Physical Sciences and Mathematics Commons^™

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 …

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 …

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 …

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, …

Three Dimensional Hydrodynamic Modeling Study, Craney Island Eastward Expansion, Lower James River And Elizabeth River, Virginia, Harry V. Wang, S. C. Kim, John D. Boon, A. Y. Kuo, G. M. Sisson, J. M. Brubaker, J. P-Y. Maa

Reports

The Craney Island Eastward Expansion Hydrodynamic Model Study was conducted in three phases: 1) model calibration and verification for the Elizabeth River, 2) model testing of four Craney Island expansion options using single variable runs (using a single variable, tidal range, for model input), 3) model testing of two expansion options using historical runs (using multiple variables in real time for model input). The expansion option designs were evaluated for both global and local hydrodynamic change through simulation comparisons with the Base Case condition.

Dark Production: A Significant Source Of Oceanic Cos, M. Von Hobe, Gregory A. Cutter, A. J. Kettle, M. O. Andreae

OES Faculty Publications

Carbonyl sulfide (COS) in air and dissolved in seawater was determined during a cruise in August 1999 in the Sargasso Sea in the northwest Atlantic Ocean. Dissolved concentrations at the sea surface displayed only a weak diel cycle with a mean of 8.6 ± 2.8 pmol dm⁻³ owing to low abundance of photochemical precursors and high temperatures causing rapid hydrolysis. Depth profiles measured over the oceanic mixed layer revealed significant vertical gradients of COS concentration with higher values at the surface, suggesting that the rate of photochemical production at the surface exceeds the rate of vertical mixing. The mean …

Uwit: Underwater Image Toolbox And Mosaicking In Matlab, R. Eustice, O. Pizarro, C. Roman, H. Singh

Christopher N. Roman

No abstract provided.

A Short Summary Of Seabed And Some Data Highlights, H. Singh, R. Eustice, C. Roman, O. Pizarro, N. Mcphee

Christopher N. Roman

No abstract provided.

Estimation Of Error In Large Area Underwater Photomosaics Using Vehicle Navigation Data, C. Roman, H. Singh

Christopher N. Roman

Creating geometrically accurate photomosaics of underwater sites using images collected from an AUV or ROV is a difficult task due to dimensional errors which grow as a function of 3D image distortion and the mosaicking process. Although photomosiacs are accurate locally their utility for accurately representing a large survey area is jeopardized by this error growth. Evaluating the error in a mosaic is the first step in creating globally accurate photomosaics of an unstructured environment with bounded error. Using vehicle navigation data and sensor offsets it is possible to estimate the error present in large area photomosaics independent of the …

Fall 2001, Nsu Oceanographic Center

Currents

No abstract provided.

New And Export Productivity Regulation By Si And Fe In The Equatorial Pacific Ocean, Fei Chai

University of Maine Office of Research Administration: Grant Reports

To identify and quantify the principal processes that control the partitioning of carbon among oceanic reservoirs and between the ocean and atmosphere on focal and regional scales, with a view towards synthesis and prediction on a global scale, is a specific goal of the U.S. JGOFS Synthesis and Modeling Project. As a contribution towards achieving this goal, Drs. Barber, Peng, Chai and Dugdale will develop an ecosystem model for the equatorial Pacific Ocean, with a focus on how silicate and iron affect new and export productivity and the partitioning of carbon between the atmosphere, surface ocean and deep ocean. The …

Emersion Stress In Intertidal Seaweeds: Role Of Active Oxygen, Ian R. Davison

University of Maine Office of Research Administration: Grant Reports

The study will examine stress-tolerance in two major groups of perennial intertidal macroalgae, the red and brown seaweeds. The research will test the hypothesis that active oxygen is involved in emersion stress of intertidal seaweeds. Damage due to active oxygen will be determined in stress-tolerant and stress- susceptible species exposed to emersion stress by measuring the peroxidation of membrane lipids. Plants will be grown in laboratory culture under conditions that increase their ability to withstand emersion stress. If the research hypothesis is correct, increases in stress tolerance should be associated with increased levels of antioxidants and/or protective enzymes. The proposed …

School Of Marine Sciences / Darling Marine Center, Kevin J. Eckelbarger

University of Maine Office of Research Administration: Grant Reports

Over the last six years, the University of Maine has made an unprecedented investment in its marine laboratory, the Darling Marine Center to benefit both University faculty and visiting researchers and their students. Facility improvements include many new laboratory and offices spaces, more research instrumentation, and basic support facilities such as a dining hall and new classrooms. The inauguration of a Visiting Investigation Program in 1991, the expansion of educational offerings, and the growth of a large undergraduate internship program, have resulted in a population explosion that shows no sign of abating. To set priorities for improvements, the University has …

