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This investigation characterized karstic and nearshore environments of Bermuda to describe 1) behavior and periodicity of cave springs; 2) submarine spring water quality; and 3) nearshore marine seagrass density. Caves can be conduits for groundwater pollution where terrestrial anthropogenic processes leach nutrient enriched water into marine caves springs that flow directly into coastal waters. Seagrass may serve as an environmental indicator due to its susceptibility to anthropogenic pollution. In 2007, environmental water monitoring devices were moored at the entrance of coastal cave springs throughout Bermuda to retrieve data on water quality, flow volume, velocity and direction. Nutrients (nitrate, phosphate, nitrite, and ammonium) and fecal bacteria (Enterococcus spp. and Escherichia coli) were measured in each cave. To qualify a link between terrestrial pollution and the nearshore environment, seagrass density within 100 m from cave entrances were measured. Bermuda caves were tidally influenced. Caves in Harrington Sound showed a delayed tidal flux with smaller ranges due to the restricted tidal inlet. Four caves exhibited a 1:1 in:out flow ratio. Caves with an imbalance flow ratio could be influenced by additional entrances, connection to an alternate water body, or cave geometry. Cave water was similar between caves. Environmental parameters and nutrients changed together, excluding seasonal variations in temperature (17.89 to 22.94 degrees C). Higher nutrients and fecal coliforms within caves indicated sewage may be leaching into the subsurface ground water system. Three seagrass species were evenly distributed within patchy meadows. Densities ranged from 0.91 to 4.5 (on a Braun-Blanket Scale). Higher mean densities in Harrington Sound, suggested the enclosed, protected nature of the sound allowed for reduced wave and current action. Syringodium filiforme decreased in density towards the ocean signifying a direct influence of cave water on seagrass beds. Tidal in and out-flux allowed for a constantly changing environment suitable for a mixture of seagrass species. Higher dissolved inorganic nutrient concentrations were associated with locations lacking seagrass. This study found 1) cave springs connected groundwater and nearshore seagrass ecosystems; and 2) components associated with terrestrial sewage pollution (DIN, HPO4=, and Enterococcus spp.) were higher within caves than nearshore waters.

Five clones of giant type bermudagrass, Cynodon dactylon (L.) pers. vars. aridus and afghanicus Harlan et de Wet, progenies from crosses among those five, and crossed, selfed, and open pollination progeny from selected F₁ plants were evaluated for response to simazine (2-chloro-4,6-bis(ethylamino)-s-triazine). The first two generations were also evaluated for their response to ametryn (2-(ethylamino)-4-(isopropylamino)-6-(methylthio)-s-triazine). Two techniques were used. Culm cuttings, rooted in wet vermiculite, were placed into test tubes of simazine or ametryn suspensions at various concentrations or water. Culms were rated (1 to 9, 9 normal, 1 dead) for herbicide injury. Seeds were placed into petri dishes on moist filter paper, germinated in a germinator (day 35C, night 21C) and treated with 8ppm simazine or water in a greenhouse. Seedlings were rated visually for herbicide injury (7 normal, 5 affected, 1 dead) weekly, later daily, until a final drying and weighing of seedlings after all those in simazine were dead. Tolerance of all treated materials was expressed as percentage of control. There were significant differences among plants in tolerance to simazine with significance up to .001, although there was great variance within genotypes affected. The correlation between ametryn and simazine reaction was low. Tolerance scores were affected by condition of culms (significance .05), dosage, and nutrient levels. The clone by nutrient level interaction was significant at .01. Tolerance to simazine varied widely (more than 60%) among progeny of any plant as maternal parent. Progeny of reciprocal crosses between resistant and susceptible clones had similar (45 to 46) mean tolerance scores intermediate between parental scores indicating no dominance. Plants with the same cytoplasm ranged from most resistant (88%) to most susceptible (11%). Maternal effect on tolerance appears absent. The range of response for progeny of parents of any tolerance level indicates several pairs of genes are involved. Open pollination seedlings from consistently resistant plants averaged more resistant than seedlings from consistently susceptible plants. Giant bermudagrass simazine tolerance must be quantitatively inherited, possibly additive, with penetrance varying with plant condition, dosage, and other environmental constraints.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 72-77). Also available via the Internet.

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Bermuda has one of the highest concentrations of cave systems of any country in the world, but as the resident human population and tourism expand, this unique habitat is becoming increasingly threatened by development and water pollution. A water quality assessment was performed in six of Bermuda’s anchialine cave pools during summer 2007. Vertical water profiles were collected at each site to determine temperature, salinity, dissolved oxygen, and pH levels throughout the water column. Each cave pool had its own unique hydrological patterns. Additionally, water samples were collected at the surface and at the maximum depth to determine the concentration of nitrate, nitrite, ammonium, phosphate, and urea in the water. Further samples were collected to establish the fecal bacteria content in the surface waters. High nitrate levels were measured in two of the cave pools, while unsafe bacterial levels were measured in three pools. In situ nutrient addition experiments were used to examine effects of nutrient enrichment on algae naturally occurring in the six cave pool. Initial assessments of the pools determined distribution of foliose species. Six algal species (Ulva sp., Caulerpa mexicana, C. racemosa, C. sertularioides, Halymenia floresii, and Cryptonemia sp.) inhabited multiple sites, but not all species occurred at all sites. Changes in the biomass of individual plants were recorded for 6 to 12 days in response to N (nitrate), P (phosphate), and NP additions. The effect of nutrient addition on increase in biomass was significant over a 6 day period for Ulva sp. and H. floresii. Intermediate to no growth was seen in C. mexicana and Cryptonemia sp. C. mexicana exhibited both increases and in biomass depending on the site. Cryptonemia sp. had low but positive growth. A significant decrease in biomass occurred with C. racemosa and C. sertularioides. Primary productivity was measured using the traditional light dark bottle method. Differences in net productivity and respiration may explain why some plants responded positively and other negatively to nutrient additions. Ulva sp. and H. floresii showed potential as bioindicators for groundwater quality.

