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Multiple Models Guide Strategies for Agricultural Nutrient Reductions


In response to degraded water quality, federal policy makers in the US and Canada called for a 40% reduction in phosphorus (P) loads to Lake Erie, and state and provincial policy makers in the Great Lakes region set a load-reduction target for the year 2025. Here, we configured five separate SWAT (US Department of Agriculture’s Soil and Water Assessment Tool) models to assess load reduction strategies for the agriculturally dominated Maumee River watershed, the largest P source contributing to toxic algal blooms in Lake Erie. Although several potential pathways may achieve the target loads, our results show that any successful pathway will require large-scale implementation of multiple practices. For example, one successful pathway involved targeting 50% of row cropland that has the highest P loss in the watershed with a combination of three practices: subsurface application of P fertilizers, planting cereal rye as a winter cover crop, and installing buffer strips. Achieving these levels of implementation will require local, state/provincial, and federal agencies to collaborate with the private sector to set shared implementation goals and to demand innovation
and honest assessments of water quality-related
programs, policies, and partnerships.

DOI: 10.1002/fee.1472 VOLUME: 15 ISSUE: 3 LENGTH: 6 pages

Microcystis Rising: Why Phosphorus Reduction Isn’t Enough to Stop CyanoHABs

DOI: 10.1289 VOLUME: 125 ISSUE: 2 LENGTH: 5 pages

Fertilizer Placement and Application Timing as Strategies to Reduce Phosphorus Loading to Lake Erie


To reduce the intensity and frequency of harmful algal blooms in western Lake Erie, it has been recommended to reduce the phosphorus load, contributed by the Maumee River watershed (MRW) in northwest Ohio. As the largest contributor of phosphorus to Lake Erie, the dominantly agricultural MRW in northwest Ohio has been recommended to reduce phosphorus loads by 40%. To achieve such reductions, three agricultural nutrient management practices, (1) fertilizer placement within the soil, (2) adjusted seasonal timing of fertilizer application, and (3) adjusted date of fertilizer application to drier days have been recommended. To determine the potential phosphorus load reduction from implementing these three management practices, a SWAT model of the MRW was developed to evaluate the effectiveness of each practice for reducing SRP and total phosphorus (TP) load to the lake. Management scenarios were modeled with variations of the three practices from 2007 to 2012, and compared to historical data. Overall, maximum fertilizer placement had the greatest potential to influence SRP and TP loads; reducing spring SRP and TP loading by 42% and 27%, respectively compared to baseline levels. Seasonal fertilizer application timing also impacted spring SRP and TP loads, but to a lesser degree. Changing the date of application from wetter days to drier days across the watershed did not significantly affect SRP or TP loads, but this result is likely due to limitations of the SWAT simulation. These results indicate that maximizing fertilizer placement has a great potential to reduce TP and SRP runoff from the MRW.

DOI: 10.1016/j.jglr.2016.07.002 VOLUME: 42 ISSUE: 6 LENGTH: 7 pages

It Takes Two to Tango: When and Where Dual Nutrient (N & P) Reductions Are Needed to Protect Lakes and Downstream Ecosystems


Preventing harmful algal blooms (HABs) is needed to protect lakes and downstream ecosystems. Traditionally, reducing phosphorus (P) inputs was the prescribed solution for lakes, based on the assumption that P universally limits HAB formation. Reduction of P inputs has decreased HABs in many lakes, but was not successful in others. Thus, the “P-only” paradigm is overgeneralized. Whole-lake experiments indicate that HABs are often stimulated more by combined P and nitrogen (N) enrichment rather than N or P alone, indicating that the dynamics of both nutrients are important for HAB control. The changing paradigm from P-only to consideration of dual nutrient control is supported by studies indicating that (1) biological N fixation cannot always meet lake ecosystem N needs, and (2) that anthropogenic N and P loading has increased dramatically in recent decades. Sediment P accumulation supports long-term internal loading, while N may escape via denitrification, leading to perpetual N deficits. Hence, controlling both N and P inputs will help control HABs in some lakes and also reduce N export to downstream N-sensitive ecosystems. Managers should consider whether balanced control of N and P will most effectively reduce HABs along the freshwater-marine continuum.

DOI: 10.1021/acs.est.6b02575 VOLUME: 50 ISSUE: 20 LENGTH: 8 pages

Forecast for Harmful Algal Blooms in Lake Erie in 2016


Forecast for Harmful Algal Blooms in Lake Erie in 2016

LENGTH: 141 pages
Broadcast, Podcast, Webinar

HABs FAQs: Are Fish Caught in a Harmful Algal Bloom Safe to Eat?


