Life Sciences Commons^™

Population Dynamics Of The Sub-Arctic Copepod Calanus Finmarchicus In The Gulf Of Maine: Demography And Mortality Estimation, Cameron R. S. Thompson

Electronic Theses and Dissertations

Calanus finmarchicus is a widely distributed copepod species that dominants the zooplankton community in the Gulf of Maine. It is of particular interest in its role as a major food source for the endangered northern right whale and stocks of herring, mackerel and cod. More accurate coupled models to predict its distribution requires better life history models. However, due to the difficulty in estimating it, mortality is often used as a closure term in those models; the value is justified mathematically rather than ecologically. Instantaneous mortality is difficult to measure, but the Vertical Life Table method (VLT) has gained some …

Gentrification And Vulnerability Of Maine Fishing Communities, Cameron R. S. Thompson

Electronic Theses and Dissertations

Maine hosts numerous small fishing villages that contribute greatly to the States economy and culture. The cumulative effects of state and federal regulation, stock depletion and other socio-economic trends threaten these communities. Drawing on ethnographic research and interviews, we examine how gentrification is affecting the vulnerability and resilience of fishing communities. This study has revealed gentrification to be a complex process, which is merely the most readily recognizable symptom of forces that are reshaping the post-industrial landscape. Fishing communities can no longer be thought of as discrete entities isolated from broad social and economic changes. Technology and new markets have …

Responses Of Atlantic Salmon Stream Communities To Marine-Derived Nutrients, Margaret Quinn Guyette

Electronic Theses and Dissertations

This research examined responses of Atlantic salmon ( Salmo salar) stream communities to experimental simulation of marine-derived nutrient input. Prior to construction of dams beginning in the early 1800s, Atlantic salmon and other anadromous species migrated from the ocean to spawn in Maine's extensive rivers and streams. Spawning fish transported marine-derived nutrients to these systems as carcasses, eggs, and waste products. These contributions may have influenced productivity in otherwise nutrient limited systems, bolstering growth and survival of young Atlantic salmon and other anadromous species and influencing other components of the stream communities.

This study involved a reach-scale experiment to explore …

Analysis Of Extracellular Proteins Expressed By Host, Crassostrea Virginica And Pathogen, Roseovarius Crassostreae In Roseovarius Oyster Disease, Erin Macro

Electronic Theses and Dissertations

Roseovarius Oyster Disease (ROD) involves the colonization of the inner shell of the Eastern Oyster (Crassostrea virginica) by the marine alpha-proteobacterium Roseovarius crassostreae. The ensuing disease can result in upwards of 90% mortality in hatchery-raised juvenile (< 25 mm shell length) oysters. Symptoms of ROD include heavy, brown ring deposits of conchiolin on the surface of the shell, as well as uneven valve growth and shell curvature. Although the bacterium does not invade oyster tissue or digestive tract, fluorescent localization of an R. crassostreae biofilm on the inner shells of ROD-affected oysters, and toxic effects of R. crassotreae extracellular products on hemocytes and larval oysters suggest that a chemical warfare takes place between the R. crassostreae biofilm and the oyster host. In this thesis, I cultured R. crassostreae under laboratory conditions and analyzed the affects of physical growth condition, temperature, culture volume, and iron limitation on bacterial growth and bacterial extracellular protein (ECP) production. Culture growth rate increased with increasing temperature. Iron limitation resulted in slower growth but had no affect on maximum culture density. Iron limited cells produced a greater volume of ECPs, especially at low cell density. ECPs from liquid and solid-phase cultures were analyzed by LC-tandem mass spectrometry. The resulting protein sequences had high similarity to proteins in other bacterial species that act as virulence factors in other hosts, including metal transporters (2), proteases (2) and a surface-associated GroEL chaperonin. I also exposed live oysters to ECPs of live R. crassostreae cells by embedding a filter capsule into the oyster shell. I sampled extrapallial fluid from oysters pre-exposure and post-exposure and analyzed the relative expression of the oyster defense protein dominin in addition to the extent of brown shell deposition as a function of bacterial presence. The injury response due to capsule embedment masked any potential response by oysters to R. crassostreae ECPs.

