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）将对响应碳酸盐化学变化的海洋敏感动物产生显著负面影响。沿海上升流区域（如北美西北海岸）极有可能成为首批显现海洋酸化影响的生态系统之一——这类区域本身已存在较高的pH波动幅度与自然极端低pH值。过去十年间，华盛顿州奥林匹克海岸海域的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。海洋资源管理者担忧海洋酸化可能引发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分类群的pH敏感性数据仍极度匮乏。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，相关研究尤为不足。近年开发的研究方法通过整合实验证据与专家意见，为破解生物脆弱性评估的相关难题提供了可行路径。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。研究结果不仅印证了以碳酸钙构建结构体的潮间带类群易受海洋酸化影响的现有研究范式，同时也揭示了诸多未被充分研究物种的知识空白。此外，本研究还基于此次评估结果，结合四个长期监测站点的群落组成情况，分析了奥林匹克海岸岩质潮间带群落可能受到的海洋酸化影响。