Dr. Stuart Ludsin answers the question “Are fish caught in or near a harmful algal bloom safe to eat?”

DURATION: ~ 1 min
Broadcast, Podcast, Webinar

HABs FAQs: How is drinking water treated to remove microcystin?


Ohio Sea Grant Special Advisor Dr. Jeffery Reutter answers the question “How is drinking water treated to remove microcystin?”

DURATION: ~ 1 min
Broadcast, Podcast, Webinar

HABs FAQs: What level of exposure to microcystin in drinking water is dangerous?


Frequently Asked Questions Harmful Algal Blooms — Ohio Sea Grant Special Advisor Dr. Jeffry Reutter answers the question “What level of exposure to microcystin in drinking water is dangerous?”

DURATION: ~ 1 min
Broadcast, Podcast, Webinar

HABs FAQs: Is the air near an algae bloom dangerous to inhale?


Frequently Asked Questions Harmful Algal Blooms — Ohio Sea Grant Special Advisor Dr. Jeffrey Reutter answers the question “Is the air near an algae bloom dangerous to inhale?”

DURATION: ~ 1 min
Broadcast, Podcast, Webinar

HABs FAQs: How can I help lower the amount of phosphorus runoff?

DURATION: ~ 1 min
Broadcast, Podcast, Webinar

HABs FAQs: What is the difference between microcystis and microcystin?

DURATION: ~ 1 min
Broadcast, Podcast, Webinar

HABs FAQs: How quickly will Lake Erie recover if we reduce phosphorus runoff?


Frequently Asked Questions Harmful Algal Blooms — Ohio Sea Grant Special Advisor Dr. Jeffry Reutter answers the question “How quickly will Lake Erie recover if we reduce phosphorus runoff?”

LENGTH: 1 page
Broadcast, Podcast, Webinar

HABs FAQs: What Conditions Cause a Harmful Algal Bloom?

DURATION: ~ 1 min
Broadcast, Podcast, Webinar

HABs FAQs: What Steps Can We Take to Reduce or Eliminate Harmful Algal Blooms?

DURATION: ~ 1 min
Broadcast, Podcast, Webinar

Characterization of The Persistent Cyanobacterial Bloom, Planktothrix in Sandusky Bay, Lake Erie


Planktothrix sp. is less studied than other bloom-forming cyanobacteria. The aim of this study was to determine characteristics of the Planktothrix bloom in Sandusky Bay. Using the 2013 Sandusky Bay metagenome and 2014 summer samples, it was found that the bloom in Sandusky Bay has limited diversity and is continuously dominated by Planktothrix. Nutrient profiles of the Bay suggest nitrogen limitation throughout the bloom season. Physical parameters recorded in Sandusky Bay are suboptimal for many known bloom-forming cyanobacteria. Given this information, it is not yet understood how Planktothrix survives and dominates Sandusky Bay. Future work will look further at community members playing a role in the nitrogen cycle in the Bay. Additionally, the succession of genotypes will be determined over time as the environmental parameters will be monitored over a longer period of time to determine how survival of Planktothrix is supported.

Thesis / Dissertation

Stone Lab Guest Lecture: Great Lakes Water Quality Agreement

DURATION: ~ 2 hrs, 5 mins
Broadcast, Podcast, Webinar

National Oceanic and Atmospheric Administration Harmful Algal Blooms Forecast 2015 Webinar

DURATION: ~ 1 hr, 52 mins
Broadcast, Podcast, Webinar

Harmful Algal Blooms Primer 2015

DURATION: 53 mins
Broadcast, Podcast, Webinar

Harmful Algal Blooms Kiosk Panel

LENGTH: 1 page

Effects of Increasing Nitrogen and Phosphorus Concentrations on Phytoplankton Community Growth and Toxicity During Planktothrix Blooms in Sandusky Bay, Lake Erie


Sandusky Bay experiences annual toxic cyanobacterial blooms dominated by Planktothrix agardhii/suspensa. To further understand the environmental drivers of these events, we evaluated changes in the growth response and toxicity of the Planktothrix-dominated blooms to nutrient amendments with orthophosphate (PO4) and inorganic and organic forms of dissolved nitrogen (N; ammonium (NH4), nitrate (NO3) and urea) over the bloom season (June – October). We complemented these with a metagenomic analysis of the planktonic microbial community. Our results showed that bloom growth and microcystin (MC) concentrations responded more frequently to additions of dissolved N than PO4, and that the dual addition of NH4 + PO4 and Urea + PO4 yielded the highest MC concentrations in 54% of experiments. Metagenomic analysis confirmed that P. agardhii/suspensa was the primary MC producer. The phylogenetic distribution of nifH revealed that both heterocystous cyanobacteria and heterotrophic proteobacteria had the genetic potential for N2 fixation in Sandusky Bay. These results suggest that as best management practices are developed for P reductions in Sandusky Bay, managers must be aware of the negative implications of not managing N loading into this system as N may significantly impact cyanobacterial bloom size and toxicity.

