Metabolic Physiology During Embryonic and Larval Development of Antarctic Echinoderms

在南极洲麦克默多湾的冷水中，底栖海洋无脊椎动物的摄食幼虫在浮游植物繁盛之前就存在于水柱中好几个月。目前还不清楚这些取食的南极无脊椎动物的幼虫是如何在饥饿条件下长时间生存的。了解这一过程的生理机制对了解南极地区幼虫的生态学具有重要意义。最近对南极棘皮动物幼虫的研究结果不支持这样的观点，即进食的幼虫通过使用其他食物来源（细菌或溶解的有机物质）在浮游植物丰度可忽略不计的时期存活下来。然而，生理数据确实表明了一种可能的生存策略，即在完全没有食物的情况下，潜在的幼虫寿命可以延长约一年。这样的寿命（不进食）是南极幼虫所特有的。这一过程在南极棘皮动物幼虫体内的代谢是本研究的重点。将检验一个假设，即南极棘皮动物的发育代谢成本将低于同等温带幼虫的相同“分化单位”（受精卵到取食幼虫形式）。关于温带幼虫的这类数据已经存在，拟议的南极幼虫研究将允许对特定阶段的发育代谢进行比较。为了获得这些代谢数据，将使用一种称为库仑呼吸法的新技术，该技术允许在发育过程中连续测量代谢率。此外，还将检查发育的生物化学，以确定南极幼虫低代谢的机制。实验数据将检验长期存在的关于低代谢细胞机制的假设，因为它们适用于南极环境中无脊椎动物的发育。这项研究的发现也可能对其他寒冷环境（如深海）中低食物条件下的幼虫发育产生影响。

Manahan 9420803 Feeding larval forms of benthic marine invertebrates in the cold waters of McMurdo Sound, Antarctica are present in the water column for many months prior to the phytoplankton bloom. It is currently not understood how these feeding larvae of antarctic invertebrates survive long periods under starvation conditions. Knowing the physiological mechanisms of this process is important for understanding the ecology of larvae from antarctic regions. Recent findings with antarctic echinoderm larvae do not support the suggestion that feeding larvae survive this period of negligible phytoplankton abundance by using other food sources (bacteria or dissolved organic material). Physiological data, however, do suggest a possible survival strategy whereby potential larval lifespans can be extended for about one year in the complete absence of food. Such lifespans (without food) for feeding larval forms are unique to antarctic larvae. The metabolism of this process in antarctic echinoderm larvae is the focus of this research. A hypothesis that the metabolic cost of development will be lower in antarctic echinoderms than for the same "unit of differentiation" (fertilized egg to feeding larval form) in comparable temperate larvae will be tested. Such data on temperate larvae already exist and the proposed studies with antarctic larvae will allow for a comparison of stage-specific developmental metabolism. To obtain these metabolic data, a novel technique called coulometric respirometry that permits continuous measurements of metabolic rate during development will be used. In addition, the biochemistry of development will be examined to determine the mechanism(s) of low metabolism in antarctic larvae. Data from experiments will test long-standing hypotheses about cellular mechanisms of low metabolism as they apply to invertebrate development in antarctic environments. The findings from this research may also have implications for larvae developing under lo w food conditions in other cold environments, such as the deep sea.