Coralline algae as recorders of environmental change

量化世界海洋在过去、现在和未来全球变化中的作用和贡献是气候和古环境研究的一个重要目标。虽然全球海洋对气候的影响很大，但在主要气候评估报告中，特别是在上一个千年期间，海洋环境的代表性大大不足。在过去的几十年里，热带珊瑚出现了多世纪的气候时间序列，最近中纬度长寿的双壳类动物也出现了。然而，亚北极和北极代理档案记录很少。为了填补这一空白，许多研究表明，中高纬度甲壳珊瑚藻是一种新兴的温带海洋环境档案，因为它们是寿命最长的浅海钙化生物之一，寿命可达数百年。更重要的是，珊瑚藻出现在亚北极和北极纬度，在太平洋和大西洋，其他高分辨率的世纪尺度海洋环境代用指标是不存在的。因此，珊瑚藻最近开始在海洋古环境代理研究中占据一个重要的位置，迄今为止发表了几份以年代际到季节为分辨率的多世纪气候重建。本提案将解决两个关键问题，通过使用珊瑚代理档案来回答：A)最近从拉布拉多中部和北部收集的珊瑚藻类将用于提供拉布拉多海流温度和盐度变化以及西北大西洋相关气候振荡的第一个bbb500年记录-在这个地区，人们对气候和海洋变化知之甚少，对生态系统和渔业产量产生了巨大影响。B)正在进行的海洋酸化已被证明对诸如贝类和珊瑚等钙质动植物的骨骼有潜在的有害影响。这在冷水区尤其如此，如亚北极的北太平洋和西北大西洋，预计它们将首当其冲受到海洋pH值下降的负面影响。来自这两个海洋的珊瑚藻将被分析其骨骼结构和元素组成的时间变化，并作为重建几个世纪以来海洋pH值的代理。

Quantifying the role and contribution of the world's oceans in past, present, and future global change is an essential goal in climate and paleoenvironmental studies. Although the global oceans influence climate greatly, the marine environment is substantially underrepresented in key climate assessment reports, especially during the last millennium. Over the past decades multicentury climate time series have emerged from tropical corals, and more recently from mid-latitude long-lived bivalves. However, subarctic and arctic proxy archival records are sparse. In order to fill this gap, a number of studies have demonstrated that mid- and high-latitude crustose coralline algae are an emerging extratropical marine environmental archive as they are amongst the longest lived shallow marine calcified organisms with life spans of several hundred years. More importantly, coralline algae occur in subarctic and arctic latitudes, both in the Pacific and Atlantic, where other high-resolution century-scale marine environmental proxies are non-existent. Hence, coralline algae have recently started to fill an important niche in marine paleoenvironmental proxy research, with several decadally to seasonally-resolved multicentury climate reconstructions published to date. This proposal will address two key themes to be answered using coralline proxy archives: A) Recently collected coralline algae from central and northern Labrador will be used to provide the first >500 year record of Labrador Current temperature and salinity variability and related climate oscillations in the northwestern Atlantic - a region where poorly understood climate and oceanographic changes have had a dramatic impact on ecosystems and fishery yields. B) Ongoing ocean acidification has been shown to potentially have a detrimental impact on the skeletons of calcareous plants and animals such as shellfish and corals. This is especially true in cold-water regions such as the subarctic North Pacific and northwest Atlantic, which are predicted to be amongst the first negatively affected by a decreasing ocean pH. Coralline algae from both oceans will be analyzed for temporal changes in skeletal structure and elemental composition, and as a proxy for reconstructing ocean pH over several centuries.