Collaborative Research: Interdisciplinary Approach to Understand Stable Isotopic Disequilibrium in Benthic Foraminifera

根据该合同，pi将检查具有“极端”化学梯度的环境，这些化学梯度强调了生物碳酸盐和环境条件以及“正常”深海条件之间的化学差异。低温甲烷渗漏中存在的极端同位素梯度为研究有孔虫方解石和环境水中溶解无机碳（DIC）之间的碳同位素不平衡（高达40 /00）的影响提供了理想的栖息地。最近的研究表明，生物因素（“生命效应”）和/或环境同位素组成影响有孔虫方解石的碳同位素特征。因此，本研究将验证以下假设：1)沉积物微生境中存在有孔虫群；2)食物类型影响有孔虫碳同位素值；3)共生体的存在在物种内部和物种之间是可变的，这种变异反映在碳同位素特征上。这项工作应该为什么控制底栖有孔虫测试（壳）的碳同位素组成的重要问题提供见解？这个问题的答案对于在渗和非渗环境下的古环境重建都是至关重要的。这些资金还将用于社区外展（当地学校的演讲；网站开发）和跨学科的实践培训，为本科生、研究生和博士后水平的几名未来科学家提供培训，包括代表性不足的群体。

Under this award the PIs will examine environments with "extreme" chemical gradients that accentuate chemical differences between biogenic carbonate and ambient conditions as well as those of "normal" deep-sea conditions. Extreme isotopic gradients present at cold methane seeps provide an ideal habitat to examine the effects of carbon isotopic disequilibrium (up to 40 0/00), between foraminiferal calcite and dissolved inorganic carbon (DIC) of ambient water. Recent work suggests that biological factors ("vital effects") and/or ambient isotopic compositions influence carbon isotopic signatures of foraminiferal calcite. Consequently, the proposed work will test the following hypotheses: 1) Infaunal foraminifera cluster in microhabitats within the sediments; 2) Food type influences foraminiferal carbon isotope values; 3) The presence of symbionts is variable within and between species, and this variability is reflected in carbon isotopic signatures. The work should provide insight to the important question of what controls the carbon isotopic composition of benthic foraminiferal tests (shells)? Answers to this question will be crucial for paleoenvironmental reconstructions in both seep and non-seep environments. The funds will also be used to include community outreach (local school presentations; web site development) and interdisciplinary, hands-on training of several future scientists at undergraduate, graduate, and post-doc levels, including under-represented groups.