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- Keyword
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- Dolostones; laser ablation ICPMS; rare earth elements; RARE-EARTH-ELEMENTS; ISOTOPIC EVIDENCE; VOLCANIC ASH; REE PATTERNS; PORE WATERS; DOLOMITIZATION; ORIGIN; SEAWATER; CARBONATES; LAURENTIA (1)
- Estuary; Long-term; Freshwater; Eutrophication; Denitrification; Land use; N; P ratio; FRESH-WATER; MISSISSIPPI RIVER; PRIMARY PRODUCERS; ORGANIC-CARBON; NITROGEN; NUTRIENT; EUTROPHICATION; MARINE; BAY; REDUCTIONS (1)
- Estuary; shoal margin collapse; channel-shoal morphodynamics; tidal bars; Western Scheldt; channel network; SEDIMENT TRANSPORT; WESTERN SCHELDT; BANK EROSION; UNIFIED VIEW; RIVER; FLOW; CURRENTS; MODEL; VEGETATION; EVOLUTION (1)
- GULF-OF-MEXICO; FRESH-WATER; SEDIMENT DEPOSITION; FORESTED WETLAND; LAND LOSS; HYDROCARBON PRODUCTION; SPARTINA-ALTERNIFLORA; WINTER TEMPERATURES; SUSPENDED SEDIMENT; FIELD OBSERVATIONS (1)
- Migration; natal origin; stock mixing; Mediterranean Sea; otolith chemistry; stable isotopes; THUNNUS-THYNNUS; MULTIDECADAL OSCILLATION; CANADIAN WATERS; NATAL ORIGIN; LIFE-HISTORY; MIGRATION; PATTERNS; PACIFIC; CONNECTIVITY; TRACKING (1)
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- Predator-prey interactions; Deepwater Horizon oil spill; Blue crabs; Periwinkle snails; Mesocosm; Oil exposure; WATER-HORIZON OIL; CALLINECTES-SAPIDUS RATHBUN; MARSH PERIWINKLE; SALT; ECOSYSTEM; BEHAVIOR; POPULATIONS; AVOIDANCE; MORTALITY; HERBIVORY (1)
- REPRODUCTION; PRECISION; MODEL (1)
- Tensile strength; Roots; Wetlands; Atrazine; Soil texture; ADSORPTION; HERBICIDES; DEISOPROPYLATRAZINE; DEGRADATION; DESORPTION; BIOMASS (1)
- Tropospheric circumpolar vortex; atmospheric teleconnections; atmospheric circulation variability; polar front jet stream; NORTH-ATLANTIC OSCILLATION; ATMOSPHERIC CIRCULATION; GEOPOTENTIAL HEIGHT; EL-NINO; ARCTIC OSCILLATION; SUNSPOT NUMBER; HEMISPHERE; VARIABILITY; TELECONNECTIONS; TEMPERATURE (1)
Articles 1 - 10 of 10
Full-Text Articles in Physical Sciences and Mathematics
Gulf Of Mexico Hypoxia: Past, Present, And Future, Nancy N. Rabalais, R. Eugene Turner
Gulf Of Mexico Hypoxia: Past, Present, And Future, Nancy N. Rabalais, R. Eugene Turner
Faculty Publications
One of the largest human-caused areas of bottom-water oxygen deficiency in the coastal ocean is on the northern Gulf of Mexico continental shelf adjacent to the Mississippi River, which discharges nitrogen and phosphorus loads into its surface waters. The beginnings of seasonal hypoxia (≤2 mg l−1 dissolved oxygen) in this area was in the 1950s with an acceleration in the worsening of severity during the 1970s. Currently, the bottom area of hypoxic areas can approach 23,000 km2, and the volume, 140 km3. Ecosystems, people, and economies are now at risk within the Mississippi River watershed and in the northern Gulf …
Age And Growth Of Hardhead Catfish And Gafftopsail Catfish In Coastal Louisiana, Usa, Shane Flinn, Stephen Midway
Age And Growth Of Hardhead Catfish And Gafftopsail Catfish In Coastal Louisiana, Usa, Shane Flinn, Stephen Midway
Faculty Publications
The Hardhead Catfish Ariopsis felis and Gafftopsail Catfish Bagre marinus are marine catfishes that have low recreational and commercial landings in U.S. waters, although they are among the most abundant species in coastal waters of the Gulf of Mexico. Few biological studies exist on marine catfishes, with most studies focusing on their unique reproductive biology. This study evaluated weight-length relationships for Gafftopsail Catfish (n = 264) and Hardhead Catfish (n = 823) sampled from across coastal Louisiana, USA, during 2016-2018; subsamples (93 and 266, respectively) were aged using lapilli for age and growth analyses. Hardhead Catfish showed a small but …
The Tensile Root Strength Of Spartina Patens Varies With Soil Texture And Atrazine Concentration, Lauris O. Hollis, R. Eugene Turner
