Food Substrates and Digestive Capabilities of Marine Deposit Feeders

9711793洛佩斯沉积物给料器在确定有机物是否脱矿或埋藏方面起着几个重要作用。这些动物的功能是为微生物生长提供表面，并以远远超过沉降的速度在海底水平和垂直移动颗粒。了解沉积物给料器的核心问题是确定它们所利用的材料并确定这些材料的来源。该项目的跨学科方法是将消化的化学反应器理论与酶可用氨基酸处理的测量相结合，重点关注肠道的水解速率和吸收速率。将开发体外和体内荧光法来测定小型沉积饲料肠道中的酶活性；这些方法同样适用于浮游动物。将进行化学分析和沉淀物饲养生物分析，以测试蛋氨酸或其他必需氨基酸是否在实验室模拟成岩作用中变得更加有限。在一个浅水的潮下地点，将检验加利福尼亚拟拟寄生物仅限于在蛋氨酸浓度相对较高的时期进食的假设。在一个200米的地点，假设穴居海胆在春季开花后比在冬季表现出更大的水解和吸收氨基酸的能力将被测试。

9711793 Lopez Deposit feeders play several important roles in determining whether organic material is demineralized or buried. These animals function to make surfaces available for microbial growth and move particles both horizontally and vertically within the seabed at a pace that far exceeds sedimentation. The central problem in understanding deposit feeders is to identify the materials that they utilize and to determine the sources of those materials. The interdisciplinary approach of this project is to combine a chemical reactor theory of digestion with measurements of the processing of enzymatically available amino acids, focusing on rates of hydrolysis in, and absorption from, the gut. In vitro and in vivo fluorometric methods will be developed to assay enzyme activity in the guts of small deposit feeders; these methods that will be applicable to planktonic animals as well. Chemical analyses and deposit-feeder bioassays will be conducted to test whether methionine or other essential amino acids become more limiting in laboratory simulations of diagenesis. In a shallow subtidal site the hypothesis that the holothuroid Parastichopus californicus is limited to feeding during times of relatively high methionine concentration will be tested. At a 200-m site the hypothesis that the burrowing urchin Brisaster latifrons will show greater hydrolytic and absorptive capacity for amino acids after the spring bloom than during winter will be tested.