Thesis--Catholic University of America. / Bibliography: p. 178-183.

Reprint of the author's thesis, Catholic University of America. / Includes bibliographical references (p. 178-183) and index.

Thesis (Ph.D.)--University of North Carolina at Wilmington, 2006. / Includes bibliographical references (leaves: 198-208)

Tidal exchanges of organic carbon, nitrogen and phosphorus between a south temperate Sarcocornia marsh and its associated estuary are examined. Subterranean water flow was small, and the hydraulic exchange between the two systems largely surficial. The dominant tidal signal was semi-diurnal, and the extent of inundation of the marsh varied considerably as a consequence of interactions of semi-lunar tidal cycles with changes in daily mean sea level. Annual net fluxes of organic carbon were directed from the marsh to the estuary, but amounted to less than 2% of marsh aerial net primary productivity. This indicates the incompatibility of E.P. Odum's outwelling hypothesis to this marsh-estuarine system. The direction of net flux of organic carbon switched on a time-scale of days. These directions were largely correlated with mesoscale oceanic events, which materially altered the extent of marsh inundation, and which provided evidence of the mutual exclusivity of outwelling of DOC from the marsh and oceanic upwelling. Laboratory mesocosm experiments using intact marsh blocks of sediment from the marsh were conducted to identify the proximate processes and interactions at the marsh-water interface responsible for the variability of marsh-estuarine exchanges. Patterns of fluxes of organic carbon, total nitrogen and phosphorus were markedly different in the structurally contrasted tidal creek and Sarcocornia Zone regions of the marsh. Both regions exported these components, but the fluxes of organic carbon and total phosphorus were significantly larger from the tidal creek than from the Sarcocornia zone, and the opposite applied to nitrogen. The presence of brachyuran crabs . the most numerous macrofauna on the marsh enhanced the flux of carbon, nitrogen and phosphorus from the marsh biocoenosis, largely as a result of the effect of their bioturbation. Evidence is examined which suggests that differential mobilization of nutrients in the two zones by crabs is responsible for biogeochemical coupling of these two regions , which may account for the elevated productivity of salt- marsh systems

Crabs are conspicuous inhabitants of temperate salt marshes and tropical mangroves and interact with their environment through several processes. However, detailed information on crab community processes is absent for most South African estuaries and nearshore coastal regions. This study evaluated the primary producers supporting crab species in the salt marsh dominated Swartkops estuary and the mangrove Mngazana estuary. Various methods estimating crab abundances were also assessed in different microhabitats and the larval distribution of crabs in the coastal zone was also investigated. Various methods for estimating crab abundance have been employed in the past, each with its inherent biases. The microhabitat of a mangrove forest in Australia was structurally altered by the manipulation of the litter, pneumatophores and the associated algae. These alterations did not affect the behavioural activity or the numbers of crabs recorded in any of the experimental treatments by either visual counts or pitfall traps. However, the number of crabs caught in the pitfall traps differed between the sites. Species-specific behaviour which was not investigated in this study may bias crab abundance estimates when using pitfall traps and therefore requires further investigation. Benthic consumers inhabiting shallow coastal environments may ultimately have the origin of their nutrition in a number of possible sources. Isotopic and gut content analysis of Thalamita crenata and juvenile Scylla serrata in the Mngazana estuary in South Africa revealed that these two portunids are able to share a habitat by resource partitioning. Differences were noted for species-specific utilization of primary producers not only between seasons within a site, but also between sites. This highlighted the use of locally produced primary producers sustaining food webs in estuaries. Mangrove production in the Mngazana estuary is very important and contributes to most of the carbon in the underlying sediments in the mangrove forest. However, the relatively large number of species and biomass encountered in this estuary may also be attributed to the fact that the different species are able to exploit of a number of different resources. The variation in stable isotope analysis of the different crab species throughout the estuary indicated that these crabs able to occupy the same habitat by feeding on a number of different resources and may preferentially select for a specific primary producer. A stable isotope of crabs in the salt marsh Swartkops estuary indicated that the dominant primary producer sustaining crab communities may even take place on a relatively smallscale. Sesarma catenata found at the inner marsh site recorded more depleted carbon signatures than those encountered in the other sites approximately 100 m away, and reflected signatures similar to the locally-encountered inner marsh plants. The relatively enriched nitrogen signatures of the anthropogenically-impacted Swartkops estuary is an indication of extensive inputs due to urbanization and industrialization, in contrast to the relatively pristine Mngazana estuary which exhibited low nitrogen signatures. Emphasis has been placed on the abiotic component of the exchange of nutrients and energy, although living organisms may also be transported, both actively and passively, between ecosystems. Little variation in either species composition or abundance was found between seasons for the larval distribution of brachyuran crabs on the east coast of South Africa. Due to the lack of published larval descriptions, larvae could not be identified to species level and it was therefore not possible to identify whether the larvae were hatched or spawned in an estuary or in a marine environment, or whether the larvae originated in the northern tropical regions. Frequent wind-reversals which are common in this region may retain larvae close inshore and supply the southern temperate locations with larvae from the northern locations. In conclusion, this study has shown that in highly productive systems with a number of potential primary producers, the crabs that inhabit the estuary show a marked diversity in resource utilization which could potentially allow a number of closely related species to occupy different trophic levels. This study also highlights the importance of locally produced sources in an estuary, which may occur on very small scales and this needs to be factored in with the design of any future stable isotope studies of this nature.