The Tensile Root Strength Of Spartina Patens Varies With Soil Texture And Atrazine Concentration, Lauris O. Hollis, R. Eugene Turner
Faculty Publications
The widely used agricultural herbicide atrazine enters wetlands and may potentially affect wetland plants that provide critical reinforcement of soil strength and contribute to ecosystem stability in ways that may vary among soil types. We conducted greenhouse experiments using four levels of atrazine doses and three different soil textures to test for differences between control and experimental treatments and interactive effects of soil texture and atrazine exposure by using the tensile root strength of the coastal wetland emergent macrophyte Spartina patens as the response variable. The tensile root strength of S. patens was not affected after 50days of atrazine exposure …
Drivers And Impacts Of Water Level Fluctuations In The Mississippi River Delta: Implications For Delta Restoration, Matthew Hiatt, John W. Day, Robert V. Rohli, John Andrew Nyman
Drivers And Impacts Of Water Level Fluctuations In The Mississippi River Delta: Implications For Delta Restoration, Matthew Hiatt, John W. Day, Robert V. Rohli, John Andrew Nyman
Faculty Publications
This review synthesizes the knowledge regarding the environmental forces affecting water level variability in the coastal waters of the Mississippi River delta and relates these fluctuations to planned river diversions. Water level fluctuations vary significantly across temporal and spatial scales, and are subject to influences from river flow, tides, vegetation, atmospheric forcing, climate change, and anthropogenic activities. Human impacts have strongly affected water level variability in the Mississippi River delta and other deltas worldwide. Collectively, the research reviewed in this article is important for enhancing environmental, economic, and social resilience and sustainability by assessing, mitigating, and adapting to geophysical changes …
The Effects Of Oil On Blue Crab And Periwinkle Snail Interactions: A Mesocosm Study, Elizabeth M. Robinson, Nancy N. Rabalais
The Effects Of Oil On Blue Crab And Periwinkle Snail Interactions: A Mesocosm Study, Elizabeth M. Robinson, Nancy N. Rabalais
Faculty Publications
We examined the sub-lethal effect of Macondo oil from the Deepwater Horizon oil spill on predator-prey interactions using blue crabs (Callinectes sapidus) and periwinkle snails (Littoraria irrorata). A 2 x 2 factorial mesocosm design determined the effect of oil (no oil vs. oil) and blue crabs (no blue crab predator vs. one blue crab predator) on periwinkle snail climbing and survival. Sixteen mesocosm tanks were used in the experiment, which were replicated three times. Each tank contained water, sand, and Spartina marsh stems. The sixteen tanks were divided between two, temperature-controlled chambers to separate oil treatments (no oil vs. oil). …
Wide-Ranging Temporal Variation In Transoceanic Movement And Population Mixing Of Bluefin Tuna In The North Atlantic Ocean, Michael A. Dance
Wide-Ranging Temporal Variation In Transoceanic Movement And Population Mixing Of Bluefin Tuna In The North Atlantic Ocean, Michael A. Dance
Faculty Publications
Uncertainty regarding the movement and population exchange of Atlantic bluefin tuna (Thunnus thynnus) from the two primary spawning areas (Gulf of Mexico, Mediterranean Sea) is increasingly implicated as a major impediment for the conservation of this species. Here, two mixture methods were applied to natural chemical markers (delta O-18 and delta C-13) in otoliths (ear stones) to comprehensively investigate the nature and degree of transoceanic movement and mixing of eastern and western populations in several areas of the North Atlantic Ocean that potentially represent mixing hotspots. Areas investigated occurred on both sides of the 45 degrees W management boundary as …