DOI: 10.1021/acs.est.5b00799 VOLUME: 49 ISSUE: 12 LENGTH: 10 pages

An Automated Approach to Agricultural Tile Drain Detection and Extraction Utilizing High Resolution Aerial Imagery and Object-based Image Analysis


Subsurface drainage from agricultural fields in the Maumee River watershed is suspected
to adversely impact the water quality and contribute to the formation of harmful algal
blooms (HABs) in Lake Erie. In early August of 2014, a HAB developed in the western
Lake Erie Basin that resulted in over 400,000 people being unable to drink their tap water
due to the presence of a toxin from the bloom. HAB development in Lake Erie is aided
by excess nutrients from agricultural fields, which are transported through subsurface tile
and enter the watershed. Compounding the issue within the Maumee watershed, the trend
within the watershed has been to increase the installation of tile drains in both total extent
and density. Due to the immense area of drained fields, there is a need to establish an
accurate and effective technique to monitor subsurface farmland tile installations and
their associated impacts.
This thesis aimed at developing an automated method in order to identify subsurface tile
locations from high resolution aerial imagery by applying an object-based image analysis
(OBIA) approach utilizing eCognition. This process was accomplished through a set of
algorithms and image filters, which segment and classify image objects by their spectral
and geometric characteristics. The algorithms utilized were based on the relative location
of image objects and pixels, in order to maximize the robustness and transferability of the
final rule-set. These algorithms were coupled with convolution and histogram image
filters to generate results for a 10km² study area located within Clay Township in Ottawa
County, Ohio.
The eCognition results were compared to previously collected tile locations from an
associated project that applied heads-up digitizing of aerial photography to map field tile.
The heads-up digitized locations were used as a baseline for the accuracy assessment.
The accuracy assessment generated a range of agreement values from 67.20% – 71.20%,
and an average agreement of 69.76%. The confusion matrices calculated a range of
kappa values from 0.273 – 0.416 with an overall K value of 0.382, considered fair in
strength of agreement. This thesis provides a step forward in the ability to automatically
identify and extract tile drains, and will assist future research in subsurface agricultural
drainage modeling.

LENGTH: 77 pages
Thesis / Dissertation

National Oceanic and Atmospheric Administration Harmful Algal Blooms Forecast 2014 Webinar


Recording of NOAA’s 2014 harmful algal blooms forecast, issued from Stone Lab.


NOAA and its research partners predict that western Lake Erie will have a significant bloom of cyanobacteria, a toxic blue-green algae, during the 2014 bloom season in late summer. However, the predicted bloom is expected to be smaller than last year’s intense bloom, and considerably less than the record-setting 2011 bloom. Bloom impacts will vary across the lake’s western basin and are classified by an estimate of both its concentration and how far it spreads.

DURATION: ~ 1 hr, 3 mins
Broadcast, Podcast, Webinar

Climate Change and Harmful Algal Blooms in Maumee Bay Webinar


This webinar covers the potential for future algal blooms in Lake Erie’s western basin.


Harmful algal blooms (HABs) are a global problem and have reemerged as a concern in Lake Erie during the last decade. While some have hypothesized HABs in Lake Erie will become more frequent and larger, there are few studies linking predicted climate and watershed models to examine this issue. This talk will describe the methods and results of an ongoing project that links climate models, watershed models and HABs models to predict the frequency and magnitude of HABs through 2099.
This webinar will describe:

Predicted climate for the Maumee Basin through 2099
How climate change is likely to affect river discharge and harmful algal blooms in western Lake Erie
Modeling tools that can help people understand and manage the impacts of extreme weather events and climate change

DURATION: ~ 1 hr, 4 mins
Broadcast, Podcast, Webinar

Organic and inorganic nitrogen utilization by nitrogen-stressed cyanobacteria during bloom conditions


