Collaborative Research: Carbonate Dissolution in Shallow Water Tropical Sediments: The Role of Seagrasses

最近，有研究认为，氧通过海草的根和根茎进入沉积物可能解决了沉积物有机质再矿化产生的酸与碳酸盐溶解量之间的差异。结合实地观察、实验室实验和建模分析，Old Dominion大学的PI将与圣何塞州立大学的PI合作，量化海草生产力对巴哈马群岛Lee Stocking岛浅水碳通量和碳酸盐溶解的影响。pi将比较从各种样品类型（裸露的鲕状砂到海草覆盖70%的密集植被区域）中恢复的沉积物和孔隙水组成，以建立沉积物中碳酸盐溶解与海草密度之间的关系。其他将进行的研究包括单个海草芽的孵化实验，以确定在可变光和孔隙水O2条件下根和根茎产生的O2量。此外，整个沉积物岩心孵育实验将确定沉积物有机质降解和碳酸盐溶解的速率。最后,Drs。Burdige和Zimmerman计划将他们的数据与通过碳酸盐沉积物成岩过程模型获得的数据进行比较。该研究结果不仅为热带系统的生态和生物地球化学过程提供了基础信息，而且有助于限制浅水碳酸盐岩滩环境中碳酸盐循环的预算。

ABSTRACTOCE-0136597Recently, it has been suggested that oxygen transport into sediments via the roots and rhizomes of seagrasses might resolve the observed discrepancy between the amount of carbonate dissolved and the amount of acid produced from remineralization of sediment organic matter. Combining field observations, laboratory experiments and modeling analysis, a PI from Old Dominion University will team up with a PI from San Jose State University to quantify the influence of seagrass productivity on carbon flux and carbonate dissolution in shallow waters of Lee Stocking Island, Bahamas, a tropical system. The PIs will compare the sediment and porewater composition recovered from a variety of sample types (bare ooid sands to densely vegetates regions with 70% seagrass cover) to establish the relationship between carbonate dissolution in sediments and seagrass density. Other studies to be carried out include incubation experiments of individual seagrass shoots to determine the amount of O2 generated by the roots and rhizomes under variable light and porewater O2 conditions. Additionally, whole sediment core incubation experiments will determine the rate of sediment organic matter degradation and carbonate dissolution. Lastly, Drs. Burdige and Zimmerman plan to compare their data with those obtained via a model of diagenetic processes in carbonate sediments. Results from this study will not only provide basic information on ecological and biogeochemical processes in tropical systems, but will help constrain budgets for carbonate cycling in shallow water carbonate bank environments.