Marine Biology Commons^™

Beyond Cortisol: Indicators Of Stress And Negative Feedback In Plasma And Blubber Of Marine Mammals, Jessica Avalos

University of the Pacific Theses and Dissertations

Marine mammals play an important role in ecosystem stability. However, anthropogenic activity is compounding pressure on many already vulnerable populations. A potential consequence of anthropogenic disturbance is physiological stress, which can impact metabolism, immunity, and reproduction, especially if it occurs repeatedly. Previous studies on marine mammals have focused on acute stress, but the impacts of repeated stress are poorly understood. Due to its accessibility on land during haul-outs, the northern elephant seal (Mirounga angustirostris) is a good system in which to study the effects of stress in marine mammals. Stress stimulates the release of glucocorticoid hormones, primarily cortisol. Elevated cortisol …

The Role Of Symbiotic Algae In The Acclimatization Of Oculina Arbuscula To Ocean Acidification, Erin M. Arneson

Electronic Theses and Dissertations

Ocean acidification (OA) caused by CO₂ emissions is projected to decrease seawater pH to 7.6 by 2100. Scleractinian corals are at risk because excess H⁺ in seawater binds to carbonate (CO₃^2-), reducing its availability for CaCO₃ skeletons. The energy demand for skeletal growth increases as pH decreases because corals must actively purge excess H⁺ from their seawater sourced calcifying fluid to maintain high calcification rates. In scleractinian corals it is hypothesized that photosynthesis by symbiotic algae is critical to meet this increased energy demand. To test this hypothesis, I conducted laboratory and field …

Effect Of Hyposaline Stress On Metabolic Rate Of The Invasive Mussel Mytilus Galloprovincialis, Hayley C. Hart

Honors Thesis

Climate change is predicted to decrease ocean salinity as the polar ice caps melt and the occurrence of precipitation events increases. Decreased ocean salinity (hyposalinity) may negatively impact marine invertebrates, especially marine mussels, as they are osmoconformers and their internal osmolarity depends on the solute concentration of their environment. Hyposalinity stress may influence cell function and alter mussel physiology. To compensate for the change in the environment, mussels may expend more energy to restore internal osmolarity, which can be assessed by quantifying metabolic rate. Thus, the purpose of our research was to examine the physiological response of Mytilus galloprovincialis, …

Energetic Consequences Of Human Impacts For Bioindicator Atlantic Ghost Crab (Ocypode Quadrata), Mustafa Remzi Gül

Theses and Dissertations

Human activities have caused notable changes in ecosystems globally over the past century, which cause substantial ecological issues. The degree of these ecological issues is often investigated using the responses of bioindicator species. Bioindicator species often reduce their population densities and individual sizes as a response to the human disturbance. Observing these variations in the demographics is often an effective way to measure the strength of the ecological changes. However, they do not provide any mechanistic reason (s) for the shifts in the demographics, which is important for making predictions about responses of the species to the future conditions. Therefore, …

The Effects Of Salinity On Zootechnical Performance Of Spotted Seatrout (Cynoscion Nebulosus) In Recirculating Aquaculture Systems, Eric Gigli

Master's Theses

The spotted seatrout (Cynoscion nebulosus) is a euryhaline finfish candidate for marine aquaculture in the northern Gulf of Mexico. Aquaculture of this species currently uses salinities of 25 psu or greater making production challenging in areas where high salinity water is not available. This study aimed to document the effects of salinity on zootechnical performance of spotted seatrout embryos, early larvae, and juveniles in recirculating aquaculture systems to assist with the development of protocols for low salinity culture.