Manuscript on nitrogen utilization by cyanobacteria


Cyanobacterial blooms often occur in lakes that have high phosphorus (P) and low nitrogen (N) concentrations, and the growth rate of the blooms is often constrained by N. For these reasons, many researchers have suggested that regulation of both P and N is required to control eutrophication. However, because N occurs in many bioavailable forms, regulation of a particular form may be beneficial rather than regulation of all N forms. To address how N-stressed cyanobacteria respond to various N inputs, N enrichment experiments (nitrate, ammonium, urea, and alanine) were performed during N-limited cyanobacterial blooms in Maumee and Sandusky Bays of Lake Erie and in Grand Lake St. Marys (GLSM). Bioavailable N (nitrate, urea, and ammonium) concentrationswere also determined. Microcystis aeruginosa dominated the Maumee Bay bloom, where the highest growth rates were in response to ammonium additions, and lowest growth rates were in response to nitrate. Urea and the amino acid alanine resulted in intermediate growth rates. Planktothrix agardhii dominated the Sandusky Bay and GLSM blooms, where nitrate, ammonium, and urea addition resulted in similar growth rates. Additions of alanine did not stimulate growth of the Planktothrix blooms. Incubations using stable isotope 15N showed the cyanobacteria had a preference for ammonium, but the other forms were also assimilated in the presence of ammonium. These results show that cyanobacterial blooms will assimilate multiple forms of N to support growth. Thus, if lake managers do decide that N abatement is necessary, then all forms of bioavailable N need to be constrained.

DOI: 10.1007/s10811-013-0118-0 VOLUME: 26 ISSUE: 1 LENGTH: 10 pages

Climate Change and Harmful Algal Blooms in Lake Erie Webinar


This 2013 climate webinar provides information about historical climate and potential future impacts of climate change in the Lake Erie basin.


Harmful algal blooms continue to be a problem for the Lake Erie ecosystem and lakeshore communities, and predicted climate change impacts like increased heavy precipitation and higher temperatures have the potential to worsen these problems in the future. Focusing on Lake Erie, this webinar will provide information about historical climate and potential future impacts of climate change in the Lake Erie basin; how climate change could impact Lake Erie nutrient levels that drive harmful algal blooms; the potential effects of reduced lake ice and higher temperatures on algal blooms’ length and size. Speakers: Dr. Rick Stumpf of NOAA and Molly Woloszyn of Midwestern Regional Climate Center

Broadcast, Podcast, Webinar

27 June 2013 Stone Laboratory Guest Lecture Series: Solving Lake Erie's Nutrient Loading and Harmful Algal Bloom Problems

Broadcast, Podcast, Webinar

12 July 2012 Stone Laboratory Guest Lecture Series: USGS Science- Partner Driven Research: Huron Erie Corridor, Asian Carps and Harmful Algal Blooms

Broadcast, Podcast, Webinar

Evidence Against Fluvial Seeding of Recurrent Toxic Blooms of Microcystis spp. in Lake Erie’s Western Basin


For almost two decades, the western basin of Lake Erie has been plagued with recurring toxic algal blooms dominated by the colonial cyanobacterium, Microcystis spp. Since the Maumee River is a major source of nutrients and sediment inputs into the lake, and Microcystis spp. has been identified as a member of the upstream river algal assemblage, the possibility exists that the river Microcystis species serve as a seed population for the toxic blooms occurring in the lake. Genetic profiling of toxic cyanobacteria using the microcystin synthesis gene, mcyA, clearly indicates that the toxic cyanobacteria of the river are distinct from the toxic Microcystis spp. of Lake Erie. Indeed, mcyA sequences are almost exclusively from toxic Planktothrix spp., similar to what has been documented previously for Sandusky Bay. UniFrac statistical analysis of cyanobacterial community composition by comparison of 16S–23S ITS sequences also show that the Maumee River and Lake Erie communities are distinct. Overall, these data show that despite the importance of nutrient inputs and sediments from the river, the toxic cyanobacterial blooms of Lake Erie do not originate from toxic species endemic to the Maumee River and instead must originate elsewhere, most likely from the lake sediments.

DOI: 10.1016/j.hal.2011.11.007 VOLUME: 15 LENGTH: 6 pages

5 July 2012 Lake Erie and Harmful Algal Blooms Webinar

Broadcast, Podcast, Webinar

Lake Erie Nutrient Loading and Harmful Algal Blooms: Research Findings and Management Implications

LENGTH: 16 pages
Technical Summary

Harmful Algal Blooms in Ohio Waters

LENGTH: 4 pages
Fact Sheet
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