Hydrographic Variability On Decadal And Interdecadal Scales In The Northern Gulf Of Alaska, Nandita Sarkar

OES Theses and Dissertations

The mixed layer depth (MLD) in the North Pacific is important to vertical mixing and hence the flux nutrients into the euphotic zone. A time series of hydrographic measurements, tem perature and salinity versus depth, at a coastal site in the northern Gulf of Alaska is used to determine the seasonal and interannual variations in the MLD. Data from this station called GAK 1 (59°50.7‘X. 149C28.0'\V) in 203 m of water begin in 1974 and end in 1998. The MLD changes seasonally from about 50 m in summer to more than 130 m in winter. These changes are in response …

Dynamical Sedimentary Models Of Shallow Marine Environments, Yong Zhang

OES Theses and Dissertations

This treatise represents a contribution of quantitative, dynamical sedimentary modeling to the analytical understanding of sedimentary processes in shallow marine environments. The dynamical sedimentary models in this treatise numerically simulate the sedimentary processes from an event time scale, based on the fundamental physics of sediment dynamics in coastal and shelf depositional environments, to a longer, facies time scale. The simulated geologic processes serve to the illustrate shoreface equilibrium profile, shelf storm bed generation, and the shelf sedimentary facies system.

This treatise presents a nearshore profile evolution model for the abandoned Huanghe Delta, a two-dimensional storm deposition model, and a sedimentary …

Transverse Variability Of The Flow And Density In Inlets Of Southern Chile, Mario Arturo Cáceres Muñoz

OES Theses and Dissertations

Measurements of velocity and density profiles were made to describe the flow transverse structure in three inlets of southern Chile. The inlets show marked differences in their transverse dynamics in response to external forcing. In Aysen Fjord (45.2°S) the mean flow showed a three layer structure that was consistent with up-fjord wind-induced exchange, while in Chacao Channel (41.8°S), the mean flow exhibited predominantly a lateral structure that featured sharp velocity shears. In both cases, a bank in the center of the sections seemed to play an important role in shaping the mean flows. In Ventisquero Sound (44.4°S), the presence of …

Trichodesmium Spp.: Numerical Studies Of Resource Competition, Carbohydrate Ballasting, And Remote-Sensing Reflectance, Tonya Denise Clayton

OES Theses and Dissertations

In recent years, a new appreciation for the role of diazotrophy in the oceans has emerged. This dissertation reports on three modeling studies designed to investigate ecological processes associated with Trichodesmium spp., the most conspicuous marine diazotroph: (1) characterization of a generalized model Trichodesmium and issues of macronutrient resource competition; (2) carbohydrate ballasting by Trchodesmium and implications for the formation of surface accumulations; and (3) the vertical distribution of Trichodesmium and implications for detection from space.

The first study focuses on issues of nitrogen and phosphorus competition and ecosystem structure. It utilizes a simple ecosystem model that includes dissolved nitrogen …

Spring/Summer 2001, Nsu Oceanographic Center

Currents

No abstract provided.

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 …

Hydrography, Nutrients, And Carbon Pools In The Pacific Sector Of The Southern Ocean: Implications For Carbon Flux, Kendra L. Daly, Walker O. Smith Jr., Gregory C. Johnson, Et Al

VIMS Articles

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Abstract

We investigated the hydrography, nutrients, and dissolved and particulate carbon pools in the western Pacific sector of the Antarctic Circumpolar Current (ACC) during austral summer 1996 to assess the region's role in the carbon cycle. Low f CO₂ values along two transects indicated that much of the study area was a sink for atmospheric CO₂. The f CO₂ values were lowest near the Polar Front (PF) and the Subtropical Front (STF), concomitant with maxima of chlorophyll a and particulate and dissolved organic carbon. The largest biomass accumulations did not occur at fronts, …

Of Manatees, Mangroves, And The Mississippi River: Is There An Estuarine Signature For The Gulf Of Mexico?, R. Eugene Turner

Faculty Publications

Important parameters of estuarine variability include morphology, flushing times, nutrient loading rates, and wetland: water ratios. This variability both reflects and disguises underlying relationships between the physics and biology of estuaries, which this comparative analysis seeks to reveal, using the Gulf of Mexico (GOM) estuaries as a starting point. A question used to focus this analysis is: are the GOM estuaries unique? The GOM receives the Mississippi River, a uniquely large, world-class river, which dominates the freshwater and nutrient inflows to the GOM continental shelf, whose margins include 35 major estuarine systems. These GOM estuaries have 28% and 41% of …

