This thesis examines the phytoplankton ecology of Wilson Inlet, Western Australia with relation to the changing physical, chemical and biological environment.

Meiofauna are an ecologically significant component of marine benthic communities worldwide. Nematodes, in particular, are arguably the most abundant metazoans on Earth and often form highly diverse communities in marine sediments. The study of meiofauna, however, often lags behind that of macrofauna, probably due to the small size of meiofaunal organisms and the paucity of suitably-trained taxonomists or para-taxonomists. Our understanding of basic ecological questions, such as the role of meiofauna in the energetics of benthic communities, as well as the nature and extent of possible relationships between meiofauna and macrofauna in detritus-based communities, is still limited. The present study aimed to address these questions in the context of intertidal seagrass (Zostera muelleri) meadows and adjoining unvegetated sediments in Papanui Inlet, Otago Peninsula. The near absence of taxonomical and ecological studies on free-living marine nematode species in New Zealand also prompted the description of several new species and as well as a comparison of species assemblages from the study sites. Meiofaunal abundance (range: 1325-4979 ind. 10cm�) in the top 5cm of sediments was not significantly different inside and outside the seagrass meadow. Meiofaunal biomass and production estimates were small relative to macrofauna (approx. 1 and 5% of macrofaunal values, respectively), with little variation in both meiofaunal and macrofaunal values between vegetated and unvegetated habitats. Analysis of the isotopic and fatty acid composition of primary producers, sediment organic matter, and consumers at the study sites suggest that a significant proportion of secondary productivity in seagrass meadows is fuelled by macrophyte detritus. These data suggest that secondary productivity in the seagrass meadow was limited by the low palatability of macrophyte detritus compared with microalgal food sources, resulting in lower trophic transfer efficiency in vegetated sediments. These results contrast with previous findings showing a large contribution of meiofauna to the secondary productivity of vegetated sediments, as well as greater secondary productivity inside than outside seagrass meadows. The nature of the sediments (coarse particle size with low organic matter content) is likely to have led to low meiofauna biomass whilst favouring large suspension feeders. The low availability of high quality food sources (i.e. seston, benthic microalgae, and epiphytes) in vegetated sediments may have contributed to the lower than expected secondary productivity inside the seagrass meadow. Most of the dominant nematode species found at the study sites were new to science, and 6 new species were described. Significant differences were found in the nematode assemblages between sites and sediment depths. There was a trend of greater nematode diversity and abundance in vegetated sediments, but this was restricted to the uppermost 2cm of sediments. The effect of seagrass on nematode assemblages is likely to be mediated by the effect of blades on sediment characteristics and the presence of roots. The present study suggests that the presence of Zostera muelleri results in greater biodiversity of sheltered soft-shore communities on a local scale. The addition of ��C-labelled macroalgal detritus (Enteromorpha) to microcosms in a feeding experiment resulted in minimal labelling of harpacticoid copepods and nematodes. Lack of change in the fatty acid composition of the latter also suggests limited assimilation of detritus during the experiment. It is likely that consumers choose benthic microalgae over detritus when both food sources are available in the field. High content of highly unsaturated fatty acids (HUFAs) in nematodes from the field suggests, for the first time, that they are a high quality food source to higher trophic levels. A feeding experiment investigating the effect of bacterivorous nematodes on detritus assimilation rates by amphipods did not support the hypothesis that nematodes increase the trophic transfer efficiency between detritus and macrofaunal detritivores. It is unclear whether amphipods preferentially fed on detritus or whether nematodes escaped predation by burrowing deeper in the sediment. Data obtained in the present study, however, shows that marine bacterivorous nematodes can biosynthesise/accumulate HUFAs in high concentrations despite their low concentrations in their diet. Nematodes could, therefore, provide an important source of these essential nutrients to bulk deposit feeders living in otherwise HUFA-poor sediments.