Thesis (M.A.)--East Carolina University, 2003. / Presented to the faculty of the Department of History. Advisor: Bradley A. Rodgers. Includes bibliographical references (leaves [162]-169). Also available via the World Wide Web. Adobe reader required.

Thesis advisor: Rudolph Hon / Pleistocene-age terra rossa paleosols are situated on and are intercalated with eolianite and marine carbonate units across the Bermuda Islands. These clay-rich soils were originally thought to the derived from weathering of the volcanic seamount and/or from dissolution of the carbonate units, the paleosols are now believed to be primarily the result of atmospheric dust deposition from Saharan North Africa and the Sahel via long range transport, with some local inputs. If so, these soil units are mixtures of atmospheric deposition during one or more glacial- interglacial cycles. Previous investigations have been conducted on the paleosols to determine their provenance, age, and to identify unique characteristics for island wide mapping. We conducted comprehensive geochemical analyses to determine the degree of chemical weathering and diagenesis, and to identify processes responsible for their formation and development. The paleosols were found to be geochemically similar across all ages, and to show an increased degree of alteration with age rather than with their duration of subaerial exposure, indicating diagenesis by infiltrating meteoric waters as well subaerial weathering. Evidence of paleosol diagenesis suggests vadose flow across the island may not be limited to preferential pathways and that while flow through the limestones is complex, infiltrating waters appear to have allowed for additional alteration of the soils. In addition to the paleosols, clay-rich deposits with paleosol-like textures were identified during coring operations in Harrington Sound and Hungry Bay, beneath present-day sea level. The source and development histories of these materials were previously unknown. Since these clay deposits are situated beneath present-day sea level it is likely that they were deposited and chemically weathered exclusively during glacial low-sea level climate conditions. Geochemical analyses were conducted on the submarine clay samples to determine if they were related to the above-sea level paleosol and to identify their sources. Major and trace element signatures showed the submarine clay deposits to be chemically similar to the paleosols and to be derived from a similar upper continental crust-like parent. Trace element fingerprinting showed the samples to be derived from a parent similar to that of the paleosols; primarily atmospheric dust with some volcanic contributions. These findings provide additional evidence that trade wind vectors for dust transport were present during Pleistocene glacial climate conditions. Weathering indicators reveal the submarine clay samples to be somewhat less weathered than paleosols of similar age and comparable periods of exposure. Like the paleosols, the submarine clays underwent an initial period of rapid subaerial weathering which suggests warm humid climate conditions during glacial low sea level periods. However, the submarine clays did not experience extended periods of diagenesis, which may explain the somewhat lower degree of weathering. Evidence of inputs from the volcanic platform to the paleosols was limited, but comparisons with shallow volcanic rock and highly weathered volcanic residual known as the Primary Red Clay showed some similarities, suggesting that in-situ chemical weathering of the volcanic platform could produce a laterite with some characteristics similar to the Bermuda paleosols. Geochemical analysis of volcanic sands collected at Whalebone Bay showed the igneous fragments to be a result of mechanical weathering and sorting of heavy refractory minerals and we interpret these sediments to be best described as a beach placer deposit. These materials are enriched in insoluble trace elements and REE, and their contribution to the paleosols is limited. / Thesis (MS) — Boston College, 2020. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Earth and Environmental Sciences.

The most importunate problem in using bermudagrasses (Cynodon sp.) for turf in the northern extremity, where semitropical grasses are adapted, is winter survival. This research was primarily conducted to investigate the effects of deacclimation of dormancy, duration of dormancy, and freezing temperatures on survival of bermudagrasses. 'Tifgreen' bermudagrass taken from the field in February, 1976, was deacclimated for 0, 2, 4, or 8 days at 27C/13C (day/night). Subsequently, rhizomes and stolons were subjected to +2, 0, -2, -4, or -6C for 24 hours. One third of the samples from each treatment were planted after 0, 45, and 90 days storage at 2.8C±1.6C. Rhizomes and stolons subjected to -4 or -6C did not survive. Deacclimation of rhizomes up to 8 days augmented growth as compared to no deaccli~ation. Increased storage periods caused decreased rhizome growth. At +2 and 0C, the percent rhizome growth was similar but significantly higher than at -2C. With 0 storage, stolon growth declined after 8 days deacclimation; however, after 45 or 90 days of storage, significant reductions occurred after only 4 days deacclimation. Fully deacclimated as well as dormant field samples of 'Midiron', 'Tifdwarf', 'Tifgreen', 'Tifway' and 'Tufcote' taken in March and April, 1977, were subjected to -2, -4, and -6C. All cultivars survived -4C whether dormant or actively growing. 'Tifgreen' bermudagrass frozen while dormant and 'Tifgreen' and 'Tifdwarf' frozen while actively growing had high recuperative potentials during regrowth. Comparing these cultivars under field conditions showed best winter survival for 'Midiron', which was the only cultivar that survived with simulated traffic. Traffic imposed immediately prior to bermudagrass dormancy reduced spring recovery more than for traffic imposed during winter. / Master of Science