REU: Fate of Chlorophyll-a During Zooplankton Gut Passage

十年来，野外研究人员利用桡足类动物消化系统中叶绿素衍生色素的浓度作为估计自然摄食率的一种方法，因为这种测量可以在野外捕获的动物身上立即进行，从而可以估计饲养过程中的自然方差，并绕过导致不确定性和伪影的孵化程序。最近，这种方法受到了批评，因为在某些情况下，色素预算没有达到叶绿素的全面核算。然而，这种方法在海洋生态学中非常有见地，因此继续被使用，尽管有争论认为预算表明色素的同化或其他未知的损失来源是重要的。本研究将试图确定误差的来源，并为动物肠道中叶绿素衍生色素的实地测量提出新的方法。海洋中食草动物的摄食是一个基本的过程，不仅是种群动态和个体生长的基础，而且是微生物食物网利用的颗粒物质转化和溶解成分释放的基础。多年来，许多争论都集中在我们无法知道海洋中动物的进食速度有多快，以及这个过程中有多少变化。大多数实验方法涉及将动物限制在不同大小的容器中，并提供已知或天然的食物供应。捕获和圈养动物所带来的错误，几乎总是被用来作为结果不十分明确的原因。一种不用把动物放在容器里的方法在近十年前就被认为是向前迈出的重要一步。不出所料，这种方法已被证明在描述海洋中食草动物自然种群的摄食模式和比率方面非常有用。它也被证明有一些不足之处，本调查将探讨这些不足之处，试图完善我们对该方法的理解，并提出改进建议，使结果更加量化。

For a decade field investigators have used the concentration of chlorophyll-derived pigments in the digestive system of copepods as a way of estimating natural feeding rates because the measurement can be done immediately on field caught animals, thereby allowing estimates of natural variance in the feeding process and bypassing incubation procedures which result in uncertainty and artifacts. Recently, the method has been criticized because pigment budgets on some occasions do not arrive at a full accounting for chlorophyll. However, the method has been so insightful in oceanic ecology that it continues to be used in spite of the contention that budgets indicate assimilation of pigment or other unknown source of loss is of major importance. This investigation will try to establish sources of error and suggest new methodology for field measurements of chlorophyll-derived pigments in animal guts. %%% Feeding by grazers in the sea is a fundamental process which underlies not only population dynamics and individual growth, but also transformation of particulate material and release of dissolved components utilized by microbial food webs. Much debate over the years has turned on our inability to know how fast animals feed in nature in the sea and how much variation is involved in the process. Most experimental approaches involve confining animals in containers of various sizes with known or natural food supplies. The errors introduced by catching and confining the animals are almost always invoked as reasons why the results are not very clear cut. A method that does not subject the animals to containers was considered a important step ahead almost a decade ago. Not surprisingly, the method has been shown to be very useful in describing feeding patterns and rates of natural populations of grazers in the sea. It has also been shown to have some deficiencies which this investigation will explore in an attempt to refine our understanding of the method and suggest changes that will make results more quantitative.