Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, 146 Williams Street, Solomons, Maryland 20688, United States.
Biology Department, College of Humanities and Sciences, Virginia Commonwealth University, Richmond, Virginia 23298, United States.
Environ Sci Technol. 2022 May 3;56(9):5371-5380. doi: 10.1021/acs.est.1c08871. Epub 2022 Apr 20.
This perspective challenges our current understanding of the marine carbon cycle, including an alternative explanation of bulk C-DOM measurements. We propose the adoption of the carbon reactivity continuum concept previously established for lakes and sediments for the oceans using kinetic data and term this the marine DOM reactivity continuum. We need to gain a fundamental understanding of the biogeochemical drivers of surface water DOM concentrations and reactivity, biological carbon pump efficiency, and the autotrophic communities that are the ultimate but variable sources of marine DOM. This perspective is intended to shift our focus to a more inclusive kinetic model and may lead us to a more accurate assessment of the active and dynamic role marine DOM plays in the global carbon cycle. Currently, the kinetic data to establish and validate such a marine DOM reactivity continuum model are still lacking, and their resolution depends on the discovery of new organic tracers that span large differences in reactivity and microbial degradation rates. We may need to refocus our efforts in deciphering the structure and reactivity of marine organic molecules in a kinetic context, including the microbial and physicochemical constraints on molecular reactivity that are present in the deep ocean.
这一观点挑战了我们目前对海洋碳循环的理解，包括对大量 C-DOM 测量的另一种解释。我们建议采用先前为湖泊和沉积物建立的碳反应性连续体概念来描述海洋，使用动力学数据，并将其命名为海洋 DOM 反应性连续体。我们需要深入了解地表水 DOM 浓度和反应性、生物碳泵效率以及作为海洋 DOM 最终但可变来源的自养生物群落的生物地球化学驱动因素。本观点旨在将我们的注意力转移到更具包容性的动力学模型上，并可能使我们更准确地评估海洋 DOM 在全球碳循环中扮演的活跃和动态角色。目前，仍缺乏建立和验证这种海洋 DOM 反应性连续体模型的动力学数据，其分辨率取决于发现能够跨越反应性和微生物降解速率差异的新型有机示踪剂。我们可能需要重新集中精力，从动力学角度揭示海洋有机分子的结构和反应性，包括深海中存在的微生物和物理化学对分子反应性的限制。
