Anthropogenic effects on nature

The Florida Everglades is a vast subtropical wetland that historically spanned over 1,000,000 hectares, but much of the Everglades has changed in the last 100 years due to anthropogenic activity. Collier County was subject to alteration in the form of logging, road building, and canal digging. These actions disrupted the natural sheet flow of water and had large environmental impacts on the region, impacts which are slowly being addressed by Everglades restoration efforts. The aim of this project was to observe the effects of environmental change at a cypress swamp forest in Collier County within the Big Cypress National Preserve. Using sediment core data including charcoal analysis, loss on ignition, and peat humification, as well as remote sensing techniques, this project uses a novel approach to assess local environmental conditions in the modern era. Historical records and contemporary data are used to evaluate change over time, and satellite imagery is used to quantify vegetative health. Modification of the environment related to anthropogenic activity is noted, and evidence of progress from restoration efforts is observed from the last two decades in our study’s data.

Urban noise is common in anthropogenic environments and impacts behavior and health in wildlife. Noise has been shown to negatively affect cognitive processes such as attention and memory in animals. Cognition is tightly linked with the survival of an organism and so urban noise can potentially hinder cognitive processes and the subsequent survival of the organism. I split my thesis into two experiments: (1) I tested if urban noise impacts avian cognitive performance by testing adult zebra finches (Taeniopygia guttata), a songbird, on several cognition tasks in the presence or absence of urban noise playback. I found that urban noise reduces cognitive performance in a novel foraging task, but not in color association or spatial memory tasks. (2) I tested if urban noise impacts growth and cognitive development by examining adult zebra finches in a variety of cognition tasks after exposing them to urban noise, pink noise, or no noise during their first 90 days of life. I took measurements of wing chord, tarsus length, mass, and bill ornamentation, to test for effects of urban noise on development. I found no evidence that urban noise exposure during development affects cognitive performance in adulthood. I found some evidence that urban noise exposure during development affects bill ornamentation, but not measures of growth. Together, these results suggest that urban noise exposure can have immediate effects on cognitive performance, but I found little evidence that chronic noise exposure during development can have long-term effects in the zebra finch.

The Indian River Lagoon (IRL) FL, USA, is an Estuary of National Significance due to its economic and high biodiversity. Microbial populations are understudied in the IRL despite their numerous ecological services. A two-year, nineteen-site Lagoon-Wide Survey (LWS) was conducted to provide the first 16S rRNA amplicon sequencing data on the microbiome of the sediment in the IRL and determine how the microbiome changed in response to environmental and anthropogenic factors. The most influential variables that explained the variability between microbiomes were porewater salinity, total organic matter (TOM), and copper (Cu). These results correlated with some of the anthropogenic pressures the IRL faces such as freshwater discharges from St. Lucie Estuary (SLE), trace metal contamination, and the accumulation of fine-grained, highly organic sediment known as “IRL muck” (muck). Research then focused on determining the microbial differences between three sets of sample types: sediment from the IRL versus the SLE; sediment that had three muck characteristics versus those with zero; and high TOM sediment that had high Cu versus high TOM sediment that had low Cu. Differentially abundant prokaryotes between sample types were determined with novel indicator analysis techniques. One technique tested the effectiveness of an indicator list to separate samples based upon the product of the sensitivity and specificity of partitioning around medoids clustering in comparison to metadata classifications. The other technique allowed for the tracking of changes in the entire indicator microbiome. These new indicator analysis techniques were created using the original LWS data and tested to determine how sediment microbiomes responded during two opportunistic surveys: dredging of muck from an IRL tributary (Eau Gallie River) and Hurricane Irma. These studies have filled the knowledge gap regarding the unknown microbiome of the IRL and how sediment microbiomes respond to extreme events such as dredging and a hurricane. They also led to the development of new indicator analysis techniques that can be used by to track changes in the entire indicator microbiome.

Non-Anglophone voices in literature can lead to a better understanding of the intricate relationships shown by Ashley Dawson tying capitalism, slow violence, and uneven development to climate change. There is skepticism that science fiction (sf) in particular can properly present climate issues in the anthropocentric era that we live in today, but scholars such as Shelley Streeby argue against such perceptions. Science fiction writers that use magical realism, such as Ngugi wa Thiong’o and Nalo Hopkinson, as ecological sf have already accomplished the task of creating speculative works that fit in perfectly under the umbrella of “serious fictions.” These writers work from a non-Anglophone perspective or from a minority group within a Western society, allowing for different modes of thinking to play a part in these bigger discourses. Writers, educators, and other scholars need to reestablish humanity’s kinship with nature.

Anthropogenic contaminants in the marine environment often biodegrade slowly, bioaccumulate in organisms, and can cause reproductive, immune, and developmental effects on wildlife; however, their effects on cetacean health and behavior have not been extensively studied. This study aims to expand knowledge concerning concentrations and biological effects of endocrine disrupting contaminants and essential and non-essential inorganic elements in stranded cetaceans. We evaluated tissue samples and pathology data from 66 odontocetes that stranded in the southeastern United States during 2012– 2017. Using mass spectrometry blubber samples were analyzed for five endocrine disrupting contaminants (atrazine, bisphenol-A, diethyl phthalate, nonylphenol ethoxylate, triclosan), and liver samples were analyzed for 12 inorganic elements (As, Cd, Co, Cu, Mg, Mn, Fe, Pb, Hg, Se, Tl, Zn). Results from this study demonstrate that exposure to certain contaminants may be associated with subtle or sublethal cellular changes in free-ranging marine mammals that could contribute to health declines or stranding.