Physical Sciences and Mathematics Commons^™

Interactive Effects Of Co2, Temperature, And Nitrate Limitation On The Growth And Physiology Of Marine Cyanobacterium Synechococcus Sp. Ccmp 1334, Alyssa K. Sharbaugh

LSU Master's Theses

The marine cyanobacterium Synechococcus sp. CCMP 1334 was grown in a continuous culture system on a 12:12 h light:dark cycle at all combinations of low and high pCO2 (400 and 1000 ppmv, respectively), nitrate availability (nitrate-limited and nutrient-replete conditions), and temperatures of 21°C, 24°C, 28°C, 32°C, and 35°C. The maximum median nutrient-replete growth rate was ~1.15 d−1 at 32 –35°C. Median growth rates at 1000 ppmv pCO2 were higher than those at 400 ppmv at all temperatures, but most of the differences were statistically insignificant. Carbon:nitrogen ratios were independent of pCO2 at a fixed relative growth rate but decreased with …

Estimation Of Economic Risk From Coastal Natural Hazards In Louisiana, Rubayet Bin Mostafiz

LSU Doctoral Dissertations

Louisiana, U.S.A., is among the most vulnerable areas globally to coastal natural hazards, with risk vulnerability likely increasing. The risks associated with non-tropical-cyclone hazards in Louisiana’s coastal zone have been understudied. This research enhances present and future (i.e., 2050) Louisiana risk assessment using locally-weighted, model-based hazard frequency/intensity and population projections.

Results suggest that property risks associated with extreme cold temperature and tornado are and will remain costlier than those for hail and lightning. Property risks of extreme cold temperature and hail are projected to decrease with the expected warming temperatures, with those of all four of these hazards peaking in …

The Global Impact Of The Antarctic Ice Sheet In A Warming World: Using Numerical Modeling And Critical Physical Geography To Assess Climate Change, Sea Level Rise, And Climate Justice

Doctoral Dissertations

Anthropogenic climate change is causing disruptions in the Earth system with negative ramifications for life on our planet. Increasing atmospheric greenhouse gas concentrations lead to accumulated heat content and the cryosphere is one of the earliest places to show changes in response to rising temperatures. The melting of the Antarctic Ice Sheet will have myriad effects on global climate due to interconnections and feedbacks between the ice sheet, ocean, and atmosphere. In this dissertation I use numerical modeling and critical geography to assess future climate conditions that occur in response to changes in Antarctic Ice Sheet melt as well as …

Anthropogenic Impacts To Essential Habitats In The Gulf Of Maine: A Case Study Of The American Lobster, Homarus Americanus, And Its Fishery, Andrew Goode

Electronic Theses and Dissertations

The Gulf of Maine has been fundamentally altered by anthropogenic forcings for decades and offers an ideal study system to monitor response to change. Through complex interactions between ocean warming, altered demographic bottlenecks, and reduced top-down controls, the American lobster (Homarus americanus Milne Edwards) capitalized on favorable conditions and proliferated within the Gulf of Maine. These changes catalyzed the expansion of the lobster fishery, elevated its status as North America’s most valuable marine resource, and shifted coastal communities towards a virtual lobster monoculture. The same processes that facilitated lobster to capitalize on favorable conditions may come with unintended consequences …

Physiological And Molecular Responses Of Eurythermal And Stenothermal Populations Of Zostera Marina L (Eelgrass) To Climate Change, Carmen C. Zayas-Santiago

OES Theses and Dissertations

As CO₂ levels in Earth’s atmosphere and oceans steadily rise, varying organismal responses may produce ecological losers and winners. Increased ocean CO₂ can enhance seagrass productivity and thermal tolerance, providing some compensation for climate warming. However, the consistency of this CO₂ effect across populations of cosmopolitan species such as Zostera marina L. (eelgrass) remains largely unknown. This study analyzed whole-plant performance metabolic profiles and gene expression patterns of distinct eelgrass populations in response to CO₂ enrichment. Populations were transplanted from Nisqually Landing and Dumas Bay, two cold water environments in Puget Sound, WA (USA) that rarely …

Projecting Regions Of North Atlantic Right Whale, Eubalaena Glacialis, Habitat Suitability In The Gulf Of Maine In 2050, Camille Ross

