Do heterogeneous seascapes of carbonate conditions across biogeographic breaks influence divergent phenotypic plasticity in natural populations?

• Main Authors: Lardies, Marco, Rodriguez-Romero, Araceli, Opitz, Tania, Gaitan-Espitia, Juan, Lardies, Lardies
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2021
• Subjects: upwelling; geographic variation; Ocean acidification
• Online Access: https://doi.org/10.5061/dryad.bnzs7h48r

Aim: Understanding how environmental variability influences stress tolerance, local adaptation, and phenotypic variation among populations is a key challenge for evolutionary ecology and climate change biology. Coastal biogeographic breaks are natural laboratories to explore this fundamental research question due to the contrasting environmental conditions experienced by natural populations across these regions. Location: In the South East Pacific (SEP) coast a major break (30º-32ºS) is characterized by extreme natural variability in seawater carbonate chemistry parameters related to temporal and spatial dynamics in upwelling events. Mollusk species that reach their range limit at this zone are exposed to naturally acidified waters that can be corrosive and impact their calcification, physiology, and fitness, making them particularly prone to the effects of ocean acidification (OA). We investigated to what extent the interplay between biogeographic breaks and local variability of seawater carbonate conditions influences the tolerances and sensitivity of populations of the limpet Scurria araucana to OA. Methods: During two years, we conducted field surveys of limpet populations at sites across the SEP break (27ºS, 30ºS and 32ºS). We collected individuals from each population to test for geographic differences in morphometric (e.g., total buoyancy weight, shell length) and physiological (e.g., oxygen consumption rate, cardiac activity, and thermal performance curves; TPC) responses to local conditions and to simulated OA scenarios. Results: Analysis of the cardiac activity indicates that limpets from the central part of the break (30ºS) exhibit higher thermal performance compared to limpets from populations at both sides of the break. Thus, heterogeneous seascape of carbonate conditions and sea surface temperature across a biogeographic break in the SEP coast influence phenotypic differences among populations of this ecosystem engineer. Main Conclusions: Natural environmental variation might be the underpinning ...