Cell-Matrix Adhesion In Muscle Development And Disease, Michelle F. Goody

Electronic Theses and Dissertations

A variety of diseases, both inherited and acquired, affect muscle tissues in humans. The anchoring of muscle fibers to their surrounding environment is critical for muscle homeostasis. Muscle fibers attach to their microenvironment through cell-matrix adhesion complexes. These anchoring complexes are placed under repeated stress during muscle contraction. Genetic mutations in these complexes weaken the attachment between muscle fibers and their microenvironment, making fibers more susceptible to damage and death. This increased fiber degeneration eventually leads to progressive muscle wasting diseases, known as congenital muscular dystrophies. Although clinical trials are ongoing, there is presently no way to cure the loss …

Characterizing Fish Assemblage Structure In The Penobscot River Prior To Dam Removal, Ian Andrew Kiraly

Electronic Theses and Dissertations

The Penobscot River drains the largest watershed in Maine, and once provided spawning and rearing habitats to at least 11 species of diadromous fish. The construction of dams blocked migrations of these fish and likely changed the structure and function of fish assemblages throughout the river. Further alteration to fish assemblage structure likely occurred as a result of habitat fragmentation and alteration. The proposed removal of two main-stem dams, improved upstream fish passage at a third dam, and construction of a fish bypass on dam obstructing a major tributary is anticipated to increase passage of diadromous and resident fishes. To …

Modeling Individual Tree And Snag Dynamics In The Mixed-Species Acadian Forest, Matthew B. Russell

Electronic Theses and Dissertations

Forest growth modeling has a long tradition of development and application in even‐aged stands targeting single-species plantations. Modeling efforts in mixed-species stands that contain uneven‐aged stand structures are much more recent. Serving as a transitional zone between the boreal and eastern broadleaf deciduous forest types, the Acadian Forest found throughout Maine and the Canadian Maritime Provinces is host to a wide variety of tree species that form complex stand structures. This study validated existing and developed component equations that comprise a widely-used individual tree growth and yield model in the northeastern US and Canadian Maritime provinces. An assessment of deadwood …

The Influence Of Anadromous Alewife On Maine Lakes And Streams: Using Nutrient Limitation Assays And Stable Isotopes To Track Marine-Derived Nutrients, Katie G. Norris

Electronic Theses and Dissertations

Anadromous fish can act as nutrient subsidies to freshwater ecosystems when they return there to spawn. However, relatively few studies have quantified the role of alewife (Alosa pseudoharengus) as an ecologically important source of marine-derived nutrients (MDN) to lakes and streams. Primary producers in lakes and streams are often limited by nutrients, such as nitrogen and phosphorus. If alewife bring nutrients to lakes and streams, then the limitation of primary producers in those systems should be alleviated. Nutrient limitation assays and stable isotopes were used to examine the effects of alewife MDN on Maine lakes and their outlet streams. Nutrient …

Forest Fragmentation Patterns In Maine Watersheds And Prediction Of Visible Crown Diameter In Recent Undisturbed Forest, Brianne Elizabeth Looze

Electronic Theses and Dissertations

Extensive harvesting practices coupled with major ownership change have led to increasing fragmentation of Maine’s forest, a reduction from larger, contiguous mature forest patches into smaller patches. Using Landsat Thematic Mapper (TM) - based forest cover and change maps (1991-2007), fragmentation metrics, and Principal Components Analysis (PCA), this study determined the extent and configuration of forest fragmentation within three ecoregions and 186 level 5 watersheds throughout the state of Maine. Forests in the Northeastern ecoregion had higher harvest rates and more interspersed patches of undisturbed forest. Forests in the South-Central ecoregion are composed of more, smaller patches than their Northeastern …

Remote Estimation Of Regional Lake Clarity With Landsat Tm And Modis Satellite Imagery, Ian M. Mccullough

Electronic Theses and Dissertations

Water clarity is an ideal metric of regional water quality because clarity can be accurately and efficiently estimated remotely on a landscape scale. Remote sensing of water quality is useful in regions containing numerous lakes that are prohibitively expensive to monitor regularly using traditional field methods. Field-assessed lakes generally are easily accessible and may represent a spatially irregular, non-random sample. Remote sensing provides a more complete spatial perspective of regional water quality than existing, interest-based sampling; however, field sampling accomplished under existing monitoring programs can be used to calibrate accurate remote water clarity estimation models. We developed a remote monitoring …