RUI: River and sediment-modulated stress in planktonic and early settlement Mya arenaria

河口是多产的、复杂的，由于其渔业、生态系统服务和娱乐潜力，具有巨大的经济价值。由于异养过程中产生的酸和来自陆地和大气的酸性输入的综合影响，它们对酸的缓冲作用通常比开放的海洋要小。在河口，重要的是要了解不同的酸负荷如何影响生物资源，特别是那些提供生态系统服务和/或渔业创收。双壳类Mya arenaria是这项拟议研究的重点物种，它是维持宝贵的沿海渔业的资源之一，同时通过其过滤能力提供服务。由于Mya贝壳是由相对可溶的碳酸钙（文石）构成的，而且蛤蜊通常栖息在富营养化的水中，当pH值下降时，它们可能特别脆弱。浮游幼虫和底栖幼鱼是关键的生命阶段-即使其丰度略有减少，也会使成年种群大幅减少。这项拟议的研究解决了四个不同的假设，河流和沉积物的相互作用对幼虫和少年Mya的生存能力的作用。研究活动包括以下内容。1.实地考察将评估在阿留申贝克河口和卡斯科湾的文石饱和状态的空间和季节变化。季节性采样将与每年Mya产卵期间的高频率采样相结合，以观察和记录降低的文石饱和状态对Mya幼虫健康状况的影响。2.利用Mya幼虫，实验室实验将模拟高频巡航期间在卡斯科湾观察到的文石饱和状态。变质的变化（面盘幼虫，pediveligers，和变质的青少年），生长速度，和生存的Mya将被评估为文石饱和状态的函数。3.空间密集的每日队列监测的潮间带泥滩在法尔茅斯，缅因州，将建立丰富的解决青少年和文石饱和状态的变化之间的联系，在Mya设置期间。将参照附近沉积物的pH值和文石饱和状态，对沉降Mya的队列监测进行检查，以确定沉积物饱和状态是否是过渡期幼虫的主要沉降线索。4.一个诊断模型将开发贝类管理社区，可用于检测文石饱和状态的水柱。该模型将在常规海洋学测量（盐度、温度、氧气和叶绿素荧光）的基础上运行。研究的智力价值：大气中二氧化碳含量增加和由此产生的碳酸水解的化学后果已得到充分了解，而由此产生的海洋酸化也已用当前一代的全球环流模型准确预测。这些预测加速了对海洋酸化对海洋生物影响的研究，特别是那些具有CaCO 3外骨骼的生物。河口水域的缓冲作用远小于海洋，受到各种酸负荷的影响，并且很可能以比开阔海洋更快的速度酸化。然而，这些地区在“酸化”研究中基本上被忽视了。 酸化对钙化生物的影响是相似的，无论是酸的起源-大气交换，净异养，或酸性河水的排放。同样，这些酸通量中的每一种都受到人类活动（例如化石燃料使用、森林砍伐、农业）的干扰。拟议的研究将进一步了解各种酸负荷对沿海水域钙化生物的综合和累积影响。研究的更广泛影响：缅因州圣约瑟夫学院是一所本科院校，有许多潜在的机会向学生介绍科学研究和发现的兴奋。该项目将对圣约瑟夫学院70%的女性学生具有特殊意义，其中许多人将首次体验研究科学。学生沉浸到研究将仿照其他赞助的研究在SJC，导致一个新的海洋科学专业，在超过35 SJC本科生参加和/或在国家/国际会议（12作为合著者）展示研究成果，并在4名学生共同撰写最近的论文出版。

Estuaries are productive, complex and have great economic value by virtue of their fisheries, ecosystem services and recreation potential. They are typically less buffered to acid than open oceans due to the combined effects of acid production during heterotrophy and acidic inputs from both land and atmosphere. Within estuaries, it is important to understand how varying acid burdens impact living resources, particularly those that provide ecosystem services and/or generate income as fisheries. The bivalve Mya arenaria, the focal species of this proposed research, is one such resource that sustains a valuable coastal fishery while providing service via its filtration capacity. Because Mya shells are constructed from a relatively soluble form of calcium carbonate (aragonite), and the clams often inhabit eutrophic waters, they may be particularly vulnerable as pH declines. Planktonic larvae and benthic juveniles are critical life stages -- even small reductions in theier abundances could substantially decrease adult populations. This proposed research addresses four distinct hypotheses concerning the roles of riverine and sediment interactions on the viability of larval and juvenile Mya. Research activities include the following. 1. Fieldwork will evaluate the spatial and seasonal changes in aragonite saturation state within the Kennebec River Estuary and Casco Bay. Seasonal sampling will be coupled with high-frequency sampling during the annual Mya spawn to observe and document the effect of lowered aragonite saturation state on the health status of larval Mya. 2. Using larval Mya, laboratory experiments will mimic the aragonite saturation state observed in Casco Bay during the high-frequency cruises. Metamorphic change (veligers, pediveligers, and metamorphosed juveniles), growth rate, and survivorship of Mya will be evaluated as a function of aragonite saturation state. 3. Spatially intensive daily cohort monitoring of the intertidal mud flats in Falmouth, Maine, will establish the link between changes in abundance of settling juveniles and aragonite saturation state during the period of Mya set. Cohort monitoring of settling Mya will be examined in reference to sediment pH and aragonite saturation state in nearby deposits to ascertain if sediment saturation state is a primary settlement cue for transitioning larvae. 4. A diagnostic model will be developed for the shellfish management community that can be used to detect aragonite saturation state of the water column. The model would run on routine oceanographic measurements (salinity, temperature, oxygen and chlorophyll fluorescence). Intellectual merit of study: The chemical consequences of increasing atmospheric CO2 and resulting hydrolysis of carbonic acid is well understood and resultant ocean acidification has been accurately predicted with the current generation of global circulation models. These predictions have accelerated research into the effects of ocean acidification on marine organisms, particularly those with CaCO3 exoskeletons. Estuarine waters are far less buffered than oceans, are subject to a variety of acid loadings, and are quite possibly acidifying at a faster rate than the open ocean. Yet, these regions have been largely ignored in 'acidification' research. Effects of acidification on calcifying organisms are similar regardless of whether of acid origin -- atmospheric exchange, net heterotrophy, or discharge of acidic river water. Likewise, each of these acid fluxes is being perturbed via anthropogenic activity (e.g. fossil fuel use, deforestation, agriculture). The proposed research will further understanding of the combined and cumulative impacts of varied acid burdens on calcifying organisms in coastal waters. Broader impacts of study: Saint Joseph's College of Maine is an undergraduate institution with many potential opportunities to introduce students to the excitement of scientific research and discovery. This project will have special significance to the 70% of women that make up the student body at Saint Joseph's College, many of whom will experience research science for the first time. The immersion of students into research will be modeled after other sponsored research at SJC, resulting in a new marine science major, in over 35 SJC undergraduates attending and/or presenting research results at national/international conferences (12 as co-authors), and in 4 students co-authoring recent papers for publication.