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Aquatic Commons (30,305 recursos)
The Aquatic Commons is a thematic digital repository covering the natural marine, estuarine /brackish and fresh water environments . It includes all aspects of the science, technology, management and conservation of these environments, their organisms and resources, and the economic, sociological and legal aspects.

Type = Thesis

Mostrando recursos 1 - 20 de 68

1. Hydrogen, carbon monoxide, and methane in the marine environment - Bullister, John Logan
EXTRACT (SEE PDF FOR FULL ABSTRACT): The horizontal and vertical distribution of three dissolved trace gases, namely molecular hydrogen, carbon monoxide, and methane, was measured in coastal and oceanic areas. Atmospheric concentrations of these gases were measured both at locations influenced by nearby human activity, and in areas far removed from these inputs.

2. Atmospheric chlorofluoromethanes as tracers of ocean circulation and mixing: measurement and calibration techniques and studies in the Greenland and Norwegian seas - Bullister, John Logan
EXTRACT (SEE PDF FOR FULL ABSTRACT): An analytical system was designed and constructed for the rapid and accurate shipboard measurement of anthropogenic chlorofluoromethanes in seawater and in air, using electron capture gas chrometography. The distribution of these compounds in the marine atmosphere and the water column in the Greenland and Norwegian seas were studied during February and March, 1982. The compounds, dissolved in the ocean from the atmosphere, can be used as tracers of subsurface ocean circulation and mixing processes.

3. The biology and ecology of the invasive Indo-Pacific lionfish - Morris Jr., James A.
The Indo-Pacific lionfishes, Pterois miles and P. volitans, are now established along the Southeast U.S. and Caribbean and are expected to expand into the Gulf of Mexico and Central and South America. Prior to this invasion little was known regarding the biology and ecology of these lionfishes. I provide a synopsis of chronology, taxonomy, local abundance, reproduction, early life history and dispersal, venomology, feeding ecology, parasitology, potential impacts, and possible control and management strategies for the lionfish invasion. This information was collected by review of the literature and by direct field and experimental study. I confirm the existence of an...

4. Spatial and temporal variability in the distribution and abundance of larval and juvenile fishes associated with pelagic Sargassum - Settle, Lawrence R.
A survey of the larval and juvenile fishes associated with the pelagic Sargassum habitat in the South Atlantic Bight and adjacent western Atlantic Ocean was conducted from July 1991 through March 1993. Fishes representing 104 taxonomic categories were identified, including reef fishes, coastal demersal, coastal pelagic, epipelagic and mesopelagic species. The most important families were Balistidae and Carangidae, each represented by 15 species. Species composition, species diversity and abundance varied both seasonally and regionally. Diversity was highest during spring through fall over the outer continental shelf and in the Gulf Stream. Abundance decreased from spring through winter and from the...

5. The role of substrate, flow and larval supply to recruitment of the red abalone (Haliotis rufescens) - Altstatt, Jessica Marianne
Precipitous declines in wild populations of the red abalone Haliotis rufescens and the eventual closure of the commercial and southern recreational fishery have led to renewed interest in supplementing wild stocks with hatchery-raised individuals. Most work to date has focused on releasing small juveniles and has had limited success. Although much is known about larval settlement, juvenile survivorship and growth of abalone, there is scanty information on natural processes in the field. The failure of many regulated fisheries worldwide suggests that both the larval and juvenile stages may be important in determining the future population, and that early juvenile mortality...

6. The food habits of four kelp-bed rockfishes (Scorpaenidae, Sebastes) off Santa Barbara, California - Larson, Ralph John
The diets of four common rockfishes from the kelp beds near Santa Barbara, California, were determined by gut contents analysis, and related to feeding strategies. The guts of one hundred specimens of each species were examined, and the importance of prey evaluated by their frequency of occurrence, numbers, and volumes. The volumes of stomach contents were standardized for the size of specimen. Estimates of overlap in diet between the species were made. Sebastes atrovirens fed primarily on small animals from the kelp canopy, and may have employed a browsing rather than pursuing strategy of feeding. It showed low overlap in...

7. Ecology and growth of juvenile California spiny lobster, Panulirus interruptus (Randall) - Engle, John Marlin
ABSTRACT TRANSCRIBED FROM ENGLE'S PH.D. ORAL DEFENSE PAMPHLET: The natural history of juvenile California spiny lobster, Panulirus interruptus (Randall), was investigated, with primary emphasis placed on ascertaining juvenile habitats, determining juvenile growth rates and component growth processes, and evaluating ecological and behavioral phenomena associated with juvenile survival and growth. Habitat surveys of island and mainland localities throughout southern and lower California revealed that small, greenish juveniles typically inhabit crevices or temporary burrows in 0-4m deep, wave-swept rocky habitats covered by dense beds of surf grass, Phyllospadix torreyi S. Watson. Phyllospadix beds were more abundant on gradually sloping rocky mainland beaches than...

