LTREB: Response of a reservoir ecosystem to changing subsidies of nutrients and detritus

LTREB：水库生态系统对养分和碎屑补贴变化的响应

• 批准号: 1930655
• 负责人: Michael Vanni
• 金额: $ 63.5万
• 依托单位: Miami University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1930655&HistoricalAwards=false
• 关键词: LTREB; Response; reservoir; ecosystem; changing

This award in long-term research in environmental biology examines how long-term changes in agriculture affect streams and lakes, using an Ohio landscape as a model system. In the 1990s, this landscape experienced a pronounced increase in conservation tillage (reduced- and no-till farming), which strongly affected nutrients and sediments in streams that feed downstream Acton Lake. Also, the abundance of bottom-feeding fish in the lake increased. These fish consume sediments and excrete nutrients into the water, providing another source of nutrients to algae. In the lake, the amount of algae is controlled mostly by concentrations of sediment in the water (which block light that algae need) and the abundance of bottom-feeding fish; this project explores long-term changes in these interactions. This research is important because similar agricultural changes are occurring throughout the US, but little is known about long-term effects on streams and lakes. The investigators will mentor several undergraduate and graduate students who will conduct research projects, and offer summer workshops for high school students, targeting students from underrepresented groups. This project tests hypotheses about the long-term dynamics and consequences of ecosystem subsidies. Over the past 25 years, watershed subsidies of nitrogen, phosphorus, and detritus (sediments) to Acton Lake have changed because of an increase in conservation tillage. Furthermore, nutrient subsidies from detritivorous fish (gizzard shad), which translocate nitrogen and phosphorus from sediments to water, have varied temporally. Over the 10-12 years, stream phosphorus and sediment concentrations declined, and Acton Lake phytoplankton increased because light limitation was alleviated by decreased suspended sediments and because of increased biomass (hence nutrient excretion) of gizzard shad. However, more recently stream soluble reactive phosphorus (SRP) concentrations increased, nitrate concentrations declined, and lake phytoplankton biomass stabilized. Furthermore, phytoplankton became increasingly limited by nitrogen relative to phosphorus, coinciding with declining nitrate and increasing SRP in streams, and with greater biomass of gizzard shad, which excrete at low nitrogen:phosphorus ratio. This long-term research in environmental biology award tests the following hypotheses: 1) in streams, SRP will continue to increase while nitrate continues to decline; 2) gizzard shad excretion rates will remain consistently high; 3) phytoplankton will become increasingly nitrogen-limited; and 4) phytoplankton biomass will be stable, or decline as nitrogen becomes more limiting. In addition, it is hypothesized that long-term environmental change and short-term weather variation will modulate watershed subsidies, and thus lake ecosystem dynamics. These hypotheses will be tested using a variety of statistical and modeling analyses on long-term data.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.

该奖项涉及环境生物学长期研究，以俄亥俄州景观作为模型系统，研究农业的长期变化如何影响溪流和湖泊。 20 世纪 90 年代，该景观经历了保护性耕作（减少耕作和免耕耕作）的显着增加，这强烈影响了阿克顿湖下游溪流中的养分和沉积物。此外，湖中底栖鱼类的数量也有所增加。这些鱼消耗沉积物并将营养物质排泄到水中，为藻类提供另一种营养来源。在湖中，藻类的数量主要由水中沉积物的浓度（阻挡藻类所需的光线）和底栖鱼类的丰度控制；该项目探讨了这些相互作用的长期变化。这项研究很重要，因为类似的农业变化正在美国各地发生，但人们对溪流和湖泊的长期影响知之甚少。研究人员将指导几名本科生和研究生开展研究项目，并为高中生提供夏季研讨会，目标对象是来自代表性不足群体的学生。该项目测试有关生态系统补贴的长期动态和后果的假设。过去25年来，由于保护性耕作的增加，对阿克顿湖的氮、磷和碎屑（沉积物）的流域补贴发生了变化。此外，食性鱼类（砂鲥鱼）将氮和磷从沉积物转移到水中，其营养补贴随时间而变化。在 10-12 年里，河流磷和沉积物浓度下降，阿克顿湖浮游植物增加，因为悬浮沉积物减少减轻了光限制，并且砂鲥鱼生物量增加（因此养分排泄）。然而，最近溪流中可溶性活性磷（SRP）浓度增加，硝酸盐浓度下降，湖泊浮游植物生物量稳定。此外，相对于磷，浮游植物越来越受到氮的限制，这与溪流中硝酸盐的下降和SRP的增加相一致，并且砂囊鲥鱼的生物量增加，其以低氮磷比排泄。这项环境生物学奖的长期研究测试了以下假设：1）在溪流中，SRP 将继续增加，而硝酸盐将继续下降； 2) 砂囊鲥鱼排泄率将持续保持较高水平； 3）浮游植物的氮含量将越来越有限； 4）浮游植物生物量将保持稳定，或者随着氮变得更加有限而下降。此外，假设长期环境变化和短期天气变化将调节流域补贴，从而调节湖泊生态系统动态。这些假设将通过对长期数据的各种统计和建模分析进行测试。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标准进行评估，被认为值得支持。

项目成果

Estimating pelagic primary production in lakes: Comparison of 14C incubation and free‐water O2 approaches

估算湖泊中上层初级生产力：14C 孵化法和自由水 O2 方法的比较

• DOI: 10.1002/lom3.10471
• 发表时间: 2022
• 期刊: Limnology and Oceanography: Methods
• 作者: Lottig, Noah R.;Phillips, Joseph S.;Batt, Ryan D.;Scordo, Facundo;Williamson, Tanner J.;Carpenter, Stephen R.;Chandra, Sudeep;Hanson, Paul C.;Solomon, Chistopher T.;Vanni, Michael J.
• 通讯作者: Vanni, Michael J.

Spatial and Temporal Variability of Nutrient Dynamics and Ecosystem Metabolism in a Hyper-eutrophic Reservoir Differ Between a Wet and Dry Year

富营养化水库养分动态和生态系统代谢的时空变化在丰水年和旱年之间存在差异

• DOI: 10.1007/s10021-020-00505-8
• 发表时间: 2021
• 期刊: Ecosystems
• 影响因子: 3.7
• 作者: Williamson, Tanner J.;Vanni, Michael J.;Renwick, William H.
• 通讯作者: Renwick, William H.

Teaching Nutrient Cycling and Climate Change Concepts Using Excretion Experiments with Common Fish

利用常见鱼类的排泄实验教授营养循环和气候变化概念

• DOI: 10.1525/abt.2023.85.9.500
• 发表时间: 2023
• 期刊: The American Biology Teacher
• 作者: Sharitt, Carrie Ann;Vanni, Michael J.
• 通讯作者: Vanni, Michael J.

Temporal patterns in sediment, carbon, and nutrient burial in ponds associated with changing agricultural tillage

与农业耕作变化相关的池塘沉积物、碳和养分埋藏的时间模式

• DOI: 10.1007/s10533-022-00916-w
• 发表时间: 2022
• 期刊: Biogeochemistry
• 影响因子: 4
• 作者: Rogers, Martina N.;Williamson, Tanner J.;Knoll, Lesley B.;Vanni, Michael J.
• 通讯作者: Vanni, Michael J.

Trophic Transfer Efficiency in Lakes

• DOI: 10.1007/s10021-022-00776-3
• 发表时间: 2022-07-05
• 期刊: ECOSYSTEMS
• 影响因子: 3.7
• 作者: Mehner, Thomas;Attermeyer, Katrin;Gaedke, Ursula
• 通讯作者: Gaedke, Ursula