published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

Zooplankton data from the 1988-2007 Station L4 time-series were used to determine inter-and intra-annual patterns of meroplankton community change at Station L4, Plymouth, UK. Abundances were calculated for five groups: Cirripedia, Decapoda, Polychaeta, Echinodermata and Bivalvia. Analyses showed that, while there is some annual variability, seasonal variation accounts for the major changes in the meroplanktonic community composition throughout the time-series. Cirripedia were the only group to show any significant change in abundance over the time-series. Further sampling at the study site produced data at a finer taxonomic resolution allowing for the analyses of the seasonal cycles of abundance of previously unresolved families and genera from the 1988-2007 time-series. A similar pattern was shown to that seen in the earlier time-series with no evidence of major changes in the meroplanktonic community being found. Comparison with historical data taken from Lebour (1947) showed little evidence of major variation in meroplanktonic species composition. The limitations of traditional methods of taxonomic resolution were highlighted during these analyses and led to the investigation of molecular techniques as a viable aid to identification. Bivalve larval samples were identified to species in many cases using PCR and sequencing reactions focussing on the 18S rRNA gene. Larvae of Phaxas pellucidus were shown to be the most common, and further analysis revealed the presence of two groups of species within the data over the time sampled, comprising the larvae of several hard-substrata species. Development of an RFLP technique focussing on the mtCOI gene, allowed for the successful discrimination of porcellanid larvae to species that were unable to be resolved morphologically. Long-term data-sets play an important role in revealing the long-term patterns of community composition and abundance of meroplanktonic larvae and should be continued to identify those patterns not evident over the time-period studied. Molecular techniques were valuable in aiding the taxonomic resolution of meroplanktonic larvae, allowing previously unknown patterns of species diversity and richness to be ascertained.

The Barren River was sampled twice monthly for one year to obtain data on aquatic yeasts. Sites upstream and downstream of the Bowling Green sewage plant, as well as the sewage effluent, were sampled to ascertain if the effluent had any effect on the yeast population of the river. Sporadic yeast counts were obtained which averaged 40 CFU/ml for the effluent, while the river averaged 15 CFU/ml. A total of 318 yeasts were isolated and identified during the study, including 16 different genera with Cryptococcus being the most common. Cryptococcus laurentii occurred most frequently of the 67 different species identified. The sewage effluent was not found to contribute significantly, either in number or in particular species, to the river yeast flora, although the effluent flora differed from the yeast flora in the river. Statistical analysis suggested relationships between yeast counts and several environmental parameters, particularly chlorine, turbidity, nitrate and phosphate levels. Some yeast pathogens of low virulence were isolated, but the probability of the river being a vector of mycotic disease was not found to be great. No seasonal variation was noted in yeast counts. The pathogenic yeast, Candida albicans, was not isolated. Two commercial yeast identification systems were tested. Neither system could be recommended for identifying aquatic yeasts.

Representative specimens of O. immunis and O. pellucidus were brought to the laboratory in order to investigate the influence of light on the occurrence of the symbionts encountered during the preliminary field study. After one week of acclimating the crayfishes they were distributed among environments control chambers that permitted exposure of the hosts and symbionts to 1) continuous light (C.L.), 2) a daily cycle of 12 hours of light and 12 hours of darkness (12L-12D) and 3) continuous darkness (C.D.).

M.Sc., Faculty of Science, University of the Witwatersrand, 2011 / Sea oor massive sulphides are deep sea mineral deposits currently being examined as a potential mining resource. Locating these deposits, which occur at depths in the order of 2km, is currently performed by expensive submersible sonar platforms as conventional sonar bathymetry products gathered by sea surface platforms do not achieve adequate spatial resolution. This document examines the use of so-called high resolution beamforming methods (such as MUSIC and ESPRIT) for sonar bathymetry, together with combinations of parameter estimation techniques, including techniques for full rank covariance matrix estimation and signal enumeration. These methods are tested for bathymetric pro le accuracy using simulated data, and compared to conventional bathymetric methods. It was found that high resolution methods achieved greater bathymetric accuracy and higher resolution than conventional beamforming. These methods were also robust in the presence of unwanted persistent signals and low signal to noise ratios.

The pre-metamorphic behaviors and settlement preferences of larvae can have significant effects on the success of adult invertebrates. This study describes various aspects of pre-metamorphic and post-metamorphic life stages of the bryozoan

