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Oceanography and Atmospheric Sciences and Meteorology

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Electronic Theses and Dissertations

2001

Articles 1 - 7 of 7

Full-Text Articles in Physical Sciences and Mathematics

The Role Of Water Motion In Algal Reproduction, Richard Gordon Dec 2001

The Role Of Water Motion In Algal Reproduction, Richard Gordon

Electronic Theses and Dissertations

Environmental conditions, such as water motion, can influence fertilization success and spore dispersal in marine algae. Previous studies on fucoid algae showed that gamete release is restricted to, or enhanced by, periods of low water motion. Few other algal taxa have been investigated, however, including species with an alternation of generations. I investigated gamete and spore release in the macroalgae Alaria esculenta and Ulva lactuca, as well as in the diatom Pseudo-nitachia multiseries to determine if water motion is inhibitory or stimulates propagule production and release. I used orbital shakers to simulate water motion; these were interspersed with stationary platforms …

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The Effects Of Temperature On The Survival, Growth And Development Of Larvae Of Two Blue Mussel Species (Mytilus Edulis And Mytilus Trossulus), Susan Hayhurst Dec 2001

The Effects Of Temperature On The Survival, Growth And Development Of Larvae Of Two Blue Mussel Species (Mytilus Edulis And Mytilus Trossulus), Susan Hayhurst

Electronic Theses and Dissertations

Factors affecting the distribution of Mytilus edulis and Mytilus trossulus in the Gulf of Maine are of great interest because of the blue mussel's economic and ecological importance. Genetic surveys of blue mussel populations indicate that eastern Maine represents the southern distributional limit for M. trossulus but that M. edulis is common throughout the Gulf of Maine. Because hydrographic features in the Gulf of Maine confound temperature variation and larval dispersal patterns, the relative importance of these potential range-limiting mechanisms cannot be ascertained from the distribution of adult mussels. Given that larvae are more vulnerable than adults to temperature extremes, …

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Relationships Between Oceanographic Satellite Data And Alexandrium Distributions In The Gulf Of Maine, Remy Martin Luerssen Dec 2001

Relationships Between Oceanographic Satellite Data And Alexandrium Distributions In The Gulf Of Maine, Remy Martin Luerssen

Electronic Theses and Dissertations

An examination is made of the qualitative and quantitative relationships between satellite derived sea-surface temperature (SST) and chlorophyll patterns and the distribution of Alexandrium, the toxic dinoflagellate species responsible for HABs in the GOM. Daily images coincident with five ECOHAB survey cruises in 1998 and 2000 are composited over each cruise period to create mean patterns for each sample period. Contours of surface Alexandrium cell concentrations are superimposed on the images as well as images showing the strength and location of SST frontal zones to examine qualitative relationships. Results indicate that high concentrations of Alexandrium are located primarily in the …

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Gametogenic Cycles Of Marine Mussels, Mytilus Edulis And Mytilus Trossulus, In Cobscook Bay, Maine, Aaron P. Maloy Dec 2001

Gametogenic Cycles Of Marine Mussels, Mytilus Edulis And Mytilus Trossulus, In Cobscook Bay, Maine, Aaron P. Maloy

Electronic Theses and Dissertations

The Mytilus edulis species complex includes three smooth-shelled blue mussels, M. edulis (Linnaeus 1 75 8), M trossulus (Gould 1 850), and M galloprovincialis (Lamarck 18 19). When any two of theses species occur sympatrically, hybridization and backcrossing of hybrid and parental genotypes is evident. Despite introgression of genes between taxa their genetic integrity is maintained. To test the hypothesis that a temporal variation in species-specific spawning times is the mechanism limiting hybridization and maintaining genetic integrity in a M edulis and M. trossulus hybrid zone in eastern Maine, mussels were sampled on monthly to semi-monthly intervals throughout 2000 from …

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Can A Little Ice Age Climate Signal Be Detected In The Southern Alps Of New Zealand?, Jessica L. Black Aug 2001

Can A Little Ice Age Climate Signal Be Detected In The Southern Alps Of New Zealand?, Jessica L. Black

Electronic Theses and Dissertations

The Little Ice Age (LIA) was a late Holocene interval of climate cooling registered in the North Atlantic region by expansion of alpine glaciers and sea ice (Grove, 1988). Here the LIA includes an early phase from about AD 1280 to AD 1390, along with a main phase from about AD 1556 to AD 1860, followed by warming and ice retreat (Holzhauser and Zumbiihl, 1999a). It has recently been demonstrated from records of North Atlantic ice-rafted debris that the LIA is the latest cooling episode in a pervasive 1500-year cycle of the climate system that may lie at the heart …

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Capturing Feedback In Complex Marine Ecosystems: Two Models, Teresa R. Johnson May 2001

Capturing Feedback In Complex Marine Ecosystems: Two Models, Teresa R. Johnson

Electronic Theses and Dissertations

Marine systems are complex and highly variable. Feedback is required to learn in and manage these systems. Unfortunately, feedback in complex marine systems is difficult to capture and ambiguous. Feedback is a function of system structure. Conventional fisheries management simplifies this structure by focusing on individual species. It assumes that variability in populations is due solely to changes in the adult population (i.e., that a stock-recruitment relationship exists) and all necessary feedback is available by simply observing the size of the adult population. Unfortunately, this approach does not consider the environment of the species and most marine stocks show poor …

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Measures Of Denitrification In Selected South Dakota Semi-Permanent Prairie Pothole Wetlands, Beverly S. Klein Jan 2001

Measures Of Denitrification In Selected South Dakota Semi-Permanent Prairie Pothole Wetlands, Beverly S. Klein

Electronic Theses and Dissertations

Wetlands are an integral part of agricultural systems in the prairie pothole regions of the North Central United States and Canadian Provinces. Little research has been done on denitrification in prairie potholes, and a better understanding of their denitrifying capability could aide in optimizing management practices near pothole areas. Most probable number (MPN) and denitrifying enzyme activity (DEA or Phase I) assays were conducted. Most probable number (MPN) measures were used to give an estimate of dissimilatory nitrate reduction to ammonia (DNRA) and denitrifying populations present in the wetlands. This study involved 3 selected semi-permanent prairie pothole wetlands near Madison, …

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