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Full-Text Articles in Physical Sciences and Mathematics

Unearthing The Effects Of European-American Settlement On A Northeast Ohio Kettle Lake Through Diatom Stratigraphy, Justine Paul A. Berina Jan 2022

Unearthing The Effects Of European-American Settlement On A Northeast Ohio Kettle Lake Through Diatom Stratigraphy, Justine Paul A. Berina

Senior Independent Study Theses

Recently, wetland conservation has highlighted the necessity for assessing limnological changes following European-American settlement. A prior study at Brown's Lake (northeast Ohio) identified a stratigraphic sequence that shows an abrupt transition from organic-rich muds to several centimeters of a bright loess layer, then a recovery to organic-rich sediments near the top. Based on 210Pb dates, the loess deposition occurred before 1846 CE, when a growing population cleared trees and farmed intensively. Likewise, organics had recovered after 1950 CE, when people abandoned farmland and practiced conservation tillage. However, the effects of settlement on limnology are poorly known. Diatoms (microscopic algae; …


Deltaic Wetland Dynamics From Seasonal To Centennial Scales, Giancarlo A. Restreppo Mar 2019

Deltaic Wetland Dynamics From Seasonal To Centennial Scales, Giancarlo A. Restreppo

LSU Doctoral Dissertations

The lower plain of the Mississippi River Delta contains approximately five coastal sedimentary basins that are topographically defined, and one shelf-crossing depocenter (the Birds Foot Delta). These depositional systems receive varying quantities of sediment from fluvial and marine sources and have rates of coastal land loss that are roughly inversely proportional to fluvial sediment supply. To combat land loss along these regions, Louisiana has launched a historic campaign to sustain and regrow coastal lands using, in part, river sediment diversions. Fine sediments constitute the majority of sediment load in the Mississippi River, but are under-studied with respect to dispersal processes, …


Reducing High Flows And Sediment Loading Through Increased Water Storage In An Agricultural Watershed Of The Upper Midwest, Usa, Nate Mitchell, Karthik Kumarasamy, Se Jong Cho, Patrick Belmont, Brent Dalzell, Karen Gran Aug 2018

Reducing High Flows And Sediment Loading Through Increased Water Storage In An Agricultural Watershed Of The Upper Midwest, Usa, Nate Mitchell, Karthik Kumarasamy, Se Jong Cho, Patrick Belmont, Brent Dalzell, Karen Gran

Watershed Sciences Faculty Publications

Climate change, land clearing, and artificial drainage have increased the Minnesota River Basin’s (MRB) stream flows, enhancing erosion of channel banks and bluffs. Accelerated erosion has increased sediment loads and sedimentation rates downstream. High flows could be reduced through increased water storage (e.g., wetlands or detention basins), but quantifying the effectiveness of such a strategy remains a challenge. We used the Soil and Water Assessment Tool (SWAT) to simulate changes in river discharge from various water retention site (WRS) implementation scenarios in the Le Sueur watershed, a tributary basin to the MRB. We also show how high flow attenuation can …


High Net Loss Of Intertidal Wetland Coverage In A Maine Estuary By Year 2100, Jack R. Mclachlan Jul 2018

High Net Loss Of Intertidal Wetland Coverage In A Maine Estuary By Year 2100, Jack R. Mclachlan

Biology and Ecology Faculty Scholarship

Rising sea levels and coastal land use are predicted to synergistically impact coastal wetlands by reducing their extent and ecosystem functioning through a process known as “coastal squeeze”. Impervious surfaces associated with coastal development prevent the natural process of wetland migration, whereby intertidal wetland area is lost at its seaward edge to rising low water lines, but is replaced by eroding uplands and accumulating new wetland at its landward edge. As these constructed surfaces prevent the replacement of lost wetland, intertidal wetlands are “squeezed” by rising sea levels until they disappear. This study uses geographic information system (GIS) to predict …


Distribution And Impacts Of Petroleum Hydrocarbons In Louisiana Tidal Marsh Sediments Following The Deepwater Horizon Oil Spill, Rachel S. Hatch Jan 2013

Distribution And Impacts Of Petroleum Hydrocarbons In Louisiana Tidal Marsh Sediments Following The Deepwater Horizon Oil Spill, Rachel S. Hatch

Theses and Dissertations--Earth and Environmental Sciences

Following the 2010 Deepwater Horizon (DWH) spill, sediment cores were analyzed from marshes at various levels of oiling to determine how deeply oil penetrated sediment in these marsh environments, and if at these sites it had quantifiably affected benthic ecosystems. Minimum mixing depths were determined from penetration of the lithogenic radionuclide 234Th, which ranged from 0.25 to 4.5 cm. Sediment accumulation rates were determined using 210Pb, with verification from 137Cs in selected cores. Lead-210 profiles revealed long-term (decadal) mixing. Bay Jimmy, Louisiana was significantly affected by the DWH oil spill, as indicated by total polycyclic aromatic hydrocarbon …