Ecology and Evolutionary Biology Commons^™

Biotic Characteristics Of Managed And Unmanaged Coastal Dunes In The Outer Banks, North Carolina, Andrew E. White

Theses and Dissertations

Under future climate change and sea level rise scenarios, Natural and Nature-Based Features (e.g., dunes) that protect coastal habitat and infrastructure will be exposed to increased wave energy and storm surge. Understanding how these forces will impact coastal dunes is necessary for their continued use as protective features. Coastal dunes develop through feedback between vegetation and sediment deposition, a process complicated by species-specific growth rates and responses to burial. Wave flume studies have tested the effects of dune vegetation on erosion and found multiple plant organs across several functional types to be important for resisting erosion. Although dune building and …

Incorporation, Morphology, And Extinction Of Framework-Building Metazoans In Early Cambrian Reef Ecosystems From The Western Usa And Mongolia And Their Effects On Reef Diversity, David Russell Cordie

Theses and Dissertations

The early Cambrian represents an important transition in the evolution of life, perhaps most vividly exemplified by reef ecosystems as they changed from microbial-supported to metazoan-supported framework reefs. Microbial reefs were initially composed of Renalcis- and Epiphyton-group calcifying microbes. Subsequent reefs began to incorporate archaeocyathan sponges within this framework. This represents a shift in the source of carbonate production, which can be quantified using thin section point counts. In archaeocyathan reefs from the western USA, carbonate contribution from metazoan framework builders increased from zero to 29.7%. Similar reefs from Mongolia increased from zero to 5.0%. Increases in Laurentian archaeocyath contributions …

River Bank Inducement Influence On A Shallow Groundwater Microbial Community And Its Effects On Aquifer Reactivity, Natalie June Gayner

Theses and Dissertations

Placing groundwater wells next to riverbanks to draw in surface water, known as riverbank inducement (RBI), is common and proposed as a promising and sustainable practice for municipal and public water production across the globe. However, these systems require further investigation to determine risks associated with river infiltration especially with rivers containing wastewater treatment plant (WWTP) effluent. Since microbes drive biogeochemical transformations in groundwater and largely affect water quality, it is important to understand how the microbial communities in drinking water wells are affected by river infiltration. This study investigated if, and to what extent, the microbial community in a …

Invertebrate Paleoecology Of High Paleo-Latitude Carboniferous Strata Of The Tepuel-Genoa Basin, Argentina, Kate M. Gigstad

Theses and Dissertations

The Late Paleozoic Ice Age (LPIA), which began in the latest Devonian and ended in the Late Permian, was a time of active environmental changes. During this time, glaciers waxed and waned over the ancient continent of Gondwana that was situated over the southern pole. This time of transition from icehouse to greenhouse in the Permian is our closest analogue to our current environmental conditions and increased knowledge of our planetary past will greatly influence our future. Much of the previous research on marine invertebrate paleoecology during the LPIA occurs in far-field or low paleolatitude localities, but less is known …

Short-Term Effects Of Nutrients On A Barrier Island Grassland Community, Ashley Moulton

Theses and Dissertations

Increased nutrient availability globally has the potential to affect community functional composition of plants in nutrient limited environments, such as coastal grassland systems. Stability of these systems are threatened worldwide by urbanization, as well as effects of sea level rise and increased frequency and intensity of storms, and atmospheric N deposition, associated with climate change. Annual net primary productivity (ANPP), species composition, and functional traits (community weighted specific leaf area (CWSLA), leaf area index (LAI), growth form and photosynthetic pathway) were measured across four treatments to assess multiple resource limitation of nitrogen (N) and phosphorus (P) and functional community response …

Functional Diversity Of Regional Marine Paleocommunities After The Permo-Triassic Mass Extinction: Case Studies From Panthalassa And Paleo-Tethys, Ashley Ann Dineen

Theses and Dissertations

The Permo-Triassic mass extinction (PTME) was the largest biodiversity collapse in Earth’s history. Published data has been interpreted as indicating that marine ecological devastation following the PTME was protracted and may have lasted 5 million years into the Middle Triassic (Anisian). However, a review of previous literature shows that understanding of biotic recovery is usually based on only a few components of the ecosystem, such as on taxonomic diversity, a single genus/phylum, or shallow water facies. Typically, paleocommunities are considered fully recovered when dominance and diversity are regained and normal ecosystem functioning has resumed. However, to more fully characterize Triassic …

