Water Quality Change in the Mississippi River

Dr. David A. White and Dr. Jenneke M. Visser published an article "Water quality change in the Mississippi River, including a warming river, explains decades of wetland plant biomass change within its Balize delta." Aquatic Botany 132 (2016) 5-11.
 

Highlights

•Wetlands in the Mississippi River’s Balize Delta, USA showed an overall plant biomass increase with a large inter-annual change from 1988–2008.

•River discharge and sediment negatively impacted the biomass over these decades, whereas river temperature had a positive impact.

•The decadal plant biomass likely increased because of the impact of a 0.9 °C/decade increase in river temperature on growing season length.

•The added river temperature increased the growing season 0.7 days each year from 1983–2012, or 14.7 days over the shorter biomass study period.

•Climate change and land use/cover change in the catchment are likely responsible for the river and wetland biomass change in the Balize Delta.

Abstract

Ecosystem properties of riverine wetlands are known for high inter-annual variability. This multi-decadal study within the wetland complex of the Mississippi River’s Balize Delta, USA assesses how river parameters (temperature, discharge, and sediment load) impact wetland plant biomass over time and space. The Mississippi River’s annual temperature has increased 0.9 °C/decade, while discharge and sediment load has varied without trend over the same period. End-of-season herbaceous biomass increased 14 g/m2/year between 1988 and 2008, extrapolating to large (m-ton) area-wide increases. The river’s temperature, discharge and sediment impacted the Delta’s biomass in two ways: the increase in temperature had a positive impact on the growing season length which increased biomass; whereas discharge and load had negative impacts affecting the inter-annual variation without a temporal trend. The results explain natural variability in ecosystem processes in a dynamic deltaic system and likely trace a signal related to both climate warming and land use change within the drainage of the Mississippi River. The discovered decadal increase in herbaceous biomass has implications on carbon storage in the inshore and offshore receiving basins of the world’s riverine wetlands experiencing longer growing seasons.

MRGO-ing, Going, Gone

Documentary film, MRGO-ING, GOING, GONE, a decade in the making, reveals the backstory of the Mississippi River Gulf Outlet—the infamous and now closed 76-mile shipping channel implicated in the catastrophic flooding following Hurricane Katrina. Produced by the Loyola University New Orleans Center for Environmental Communication and e/Prime Media, it’s a story of wetlands destruction, coastal erosion, flooding, political wrangling and mismanaged public resources. A free, public screening of the documentary was held on Wednesday, Oct. 23 at 7 p.m. at the Chalmette Cinema located at 8700 W. Judge Perez Dr. The documentary premiered on New Orleans public television station WYES on October 20 and has since aired several times.

Filmmakers Bob Thomas, Ph.D., director of the Loyola Center for Environmental Communication, and Kevin McCaffrey, executive producer of e/Prime Media, interviewed more than 30 experts, including many who witnessed some of the most distressing environmental consequences of the shipping channel in St. Bernard Parish. The film also features The Lens reporter and Pulitzer Prize-winning environmental journalist Bob Marshall. Though the Mississippi River Gulf Outlet was closed in 2009, the nation could potentially spend billions of dollars repairing the damage caused by it, according to experts interviewed in the documentary. 

United Nations Environment Programme Environmental Effects Assessment Panel

Biological Sciences Professor Paul Barnes joined an elite team of scientists from around the world on the United Nations Environment Programme’s Environmental Effects Assessment Panel to investigate the latest effects of stratospheric ozone depletion, which will culminate in a report published once every four years. In Feb. 23-March 3, 2014 the committee met in Cuernavaca, Mexico, to detail how additional UV rays seeping through the Earth’s atmosphere affect human health, manufactured materials, ecological systems, climate change and other areas. The group will meet again this August in Zhengzhou, China. Barnes’ contribution to the international research effort focuses on what happens to plants and ecosystems under the diminished ozone layer. Ozone depletion and the resulting increased UV could affect things like how fast dead plant material decomposes—ultimately affecting the availability of vital nutrients for plants and soil. Plants exposed to more of the sun’s harmful rays also react by adding more “sunscreen” chemicals to their leaves for protection, according to Barnes. Those consequences have a complicated domino effect on the entire ecosystem, disruptively flowing through the entire food chain. For example, when plants change chemically for sun protection, it can affect the herbivores that eat the plants, according to Barnes. Barnes also lent his expertise to the European Union March 30 in Bled, Slovenia. He acted as an outside evaluator, providing feedback on UV and climate change research funded by the EU. Barnes will work with the European Cooperation in Science and Technology, which coordinates nationally funded research for Europe.

Relevant web sites:

http://ozone.unep.org/new_site/en/assessment_panels_bodies.php?committee_id=8
http://www.cost.eu/

Associated publications and presentations by Dr. Barnes include:

Barnes, P.W., H.L. Throop, S.R. Archer, D. D. Breshears, R.L. McCulley, and M.A. Tobler.  2014.  Sunlight and soil-litter mixing:  drivers of litter decomposition in drylands.  Progress in Botany (In Press).

Wargent, J.J., B.C.W. Nelson, T.K. McGhie, and P.W. Barnes.  2014.  Acclimation to UV-B radiation and visible light in Lactuca sativa involves up regulation of photosynthetic performance and orchestration of metabolome-wide responses.  Plant, Cell & Environment (In Press).

Barnes, P.W., A.R. Kersting, S.D. Flint, W. Beyschlag, and R.J. Ryel.  2013.  Adjustments in epidermal UV-transmittance in sun-shade transitions.  Physiologia Plantarum 149: 200-213.  DOI: 10.1111/ppl.12025.    

Barnes, P.W., M.A. Tobler, A.E. Barkley, S.D. Flint, R.J. Ryel, K.M. Keefover-Ring, R.L. Lindroth.  2014.  Rapid changes in UV-shielding in plants:  mechanisms, species patterns and physiological significance.  European Union COST Action UV4growth Final Meeting, Bled, Slovenia. (Invited Presentation) A.E. Barkley was an Environmental Studies Minor.

Levi, E.M., S.R. Archer, H.L. Throop, K.I. Predick, P.W. Barnes, and M.A. Tobler.  2013.  Soil deposition and UV radiation influence litter decomposition in a shrub-invaded dryland ecosystem.  RISE Conference, Tucson, AZ (poster).

Barnes, Paul. W., Mark A Tobler, Stephan D. Flint, Ronald J. Ryel, Kenneth Keefover-Ring, and Richard L. Lindroth.  2013.  Diurnal changes in leaf UV-absorbing compounds and epidermal UV-transmittance.  Ecological Society of America, Minneapolis, MN, August 2013.  Oral presentation.