Dapeng Bay is located in the southwest coast of Taiwan. It is a cystic shaped shallow lagoon, which has only one entry for exchanging lagoon water with the coastal current. The water quality is depending on the refreshing rate and the mixing level in the lagoon. In order to understand the circulation pattern monthly measurements using an ADP are carried out. Three water quality monitoring stations are constructed for regular online observation of the water quality in the lagoon. The flows are on the west-northwest direction during the flood and toward the west during ebb. Strong currents are observed in the tidal inlet channel. The general circulation patterns are mainly dominated by tide though wind effects can observed from the measurements. This study established a three-dimensional hydrodynamic modeling system using the FVCOM model developed at the U.S. Marine Ecosystem Dynamics Modeling Laboratory for the simulation of Dapeng Bay currents. The study includes the comparison of the recent circulation and the flow fields after broaden of the inlet navigation channel. This will change not only the shape but also dredge the channel deeper. These variations may differ the circulation patterns and the exchange quantities as well. The model results are first compared with the observations for the present situation as calibration. The simulation results for the studies of the changing of the inlet channel will be discussed.

The exchange flow through tidal inlets generates two-dimensional large coherent vortical structures (2DLCS), that are much broader than the water depth and exist because of the inherent instability of shallow shear flows. These vortical starting jets are critical to the mixing that occurs in the inlet area. Depending on the tidal period T, the width of the inlet W, and the maximum velocity in the inlet UMAX, the mixing will vary from poor exchange to efficient exchange. Here, we present laboratory and numerical experiments that study the formation of the 2DLCS at the mouth of the inlets. Experiments were conducted at large scale, in the shallow flat-bottomed water basin at the Institute of Hydromechanics of the University of Karlsruhe, Germany, which has the capability to generate a sinusoidal flow that simulates a series of tidal cycles. A set of idealized inlets were arranged in the tank, and by varying the tidal period and the maximum velocity, three different types of life-history were obtained (stationary dipole, dipole entrains, and dipole escapes). These types of life-history are defined by the mixing number depending if KW is equal, less or greater than a critical value. The experiments were visualized using color dye tracers. To quantify the shallow water velocity field, the Particle Image Velocimetry (PIV) technique was used. From the PIV data the vorticity field was obtained, and the regions where the vortex formed were identified. Then, a vortex time-evolution analysis was developed using iv physical parameters such as the position on the basin of the vortex, the equivalent diameter, and the maximum vorticity among others. The mixing number accurately predicts the behavior of the vortex for the first cycle on idealized inlets for the subsequent cycles; the structures behave differently than predicted by KW, because the blocking effect of the vortex /formed in the previous cycle. For characteristic times t*  tUWless than about 2, the dipole is attached to the inlet and forms rapidly. For later times, the dipole advects downstream, and slowly dissipates. Numerical experiments are also presented. Comparing the numerical data with the laboratory data, good agreement is reached, but important limitations are identified for the grid resolution and domain size.

Despite the numerous advantages associated with using compact cylindrical cyclone gas/liquid separators, particularly for upstream production operations, the lack of a full understanding of the complex hydrodynamic process taking place in it and its “unfamiliarity” to oil field personnel has hindered its widespread use. The complexity associated with this technology is attributed to two limiting physical phenomena, liquid carry-over and gas carryunder. While a lot of work has been done to better understand and predict the liquid carry-over operational envelope, little or no information about methods capable of adequately predicting or characterizing the gas carry-under performance of such separators is available. Traditionally, to mitigate the gas carry-under phenomena, the use of complex control algorithms and systems has been employed. These systems make the technology expensive (as opposed to the potential cost reduction it promises) and impractical for realistic use in the oil field where reliability is of critical importance. A simpler solution, the use of changeable or adjustable inlet-slots that regulate the artificial gravity environment created in the separator, could significantly improve the gas carry-under performance of cylindrical cyclone separators. This research has focused primarily on the use of adjustable inlet-slots. Theoretical analysis and experimental data investigating the benefits of variable inlet geometry have been provided. This work lays the foundation or validation required to perform more tests on a field-scale version to verify the results presented here. A modular design of such a variable inlet-slot inletsection has the potential of simplifying the design and specifications of cylindrical cyclone gas/liquid separators. From the results of this investigation, it was found that the gas carry-under performance of a cylindrical cyclone gas/liquid separator could be improved considerably over a wider range of operating conditions by adjusting the size of the inlet-slots. This contradicts earlier reports of liquid carry-over improvement in separator performance. Also, for the first time, a simple method for theoretically analyzing the percent improvement in separator gas carry-under performance using the optimum g-force concept is presented. This method could be incorporated into design software for determining the slot-size configuration required for varying separator-operating conditions.

