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Full-Text Articles in Physical Sciences and Mathematics

Denitrification Potential Of Sediment From A Future Mississippi River Diversion Site In Louisiana, Roy Ryuta Iwai Jan 2002

Denitrification Potential Of Sediment From A Future Mississippi River Diversion Site In Louisiana, Roy Ryuta Iwai

LSU Master's Theses

Denitrification potential was determined in surface sediment from Lake Cataouatche, the receiving basin for a future Mississippi River diversion located in the northern portion of the Barataria Basin estuary. Nitrate removal and denitrification was measured in the laboratory using static sediment microcosms flooded with lake water. Dissolved potassium nitrate (KNO3) was added to the microcosms to achieve: 1) an initial nitrate concentration similar to the mean Mississippi River concentration (~1.4 mg NO3-N l-1), and, 2) a high initial nitrate concentration to elicit a denitrification potential (~50 mg NO3-N l-1). Denitrification …


The Effects Of Fall Coldfront Passages On The Nekton Community In A Tidal Creek In Port Fourchon, La, As Monitored By Hydroacoustics, David J. Harmon Jan 2002

The Effects Of Fall Coldfront Passages On The Nekton Community In A Tidal Creek In Port Fourchon, La, As Monitored By Hydroacoustics, David J. Harmon

LSU Master's Theses

Split-beam hydroacoustic sampling with two, 420 KHz, 2x6 degree elliptical transducers was evaluated as a tool to quantify nekton movements in a Louisiana estuary. I measured the effects of atmospheric cold front passages on nekton in a tidal creek in Port Fourchon, LA during the fall of 2000. Six “fronts” were sampled between October 6 and December 18, 2000. Nekton density ranged from 0 to 24.4 fish/m3 with an overall mean of 2.44 fish/m3. Net samples were taken to supplement the acoustic data with species composition data. Species composition changed from October to December. A higher number …


Feeding Habits Of Blacktip Sharks, Carcharhinus Limbatus, And Atlantic Sharpnose Sharks, Rhizoprionodon Terraenovae, In Louisiana Coastal Waters, Kevin Patrick Barry Jan 2002

Feeding Habits Of Blacktip Sharks, Carcharhinus Limbatus, And Atlantic Sharpnose Sharks, Rhizoprionodon Terraenovae, In Louisiana Coastal Waters, Kevin Patrick Barry

LSU Master's Theses

Little is known regarding the feeding behavior of many shark species. Even less is known about shark feeding habits in Louisiana coastal waters. The stomach contents of gillnet-captured blacktip sharks (n=356), Carcharhinus limbatus, and Atlantic sharpnose sharks (n=55), Rhizoprionodon terraenovae, were examined in this study. Roughly half of the blacktip stomachs (52%) and sharpnose stomachs (45%) contained prey items. The primary prey item in terms of percent number, occurrence, and weight for blacktips and sharpnose was the gulf menhaden, Brevoortia patronus. Both blacktips and sharpnose appear to mainly be piscivores; however, no members of Sciaenidae, the most common family of …


Sedimentation Rates And Metal Retention In An Urban Louisiana Swamp, Renee Lynn Sanders Jan 2002

Sedimentation Rates And Metal Retention In An Urban Louisiana Swamp, Renee Lynn Sanders

LSU Master's Theses

Naturally vegetated areas converted to urban uses increases impervious surfaces in a watershed with corresponding increases in nutrient, sediment, and metal loadings to downstream ecosystems. Wetlands mitigate detrimental impacts by transforming or retaining pollutants. Current and historic sedimentation and metal retention rates were measured in an urban, depressional wetland in Baton Rouge, Louisiana to evaluate landscape position and watershed development on these processes. Sedimentation disks, feldspar marker horizons, and Cs137 analyses were used in three distinct landscape positions. Inflow channels had the highest elevation and water velocity while the interior was located in the lowest elevations with the longest hydroperiod. …


The Importance Of Zooplankton In The Diets Of Blue Runner (Caranx Crysos) Near Offshore Petroleum Platforms In The Northern Gulf Of Mexico, Sean Francis Keenan Jan 2002

The Importance Of Zooplankton In The Diets Of Blue Runner (Caranx Crysos) Near Offshore Petroleum Platforms In The Northern Gulf Of Mexico, Sean Francis Keenan

LSU Master's Theses

Blue runner (Caranx crysos), common around offshore petroleum platforms in the Gulf of Mexico, were found to forage extensively on meso- and macro-zooplankton during the summer months. Larval decapods and stomatopods, hyperiid amphipods, pteropods, and larval and juvenile fishes were common components of their diet. Feeding periodicity results suggest that blue runner around platforms were capable of feeding throughout the night at the same intensity as the day. Size selectivity indicated that larger prey, such as fish were consumed during the night and smaller decapod crustaceans were consumed during the day. Blue runner collected from open waters away from platforms …