Dissertation Research:Shifting Baselines? The ecological implications of simultaneous eutrophications and overfishing

改变基线？ 过度捕捞和人为造成的营养污染是全球沿海环境面临的最紧迫的问题之一。 这两种压力因素都会影响藻类和海草的生长限制性营养物质（氮（N）和磷（P））的供应，而藻类和海草是大多数海洋生态系统的基础。 人类的投入增加了主要来自污水的营养物质的供应，而过度捕捞则减少了营养物质的供应，因为鱼类通过排泄提供了大量的营养物质。 这些对比鲜明的投入提出了一个悖论，即人类来源的营养素可能取代鱼类来源的营养素。 然而，人类来源的营养素相对于鱼类来源的营养素而言磷含量较高，这可能会改变营养素供应的基线，进而改变藻类和海草物种的多样性和生长速度。 过度捕捞和营养富集将在巴哈马群岛的实验性斑块珊瑚礁生态系统上同时进行独立模拟。 将确定对藻类和海草物种的多样性、生长和营养限制的影响。 实验珊瑚礁系统将被用作实地考察地点，实验结果将用于向当地高中学生进行宣传。亚热带和热带海洋生态系统已经进化到在极低的营养条件下运作，使它们特别容易受到营养动态哪怕是微小变化的影响。这些生态系统提供的巨大服务似乎关键取决于N和P的数量和相对供应，但缺乏对同时过度捕捞和富营养化对这些服务的影响的了解，特别是在加勒比地区。增加对营养物影响的了解对于全球海洋生态系统的管理和养护至关重要。

Shifting Baselines? The ecological implications of simultaneous eutrophication and overfishingOverfishing and human-derived nutrient pollution are among the most pressing issues facing coastal environments globally. Both these stressors affect the supply of growth-limiting nutrients (nitrogen (N) and phosphorus (P)) for algae and seagrasses, the base of most marine ecosystems. Human inputs increase the supply of nutrients, which are largely sewage-derived, while overfishing has been shown to reduce nutrient supply because fish provide substantial inputs of nutrients via excretion. These contrasting inputs present the paradox that human-derived nutrients may supplant fish-derived nutrients. However, human-derived nutrients are high in P relative to fish-derived nutrients, which may be altering the baseline at which nutrients are supplied and in turn changing the diversity and growth rates of algae and seagrass species. Overfishing and nutrient enrichment will be simulated independently and simultaneously on experimental patch-reef ecosystems in the Bahamas. The implications for changes in diversity, growth and nutrient limitation of algae and seagrass species will be determined . The experimental reef system will be used as a field trip site and experimental results will be used in outreach efforts to local high school students. Subtropical and tropical marine ecosystems have evolved to function under extremely low nutrient conditions, making them particularly susceptible to even minor alterations in nutrient dynamics. The enormous services provided by these ecosystems appear to critically hinge on the amount and relative supply of N and P, yet understanding of the effects of simultaneous overfishing and eutrophication for these services is lacking, particularly in the Caribbean. Increased understanding of nutrient effects is critical to the management and conservation of marine ecosystems globally.