8. Factors influencing choice of fishing location in Nankumba Peninsula: A case of study of gillnet and chilimira fisheries - Mvula, Stanley W.T.
This study was carried out to identify factors that influence choice of fishing location and carry out profitability analysis of Chilimira and Gillnet in different fishing locations. A survey using semi-structured questionnaire was administered to 99 Gillnet and 101 Chilimira fishers in Nankumba Peninsula in Mangochi District. The logit model was used to determine the factors influencing choice of fishing location among the fishers. The study showed that 92.1% of Chilimira fishers are operating in offshore areas while 69.7% Gillnet fishers are operating in inshore areas. Chilimira offshore fishers have higher daily average gross margins than their inshore counterparts and Gillnet...

9. Differential predation upon embryos and larvae of temperate Pacific echinoderms - Rumrill, Steven Seward

10. Diet of Bottlenose Dolphins Tursiops truncatus in the Northwest Panhandle and Foraging Behavior Near Savannah, Georgia - Bowen, Sabrina Rose
The foraging ecology of bottlenose dolphins Tursiops truncatus in the Northwest Florida Panhandle and estuaries in northern Georgia was determined using diet analysis and behavioral surveys. Stomach content analysis was completed on bottlenose dolphins(N = 25) that stranded in the Northwest Florida Panhandle from November 2006 to March 2009. The most abundant prey species were spot Leiostomus xanthurus (20.4%), squid (10.9%), pinfish Lagodon rhombiodes (10.3%), and Atlantic croaker Micropogonias undulatus (8.5%). Dolphins that stranded during months with a red tide Karenia brevis bloom consumed more pinfish, and spot; whereas dolphins that stranded in non-bloom months consumed more squid, Atlantic croaker, and silver perch Bairdiella...

11. The role of mate guarding, Male Size and Male Investment on Individual Reproductive Success in the Blue Crab, Callinectes Sapidus. - Jivoff, Paul Robert
Male blue crabs, Callinectes Sapidus, guard their mates before and after mating, suggesting that the conditions regulating both types of mate guarding dictate individual reproductive success. I tested the hypothesis that large male blue crabs have advantages in sexual competition using experimental manipulations, a simulation model, and field data on crabs from mid-Chesapeake Bay between 1991-1994.

12. Estimación de costos de garantía en sistemas K de N con políticas FRW y PRW, bajo aproximación de reparación física y de caja negra - Pereira Hoyos, Luz Adriana
Este trabajo se enmarca en el estudio de los costos de garantía de un sistema con estructura k de n, modelando los tiempos de falla del sistema bajo dos aproximacions: Física y de Caja negra, para políticas de garantía “Free-Replacement Warranty” (FRW) y “Pro-Rata Warranty” (PRW); con el objetivo de determinar si existe algún efecto al ignorar la estructura del sistema y el estado de sus componentes en el tiempo. En los escenarios simulados, se observa que existe un efecto de sobreestimación en la distribución del costo de garantía y por lo tanto en la estimación del costo y del...

13. Anserma puntal del occidente por sus raíces Umbra - Duque Escobar, Gonzalo
A pesar de que la comunidad indígena se creyó extinguida en 1625, existen vestigios de la cultura Umbra diferente a la Embera, aún viva. Tras la ocupación de la tierra de los Umbra, con la colonización antioqueña Ansermaviejo indígena cede paso al moderno poblado que en el siglo XX consolida una economía cafetera, para un apogeo que llega hasta la década de los 70 cuando se crean implementa con el monocultivo del café un modelo agroindustrial que conduce a la actual crisis socioambiental, situación que obliga a las acciones estructurales que propone el Paisaje Cultural Cafetero.

14. Propuesta de diseño de metodologia para evaluar el impacto del e-learning en el proceso de aprendizaje de estudiantes de educacion a distancia - Cardona Román, Diana Marcela
En las últimas décadas los procesos de educación se han visto cada vez mas involucrados con las tecnologías de la información y comunicaciones (TIC) en la sociedad de la información (SI). Por esta razón, el e-learning se ha incorporado masivamente en la oferta educativa de cursos virtuales como en los ambientes de educación a distancia (EaD). Justamente, el presente trabajo propone una metodología para evaluar el proceso de aprendizaje del estudiante en ambientes de educación a distancia bajo la modalidad elearning. Esto debido a que en el estado actual del conocimiento no se encuentra suficiente evidencia de un modelo que permita...

