The role of sponges in altering seawater DOM on Caribbean reefs

海绵在改变加勒比珊瑚礁海水 DOM 中的作用

• 批准号: 2218863
• 负责人: Wendy Strangman
• 金额: $ 94.67万
• 依托单位: University of North Carolina at Wilmington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-15 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2218863&HistoricalAwards=false
• 关键词: role; sponges; altering; seawater; DOM

Sponges now dominate Caribbean reefs after decades of declines of reef-building corals. Unlike most benthic reef organisms, sponges are ecosystem engineers that pump and filter huge volumes of seawater, turning-over the water-column and transforming seawater chemistry. The ability of sponges to alter dissolved organic matter (DOM) is recently the subject of increased scientific interest, along with new evidence of ample production of DOM by seaweeds, prompting novel hypotheses about the role of sponges in carbon and nutrient biogeochemical cycling and ecosystem function. The most common species of emergent (large, non-cryptic) sponges on Caribbean reefs range from those having a high abundance of microbial symbionts in their tissues (HMA) to those with low microbial abundance (LMA). Most studies of emergent sponges have shown that HMA species are net consumers of DOM, while LMA species are net producers. While the quantity of DOM in seawater is easily measured, little is known about the composition of the DOM that is processed by sponges. This project is using complimentary analytical approaches, including new chemical derivatization techniques, to characterize ambient and seaweed-derived DOM components in seawater and the effects of processing by HMA and LMA sponges on these components under laboratory conditions and in the coral reef environment. These studies are providing the most complete characterization of DOM and nutrient cycling by sponges on tropical reefs to date. Broader impacts of this project include research support for two new female faculty in a Department of Chemistry and Biochemistry, STEM outreach from female role-models through UNCW’s MarineQuest program to a local charter grade school for girls that specializes in serving under-represented groups, and world-wide public outreach through educational YouTube videos. Building on recent discoveries of the effects of sponge processing on the DOM pool in seawater, this interdisciplinary and collaborative research project is transforming our knowledge of biogeochemical cycling on coral reefs and inspiring novel explanations for differences in reef resilience across the tropics, including the continued decline of Caribbean reef corals. This project is targeting 4 HMA and 2 LMA sponge species with cylindrical shapes and uses a suite of complimentary analytical methods to characterize the naturally occurring DOM compounds in seawater before and after sponge processing using both field and laboratory experiments. Measurements of DOM in seawater include bulk quantification, carbohydrate and amino acid quantification, and solid phase extraction before and after derivatization using targeted and untargeted approaches that employ LC-MS/MS, GC/MS and UPLC-QToF. Untargeted UPLC-QToF MS metabolomics techniques reveal which compounds are significantly altered as seawater moves through the sponge body on the reef. Laboratory incubation experiments characterize the production of DOM by 3 common seaweed taxa and subsequent processing by each of the 6 target sponge species. Considering that DOM is one of the largest reservoirs of organic carbon on the planet, this research project is transforming our understanding of the composition and cycling of seawater DOM by sponges for a tropical reef ecosystem.This project is funded by the Biological and Chemical Oceanography Programs.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

经过数十年造礁珊瑚数量的减少之后，海绵现在在加勒比海珊瑚礁中占据主导地位。与大多数底栖珊瑚礁生物不同，海绵是生态系统工程师，可以泵送和过滤大量海水，翻转水柱并改变海水化学成分。海绵改变溶解有机物 (DOM) 的能力最近成为科学界日益关注的主题，同时有新证据表明海藻大量产生 DOM，引发了关于海绵在碳和养分生物地球化学循环和生态系统功能中的作用的新假设。加勒比珊瑚礁上最常见的新兴（大型、非隐秘）海绵物种范围从组织中微生物共生体丰度高的海绵（HMA）到微生物丰度低的海绵（LMA）。大多数对新生海绵的研究表明，HMA 物种是 DOM 的净消费者，而 LMA 物种是 DOM 的净生产者。虽然海水中 DOM 的含量很容易测量，但对于海绵加工的 DOM 的成分却知之甚少。该项目正在使用补充分析方法，包括新的化学衍生技术，来表征海水中环境和海藻衍生的 DOM 成分，以及在实验室条件和珊瑚礁环境中 HMA 和 LMA 海绵处理对这些成分的影响。这些研究提供了迄今为止最完整的热带珊瑚礁海绵 DOM 和养分循环特征。该项目更广泛的影响包括为化学和生物化学系的两名新女教员提供研究支持，通过 UNCW 的 MarineQuest 计划将 STEM 推广到女性榜样，推广到专门为弱势群体服务的当地特许女子小学，以及通过 YouTube 教育视频进行全球公共推广。基于最近发现的海绵加工对海水中 DOM 池的影响，这个跨学科和合作研究项目正在改变我们对珊瑚礁生物地球化学循环的认识，并激发对热带地区珊瑚礁恢复力差异的新解释，包括加勒比珊瑚礁珊瑚的持续衰退。该项目针对 4 种 HMA 和 2 种 LMA 圆柱形海绵，并使用一套互补的分析方法，通过现场和实验室实验来表征海绵加工前后海水中天然存在的 DOM 化合物。海水中 DOM 的测量包括批量定量、碳水化合物和氨基酸定量以及衍生化前后的固相萃取，使用采用 LC-MS/MS、GC/MS 和 UPLC-QToF 的靶向和非靶向方法。非靶向 UPLC-QToF MS 代谢组学技术揭示了当海水流过珊瑚礁上的海绵体时哪些化合物发生显着改变。实验室孵化实验描述了 3 种常见海藻类群 DOM 的生产以及 6 种目标海绵物种的后续加工。考虑到 DOM 是地球上最大的有机碳库之一，该研究项目正在改变我们对热带珊瑚礁生态系统中海绵对海水 DOM 的组成和循环的理解。该项目由生物和化学海洋学计划资助。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查进行评估，被认为值得支持 标准。