Eutrophication and harmful algal blooms (HABs) are becoming an increasing concern in the Great Lakes. Although there is a total maximum daily load (TMDL) for phosphorus in the Milwaukee Estuary, abundance/biovolume of potential HAB-producing cyanobacteria and cyanotoxin presence in Milwaukee-area rivers and the estuary are largely unknown. USGS evaluations of nutrients in the MMSD Watercourse Corridor Study includes the characterization of processes for stream nutrients to cause estuary eutrophication, low dissolved oxygen, algal growth, and potential HABs by building off the state of science and gaps from the Fox and Maumee Rivers.
During the current 5-year study period for Phase VI (2021-2025) of the Milwaukee Metropolitan Sewerage District (MMSD) Watercourse
Corridor Study, the following six topics are being addressed by one or more USGS subprojects:
1. Ecological Assessments and Trends
2. Geomorphology and Habitat Studies Related to Stream and Estuary Rehabilitation
3. Contaminants in Water and Sediment
5. Nutrient Evaluations
6. Continuous Real-Time Streamflow
This webpage focuses on topic 5. Nutrient Evaluations.
BACKGROUND
Eutrophication and harmful algal blooms (HABs) are becoming an increasing concern in the Great Lakes, especially Lake Erie and Green Bay. The Milwaukee Estuary currently has limited eutrophication problems and limited or no HABs problems; however, changes in stream hydrology may enhance the release of legacy phosphorus from fine-grained stream sediment, thereby enhancing eutrophication and the production of HABs in tributaries to the Milwaukee Estuary. Recent sediment fingerprinting studies in the Kinnickinnic River system showed that the sources of sediment-bound phosphorus were mainly residential areas and secondarily stream banks (Blount, Lenoch, and Fitpatrick, 2023). Phosphorus concentrations were highest in suspended sediment, suggesting that instream sediment is further enriched in phosphorus while being transported through the channel network, similar to nearby agricultural watersheds. Although there is a total maximum daily load (TMDL) for phosphorus in the Milwaukee Estuary, abundance/biovolume of potential HAB-producing cyanobacteria and cyanotoxin presence in Milwaukee-area rivers and the estuary are largely unknown.
OBJECTIVES
The objectives of this study are to describe the processes for stream nutrients to cause estuary eutrophication, low dissolved oxygen, algal growth, and potential HABs by building off the state of science and gaps from the Fox and Maumee Rivers. The USGS will provide a nutrient assessment by identifying hot spots for nutrient availability and phosphorus and nitrogen release in selected Milwaukee streams, relating sediment nutrient dynamics to water column nutrient loads and dissolved oxygen, and determining baseline abundance and biovolume of potential HAB-producing cyanobacteria in selected Milwaukee streams.
APPROACH
The USGS will conduct a baseline study of indicators of sediment-phosphorus and nitrogen availability in stream sediment and algae species at tributary and estuary sites to determine the potential for fueling HABs in Milwaukee-area rivers and the Milwaukee Estuary. Sediment cores and water samples will be collected at up to 32 tributary and estuary sites and analyzed by the USGS Upper Midwest Environmental Science Center for nutrient concentrations. Environmental DNA samples will be collected at the core tributary sites and estuary sites to determine baseline abundance and biovolume of potential HAB-producing cyanobacteria.
CONTACT
- Faith Fitzpatrick (USGS Upper Midwest Water Science Center)
- Hayley Olds (USGS Upper Midwest Water Science Center)
- Overview
Eutrophication and harmful algal blooms (HABs) are becoming an increasing concern in the Great Lakes. Although there is a total maximum daily load (TMDL) for phosphorus in the Milwaukee Estuary, abundance/biovolume of potential HAB-producing cyanobacteria and cyanotoxin presence in Milwaukee-area rivers and the estuary are largely unknown. USGS evaluations of nutrients in the MMSD Watercourse Corridor Study includes the characterization of processes for stream nutrients to cause estuary eutrophication, low dissolved oxygen, algal growth, and potential HABs by building off the state of science and gaps from the Fox and Maumee Rivers.
Sources/Usage: Public Domain.Benthic algae growing at Oak Creek at East Drexel Avenue in Oak Creek, Wisconsin. https://waterdata.usgs.gov/monitoring-location/04087202/ During the current 5-year study period for Phase VI (2021-2025) of the Milwaukee Metropolitan Sewerage District (MMSD) Watercourse
Corridor Study, the following six topics are being addressed by one or more USGS subprojects:
1. Ecological Assessments and Trends
2. Geomorphology and Habitat Studies Related to Stream and Estuary Rehabilitation
3. Contaminants in Water and Sediment
5. Nutrient Evaluations
6. Continuous Real-Time Streamflow
This webpage focuses on topic 5. Nutrient Evaluations.
BACKGROUND
Eutrophication and harmful algal blooms (HABs) are becoming an increasing concern in the Great Lakes, especially Lake Erie and Green Bay. The Milwaukee Estuary currently has limited eutrophication problems and limited or no HABs problems; however, changes in stream hydrology may enhance the release of legacy phosphorus from fine-grained stream sediment, thereby enhancing eutrophication and the production of HABs in tributaries to the Milwaukee Estuary. Recent sediment fingerprinting studies in the Kinnickinnic River system showed that the sources of sediment-bound phosphorus were mainly residential areas and secondarily stream banks (Blount, Lenoch, and Fitpatrick, 2023). Phosphorus concentrations were highest in suspended sediment, suggesting that instream sediment is further enriched in phosphorus while being transported through the channel network, similar to nearby agricultural watersheds. Although there is a total maximum daily load (TMDL) for phosphorus in the Milwaukee Estuary, abundance/biovolume of potential HAB-producing cyanobacteria and cyanotoxin presence in Milwaukee-area rivers and the estuary are largely unknown.
Sources/Usage: Public Domain.North Branch Oak Creek at South Wildwood Drive at Oak Creek, Wisconsin looking upstream during summer. OBJECTIVES
The objectives of this study are to describe the processes for stream nutrients to cause estuary eutrophication, low dissolved oxygen, algal growth, and potential HABs by building off the state of science and gaps from the Fox and Maumee Rivers. The USGS will provide a nutrient assessment by identifying hot spots for nutrient availability and phosphorus and nitrogen release in selected Milwaukee streams, relating sediment nutrient dynamics to water column nutrient loads and dissolved oxygen, and determining baseline abundance and biovolume of potential HAB-producing cyanobacteria in selected Milwaukee streams.
APPROACH
The USGS will conduct a baseline study of indicators of sediment-phosphorus and nitrogen availability in stream sediment and algae species at tributary and estuary sites to determine the potential for fueling HABs in Milwaukee-area rivers and the Milwaukee Estuary. Sediment cores and water samples will be collected at up to 32 tributary and estuary sites and analyzed by the USGS Upper Midwest Environmental Science Center for nutrient concentrations. Environmental DNA samples will be collected at the core tributary sites and estuary sites to determine baseline abundance and biovolume of potential HAB-producing cyanobacteria.
Sources/Usage: Public Domain.This slideshow contains photos related to the MMSD Watercourse Corridor Study: 5. Nutrient Evaluations. CONTACT
- Faith Fitzpatrick (USGS Upper Midwest Water Science Center)
- Hayley Olds (USGS Upper Midwest Water Science Center)