Paleoecology Of Glacial And Non Glacial Carboniferous Faunas During The Late Paleozoic Ice Age In Patagonia, Nicole Braun

Theses and Dissertations

The Late Paleozoic Ice Age (LPIA) records the only icehouse to greenhouse transition in Earth’s history that involved complex marine and terrestrial life and serves as an analogue for Quaternary climate change. Identifying biotic responses to paleoenvironmental variations during the LPIA is important in order to understand how our modern fauna may respond to contemporary climate change. Low-paleolatitude (far-field) marine faunas far from ice centers have been recognized and used as a global proxy for biotic responses to the LPIA, but the biotic responses in high-paleolatitude (near-field) regions close to Gondwanan ice centers have received much less attention. We tested …

Paleoredox Geochemistry And Bioturbation Levels Of The Exceptionally Preserved Early Cambrian Indian Springs Biota, Poleta Formation, Nevada, Usa, Jonah Meron Novek

Theses and Dissertations

The early Cambrian Indian Springs biota, western Nevada, USA exhibits Burgess Shale-type (BST) preservation of a diverse array of animal phyla, including the earliest definitive echinoderms. It therefore provides an important window on animal life during the Cambrian radiation. The objective of this study is to analyze the trace metal paleoredox geochemistry and bioturbation levels of this BST deposit in order to characterize the paleoenvironmental conditions in which these animals lived and their fossils were preserved. A total of 28 rock samples were collected from outcrops at three previously reported intervals of exceptional preservation at the Indian Springs locality, as …

Microbially Induced Sedimentary Structures As An Ecological Niche In Subtidal Early Triassic Environments Of Eastern Panthalassa, Erin Wimer

Theses and Dissertations

Early Triassic microbially induced sedimentary structures (MISS) are a critical link in understanding the dynamics between changing environmental conditions and their effect on marine communities. The Permo-Triassic mass extinction (PTME) resulted in vacated ecospace and reduced bioturbation that allowed MISS to expand into Early Triassic subtidal environments. Data from southern Idaho and Montana indicate that MISS inhabited and proliferated in subtidal marine environments during the Griesbachian. This propagation led to changes in shallow substrate geochemical conditions that directly affected macrofaunal communities. The proliferation of microbial mats would have created anoxic and euxinic porewaters and made vertical bioturbation physiologically difficult. Geochemical …

Early Triassic Echinoids Of The Western United States: Their Implications For Paleoecology And The Habitable Zone Hypothesis Following The Permo-Triassic Mass Extinction, Jenna Rolle

Theses and Dissertations

Confronted with global climate change and ocean acidification, our collective knowledge of ecosystem response during times of environmental crisis in Earth's ancient past may provide insights towards combating ecological degradation in modern oceans. Early Triassic marine environments were characterized by oceanic warming due in part to elevated levels of atmospheric CO₂ and periodic intervals of localized anoxia, resulting in an overall restructuring of faunal dominance, distribution, and biodiversity. Re-assembly of ecological communities during the Early Triassic are largely unknown; however, a previous paleoecological study by Tyler Beatty et al. (2008), suggests that post-extinction recovery length was minimized in shallow …

Sedimentology And Paleoecology Of Fossil-Bearing, High-Latitude Marine And Glacially Influenced Deposits In The Tepuel Basin, Patagonia, Argentina, Kathryn N. Pauls

Theses and Dissertations

The glacial and non-glacial intervals of the Late Paleozoic Ice Age (LPIA) are of great interest because they are our best deep time analogue for Pleistocene climate change. The changes and adaptations of the biota, as seen in the rock record, can serve as a proxy for understanding future trends in Earth's climate system. Most of the known LPIA marine faunal data come from low-latitudinal regions, and thus have been used as a global proxy. However, modern organisms in the low-latitudes (far-field basins) respond differently to a changing climate relative to marine organisms in the polar regions (near-field basins). In …

Air-Water Gas Exchange And The Carbon Cycle Of Green Bay, Lake Michigan, James Waples

Theses and Dissertations

The purpose of this study was to constrain estimates of the kinetics of gas transfer across the air-water interface as well as quantify the net flux of carbon between southern Green Bay (1635 km²) and the atmosphere.

In 1994 and 1995, over 3500 measurements of surface water CH₄ and CO₂ were made using a continuous sample disk equilibrator. Estimates of CH₄ flux from southern Green Bay to the atmosphere based on air-water concentration gradients, shear corrected wind speeds and the U/K (wind speed/transfer coefficient) relationship of Broecker et al. (1978) agreed to within ~10% of …