Morphostatic Long-Term Hypsometric Analysis Of Coastal Bay Environments: Hog Island Bay, Virginia, Kathleen Marie Overman

OES Theses and Dissertations

Sea level has been rising at a variable rate since the end of the last glaciation approximately 18,000 years ago. As the transgressing sea inundates the shore areas a series of landform state changes occur in coastal regions. One such change of state in a coastal paleo-river channel is from an estuary into a coastal lagoon. At large temporal intervals (thousands of years) the hypsometry of a coastal lagoon varies as a result of sea level rise due to these changes of state. Using a morphostatic technique, the time period in which an estuary transforms into a coastal lagoon can …

The Implications Of The Target-Area Hypothesis On The Population Dynamics Of The Spotted Spiny Lobster, Panulirus Guttatus, Denice N. Robertson

Biological Sciences Theses & Dissertations

The target-area hypothesis, based on the theory of island biogeography, predicts that larger islands are more effective at intercepting passive immigrants. Most marine invertebrates have meroplanktonic larvae and open population dynamics, so immigration to populations in isolated benthic habitats is primarily by pelagic larval recruits. Thus, recruitment to isolated habitat “islands” may be more continuous and predictable on large islands than on small ones. Consequently, populations on large islands should not only be larger than those on small islands, but should also have more evenly distributed size structures. These differences in size structure among populations in isolated habitats of differing …

2001 Gloucester Point Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.

2001 Wachapreague Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.

Reconstructing Basin-Scale Eulerian Velocity Fields From Simulated Drifter Data, M. Toner, A. C. Poje, A. D. Kirwan, C. K. R. T. Jones, B. L. Lipphardt, C. E. Grosch

CCPO Publications

A single-layer, reduced-gravity, double-gyre primitive equation model in a 2000 km x 2000 km square domain is used to test the accuracy and sensitivity of time-dependent Eulerian velocity fields reconstructed from numerically generated drifter trajectories and climatology. The goal is to determine how much Lagrangian data is needed to capture the Eulerian velocity field within a specified accuracy. The Eulerian fields are found by projecting, on an analytic set of divergence-free basis functions, drifter data launched in the active western half of the basin supplemented by climatology in the eastern domain. The time-dependent coefficients are evaluated by least squares minimization …

Observations Of Intratidal Variability Of Flows Over A Sill/Contraction Combination In A Chilean Fjord, Arnoldo Valle-Levinson, Fernando Jara, Carlos Molinet, Doris Soto

CCPO Publications

Underway velocity measurements were carried out for the first time in a Chilean fjord using an acoustic Doppler velocimeter with the purpose of elucidating the intratidal variability of flows through a pass, Paso Galvarino. The pass included a sill, where the bottom sloped by roughly 30%, and a coastline contraction of -90%. The relatively small dimensions of the pass allowed for rapid sampling of the flow evolution throughout the tidal cycle. The backscattered sound signal from the velocimeter and from an echo sounder were used to describe the vertical excursions of the pycnocline throughout the domain and to identify regions …

Wind And Gulf Stream Influences On Along-Shelf Transport And Off-Shelf Export At Cape Hatteras, North Carolina, Dana K. Savidge, John M. Bane Jr.

CCPO Publications

Along-shelf transports across three cross-shelf lines on the continental shelf near Cape Hatteras have been calculated from moored current meter data over a continuous 24 month period in 1992-1994. The along-shelf convergence has been used to infer off-shelf export. Transport and transport convergence have been related to wind and Gulf Stream forcing and to variability in sea level at the coast. The along-shelf transport variability is primarily wind-driven and highly correlated with sea level fluctuations at the coast. Both winds and along-shelf transport exhibit a near-annual period variability. Along shelf transport is not well correlated with Gulf Stream offshore position. …

2001 Hampton Roads Station Tide Prediction Calendars, Virginia Institute Of Marine Science, David A. Evans

Miscellaneous

These calendars are produced monthly using David Evans' Tidecal.

Future Research Vessels, Larry P. Atkinson

CCPO Publications

The academic research vessel fleet in the United States is embarking on a great experiment. By 2004 we will know if SWATH vessels such as the Mlo Moana and the possible built Woods Hole Oceanographic Institution coastal SWATH have such great advantages that all future vessels will be of SWATH design. Or, we will find that the two hull forms have distinct niches and the fleet will evolve with a strategic mix. Regardless of the Mure hull form research vessels will grow in size to accommodate advanced technology and the people to run and maintain it. The research vessel will …