Characterizing the vulnerability of intertidal organisms in Olympic National Park to ocean acidification

Ocean acidification (OA) will have a predominately negative impact on marine animals sensitive to changes in carbonate chemistry. Coastal upwelling regions, such as the Northwest coast of North America, are likely among the first ecosystems to experience the effects of OA as these areas already experience high pH variability and naturally low pH extremes. Over the past decade, pH off the Olympic coast of Washington has declined an order of magnitude faster than predicted by accepted conservative climate change models. Resource managers are concerned about the potential loss of intertidal biodiversity likely to accompany OA, but as of yet, there are little pH sensitivity data available for the vast majority of taxa found on the Olympic coast. The intertidal zone of Olympic National Park is particularly understudied due to its remote wilderness setting, habitat complexity, and exceptional biodiversity. Recently developed methodological approaches address these challenges in determining organism vulnerability by utilizing experimental evidence and expert opinion. Here, we use such an approach to determine intertidal organism sensitivity to pH for over 700 marine invertebrate and algal species found on the Olympic coast. Our results reinforce OA vulnerability paradigms for intertidal taxa that build structures from calcium carbonate, but also introduce knowledge gaps for many understudied species. We furthermore use our assessment to identify how rocky intertidal communities at four long-term monitoring sites on the Olympic coast could be affected by OA given their community composition.海洋酸化（Ocean Acidification, OA）对碳酸盐化学变化敏感的海洋动物将产生显著负面影响。沿岸上升流区（如北美西北海岸）极有可能成为首批受到海洋酸化影响的生态系统之一，因为这些区域本身已存在较高的pH值变异性，且自然极端pH值偏低。过去十年间，华盛顿州奥林匹克海岸外的海水pH值下降速度，比公认的保守气候变化模型预测值快了一个数量级。自然资源管理者担忧海洋酸化可能引发的潮间带生物多样性丧失，但截至目前，针对奥林匹克海岸绝大多数生物类群的pH敏感性数据仍十分匮乏。奥林匹克国家公园的潮间带区域因地处偏远荒野、生境复杂且生物多样性极高，相关研究尤为匮乏。近年开发的研究方法通过结合实验证据与专家意见，为解决生物敏感性评估中的诸多难题提供了可行方案。本研究采用此类方法，针对奥林匹克海岸发现的700余种海洋无脊椎动物与藻类物种，评估了其对pH值的敏感性。研究结果不仅验证了以碳酸钙构建结构的潮间带类群对海洋酸化敏感的现有研究范式，同时也揭示了多数未被充分研究的物种所存在的知识空白。此外，本研究基于评估结果，结合群落组成情况，分析了奥林匹克海岸四个长期监测站点的岩相潮间带群落可能受到海洋酸化的影响程度。