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

根据这一奖项，PIS将研究具有“极端”化学梯度的环境，这些环境突出生物成因碳酸盐和环境条件以及“正常”深海条件之间的化学差异。冷甲烷渗漏的极端同位素梯度为研究环境水中有孔虫方解石和溶解无机碳(DIC)之间的碳同位素不平衡(高达400/00)的影响提供了理想的环境。最近的工作表明，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，拟议的工作将检验以下假设：1)沉积物内微生境中的有孔虫集群；2)食物类型影响有孔虫的碳同位素值；3)共生体的存在在物种内和物种之间是不同的，这种差异反映在碳同位素特征上。这项工作应该有助于洞察什么控制海底有孔虫测试(贝壳)的碳同位素组成这一重要问题？这个问题的答案对于SEEP和非SEEP环境中的古环境重建都是至关重要的。这笔资金还将用于社区推广(当地学校介绍；网站开发)和对几名未来的本科生、研究生和博士后水平的科学家进行跨学科的动手培训，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.