An Urgent Replacement and Upgrade in Isotope Ratio Mass Spectrometry at Trent's Water Quality Centre

北极正在迅速变化，人们越来越担心这些变化会如何影响该地区特有的各种物种，这些物种对北方土著人民具有巨大的经济和文化重要性。气候变化对海洋哺乳动物影响的长期研究通常局限于几年或最多几十年，但我们知道，北极的环境条件在全新世，特别是在过去的几百年里发生了很大的变化。我的研究项目通过分析博物收藏（从古生物学和考古遗址收集的材料以及博物馆存档的组织样本）中骨骼样本（胶原蛋白）的蛋白质成分的体积和化合物特异性稳定同位素组成，重建了北极海洋哺乳动物（北极熊、环斑海豹、海象、弓头鲸、独角鲸、白鲸）在过去12000年里的长期生态变化。这些数据为了解这些动物营养地位的变化以及支持海洋食物网的海冰藻类的相对重要性提供了见解。与大多数古环境重建不同，这些数据揭示了食物网顶部或附近的生物如何对长期环境变化做出反应，这是一个只有通过这些独特的自然历史收集才能获得的视角。如果我们缺乏长远的眼光，我们就无法充分解决气候变化对这些物种的影响。本提案所要求的设备（一台新的元素分析仪和同位素比例质谱仪，能够测量小型固体有机样品上的d13C， d15N和34S）代表了对我们现有仪器的紧急升级，这些仪器无法产生完成本研究所需的所有同位素测量。这种新设备将提高分辨率，使我们能够解决北极海洋哺乳动物觅食生态中长期环境变化的原因和后果，最大限度地减少经常困扰这类数据的不均衡性。它将为本科生和研究生提供极好的机会，使他们成为同位素比质谱领域的高素质人才，并确保大学社区的所有成员都能公平地使用这种仪器。

The Arctic is changing rapidly and there is growing concern about how these changes may impact various species that are endemic to this region and are of tremendous economic and cultural importance to the Indigenous peoples of the north. Long-term studies of the impacts of climate change on marine mammals are typically limited to a few years or at most a few decades, but we know that the environmental conditions in the Arctic have varied substantially through the Holocene and particularly in the last few hundred years. My research program reconstructs long-term variation in the ecology of Arctic marine mammals (polar bear, ringed seal, walrus, bowhead whale, narwhal, beluga whale) over the last 12,000 years by analysing the bulk and compound-specific stable isotope compositions of the proteinaceous component of bone samples (collagen) from natural history collections (materials collected from palaeontological and archaeological sites as well as tissue samples archived by museums). These data provide insight into variation in the trophic position of these animals and the relative importance of sea ice algae supporting marine food webs. Unlike most palaeoenvironmental reconstructions, these data shed light on how organisms at or near the top of the food web have responded to long-term environmental variation, a perspective that cannot be accessed except through these unique natural history collections. We cannot adequately address how climate change influences these species today if we lack a long-term perspective. The equipment requested in this proposal (a new elemental analyzer and isotope ratio mass spectrometer capable of measuring d13C, d15N, and 34S on small solid organic samples) represents an urgent upgrade to our existing instrumentation that is incapable of generating all of the isotopic measurements needed to complete this research. This new equipment will increase the resolution with which we can address the causes and consequences of long-term environmental variation in the foraging ecology of Arctic marine mammals, minimizing the equifinality that often plagues these kinds of data. It will provide excellent opportunities for undergraduate and graduate students to become highly competent in the field of isotope ratio mass spectrometry and ensure equitable access to this instrumentation for all members of the university community.