O presente trabalho teve como objetivo estudar a atividade ovulatória ao longo do ano, as concentrações plasmáticas de melatonina e prolactina no período de 24 horas nos solstícios e equinócios de ovelhas lanadas Romney Marsh (10) e deslanadas Santa Inês (10) mantidas sob fotoperíodo natural em baixas latitudes no hemisfério Sul. Para o monitoramento da atividade ovulatória foram colhidas semanalmente sangue da veia jugular das fêmeas durante o período de um ano para determinação das concentrações plasmáticas de progesterona. Para a determinação das concentrações plasmáticas de prolactina e melatonina, foram realizadas colheitas de sangue a cada duas horas durante 24 horas nos dois solstícios e dois equinócios. As ovelhas das raças Santa Inês e Romney Marsh, apresentaram comportamento da atividade ovariana distintos, ou seja, as fêmeas lanadas foram estacionais, enquanto que as fêmeas deslanadas apresentaram atividade ovulatória o ano todo. O ciclo circadiano das concentrações plasmáticas de melatonina de ovelhas Romney Marsh e deslanadas Santa Inês apresentou um padrão sazonal idêntico, mas não apresentou um ritmo circanual. A duração da secreção noturna de melatonina acompanhou a duração do escotoperíodo de cada estação do ano. O perfil plasmático de prolactina de ovelhas Romney Marsh foi mais elevado que ovelhas Santa Inês em todas as estações, mas o padrão sazonal foi idêntico. As concentrações plasmáticas foram mais elevadas na primavera e no verão que no outono e inverno. / This study evaluated the ovulatory activity throughout the year, plasma melatonin and prolactin concentrations on 24 hours during solstices and equinoces on wool (Romney Marsh - 10) and hair (Santa Inês - 10) ewes kept under natural photoperiod and lower latitudes in the southern hemisphere. To monitor the ovulatory activity, blood samples were collected weekly from the jugular vein throughout the year to determine the plasma progesterone concentrations. To determine the plasma melatonin and prolactin concentrations blood samples were collected each two hours during 24 hours on the solstices and equinoces. Santa Inês and Romney Marsh females showed different ovulatory activity. Wool ewes showed a strong seasonality, and hair ewes were in ovulatory activity all the year. The circadian cycle of plasma melatonin concentrations from Romney Marsh and Santa Inês females showed the same seasonal pattern, and did not showed circannual pattern. The duration of nocturnal secretion plasma melatonin was the same of scotoperiod duration on each season of the year. The plasma prolactin profile from Romney Marsh ewes were higher than Santa Inês ewes in all seasons, but the seasonal pattern was identic. Plasma concentrations were higher in spring and summer than autumm and winter.

