Table_1_Integrated Assessment of Ocean Acidification Risks to Pteropods in the Northern High Latitudes: Regional Comparison of Exposure, Sensitivity and Adaptive Capacity.XLSX

Exposure to the impact of ocean acidification (OA) is increasing in high-latitudinal productive habitats. Pelagic calcifying snails (pteropods), a significant component of the diet of economically important fish, are found in high abundance in these regions. Pteropods have thin shells that readily dissolve at low aragonite saturation state (Ωar), making them susceptible to OA. Here, we conducted a first integrated risk assessment for pteropods in the Eastern Pacific subpolar gyre, the Gulf of Alaska (GoA), Bering Sea, and Amundsen Gulf. We determined the risk for pteropod populations by integrating measures of OA exposure, biological sensitivity, and resilience. Exposure was based on physical-chemical hydrographic observations and regional biogeochemical model outputs, delineating seasonal and decadal changes in carbonate chemistry conditions. Biological sensitivity was based on pteropod morphometrics and shell-building processes, including shell dissolution, density and thickness. Resilience and adaptive capacity were based on species diversity and spatial connectivity, derived from the particle tracking modeling. Extensive shell dissolution was found in the central and western part of the subpolar gyre, parts of the Bering Sea, and Amundsen Gulf. We identified two distinct morphotypes: L. helicina helicina and L. helicina pacifica, with high-spired and flatter shells, respectively. Despite the presence of different morphotypes, genetic analyses based on mitochondrial haplotypes identified a single species, without differentiation between the morphological forms, coinciding with evidence of widespread spatial connectivity. We found that shell morphometric characteristics depends on omega saturation state (Ωar); under Ωar decline, pteropods build flatter and thicker shells, which is indicative of a certain level of phenotypic plasticity. An integrated risk evaluation based on multiple approaches assumes a high risk for pteropod population persistence with intensification of OA in the high latitude eastern North Pacific because of their known vulnerability, along with limited evidence of species diversity despite their connectivity and our current lack of sufficient knowledge of their adaptive capacity. Such a comprehensive understanding would permit improved prediction of ecosystem change relevant to effective fisheries resource management, as well as a more robust foundation for monitoring ecosystem health and investigating OA impacts in high-latitudinal habitats.

随着海洋酸化（OA）对高纬度生产型栖息地的影响日益加剧，浮游钙化贝类（海蛞蝓）的暴露风险也在不断上升。海蛞蝓是具有重要经济价值鱼类饮食中的重要组成部分，这些地区海蛞蝓的数量极为丰富。海蛞蝓具有薄壳，在低方解石饱和状态（Ωar）下容易溶解，这使得它们对海洋酸化特别敏感。在本研究中，我们对东太平洋亚极地环流、阿拉斯加湾（GoA）、白令海和安蒙森湾中的海蛞蝓进行了首次综合风险评估。通过整合海洋酸化暴露、生物敏感性和恢复力的测量值来确定海蛞蝓种群的风险。海洋酸化暴露基于物理化学水文观测和区域生物地球化学模型输出，描绘了碳酸盐化学条件季节性和十年变化。生物敏感性基于海蛞蝓形态计量学和壳体构建过程，包括壳体溶解、密度和厚度。恢复力和适应性能力基于物种多样性和空间连通性，这些数据源自颗粒追踪模型。在亚极地环流的中西部、白令海部分地区和安蒙森湾发现了广泛的壳体溶解现象。我们识别出两种不同的形态类型：L. helicina helicina和L. helicina pacifica，分别具有高锥形和平坦的壳体。尽管存在不同的形态类型，但基于线粒体单倍型的遗传分析确定了一个单一物种，形态学形式之间没有差异，这与广泛的空间连通性的证据相一致。我们发现壳体形态计量特征取决于ω饱和状态（Ωar）；在Ωar下降的情况下，海蛞蝓构建平坦且较厚的壳体，这表明了一定的表型可塑性。基于多种方法的综合风险评估假设，由于海蛞蝓已知的高度脆弱性以及尽管其连通性，但物种多样性有限，以及我们对它们的适应性能力的知识不足，在东太平洋高纬度地区随着海洋酸化的加剧，海蛞蝓种群持续存在面临高风险。这种全面的理解将有助于提高与有效渔业资源管理相关的生态系统变化的预测，并为监测生态系统健康和研究高纬度栖息地中的海洋酸化影响提供一个更加稳固的基础。