Ocean Acidification: Century Scale Impacts to Ecosystem Structure and Function of Aleutian Kelp Forests

海洋钙化生物最容易受到冷水生态系统中海洋快速酸化的影响。研究人员建议确定阿拉斯加是否存在全球独特且广泛分布的石灰岩？由于OA和食物网改变的综合影响，阿留申群岛的Clathromorphum nereostratum面临灭绝的威胁。C. Nereostratum是一种生长缓慢的珊瑚虫，可以存活至少2000年。它会产生巨大的能量？生物礁在这些地区占主导地位？在海藻森林和被砍伐的海胆荒地下的岩石基质。它在其钙质骨骼中形成了生长带（类似于树木年轮），有效地记录了几个世纪以来的年钙化率。初步数据表明，C。沙蚕在1990年开始急剧下降？在阿留申群岛的某些地方。研究人员现在建议使用高分辨率显微镜和microCT成像来检查C。Nereostratum在过去的300年中发生了变化（即，自工业革命以来）横跨阿留申群岛西部。他们将比较他们记录的藻类骨骼密度及其随时间的变化与过去气候的重建，以推断变化的原因。此外，调查人员还将调查是否有嫌疑人？由于海洋持续酸化，美国对海胆吃草的防御能力受到了损害。研究人员将调查C. nereostratum生物侵蚀发生在横跨阿留申群岛西部的10个地点，包括海带森林的内部和外部。在每个地点，他们将把这些模式与观察和监测的生态系统营养结构和最近的C。沙蚕钙化率。现场观察将与实验室实验相结合，以确定它是否是一个下降的温度？的骨骼密度（由于最近的OA和变暖），放牧强度的增加（由于最近的营养水平功能障碍），或其相互作用的影响，可能是负责生物侵蚀模式内与森林外。通过对C.他们将确定海带森林是否通过光合作用局部增加pH值，从而缓冲OA对珊瑚钙化的影响。将实地观察与实验室控制实验相结合，操纵二氧化碳和温度，将有助于阐明钙化的驱动因素，并预测这些物种之间的相互作用在不久的将来可能会如何变化。该项目将提供第一个现场例子，说明持续的海洋酸化如何影响亚北极北太平洋长寿的碳酸盐生产生物的生理学。这也将是首批记录OA、海洋变暖和食物网变化对生态过程的影响是否以复杂的方式相互作用，以重塑自然界物种相互作用的结果的研究之一。该项目将支持一名博士后研究员，并让研究生和本科生参与实地工作。该项目将支持一名美国土著大学生的研究，并包括与沿海部落和其他公众成员的联系。

Marine calcifying organisms are most at risk to rapid ocean acidification (OA) in cold-water ecosystems. The investigators propose to determine if a globally unique and widespread calcareous alga in Alaska?s Aleutian archipelago, Clathromorphum nereostratum, is threatened with extinction due to the combined effects of OA and food web alterations. C. nereostratum is a slow growing coralline alga that can live to at least 2000 years. It accretes massive ?bioherms? that dominate the regions? rocky substrate both under kelp forests and deforested sea urchin barrens. It develops growth bands (similar to tree rings) in its calcareous skeleton, which effectively record its annual calcification rate over centuries. Pilot data suggest the skeletal density of C. nereostratum began to decline precipitously in the 1990?s in some parts of the Aleutian archipelago. The investigators now propose to use high-resolution microscopy and microCT imaging to examine how the growth and skeletal density of C. nereostratum has changed in the past 300 years (i.e., since the industrial revolution) across the western Aleutians. They will compare their records of algal skeletal densities and their variation through time with reconstructions of past climate to infer causes of change. In addition, the investigators will examine whether the alga?s defense against grazing by sea urchins is compromised by ongoing ocean acidification. The investigators will survey the extent of C. nereostratum bioerosion occurring at 10 sites spanning the western Aleutians, both inside and outside of kelp forests. At each site they will compare these patterns to observed and monitored ecosystem trophic structure and recent C. nereostratum calcification rates. Field observations will be combined with laboratory experiments to determine if it is a decline in the alga?s skeletal density (due to recent OA and warming), an increase in grazing intensity (due to recent trophic-level dysfunction), or their interactive effects that are likely responsible for bioerosion patterns inside vs. outside of forests. By sampling C. nereostratum inside and outside of forests, they will determine if kelp forests locally increase pH via photosynthesis, and thus buffer the effects of OA on coralline calcification. The combination of field observations with laboratory controlled experiments, manipulating CO2 and temperature, will help elucidate drivers of calcification and project how these species interactions will likely change in the near future. The project will provide the first in situ example of how ongoing ocean acidification is affecting the physiology of long-lived, carbonate producing organisms in the subarctic North Pacific. It will also be one of the first studies to document whether OA, ocean warming, and food web changes to ecological processes are interacting in complex ways to reshape the outcome of species interactions in nature. The project will support a postdoctoral investigator, and involve graduate and undergraduate students in the field work. The project will support research by a Native American undergraduate student and include outreach to coastal tribes and other members of the public.