Embryos obtained from a volitional spawn at 29 psu were incubated at three salinities (12.5, 18.75, or 25 psu) until …

Physiological Effects Of Climate Change On The American Lobster, Homarus Americanus, Amalia M. Harrington

Electronic Theses and Dissertations

Increases in anthropogenic input of carbon dioxide into the atmosphere have caused widespread patterns of ocean warming and ocean acidification. Both processes will likely have major impacts on commercial fisheries and aquaculture, with acidification posing a particular threat to many marine calcifying invertebrates. In the State of Maine, commercial fisheries landings and a growing aquaculture industry have a combined value in excess of $600 million, 75% of which is sustained by marine calcifiers. Moreover, the American lobster (Homarus americanus) supports the most economically valuable fishery in the Gulf of Maine and Atlantic Canada. Previous research has documented a …

Development Of A Biomarker Panel For Identifying Stressed Marine Mammals, Laura Pujade

University of the Pacific Theses and Dissertations

Increasing anthropogenic disturbance in marine ecosystems such as fishing, oil-drilling, and noise pollution can have detrimental effects on the reproduction and survival of apex predators such as marine mammals. Stress activates the hypothalamic-pituitary-adrenal (HPA) axis, resulting in increased circulating glucocorticoid (GCs) hormones, which alter expression of target genes encoding metabolic enzymes and other mediators of stress. Prolonged HPA axis stimulation may increase catabolism of nutrient stores and suppress immune and reproductive functions, impacting the fitness of marine mammals. GCs measurements are used to identify wild animals experiencing stress. However, these measurements may not be sensitive enough to distinguish between an …

Blubber Transcriptome And Proteome Responses To Repeated Adrenocorticotropic Hormone Administration In A Marine Mammal, Jared Deyarmin

University of the Pacific Theses and Dissertations

Chronic physiological stress impacts animal fitness by catabolizing metabolic stores and suppressing reproduction and immunity. This can be especially deleterious for capital breeding carnivores, such as marine mammals, which rely on lipid stores accrued during intensive foraging to sustain prolonged periods of fasting associated with reproduction. Therefore, chronic stress may cause a decrease in fitness in these animals, leading to population declines and potentially detrimental shifts in food web dynamics as a result. However, the impacts and indicators of chronic stress in animals are currently poorly understood. To identify downstream mediators of repeated stress responses in marine mammals, adrenocorticotropic hormone …

Determining The Physiological And Behavioral Aspects Of Salinity Tolerance In The Asian Clam, Corbicula Fluminea, John Roden

Undergraduate Honors Theses

The Asian clam, Corbicula fluminea, is an invasive bivalve species that now occurs through most of the lower 48 United States. While a significant degree of salinity tolerance has been observed in C. fluminea, owing to its estuarine lineage, the physiological and behavioral responses to changes in salinity by these organisms are not completely understood. It was hypothesized that Corbicula would initially avoid elevated salinity levels (>1 g/L) behaviorally through valve closure, but would eventually have to open to dispel anaerobic waste products and deal with the salinity. To explore this, Corbicula were collected and put through …

The Interactive Effects Of Ocean Acidification, Food Availability, And Source Location On The Growth And Physiology Of The California Mussel, Tharadet Daniel Man

Cal Poly Humboldt theses and projects

Research shows ocean acidification (OA) can have largely negative impacts on marine organisms and ecosystems. Prior laboratory studies show that shelled marine invertebrates (e.g., molluscs) exhibit reduced growth rates and weaker shells when experiencing OA-related stress. However, populations of the critical intertidal mussel species, Mytilus californianus, which experience naturally acidic water due to upwelling in certain parts of Northern California have been observed to have relatively stronger and thicker shells and higher growth rates than those that experience less frequent exposure to upwelling. To address the discrepancies between negative effects of OA exposure in the laboratory and seemingly positive …

Combined Effects Of Dissolved Oxygen And Temperature On Aerobic Respiration And Respiratory Recovery Responses Of The Spioniform Polychaete, Streblospio Gynobranchiata, In Relation To Body Size, Alyssa Bennett

Master's Theses

Elevated surface temperatures exacerbate the threat of hypoxia within coastal ecosystems. These two primary stressors likely interact as they elicit opposing physiological responses from marine organisms. Metabolic depression is typically associated with hypoxia, while metabolic rates increase with temperature. Moreover, physiological effects of combined stressors may not be additive. In light of increasing pressures from hypoxia, elevated ocean temperatures, and other stressors within coastal regions, studies need to examine effects of multiple stressors on physiology of coastal organisms.