xi, 124 p. : col. ill. and map. / The Arcata Marsh and Wildlife Sanctuary (AMWS), located on the Humboldt Bay of northwestern California in the town of Arcata, is an excellent example of reciprocity between humans and the natural environment. The AMWS is a constructed wetland ecosystem that works in conjunction with the town's wastewater treatment plant, providing a healthy habitat for birds and other wildlife and a context for the folkloric activity of birding. Interviews with seven local birders at the AMWS and an analysis of the material, economic, biological, social, and spiritual implications of the activity in context serve to support the assertion that reciprocity is an important factor in the sustainability of folkloric interactions between humans and the natural environment. / Committee in charge: Sharon Sherman, Chairperson; Kathryn Lynch, Member; Jill Harrison, Member

This study develops techniques for the preparation and counting of testate amoebae for Holocene sea-level reconstructions. In addition, this study provides a ~3000 year relative sea-level reconstruction for south Hinnøya in the Vesterålen islands off mainland Norway, adding new data to a poorly defined period of the Holocene sea-level history of north-western Norway. This is important to quantify rates of glacial-isostatic adjustment (GIA), to refine GIA models, and to establish baseline (pre-industrial) rates of relative sea-level change. Surface sediments from two salt marshes (Storosen and Svinøyosen) in south Hinnøya are used to assess the effects of using different preparation procedures and count totals when analysing for testate amoebae. Analytical efficiency can be improved upon by using a mild alkali, chemical disaggregant (5 % KOH) to break up fibrous salt-marsh sediment and concentrate tests prior to counting. A count total of 100 individuals, rather than 150, can be used to make time gains with little or no effects on assemblages. Training sets of salt-marsh surface testate amoebae, foraminifera and elevational data are established for the two field sites. For testate amoebae, species – elevation relationships are constructed using regression modelling and applied to downcore fossil samples using a transfer function to derive estimates of sea level for the past ~100 years. The greater water depths reconstructed between ~3000 and ~100 years ago are not covered by modern foraminiferal training sets and are therefore estimated qualitatively from the fossil foraminiferal assemblages supplemented by information derived from fossil molluscs. Chronology is based on a combination of AMS14C, 210Pb, 137Cs and a suite of geochemical markers. At south Hinnøya, sea level has been falling at a rate of ~0.5 mm yr-1 over the last 3000 years.