Cyclone separators are widely used in agricultural processing industries as air pollution abatement devices. The performance of cyclones is a function of the geometry of the cyclone, operating parameters, and the particle size distribution (PSD) of the entrained aerosol. Multiple models have been proposed to predict the performance of cyclones given different geometric proportions, but many of these models do not quantify changes in performance with changes in inlet velocity or cyclone diameter given fixed geometric proportions. The Texas A&M Cyclone Design (TCD) method is a simple method for designing cyclones based on an inlet design velocity. The TCD method specifies “ideal” inlet velocities of 975 ± 120 m/min (3200 ± 400 fpm) and 914 ± 120 m/min (3000 ± 400 fpm) for 1D3D and 2D2D cyclones, respectively. However, there is evidence that higher dust collection efficiencies may be obtained from cyclones using different inlet velocities than those specified as the “ideal” velocity. Furthermore, the TCD method assumes that cyclone performance is independent of cyclone diameter. The present research demonstrates that, for large particles, the collection efficiency of 15.24 cm (six inch) diameter 1D3D and 2D2D cyclones is similar for inlet velocities from 10.16 standard m/s (2000 fpm) up to the design velocity, with significantly lower pressure drop at lower inlet velocities, resulting in lower energy requirements. However, the performance of cyclones is a function of cyclone diameter. Using similar operating parameters, the collection efficiency of a 60.96 cm (24 inch) diameter 1D3D cyclone was significantly lower (α = 0.05) than that of a 15.24 and a 30.48 cm (6 and 12 inch) diameter cyclone, and the collection efficiency of a 91.44 cm (36 inch) cyclone was significantly lower (α = 0.05) than that of a 60.96 cm (24 inch) diameter cyclone. The results of this research suggests the need for a new mathematical model to predict the performance of cyclones.

Shipwrecks have a way of catching the imagination of both professionals and the general public. During the fall of 2004 a shipwreck was discovered in Delaware Bay near Lewes, Delaware. This vessel, believed to be British, was lost during the second half of the eighteenth century. Preliminary examination of the wreck site suggested that it was a merchant ship bound for the colonies. While wrecks dating to this period representing various countries have been found, no British merchant vessels bound for the colonies have been examined archaeologically. This project provided the opportunity to investigate a ship and its cargo in light of the historical events of the period. Analysis of artifacts recovered from the site provided important glimpses of colonial American consumer practices in the period leading up to the American Revolution. In light of the general colonial displeasure over increased Parliamentary restrictions, colonists adjusted their buying habits. Study of the artifact assemblage suggests British merchants were attempting to substitute non-British manufactured goods for some objects. This study also indicated that colonists were perhaps not idealistic in practice when it came to denying themselves consumer goods. Further excavation of this vessel, and the study of other inbound merchantmen, should help confirm the conclusions regarding British policy and its effect on pre-revolutionary consumer practices. Based upon evidence derived from a handful of artifacts, this study tentatively identified the vessel as the ship Severn, lost in 1774 off the coast of Delaware.