Mass-specific aerobic respiration (V_O2) was characterized as a proxy for metabolic cost of Streblospio gynobranchiata, at combined levels of …

Understanding And Optimizing Growth And Development Of California Yellowtail (Seriola Dorsalis) In Aquaculture Using Physiological Tools, Laura Schwebel

Theses

Physical fitness metrics were used to assess the health and development of California Yellowtail, Seriola dorsalis, in an aquaculture environment during two grow-out experiments. The first experiment sought to evaluate the effects of a common aquaculture deformity (an improperly inflated swim bladder) that has been hypothesized to impact energy allocation, growth, and development. Metrics including metabolic rate, critical swimming speed, feed conversion ratio, and growth rate, were monitored over a 32-week period in three groups of California Yellowtail: wild-caught (“wild”), healthy hatchery-reared (“inflated”), and hatchery-reared with uninflated swim bladders (“uninflated”). At the start of the grow-out period, wild fish …

Divergent Responses Of Larval And Juvenile Blue Mussels To Low Salinity Exposure, Melissa A. May

Electronic Theses and Dissertations

In this study, we compared the osmotic stress response of larval and juvenile blue mussels (Mytilus edulis) at the transcriptomic, metabolomic, and whole organism levels. Blue mussels inhabit coastal areas, where they face climate-induced reductions in nearshore salinity. Despite their ecological and economic importance, scientists do not fully understand the underlying transcriptomic and cellular mechanisms of the osmotic stress response in blue mussels or how the ability to respond to stress changes throughout development. Blue mussels spend the first weeks of life developing through several larval stages in the plankton. These early life history stages are more vulnerable …

Time-Activity And Energy Budgets Of Eared Grebes (Podiceps Nigricollis) At Salton Sea, Samantha San Francisco

Theses

Time-activity budgets have been a widely accepted way of approximating the daily energy expenditure of many species, including waterbirds. For this study, focal animal sampling was used to study Eared Grebes (Podiceps nigricollis) at their post-wintering stopover site, Salton Sea. Daylight time-activity budgets were converted to energy budgets using energy equivalents for diving, preening, swimming, and resting on water developed for Eared Grebes previously by H. I. Ellis (1994). Post-wintering Eared Grebes arrive at Salton Sea in waves at differing times in the spring. As a result, there can be individuals in a variety of physiological states during …

Characterization Of Andrenocortical Tissue Morphology, Histology, And Steroid Synthesis Among Finetooth (Carcharhinus Isodon), Blacktip (Carcharhinus Limbatus), Atlantic Sharpnose (Rhizoprionodon Terraenovae), And Bonnethead (Sphyrna Tiburo) Sharks, Danielle Elizabeth Bailey

Master's Theses

Adrenocortical (interrenal) tissue is composed of steroidogenic cells that produce corticosteroids involved in the stress response and hydromineral balance. Previous research characterizing the elasmobranch interrenal suggests that the number of interrenal bodies that produce the single primary corticosteroid, 1a-hydroxycorticosterone (1a-OHB), varies among species. However, potential species-specific differences in the amount of interrenal tissue and major steroid products produced have been understudied. To address this critical gap in our understanding of elasmobranch biology, this study examined interrenal morphology, cell structure, steroidogenic enzyme distribution (3bHSD), and steroid production in four shark species: Finetooth Carcharhinus isodon, Blacktip Carcharhinus limbatus, Atlantic Sharpnose …

Examining The Combined Effects Of Dissolved Oxygen, Temperature, And Body Size On The Physiological Responses Of A Model Macrobenthic Polychaete Species, Capitella Teleta, Kelsey Burns Gillam

Dissertations

While the scientific community is in consensus that coastal systems are threatened by climate change, few climate change studies test the effects of more than one variable directly related to climate change. The dissolved oxygen (DO) levels of the ocean are currently subject to both global warming and eutrophication; 94% of all hypoxia zones are expected to experience >2°C increase by 2035. This dissertation aims to examine how a model organism responds to simultaneous thermal and DO stress involving four levels of DO (100%, 70%, 50%, and 20%) saturation and three temperatures (15°C, 20°C, and 25°C).

The polychaete, Capitella teleta …