Chemical Characterization and Reactivity of Dissolved Organic Matter in Seawater

溶解有机物（DOM）在海洋碳循环中的核心作用以及DOM对许多物理、化学和生物过程的影响已被广泛认识，但有关DOM的来源、反应性和循环的基本问题仍有待回答。 这些问题的许多答案都隐藏在DOM的化学结构中，但DOM的表征具有挑战性，因为海水中的浓度很低，盐含量丰富。 DOM的分离和化学表征的新方法正在开始这一主要碳库的转变。 切向流超滤已成为分离不同粒径的海洋有机物的一种强有力的方法。 最近在表征超滤物质方面的努力提供了大量关于海洋DOM的新信息。 在今后三年中，研究将侧重于海水DOM的特性，并建立在过去三年对超滤DOM特性的研究的主要结果的基础上。 拟议研究的主要目标是： 1)研究海洋有机质的大小、组成和微生物反应性之间的关系; 2）表征海洋陆源DOM的分布和循环。

The central role of Dissolved Organic Matter (DOM) in the ocean carbon cycle and the influence of DOM on numerous physical, chemical, and biological processes are widely recognized, but fundamental questions about the sources, reactivity, and cycling of DOM remain to be answered. Many of the answers to these questions lie hidden within the chemical structures of DOM, but characterization of DOM is challenging because concentrations are low and salts are abundant in seawater. Novel approaches to the isolation and chemical characterization of DOM are beginning transformations of this major carbon reservoir. Tangential-flow ultrafiltration has emerged as a powerful approach for the isolation of different size classes of marine organic matter. Recent efforts in the characterization of ultrafiltered material have provided a wealth of new information about marine DOM. Over the next three years research will focus on the characterization of seawater DOM and build upon major findings of the past three years of research on the characterization of ultrafiltered DOM. The major objectives of the proposed research are: 1) to investigate relationships among size, composition, and microbial reactivity of marine organic matter, and 2) to characterize the distribution and cycling of terrigenous DOM in the ocean.