Meiofauna are an ecologically significant component of marine benthic communities worldwide. Nematodes, in particular, are arguably the most abundant metazoans on Earth and often form highly diverse communities in marine sediments. The study of meiofauna, however, often lags behind that of macrofauna, probably due to the small size of meiofaunal organisms and the paucity of suitably-trained taxonomists or para-taxonomists. Our understanding of basic ecological questions, such as the role of meiofauna in the energetics of benthic communities, as well as the nature and extent of possible relationships between meiofauna and macrofauna in detritus-based communities, is still limited. The present study aimed to address these questions in the context of intertidal seagrass (Zostera muelleri) meadows and adjoining unvegetated sediments in Papanui Inlet, Otago Peninsula. The near absence of taxonomical and ecological studies on free-living marine nematode species in New Zealand also prompted the description of several new species and as well as a comparison of species assemblages from the study sites. Meiofaunal abundance (range: 1325-4979 ind. 10cm�) in the top 5cm of sediments was not significantly different inside and outside the seagrass meadow. Meiofaunal biomass and production estimates were small relative to macrofauna (approx. 1 and 5% of macrofaunal values, respectively), with little variation in both meiofaunal and macrofaunal values between vegetated and unvegetated habitats. Analysis of the isotopic and fatty acid composition of primary producers, sediment organic matter, and consumers at the study sites suggest that a significant proportion of secondary productivity in seagrass meadows is fuelled by macrophyte detritus. These data suggest that secondary productivity in the seagrass meadow was limited by the low palatability of macrophyte detritus compared with microalgal food sources, resulting in lower trophic transfer efficiency in vegetated sediments. These results contrast with previous findings showing a large contribution of meiofauna to the secondary productivity of vegetated sediments, as well as greater secondary productivity inside than outside seagrass meadows. The nature of the sediments (coarse particle size with low organic matter content) is likely to have led to low meiofauna biomass whilst favouring large suspension feeders. The low availability of high quality food sources (i.e. seston, benthic microalgae, and epiphytes) in vegetated sediments may have contributed to the lower than expected secondary productivity inside the seagrass meadow. Most of the dominant nematode species found at the study sites were new to science, and 6 new species were described. Significant differences were found in the nematode assemblages between sites and sediment depths. There was a trend of greater nematode diversity and abundance in vegetated sediments, but this was restricted to the uppermost 2cm of sediments. The effect of seagrass on nematode assemblages is likely to be mediated by the effect of blades on sediment characteristics and the presence of roots. The present study suggests that the presence of Zostera muelleri results in greater biodiversity of sheltered soft-shore communities on a local scale. The addition of ��C-labelled macroalgal detritus (Enteromorpha) to microcosms in a feeding experiment resulted in minimal labelling of harpacticoid copepods and nematodes. Lack of change in the fatty acid composition of the latter also suggests limited assimilation of detritus during the experiment. It is likely that consumers choose benthic microalgae over detritus when both food sources are available in the field. High content of highly unsaturated fatty acids (HUFAs) in nematodes from the field suggests, for the first time, that they are a high quality food source to higher trophic levels. A feeding experiment investigating the effect of bacterivorous nematodes on detritus assimilation rates by amphipods did not support the hypothesis that nematodes increase the trophic transfer efficiency between detritus and macrofaunal detritivores. It is unclear whether amphipods preferentially fed on detritus or whether nematodes escaped predation by burrowing deeper in the sediment. Data obtained in the present study, however, shows that marine bacterivorous nematodes can biosynthesise/accumulate HUFAs in high concentrations despite their low concentrations in their diet. Nematodes could, therefore, provide an important source of these essential nutrients to bulk deposit feeders living in otherwise HUFA-poor sediments.

