda; Ocean fronts; Vertical distribution; Shell dissolution; Oceanography; Ecology; Zoology; Marine Biology & Hydrobiology; Limacina helicina
• Online Access: https://escholarship.org/uc/item/8jc0t2vg

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.