Download or read book Native Eelgrass Zostera Marina Mediates Growth and Reproduction of an Introduced Marine Bivalve Through Food Limitation written by Bengt J. Allen and published by . This book was released on 1999 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Inventory of Eelgrass Zostera Marina L in San Francisco San Pablo Bay written by Sandy Wyllie-Echeverria and published by . This book was released on 1989 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Context dependent Species Interactions in Seagrass Ecosystems written by and published by . This book was released on 2014 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: A unifying observation in ecology is that environmental context can play a key role in regulating the sign, strength, and mechanisms of species interactions. Estuaries and coastal seas are ideal ecosystems for exploring the impacts of environmental variability on ecological interactions because they are characterized by strong, dynamic gradients of abiotic conditions, such as physical disturbance and biogeochemical stress. Estuaries also are heavily impacted by biotic disruptions, including overexploitation of top predators and invasion by non-native species. For my dissertation, I explored the effects of abiotic and biotic environmental context on species interactions in subtidal and intertidal meadows of eelgrass Zostera marina, a marine angiosperm and key habitat-forming species in temperate estuaries worldwide, in three unique chapters. First, I tested how disturbance mediates competition between eelgrass and the burrowing ghost shrimp Neotrypaea californiensis in several California estuaries by conducting a series of transplantation and disturbance experiments. I found that both live eelgrass and structural mimics of belowground eelgrass tissues cause rapid declines in local ghost shrimp abundances, indicating that plant structure is an important mechanism in determining ghost shrimp distributions. However, ghost shrimp quickly colonize disturbances to eelgrass patch edges, which are common in shallow estuaries. Thus, coexistence is maintained by disturbance and a competition-colonization trade-off: eelgrass is competitively superior, but physical disturbances permit ghost shrimp coexistence at the landscape scale by modulating the availability of space. Second, I explored how light availability influences the sign, strength, and mechanisms of interactions between eelgrass and blue mussels, Mytilus edulis. I hypothesized that light availability regulates bivalve habitat modification and subsequent impacts on seagrasses by shifting net effects between alleviation of nutrient stress and intensification of sulfide stress. I manipulated light availability and blue mussel abundance in eelgrass mesocosms and measured biogeochemical and plant responses. I found that light modifies the effect of mussels on porewater ammonium, but eelgrass was not nutrient limited and, therefore, mussels did not enhance growth. Mussels increase sediment sulfides irrespective of light availability and, by reducing net oxygen flux (production and respiration), mussels and low light availability exacerbate sulfide intrusion of eelgrass tissues. Surprisingly, I found that sulfide stress did not affect plant growth, survival, or energy stores. Thus, habitat modification by mussels represents a risk to eelgrass, especially during low productivity conditions, but eelgrass can resist harm from short-term stress, even during light limitation. These findings suggest that while bivalve impacts on seagrasses may be variable in oligotrophic estuaries, they are likely negative in eutrophic systems, which are increasing globally. Third, I examined how invasive mussels impact their native bivalve competitors through both direct effects and indirect, predator-mediated interactions. Competition is a major process by which introduced species impact native populations, communities, and ecosystems, but ecological theory predicts that invading prey can also interact with their native competitors indirectly through shared native predators. Nevertheless, indirect effects are largely overlooked in invasive species science and management. In southern California estuaries, introduction of the Asian mussel Arcuatula senhousia has been linked to profound changes in native bivalve assemblages. I performed three field experiments to assess the mechanisms of competition between Arcuatula and native bivalves, and evaluate the potential for Arcuatula to indirectly mediate native predator-prey dynamics. I found that Arcuatula reduces the diversity, abundance, and size of native bivalve recruits by preemptively exploiting sediment surface space. When paired with native shallow-dwelling clams, Arcuatula reduces adult survival through overgrowth competition. However, Arcuatula also attracts native predators, indirectly increasing predation of native clams, especially poorly-defended species. Therefore, the vulnerability of invasive prey to predation can greatly exacerbate impacts on their native competitors. Overall, my dissertation improves our basic understanding of the causes and consequences of variation in species interactions in shallow estuaries and coastal lagoons. Furthermore, this research enhances our ability to predict the impacts on species interactions caused by human-induced ecosystem disruptions, such as habitat destruction, eutrophication, and non-native species introductions, which are widespread concerns for estuaries and coastal seas.