The aim of this study was to determine the size and age compositions, growth rates, reproductive biology, dietary compositions and mesh selectivity of the King George whiting Sillaginodes punctata, the Australian herring Arripis georgiana, the yelloweye mullet Aldrichetta forsteri and the sea mullet Mugil cephalus in Wilson Inlet. These biological variables were chosen for analysis since the resultant data would be of use for managing these commercially important marine species in this seasonally closed estuary, which is located on the southern coast of Western Australia. Samples of each of the above species were typically collected, in at least every other month between April 1988 and April 1990, by using seine netting and gill netting at several sites, distributed at regular intervals throughout the 48 km2 basin of Wilson Inlet, and by gill netting at one site in each of two tributary rivers. The ages of Sillaginodes punctata, Aldrichetta forsteri and Mugil cephalus were determined using the annuli on scales, whereas those of Arripis georgiana were determined using the annuli on otoliths. The annuli on the above hard structures of the four species were shown to be formed annually before they were used for aging purposes. Although at least four year classes of each species were found in Wilson Inlet, the 0+ year class of none of the species was well represented in this estuary. The paucity of this age class was probably attributable, in most cases, to the spawning grounds of these species being located some distance away on the lower west coast of Australia. However, the absence of any 0+ S. punctata in one year was attributed to the mouth of Wilson Inlet being closed at a crucial time, which thereby prevented the recruitment of this species into this estuary. Virtually all of the S. punctata caught in Wilson Inlet were less than the LSo at first maturity, which implies that none of this species return to this estuary after they have emigrated to sea, matured and spawned. However, appreciable numbers of each of the other three species were found at lengths greater than their respective Lsos. There was clear evidence that large A. forsteri tended to leave the estuary soon after the bar at the estuary mouth was breached. In contrast, length-frequency distributions indicated that large A. georgiana often tended to remain in the estuary, even when they exceeded the LSo at first maturity and the estuary mouth was open. The maximum lengths attained by S. punctata, A. georgiana, A. forsteri and M. cephalus were 491,373,430 and 525 mm, respectively, while the maximum ages attained by these four species were 5+, 7+, 5+ and 4+, respectively. While there was no significant difference between the growth rates of the two sexes of either S. punctata or M. cephalus, the overall growth rates of the females of A. georgiana and A. forsteri were both greater than those of their males. Each fish was assigned a maturity stage using the criteria of Laevastu (1965). The maximum maturity stage recorded for the gonads of S. punctata was IV (maturing). The fact that no S. punctata with spawning (stage VI), spent (stage VII), recovering spent (stage VIII) or resorbing gonads were found provides overwhelming evidence that this whiting species neither spawns in Wilson Inlet nor returns to this estuary after it has spawned at sea. Furthermore, spawning and recently-spent gonads were never found in individuals of either A. georgiana, A. forsteri or M. cephalus, whch implies that these species also do not spawn in the estuary. However, some A. georgiana and A. forsteri with recovering spent gonads were found in Wilson Inlet, which indicates that some individuals of these two species enter the estuary after spawning at sea. There was no indication that this also applied with M. cephalus. Yet, the gonads of some individuals of this latter species and also of A. georgiana contained resorbing gonads, i. e gonads that had reached a reasonably advanced stage, but not maturity, and which were now undergoing regression. The fish with these gonads had presumably been trapped in the estuary at the time their gonads were developing and could not therefore emigrate out to their marine spawning areas. The dietary compositions of the four species were shown to be significantly different. Sillaginodes punctata and A. georgiana fed mainly on benthic macroinvertebrates, while all but the smallest M. cephalus were detritivores and A. forsteri was an omnivore. Furthermore, S. punctata fed mainly on errant polychaetes and nemerteans, whereas A. georgiana ingested decapods, mysids and other teleosts. The diets of each species underwent size-related changes. The differences in dietary compositions among and within species would reduce the likelihood of inter- and intraspecific competition for food resources. Comparisons have been made between traditional methods for estimating the selectivity of S. punctata, A. georgiana, A. forsteri and M. cephalus in gill nets and a new method of analysis developed (with Dr. N. Hall), which incorporates the best features of the traditional methods.

Thesis (Ph. D.)--University of Wisconsin-Madison, 1975. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Bibliography: leaves 251-259.