Spatial Variations In Chlorophyll A, C, N, And P In A Louisiana Estuary From 1994 To 2016, R. Eugene Turner, Erick M. Swenson, Charles S. Milan, James M. Lee
Spatial Variations In Chlorophyll A, C, N, And P In A Louisiana Estuary From 1994 To 2016, R. Eugene Turner, Erick M. Swenson, Charles S. Milan, James M. Lee
Faculty Publications
Intense sampling of an estuary can reveal relative spatial changes that are significant irrespective of whether or not the estuary is eutrophic, micro- or meso-tidal, disturbed, or restored. This waterscape' perspective is analogous to a landscape perspective. We collected monthly water samples in the Barataria Basin watershed from 1994 to 2016 at 37 stations along a 129km transect from 1km offshore to a freshwater stream. The average Chlorophyll a (Chl) concentration from 267 trips was supported from both nitrogen-fixing cyanobacteria in a freshwater lake and partially from nutrients in seaward sources. Estuarine salinity was correlated with the discharge of the …
An Objective Procedure For Delineating The Circumpolar Vortex, Nazla Bushra, Robert V. Rohli
An Objective Procedure For Delineating The Circumpolar Vortex, Nazla Bushra, Robert V. Rohli
Faculty Publications
The broad-scale, steering atmospheric circulation in the Northern Hemisphere, represented by the tropospheric circumpolar vortex (CPV), is an important driver of environmental processes. The area and circularity of the CPV are analyzed hereby delineating the leading edge of the CPV at the steepest 500-hPa geopotential height gradient globally. The daily CPV area and circularity were aggregated to monthly averages for contrast with measurements identified in previous research for the overlapping period of record (1979-2001). Accuracy of representation of the CPV is assessed through correlations to air-sea teleconnections known to be associated with broad-scale, extratropical steering circulation. Correlation to monthly teleconnection …
In Situ Geochemistry Of Middle Ordovician Dolomites Of The Upper Mississippi Valley, Achim D. Herrmann
In Situ Geochemistry Of Middle Ordovician Dolomites Of The Upper Mississippi Valley, Achim D. Herrmann
Faculty Publications
The dolomitization and diagenetic history of Ordovician carbonates of southern Wisconsin is complex. Previous studies attributed dolomitization to various diagenetic factors and environments. In this study, high-resolution, in situ laser ablation inductively coupled mass spectrometry analysis of rare earth element patterns of dolomite was used to assess the diagenetic fluids responsible for dolomitization of the Ordovician Decorah Formation. Integrated geochemical data and petrographic evidence suggest that the dolostones are formed in two different diagenetic realms: shallow burial and hydrothermal. Shallow burial dolomites exhibit three distinct rare earth element patterns. Dolomite from the middle portion of the Guttenberg Member exhibits light …
Effects Of Shoal Margin Collapses On The Morphodynamics Of A Sandy Estuary, M. R. Hiatt
Effects Of Shoal Margin Collapses On The Morphodynamics Of A Sandy Estuary, M. R. Hiatt
Faculty Publications
Shoal margin collapses of several million cubic meters have occurred in the Western Scheldt estuary, the Netherlands, on average five times a year over the last decades. While these collapses involve significant volumes of material, their effect on the channel-shoal morphology is unknown. We hypothesize that collapses dynamicize the channel-shoal interactions, which could impact the ecological functioning, flood safety, and navigation in the estuary. The objective is to investigate how locations, probability, type, and volume of shoal margin collapse affect the channel-shoal dynamics. We implemented an empirically validated parameterization for shoal margin collapses and tested its effect on simulated estuary …