Download or read book Status of Eelgrass Zostera Marina on the North Atlantic Coast February 1938 written by Clarence Cottam and published by . This book was released on 1938 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Supplementary Bibliography on Eelgrass Zostera Marina written by C. Peter McRoy and published by . This book was released on 1968 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: This bibliography lists 204 references on eelgrass to supplement an earlier list (Special Scientific Report--Wildlife No. 79) issued in 1964.
Download or read book Light Level as a Potential Limiting Factor in the Growth of Zostera Marina Eelgrass in the Pacific Northwest written by Mark Justin Hylarides and published by . This book was released on 2015 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: From Abstract: Eelgrasses serve as important nursery habitats in the Pacific Northwest for diverse marine life and are widely recognized as indicators of coastal ecological health. Seasonal differences in respiration and Photosynthesis-Irradiance (P-I) relationships of a population of marine eelgrass Zostera marina in Rosario Bay, WA were investigated in order to characterize its growth potential in different seasons. The local light availability in situ for each season was also estimated by combining direct light measurements under different conditions with hourly weather and tide measurements. Measurement of the P-I relationship of blade sections and extrapolation to whole plants demonstrated that sufficient light is present even in the lowest-light season (winter) so that clean eelgrass is able to at least support its metabolism by photosynthesis and experience net growth. However, epiphytic algae living on the blades of Z. marina likely reduces its access to light, especially in summer, and could potentially lead to light limiting conditions.
Download or read book A Summary of Eelgrass Zostera Marina Reproductive Biology with an Emphasis on Seed Biology and Ecology from the Chesapeake Bay Region written by Robert Joseph Orth and published by . This book was released on 2007 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Population Growth of Eelgrass Zostera Marina L written by Patrick J. Ewanchuk and published by . This book was released on 1995 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluating Eelgrass Zostera Marina Site Quality by the Settlement Performance and Survival of a Marine Fish written by and published by . This book was released on 2011 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: The quantity of suitable habitat can be simply defined by the distribution and abundance of organisms, but it is the quality of the habitat that may have more direct demographic consequences. Habitat quality is best assessed by determining demographic rates and the performance of the focal species residing within a habitat. Using this framework, I used two demographic rates (settlement and survival) and two performance measures (growth and condition) of the giant kelpfish (Heterostichus rostratus) to evaluate whether eelgrass (Zostera marina) habitat quality varies spatially (i.e., site quality) within San Diego Bay, CA. Seven sites were selected that encompass the northern and central areas of the bay. Settlement was estimated bi-weekly from May-July 2009 with artificial seagrass units (ASUs) and standard monitoring units for the recruitment of fishes (SMURFs). Eelgrass habitat complexity (shoot height and density) was measured at each site, and three complexity treatments were replicated with ASUs in large mesocosms to estimate survival of giant kelpfish after exposure to kelp bass (Paralabrax clathratus) as predators. Growth and condition were derived from juvenile giant kelpfish collected from sites two months after the settlement period. Growth and condition were estimated from otolith daily growth increments and total lipid content, respectively. Settlement, growth, and condition were evaluated using a multivariate approach to provide an assessment of habitat quality among sites. Combined with habitat-dependent survival from predators in laboratory trials that reflected site-specific habitat attributes, sites were ranked along a gradient of habitat quality. The multivariate analysis of site quality based on demographic and performance variables was then overlaid with a similar analysis of environmental variables. Environmental variables that would serve as proxies for habitat quality were not concordant with the suite of demographic and performance variables used to differentiate site quality. Consequently, a multivariate approach using demographic rates and individual performance is the most appropriate method to evaluate habitat quality, whether among different habitats or among sites with the same habitat.
