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Louisiana State University

Faculty Publications

Nutrients

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Full-Text Articles in Physical Sciences and Mathematics

The Tensile Root Strength Of Spartina Patens Declines With Exposure To Multiple Stressors, R. Eugene Turner, Lauris O. Hollis Jan 2021

The Tensile Root Strength Of Spartina Patens Declines With Exposure To Multiple Stressors, R. Eugene Turner, Lauris O. Hollis

Faculty Publications

Coastal wetlands may be subjected to numerous biotic and abiotic stressors from natural and anthropogenic forces in the landscape. The influx of nutrients, inorganic compounds and xenobiotics are suspected of degrading the belowground biomass of coastal macrophytes. Spartina patens acts as an ecosystem engineer for lower salinity coastal marshes and its biomechanical properties are vital to the stability and resilience of coastal wetlands. S.patens was exposed to one natural (flooding) and two anthropogenic stressors (atrazine and nutrient addition) in a greenhouse experiment to test the hypothesis that these three stressors reduce the tensile root strength of S. patens. A one-way …


Dinoflagellate Cysts Track Eutrophication In The Northern Gulf Of Mexico, Andrea M. Price, Melissa M. Baustian, R. Eugene Turner, Nancy N. Rabalais, Gail L. Chmura Dec 2017

Dinoflagellate Cysts Track Eutrophication In The Northern Gulf Of Mexico, Andrea M. Price, Melissa M. Baustian, R. Eugene Turner, Nancy N. Rabalais, Gail L. Chmura

Faculty Publications

We examined organic-walled dinoflagellate cysts from one 210Pb-dated sediment core and 39 surface sediment samples from the northern Gulf of Mexico to determine the relationship between nutrient enrichment and cyst assemblages in this region characterized by oxygen deficiency. The core spans from 1962 to 1997 and its sampling location is directly influenced by the Mississippi River plume. Surface sediments were collected in 2006, 2007, 2008, and 2014 and represent approximately 1 to 4 years of accumulation. A total of 57 cyst taxa were recorded, and four heterotrophic taxa in particular were found to increase in the top section (1986–1997) of …


Below- And Aboveground Biomass Of Spartina Alterniflora: Response To Nutrient Addition In A Louisiana Salt Marsh, Faith A. Darby, R. Eugene Turner Feb 2008

Below- And Aboveground Biomass Of Spartina Alterniflora: Response To Nutrient Addition In A Louisiana Salt Marsh, Faith A. Darby, R. Eugene Turner

Faculty Publications

The responses of Spartina alterniflora above- and belowground biomass to various combinations of N, P, and Fe were documented in a 1-year field experiment in a Louisiana salt marsh. Five levels of N additions to 0.25 m2 plots resulted in 18% to 138% more live aboveground biomass compared to the control plots and higher stem densities, but had no effect on the amount of live belowground biomass (roots and rhizomes; R&R). There was no change in the aboveground biomass when P or Fe was added as part of a factorial experiment of +P, +N, and +Fe additions, but there was …


Suspended Sediment, C, N, P, And Si Yields From The Mississippi River Basin, R. Eugene Turner, Nancy N. Rabalais Jan 2004

Suspended Sediment, C, N, P, And Si Yields From The Mississippi River Basin, R. Eugene Turner, Nancy N. Rabalais

Faculty Publications

The annual loads of C,N,P, silicate, total suspended sediment (mass) and their yields (mass area−1) were estimated for six watersheds of the Mississippi River Basin (MRB) using water quality and water discharge records for 1973 to 1994. The highest load of suspended sediments is from the Missouri watershed (58 mt km2 yr−1), which is also the largest among the six major sub-basins. The Ohio watershed delivers the largest load of water (38%). The Upper Mississippi has the largest total nitrogen load (32%) and yield (1120 kg TN km2 yr−1). The loading of organic carbon, total phosphorus and silicate from the …