Much of the world's oceans lie below a depth of 200 meters, but very little is known about the creatures that inhabit these deep-sea environments. The deep-sea fish family Melamphaidae (Stephanoberyciformes) is one such example of an understudied group of fishes. Samples from the MAR-ECO (www.mar-eco.no) project represent one of the largest melamphaid collections, providing an ideal opportunity to gain information on this important, but understudied, family of fishes. The key to the family presented here is the first updated, comprehensive key since those produced by Ebeling and Weed (1963) and Keene (1987). Samples from the 2004 MAR-ECO cruise and the U.S. National Museum of Natural History provided an opportunity to review two possible new species, the Scopelogadus mizolepis subspecies, and a Poromitra crassiceps species complex. Results show that Scopeloberyx americanus and Melamphaes indicoides are new species, while the two subspecies of Scopelogadus mizolepis are most likely o nly one species and the Poromitra crassiceps complex is actually several different species of Poromitra. Data collected from the MAR-ECO cruise provided an opportunity to study the distribution, reproductive characteristics and trophic ecology of the family Melamphaidae along the Mid-Atlantic Ridge (MAR). Cluster analysis showed that there are five distinct groups of melamphaid fishes along the MAR. This analysis also supported the initial observation that the melamphaid assemblage changes between the northern and southern edges of an anti-cyclonic anomaly that could be indicative of a warm-core ring. Analysis of the reproductive characteristics of the melamphaid assemblage revealed that many of the female fishes have a high gonadosomatic index (GSI) consistent with values found for other species of deep-sea fishes during their spawning seasons. / This may indicate that melamphaids use this ridge as a spawning ground. Diets of the melamphaid fishes were composed primarily of ostracods, a mphipods, copepods and euphausiids. Scopelogadus was the only genus shown to have a high percent of gelatinous prey in their digestive system, while Melamphaes had the highest concentration of chaetognaths. This work presents data on the ecology and taxonomy of the family Melamphaidae and provides a strong base for any future work on this biomass-dominant family of fishes. / by Kyle Allen Bartow. / Thesis (Ph.D.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.

Understanding of the fundamental ecology of deep-sea ecosystems remains immature relative to more familiar shallow-water and terrestrial habitats, despite more than two hundred years of scientific investigation. This thesis aims to progress knowledge of deep-sea benthic ecology by the analysis of over three hundred box core samples collected from the Northwest Atlantic continental slope as part of the international NEREIDA programme. Aspects of the ecology of Peracarida (Crustacea) are studied, and this is facilitated by the coupling of a large faunal dataset with extensive environmental information. To further enhance the power of this dataset, phylogenetic and functional characteristics of assemblages are investigated. Using community phylogenetic methodology, it is demonstrated that the peracarid assemblages studied are structured more strongly by variation in environmental parameters than they are by competitive interactions. Analyses demonstrate that the intensity of bottom trawling, seafloor temperature, current speed, food availability, sediment characteristics and physical habitat heterogeneity all influence deep-sea peracarid assemblage biodiversity metrics. Further, the importance of high poriferan biomass for the promotion of peracarid assemblages of high density, biomass, richness and diversity is highlighted. Of relevance to the management of deep-sea ecosystems, the results of this thesis suggest that caution should be exercised when applying species distribution models to data-deficient environments, whilst the location of spatial closures in the NAFO Regulatory Area may not be fully optimal for the protection of all components of diverse benthic assemblages against the impacts of bottom trawling. The importance of deep-sea diversity is demonstrated by the finding of positive biodiversity – ecosystem functioning relationships. However, the form of these relationships is found to be dependent on the biodiversity and ecosystem functioning metrics employed, and a hypothesis for a generalised form of biodiversity – ecosystem functioning relationships is proposed. Finally, this thesis calls for more ambitious deep-sea ecological investigations, and it is hoped that its findings will encourage future research initiatives, helping to further illuminate this enigmatic and fascinating environment.

Restoration of oyster reef structures rehabilitates habitats and the multi-level ecological communities built on eastern oysters (Crassostrea virginica), the keystone species. Quantitative descriptions of ecological interactions within a habitat are required to delineate essential fish habitats for management and protection. Parallel development of primary (oysters) and secondary trophic levels (benthic fishes) offer an ecological metric of restoration progress over time. The interaction between larval oysters and larval fishes (e.g., Gobiosoma bosc, Chasmodes bosquianus) is quantitatively examined. Oyster settlement estimates for Palace Bar reef, Piankatank River, Virginia are of the same order of magnitude as field densities of recently settled oysters. Benthic fish settlement estimates are within an order of magnitude of observed adult densities. Zooplankton community composition around the reef is temporally variable and plankton densities range from 10 2--106 animals per m3 across temporal scales. Nocturnal densities of naked goby and striped blenny larvae around Palace Bar reef were 3 to 4 orders of magnitude higher than densities observed during daylight hours. Diurnal changes in larval fish abundance near Palace Bar reef are related to ambient light intensities and diurnal vertical migration by prey species. Naked goby, striped blenny, and feather blenny (Hypsoblennius hentzi) larvae selectively consumed bivalve veligers, in multi-factorial laboratory feeding experiments. Temporal co-occurrence of larval oysters and larval fishes was not observed in 1996 field collections although historic oyster settlement data strongly support the probability of co-occurrence during most years. Two different methods are used to estimate the larval oyster - larval fish interaction in the absence of field data. Given existing oyster and fish demographics on Palace Bar reef, larval fishes have the capacity to drastically reduce, perhaps eliminate, local veliger populations if they co-occur. The strength of this interaction is directly related to oyster demography-fecundity relationships. In the absence of veligers, larval fishes consume other plankton taxa that are abundant around the reef. Naked gobies and striped blennies are generalists. Oyster reefs provide optimal rather than essential habitat. Reef restoration will facilitate development of related ecological communities by providing optimal habitat conditions for these ubiquitous estuarine species.

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