15. LISTA DE LOS MOLUSCOS (GASTROPODA-BIVALVIA) DULCEACUÍCOLAS Y ESTUARINOS DE LA CUENCA DEL ORINOCO (VENEZUELA) - Lasso, Carlos A.; Martínez-Escarbassiere, Rafael; Capelo, Juan Carlos; Morales-Betancourt, Mónica A.; Sánchez-Maya, Alejandro
Se realizó una revisión bibliográfica y de colecciones en museos, así como de datos originales de los autores, para reconocer las especies dulceacuícolas y estuarinas de moluscos gastrópodos y bivalvos presentes en la cuenca del Orinoco (Venezuela). Se consolida un listado preliminar para la cuenca de 104 especies distribuidas entre la clase Gastropoda (14 familias y 58 especies) y la clase Bivalvia (13 familias y 45 especies). Entre los gastrópodos la familia Ampullaridae fue la más diversa (22 sp.) y entre los bivalvos, Mycetopodidae (16 sp.). Se incluye información sobre la distribución geográfica en las subcuencas de la Orinoquia, además...

16. Through South America - Van Dyke, Harry Weston
On the northeastern shoulder of the continent lies a huge block of territory as large as France and Spain combined. It is in reality an island, since it is bounded on the north and east by the Caribbean Sea and Atlantic Ocean, on the south by the Amazon River, and on the northwest and west by the continuous waterway formed by the Orinoco, the Casiquiare and the Negro rivers, the last named an affluent of the Amazon. Like the north Andean republics, the Guiana country is made up of mountains, highlands, and low-lying plains, and lies wholly in the tropics;...

17. La economía colombiana en la década de los noventa: dilema entre el mercado interno y el mercado internacional / The Colombian economy in the nineties: the dilemma between the domestic and international market - Restrepo Uribe , Ramiro
El proceso de "Apertura y Modernización" de la economía colombiana forzó a algunos sectores económicos al reto de la competencia internacional. En la década de los noventa el proceso produjo la caída de la participación relativa de la agricultura y la industria manufacturera en PIB y el sacrificio del mercado interno sin el correspondiente éxito en el mercado internacional./ Abstract.The process of "opening up and modernization" of the Colombian economy forced some industries to the challenge of international competition. In the nineties the process produced the fall in the relative share of agriculture and manufacturing in GDP and the sacrifice...

18. Behavior ecology of the Humboldt squid, Dosidicus gigas: insights from an animal-borne video and data logging system - Bell, Lauren Elizabeth
Dosidicus gigas is a large pelagic cephalopod of the eastern Pacific that has recently undergone an unexpected, significant range expansion up the coast of North America. The impact that such a range expansion is expected to have on local fisheries and marine ecosystems has motivated a thorough study of this top predator, a squid whose lifestyle has been quite mysterious until recently. Unfortunately, Dosidicus spends daylight hours at depths prohibitive to making observations without significant artificial interference. Observations of this squid‟s natural behaviors have thus far been considerably limited by the bright illumination and loud noises of remotely-operated-vehicles, or else...

19. A Comparison of the SNP Variation in the Calcification PMCA Gene of Lottia gigantea between a Santa Barbara Population and a More Acidic Monterey Bay Population - Aguilera, Stacy
As the atmospheric levels of CO2 rise from human activity, the carbonic acid levels of the ocean increase, causing ocean acidification. This increase in acidity breaks down the calcified bodies that many marine organisms depend upon. Upwelling regions such as Monterey Bay in California have pH levels that are not expected to reach the open ocean for a few decades. This study reviews one of the common intertidal animals of the California coast, the Owl Limpet Lottia gigantea, and its genetic variation of the plasma membrane Ca2+ ATPase (PMCA) in relation to the acidity of its environment. The PMCA protein...

20. Diet and condition of American Alligators (Alligator mississippiensis)in three central Florida lakes - Rice, Amanda Nicole
Understanding the diet of crocodilians is important because diet affects condition, behavior, growth, and reproduction. By examining the diet of crocodilians, valuable knowledge is gained about predator-prey interactions and prey utilization among habitats. In this study, I examined the diet and condition of adult American alligators (Alligator mississippiensis) in three central Florida lakes, Griffin, Apopka, and Woodruff. Two hundred adult alligators were captured and lavaged from March through October 2001, from April through October 2002, and from April through August 2003. Alligators ate a variety of vertebrate and invertebrate prey, but vertebrates were more abundant and fish dominated alligator diets in...

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