Honors Theses

North Atlantic right whales (Eubalaena glacialis) are endangered. Understanding the role environmental conditions play in habitat suitability is key to determining the regions in need of protection for conservation of the species, particularly as climate change shifts suitable habitat. This thesis uses three species distribution modeling algorithms, together with historical data on whale abundance(1993 to 2009) and environmental covariates to build monthly ensemble models of past E. glacialis habitat suitability in the Gulf of Maine. Then, the models are projected onto the year 2050 for a range of climate scenarios. Specifically, the distribution of the species was modeled …

On The Frontlines - The Fishermen Of Ibrahim Hyderi, Muhammad Haris Aslam Khan

MSJ Capstone Projects

Climate change has become a matter of recent debate for much of the world. According to a report published by a German watch, a non-governmental organization, in 2019, Pakistan among the five countries at severe risk of climate change disasters.

During the last two decades, Pakistan saw more than 141 extreme climatic catastrophes. Only in 2016, more than 566 people died due to these conditions.

A report published by Asian Development Bank in 2017 indicates Pakistan’s climate change profile. It states that more than 1,600 people have lost their lives in the super flood of 2010 alone. A loss of …

A Numerical Investigation Of Sediment Dynamics In The Northern Gulf Of Mexico In Connection With Hurricanes, Fluid Mud, Climate Change, And Biogeochemical Cycling, Zhengchen Zang

LSU Doctoral Dissertations

Sediment transport and deposition in marginal seas is jointly controlled by many factors including hydrodynamics, fluvial inputs, and the characteristics of sediment particles. This dissertation study employs the coupled ocean-atmosphere-wave-and-sediment transport modeling system (COAWST) to investigate the mechanism of sediment transport in the northern Gulf of Mexico (nGoM) on different temporal scales, as well as its interaction with biogeochemical processes.

First of all, a three-way coupled (atmosphere-wave-ocean) hurricane model reproduced the hydro- and sediment dynamics during hurricane Gustav (2008). Intensive alongshore and offshore currents were simulated on the eastern/western sectors of hurricane track, respectively. High suspended sediment concentration (SSC) was …

Investigating Physical Processes Associated With Chesapeake Bay And Changjiang Estuary, Arash Niroomandi

Civil & Environmental Engineering Theses & Dissertations

Coastal and estuaries are landforms that not only have great impacts on large marine ecosystem, but also play a significant role in moderating or aggravating natural hazards and erosion risks that are expected to increase with climate change. This dissertation explores some of the concerns associated with coasts and coastal systems. In the second chapter, a thirty seven year wave hindcast (1979-2015) in Chesapeake Bay using NCEP's Climate Forecast System Reanalysis (CFSR) wind is presented. The long-term significant wave heights are generated by the third-generation nearshore wave model SWAN, which is validated using the wave height measurements at buoy stations …

Effects Of Temperature On Activity Of Aquatic Hyphomycetes: A Microcosm Study, Kyra Harrington‌‌

Honors Theses

Predicted increases in temperature under climate change scenarios are expected to affect not only atmospheric and water temperatures, but also the rate of heterotrophic activity and carbon dynamics and retention in ecosystems. The magnitude of the increase in metabolic activity of living organisms with increased temperature can be predicted by the Metabolic Theory of Ecology, however, multiple factors can cause deviations from simple predictions. The goal of this study is to assess the temperature sensitivity of aquatic hyphomycetes and fungi-mediated leaf litter decomposition by following responses to temperature of fungal biomass accrual, respiration and decomposition rates in laboratory microcosms simulating …

How Does Climate Change Affect Coral Reefs?, Rachel Goff

Honors Theses

Climate change is a very real phenomenon that currently affects many of the ecosystems on Earth. Climate change occurs on a global scale and can be very detrimental to different environments. This occurrence can cause ocean warming, sea level rise, ocean acidification, and increased storm intensity. According to the EPA, the ocean's temperature has increased 1.4°F over the past century, and sea levels have risen 3.2 millimeters through the past 20 years. These changes to the oceans can greatly affect many of the ecosystems that reside in them. One of the main ecosystems that are being affected by climate change …