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基本目标。尽管全球海洋对气候影响很大，但在关键的气候评估报告中，特别是在上个千年期间，海洋环境的比例严重偏低。在过去的几十年里，热带珊瑚出现了多中心的气候时间序列，最近又出现了中纬度长寿命双壳类的气候时间序列。然而，亚北极和北极地区的代理档案记录很少。为了填补这一空白，一些研究表明，中高纬度甲壳珊瑚藻类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，珊瑚藻类出现在亚北极和北极纬度，包括太平洋和大西洋，那里不存在其他高分辨率的世纪尺度海洋环境指标。因此，珊瑚藻类最近开始填补海洋古环境替代研究中的一个重要领域，到目前为止，已发表了几个从年代到季节分解的多中心气候重建。A)最近从拉布拉多中部和北部收集的珊瑚藻类将被用来提供拉布拉多当前温度和盐度变化以及大西洋西北部相关气候振荡的第一个500年记录--在该地区，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)持续不断的海洋酸化已被证明可能对贝类和珊瑚等钙质动植物的骨骼产生有害影响。在亚北极北太平洋和西北大西洋等冷水地区尤其如此，据预测，这些地区将首批受到海洋pH值下降的负面影响。来自两个大洋的珊瑚藻类将被分析骨骼结构和元素组成的时间变化，并作为几个世纪以来重建海洋pH值的指标。

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.