Dataset Information

Biogeochemical Processes and Microbial Dynamics Governing Phosphorus Retention and Release in Sediments: A Case Study in Lower Great Lakes Headwaters.

ABSTRACT: The ability of headwater bed and suspended sediments to mitigate non-point agricultural phosphorus (P) loads to the lower Great Lakes is recognized, but the specific biogeochemical processes promoting sediment P retention or internal P release remain poorly understood. To elucidate these mechanisms, three headwater segments located within priority watersheds of Southern Ontario, Canada, were sampled through the growing season of 2018-2020. The study employed equilibrium P assays along with novel assessments of legacy watershed nutrients, nitrogen (N) concentrations, sediment redox, and microbial community composition. 20-year data revealed elevated total P (TP) and total Nitrogen (TN) at an inorganic fertilizer and manure fertilizer-impacted site, respectively. Overall, sampled sites acted as P sinks; however, agricultural sediments exhibited significantly lower buffering capacity compared to a reference forested watershed. Collection of fine suspended sediment (<63 µm) through time-integrated sampling showed the suspended load at the inorganic-fertilized site was saturated with P, indicating a greater potential for P release into surface waters compared to bed sediments. Through vertical microsensor profiling and DNA sequencing of the sediment microbial community, site-specific factors associated with a distinct P-source event were identified. These included rapid depletion of dissolved oxygen (DO) across the sediment water interface (SWI), as well as the presence of nitrate-reducing bacterial and ammonia-oxidizing archaeal (AOA) genera. This research provides valuable insights into the dynamics of P in headwaters, shedding light on P retention and release. Understanding these processes is crucial for effective management strategies aimed at mitigating P pollution to the lower Great Lakes.

SUBMITTER: Falk N

PROVIDER: S-EPMC10509119 | biostudies-literature | 2023 Nov

REPOSITORIES: biostudies-literature

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Publications

Biogeochemical Processes and Microbial Dynamics Governing Phosphorus Retention and Release in Sediments: A Case Study in Lower Great Lakes Headwaters.

Falk Nicholas N Droppo Ian G IG Drouillard Ken G KG Weisener Christopher G CG

Environmental management 20230728 5

The ability of headwater bed and suspended sediments to mitigate non-point agricultural phosphorus (P) loads to the lower Great Lakes is recognized, but the specific biogeochemical processes promoting sediment P retention or internal P release remain poorly understood. To elucidate these mechanisms, three headwater segments located within priority watersheds of Southern Ontario, Canada, were sampled through the growing season of 2018-2020. The study employed equilibrium P assays along with novel ...[more]

PMID: 37505273

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Dataset Information

Biogeochemical Processes and Microbial Dynamics Governing Phosphorus Retention and Release in Sediments: A Case Study in Lower Great Lakes Headwaters.

Publications

Biogeochemical Processes and Microbial Dynamics Governing Phosphorus Retention and Release in Sediments: A Case Study in Lower Great Lakes Headwaters.

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