CH3Br and CH3Cl (methyl halides) are the most abundant natural vectors of bromine and chlorine into the stratosphere and play an important role in stratospheric ozone destruction. The current knowledge of their respective natural sources is incomplete leading to large uncertainties in their global budgets. Beside the issue of quantification, characterisation of possible sources is needed to assist modelling of future environmental change impacts on these sources and hence the stratosphere. This study describes measurements conducted at two temperate salt marsh and three temperate forest sites in Scotland, and one tropical rainforest site in Malaysian Borneo to quantify and characterise natural methyl halide producing processes in these respective ecosystems. Measurements were conducted with static enclosure techniques, and methyl halide fluxes were calculated from the concentration difference between blank/background and afterenclosure samples. Methyl halide concentrations were determined via oxygen-doped GCECD with a custom-built pre-concentration unit. External factors such as photosyntheticallyactive radiation (PAR), total solar radiation, air temperature, soil temperature, internal chamber temperature and soil moisture were recorded in parallel to the enclosures to determine possible dependencies. Salt marsh studies were carried out at Heckie’s Hole in East Lothian, and Hollands Farmin East Dumfriesshire for 2 years. The study subjects were salt marsh plants that were enclosed during daylight hours in transparent enclosures for 10min each at 2–4 week intervals throughout the year. Parallel to this monitoring programme, systematic manipulation experiments and diurnal studies were carried out to learn more about the possible influence of potential drivers such as sunlight and temperature. Mean annual net fluxes ( standard deviation (sd)) were 300 44 ngm-2 h-1 for CH3Br and 660 270 ngm-2 h-1 for CH3Cl, with fluxes of both gases following a diurnal as well as an annual cycle, being lowest during winter nights and highest during summer days. A possible link between variations of daytime fluxes over the course of a year and changes in temperature was found. CH3Cl and CH3Br fluxes were positively correlated to each other and average fluxes of CH3Cl were linked to dry mass of certain species such as Puccinellia maritima, Aster tripolium, Juncus gerardi and Plantago maritima as found at the different measurement locations. No link between methyl halide fluxes and total halogen content or halogen concentration of the enclosed vegetation was found. Work in temperate forests was carried out for over one year at Fir Links, a mixed beech/ sycamore forest in East Lothian, and on one occasion each in Griffin Forest, a sitka spruce plantation in Perthshire, and finally the Hermitage of Braid, a mixed woodland park in Edinburgh. The study subject was leaf and needle litter which was enclosed in opaque 12 L containers for 10min–24h. During enclosure, internal chamber temperature was recorded, and leaf/needle litter water content was determined after enclosure. Combined average CH3Br and CH3Cl fluxes from temperate forest litter were 4.3 10-3 ngg-1 h-1 and 0.91 ngg-1 h-1, respectively. Average fluxes measured from leaf and needle litter were comparable in magnitude and CH3Br and CH3Cl were positively correlated. However no correlation of methyl halide fluxes to either temperature or litter water content was observed. Work at Danum Valley inMalaysian Borneo focused on flux measurements from both trees and leaf litter in a tropical dipterocarp forest. Fluxes from tropical trees were measured with transparent branch chambers at 20min enclosure times whilst methyl halide fluxes from leaf litter were measured with opaque 12 L containers at 24h enclosure times. Mean CH3Br and CH3Cl fluxes from branch enclosures were 0.53 ngg-1 h-1 and 27 ngg-1 h-1, respectively, and CH3Br and CH3Cl fluxes from tropical leaf litter were 1.4 10-3 ngg-1 h-1 and 2.3 ngg-1 h-1 respectively. Again fluxes of CH3Br and CH3Cl were positively correlated but no direct environmental driver for flux variations was found. The magnitude of methyl halide fluxes was species specific with individuals of the genus Shorea generally producing large amounts of methyl halide. Tropical rainforests were confirmed to be potentially the largest single natural source of CH3Cl. Global estimates were derived from extrapolating measured fluxes from the respective global land cover areas. These estimates suggest that the ecosystems examined in this study could account for over 1/3 of global CH3Cl production and up to 13%of global CH3Br production in nature. The ratio of CH3Br to CH3Cl emissions for these ecosystems is likely to be dependent on the abundance of bromine in the plant material with higher bromine content boosting CH3Br production and suppressing CH3Cl production. For this reason salt marshes are only a very minor source of CH3Cl.

The Biloxi Marsh of the eastern Mississippi River delta plain is exposed to meteorological forces ranging from large-scale, mid-latitude cyclones to smaller scale storms and squalls. Each time that these marsh platforms are exposed to a storm event, the potential exists for either deposition or erosion to take place. This study examines the connection between wind speeds, stratigraphic composition, marsh edge morphology, and marsh edge erosion at 4 sites in the Biloxi Marsh. As much as 2.17 m of erosion were measured during the 9-month study with a maximum, averaged erosion rate of 0.03 m day-1. Shell berm transgression was also documented as the result of winds from a low-pressure system near the site that resulted large waves. Shell berm movement occurred as a result of high wind speeds on shore but there was no connection between wind speeds and erosion for the duration of this study across all sites.