Food Substrates and Digestive Capabilities of Marine Deposit Feeders

9711793洛佩兹沉积物进给器在确定有机物质是脱矿还是埋藏方面发挥着几个重要作用。这些动物的功能是使表面可供微生物生长，并在海床内以远远超过沉积的速度水平和垂直移动颗粒。了解沉积物供给者的中心问题是确定它们所使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理论与酶可用氨基酸的加工过程的测量相结合，重点关注肠道中的水解率和从肠道吸收的速率。体外和体内的荧光法将被开发来检测小型沉积物摄食者肠道中的酶活性；这些方法也将适用于浮游动物。将进行化学分析和沉淀物生物分析，以测试蛋氨酸或其他必需氨基酸在实验室模拟成岩作用时是否变得更加有限。在浅海潮下水域，海参仅限于在蛋氨酸浓度相对较高的时期取食的假设将得到检验。在200米高的地点，洞穴海胆在春季开花后对氨基酸的水解力和吸收能力将比冬季更大的假设将得到验证。

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.