Sieving oyster spat7/9/2023 ![]() For instance, shell formation in early developing bivalve larvae is acutely hindered due to the reduced saturation state of aragonite (Ωarag Waldbusser et al., 2015a) which frequently accompanies OA conditions. Consequently, larval sensitivity to acidification stress may vary across developmental stages and involve a range of different physiological responses (Kapsenberg et al., 2018). One of the challenges for identifying genetic components of fitness for a specific environmental stressor like OA in many of the most sensitive marine species is that larval development is often a protracted and complex physiological process. These attributes of marine invertebrates allow for rapid adaptive responses to selection, with significant genetic changes in larval populations detected within a single generation (Bitter et al., 2019 Brennan et al., 2019 Pespeni et al., 2013). Marine calcifiers, such as bivalves and echinoderms, are also highly vulnerable to OA, which is one of the primary ways that climate change is affecting marine ecosystems (Doney et al., 2009). Marine invertebrate species are well suited to studies on how changes in ocean conditions may drive adaptive responses: They are typically genetically diverse (Bazin et al., 2006), highly fecund (Llorda, 2002), and sensitive to environmental stressors, especially during larval development (His et al., 1999). ![]() Understanding how marine species will adapt to ocean acidification (OA) is of critical importance in order to better understand potential impacts of future ocean conditions on marine ecosystems. The adaptive capacity of a population depends on many intrinsic and external factors but is fundamentally based on its standing genetic diversity from which new combinations of traits can arise (Munday et al., 2013). For sessile species that cannot migrate to favorable habitats, physiological plasticity may provide short‐term acclimation to environmental stressors but long‐term survival of vulnerable species will likely have to rely on genetic adaptation (Hoffmann & Sgrò, 2011). These results indicate the potential for a rapid adaptive response of oyster populations to OA conditions however, underlying genetic changes associated with larval development differ between these wild and domesticated oyster stocks and influence their adaptive responses to OA conditions.Īs global oceans warm and become increasingly acidified, many marine species are threatened by environmental conditions that challenge or exceed their physiological limits (Doney et al., 2012). ![]() Functional enrichment analyses of genetic markers with significant changes in allele frequency revealed that the structure and function of cellular membranes were disproportionately affected by high pCO 2 conditions in both groups. Domesticated larvae had ~26% fewer loci with changing allele frequencies across developmental stages and <50% as many loci affected by acidified culture conditions, compared to larvae from wild broodstock. Using pooled DNA samples, we determined changes in allele frequencies across larval development, from early “D‐stage” larvae to metamorphosed juveniles (spat), in both groups and environments. Here we evaluated phenotypic and genetic changes during larval development of Pacific oysters ( Crassostrea gigas) reared in ambient (~400 µatm) and high (~1600 µatm) pCO 2 conditions, both in domesticated and naturalized “wild” oysters from the Pacific Northwest, USA. To date, however, it remains unclear how the selective effects of OA occur within the context of complex genetic interactions underpinning larval development in many of the most vulnerable taxa. Previous studies have provided evidence to suggest that larval resilience to high pCO 2 seawater for these species is a trait with a genetic basis and variability in natural populations. The adaptive capacity of marine calcifiers to ocean acidification (OA) is a topic of great interest to evolutionary biologists and ecologists.
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