Download or read book The Ecological Consequences of Genetic Diversity in Eelgrass Zostera Marina written by Anne Randall Hughes and published by . This book was released on 2006 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Population Genetic Study of the Zostera Marina eelgrass Ecotypes of Barnegat Bay New Jersey and Implications for Grass Bed Restoration written by Stephanie Marie Smith and published by . This book was released on 2007 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Regulation of Growth of Eelgrass Zostera Marina L in Danish Coastal Waters written by Kaj Sand-Jensen and published by . This book was released on 1983 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Observational and Experimental Analysis of Eelgrass and Its Epifaunal Community in Bodega Harbor California written by Grace Ha and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Seagrass - marine flowering plants that create underwater meadows through-out temperate and tropical coastal waters - are important foundation species, acting as key nursery grounds for many commercial and recreational fisheries, performing ecosystem functions including flow modification and sediment stabilization, and providing habitat to diverse and productive communities of marine life. Given the decline of seagrass globally, there is particular need for documenting and understanding the dynamics of seagrass ecosystems. Focusing on the eelgrass (Zostera marina L.) beds of Bodega Harbor, California, USA, I approached this task through methods that incorporated natural history, field research, statistical analysis, and taxonomy. In Chapter 1, I conducted a 16-month survey of eelgrass and its epifauna and analyzed species abundances in the context of the extreme warm-water event known as "The Blob" that occurred along the Californian coastline in 2014. My research found a diverse invertebrate assemblage comprising mostly native detritivore-grazers, which contrasted sharply with nearby San Francisco Bay, which has been dominated by invasive species. Invertebrate population dynamics correlated closely to that of the eelgrass they inhabited, and in general, both habitat and epifauna declines coincided with increasing seawater temperatures. In Chapter 2, I used eelgrass as a model system to test the role of camouflage in predator-prey interactions. I conducted field experiments, testing whether prey survival was affected by color-matching between prey and habitat, using the green amphipod, Ampithoe lacertosa and artificial habitats made of eelgrass, and clear, red, and green plastic ribbon. With seine nets and underwater video recordings, I also collected data on fish predator abundance and diversity. Although generalized linear regressions in-dicated habitat color significantly affected prey survival, greater color-matching did not predict greater prey survival. Further analysis using structural equation modeling indicated that the effect of habitat on prey survival was significantly mediated by fish density and, to a lesser degree, fish diversity. Even after taking these effects into account, I did not find survival to clearly correspond to increasing color-match between prey and habitat. These results were consistent with the equivocal conclusions of previous studies on the anti-predator hypothesis of camouflage, altogether suggesting further theory development and experimentation is needed to explain the frequency of apparent camouflage in nature. In Chapter 3, I described a new species of porcellidiid copepod - found during the epifaunal surveys I conducted in 2013-2014. This was the first porcellidiid copepod species to be described from North America, although porcellidiid copepods have been previously recorded in Northeast Pacific coastal surveys. Porcellidium species nova n. sp., can be distinguished by a deep cleft in the female genital double somite, a lack of plumulose setae and three coupling denticles (two bulbous denticulate pads and one smooth protrusion) on the male antennule, and clear coloration with purple/maroon bands across the first and last metasomes. I have provided a partial revision to a key to Porcellidium species, along with a discussion of the natural history and distribution of porcellidiid copepods along the Northeastern Pacific coastline.
Download or read book Basal Food Web Dynamics in a Natural Eelgrass Zostera Marina Community written by Matthew A. Whalen and published by . This book was released on 2011 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Eelgrass zostera Marina L Leaf Growth and Restoration Ecology written by Jeffrey L. Gaeckle and published by . This book was released on 2006 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Spatial Model of Eelgrass Zostera Marina Habitat in Humboldt Bay California written by Whelan Gilkerson and published by . This book was released on 2008 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study was conducted to model the extent of eelgrass habitat in Humboldt Bay, California through physical surveys of the maximum depths and upper limits of growth in conjunction with recently acquired high-resolution bathymetry data and supplemental imagery. A combination of chronic turbidity, frequent coastal stratus, and wind-waves, make Humboldt Bay a challenging environment to assess subtidal eelgrass (Zostera marina) habitat from remotely-sensed imagery. Additionally, eelgrass and green algae overlap extensively in shallow intertidal areas, confounding efforts to distinguish between habitat types from imagery alone. A relative exposure index (REI) was developed to identify areas of eelgrass habitat that may be prone to disturbance from wind-waves. Approximately 2200 hectares of eelgrass habitat were identified. Accuracy was assessed at 91% for modeled eelgrass habitat in South Humboldt Bay based on a comparison with hyperspectral imagery captured in October, 2004. Modeling the extent of eelgrass habitat represents an important step towards understanding the extent to which future restoration or mitigation may be possible in Humboldt Bay.
Download or read book Nitrogen Dynamics of Eelgrass Zostera Marina During a Late Summer Period of High Growth and Low Nutrient Availability written by Morten Foldager Pedersen and published by . This book was released on 1992 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:
