Anticipated Impacts of Climate Change on 21st Century Maumee River Discharge and Nutrient LoadsOHSU-RS-1562 ABSTRACT:
Climate change holds great potential to affect the Lake Erie ecosystem by altering the timing and magnitude of precipitation driven river discharge and nutrient runoff in its highly agricultural watershed. Using the SWAT hydrologic model and an ensemble of global climate models, we predicted Maumee River (Ohio) discharge during the 21st century under two Intergovernmental Panel on Climate Change (IPCC) greenhouse gas emissions scenarios: RCP4.5 (mid-range, moderate reductions) and RCP8.5 (high, “business as usual”). Annual discharge was projected to increase under both scenarios, both in the near-century (RCP4.5 = 6.5%; RCP8.5 = 2.0%) and late-century (RCP4.5 = 9.2%; RCP8.5 = 15.9%), owing to increased precipitation and reduced plant stomatal conductance. Holding fertilizer application rates at baseline levels, we found that reduced winter surface runoff and increased plant phosphorus (P) uptake led to a respective decrease in annual total P (TP) runoff in the near-century (RCP4.5 = − 4.3%; RCP8.5 = − 6.6%) and by the late-century (RCP4.5 = − 14.6%; RCP8.5 = − 7.8%). Likewise, soluble reactive P (SRP) runoff was predicted to decrease under both scenarios in the near-century (RCP4.5 = − 0.5%; RCP8.5 = − 3.5%) and by the late-century (RCP4.5 = − 11.8%; RCP8.5 = − 8.6%). By contrast, when fertilizer application was modeled to increase at the same rate as plant P uptake, TP loading increased 4.0% (0.9%) in the near-century and 9.9% (24.6%) by the late-century and SRP loading increased 10.5% (6.1%) in the near-century and 26.7% (42.0%) by the late-century under RCP4.5 (RCP8.5). Our findings suggest that changes in agricultural practices (e.g., fertilization rates) will be key determinants of Maumee River discharge during the 21st century.
DOI: 10.1016/j.jglr.2016.08.008 VOLUME: 42 ISSUE: 6 LENGTH: 10 pages
Quantifying Emissions of Methane Derived From Anaerobic Organic Matter Respiration and Natural Gas Extraction in Lake ErieOHSU-RS-1550 ABSTRACT:
Despite a growing awareness of the importance of inland waters in regional and global carbon © cycles, particularly as sources of the greenhouse gases carbon dioxide (CO2) and methane (CH4), very little is known about C sources and fluxes in the Laurentian Great Lakes, Earth’s largest surface freshwater system. Here, we present a study of CH4 dynamics in Lake Erie, which has large spring algae blooms linked to fertilizer runoff and followed by hypoxia, as well as an extensive network of natural gas wells and pipelines in Canadian waters. Lake Erie is a positive source of CH4 to the atmosphere in late summer, even in shallow regions without water column hypoxia. Stable isotopic measurements indicate that both biogenic and thermogenic CH4 contribute to emissions from Lake Erie. We estimate that Lake Erie emits 1.360.6 3 105 kg CH4-C d21 in late summer, with approximately 30% of CH4 derived from natural gas infrastructure. Additional work is needed to determine the spatial and temporal dynamics of CH4 emissions from Lake Erie and to confirm estimates of source contribution. Studies of the C cycle in large lakes are not as straightforward as those in smaller lakes, as, in addition to O2 availability, subsurface currents and high winds may exert significant control over dissolved CH4 patterns. If climate warming and increasing precipitation intensity lead to increased algal biomass and/or greater extent and duration of hypoxia, this may increase emissions of CH4 from Lake Erie in a positive feedback to climate change.
DOI: 10.1002/lno.10273 VOLUME: 61 ISSUE: 1 LENGTH: 10 pages
Ice Cover Extent Drives Phytoplankton and Bacterial Community Structure in a Large North-temperate Lake: Implications For a Warming ClimateOHSU-RS-1567 ABSTRACT:
Mid-winter limnological surveys of Lake Erie captured extremes in ice extent ranging from expansive ice cover in 2010 and 2011 to nearly ice-free waters in 2012. Consistent with a warming climate, ice cover on the Great Lakes is in decline, thus the ice-free condition encountered may foreshadow the lakes future winter state. Here, we show that pronounced changes in annual ice cover are accompanied by equally important shifts in phytoplankton and bacterial community structure. Expansive ice cover supported phytoplankton blooms of filamentous diatoms. By comparison, ice free conditions promoted the growth of smaller sized cells that attained lower total biomass. We propose that isothermal mixing and elevated turbidity in the absence of ice cover resulted in light limitation of the phytoplankton during winter. Additional insights into microbial community dynamics were gleaned from short 16S rRNA tag (Itag) Illumina sequencing. UniFrac analysis of Itag sequences showed clear separation of microbial communities related to presence or absence of ice cover. Whereas the ecological implications of the changing bacterial community are unclear at this time, it is likely that the observed shift from a phytoplankton community dominated by filamentous diatoms to smaller cells will have far reaching ecosystem effects including food web disruptions.
DOI: 10.1111/1462-2920.12819 VOLUME: 18 ISSUE: 6 LENGTH: 15 pages
In a perfect world, people are objective when they perceive risks and make decisions in climate and other domains. But psychological research suggests that this is not always how the human mind works.
DURATION: ~ 1 hr, 3 mins
|Broadcast, Podcast, Webinar|
LENGTH: 1 page
|Education / Curriculum Publication|
This webinar covers the potential for future algal blooms in Lake Erie’s western basin.ABSTRACT:
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.
Predicted climate for the Maumee Basin through 2099
DURATION: ~ 1 hr, 4 mins
|Broadcast, Podcast, Webinar|
Climate Change and Harmful Algal Blooms in Lake Erie WebinarOHSU-CAST-1509
This 2013 climate webinar provides information about historical climate and potential future impacts of climate change in the Lake Erie basin.ABSTRACT:
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|