Marine Biology Commons^™

Streamlining And Core Genome Conservation Among Highly Divergent Members Of The Sar11 Clade, Jana Grote, Cameron Thrash, Megan Huggett, Zachary Landry, Paul Carini, Stephen Giovannoni, Michael Rappe

Research outputs 2012

SAR11 is an ancient and diverse clade of heterotrophic bacteria that are abundant throughout the world’s oceans, where they play a major role in the ocean carbon cycle. Correlations between the phylogenetic branching order and spatiotemporal patterns in cell distributions from planktonic ocean environments indicate that SAR11 has evolved into perhaps a dozen or more specialized ecotypes that span evolutionary distances equivalent to a bacterial order. We isolated and sequenced genomes from diverse SAR11 cultures that represent three major lineages and encompass the full breadth of the clade. The new data expand observations about genome evolution and gene content that …

Fussy Feeders: Phyllosoma Larvae Of The Western Rocklobster (Panulirus Cygnus) Demonstrate Prey Preference, M I Saunders, P A Thompson, A G Jeffs, Christin Sawstrom, N Sachlikidis, L E Beckley, A M Waite

Research outputs 2012

The Western Rocklobster (Panulirus cygnus) is the most valuable single species fishery in Australia and the largest single country spiny lobster fishery in the world. In recent years a well-known relationship between oceanographic conditions and lobster recruitment has become uncoupled, with significantly lower recruitment than expected, generating interest in the factors influencing survival and development of the planktonic larval stages. The nutritional requirements and wild prey of the planktotrophic larval stage (phyllosoma) of P. cygnus were previously unknown, hampering both management and aquaculture efforts for this species. Ship-board feeding trials of wild-caught mid-late stage P. cygnus phyllosoma in the eastern …

Geostatistical Spatiotemporal Modelling With Application To The Western King Prawn Of The Shark Bay Managed Prawn Fishery, Ainslie M. Denham

Theses: Doctorates and Masters

Geostatistical methodology has been employed in the modelling of spatiotemporal data from various scientific fields by viewing the data as realisations of space-time random functions. Traditional geostatistics aims to model the spatial variability of a process so, in order to incorporate a time dimension into a geostatistical model, the fundamental differences between the space and time dimensions must be acknowledged and addressed. The main conceptual viewpoint of geostatistical spatiotemporal modelling identified within the literature views the process as a single random function model utilising a joint space-time covariance function to model the spatiotemporal continuity. Geostatistical space-time modelling has been primarily …

Do Different Levels Of Fishing Pressure, Through Spatial Management, Influence Communities And Ecological Interactions In Seagrass Meadows In South Western Australia?, Karina Inostroza

Theses : Honours

Marine Protected Areas (MPAs) are internationally recognised as a significant spatial management and cost-effective strategy to restore and conserve the marine ecosystems structure and function from human impact. MPAs have been declared with the aim to address a single or a set of management objectives in response to anthropogenic threats, such as fishing, which can have repercussions on biodiversity through indirect interactions or top-down control within an ecosystem or across ecosystems where consumers migrate to forage. However, this indirect impact of fishing remains poorly understood, and as a consequence, the effectiveness of MP As in conserving those ecological processes and …

Historical Datasets Of Dugong (Dugong Dugon) Observations In The Kimberley Region Of Western Australia - Data Report - Report No. 2008-03, David K. Holley, R. I.T. Prince

Research outputs pre 2011

Research Need and Objective :

Many sections of the northern WA coastline have become heavily industrialised in the last three decades particularly throughout the Pilbara region where offshore and onshore oil and gas exploration and processing facilities are abundant. There have been recent moves to develop similar industry along the Kimberley coast to access the Browse Basin, a 140,000 Km2 offshore gas field approximately 300km off the Kimberley Coast. This has resulted in extensive debate and the need to define the natural values of this region, which is considered to be one of the world’s most ecologically diverse (WWF 2008). …

The Use Of Detached Kelp (Ecklonia Radiata) By Seagrass-Associated Mesograzers In Temperate South-Western Australia, Christopher Doropoulos

Theses : Honours

The movement of nutrients and organisms between habitats provide important spatial subsidies on local and regional scales, resulting in increased primary and secondary production, especially where inputs supplement habitats of relatively low levels of comparable resources. In coastal south-western Australia, the brown kelp, Ecklonia radiata, is produced in large quantities on offshore reefs from where it detaches and passes through neighbouring habitats. This allochthonous resource is present in large quantities in seagrass meadows and thereby potentially influences the trophic dynamics of this habitat, providing an additional food source for grazers to those produced in situ. This study investigated the effects …

Retrospective Analysis Of Epiphyte Assemblages In Relation To Seagrass Loss In A Eutrophic Coastal Embayment, Ml Cambridge, Jr How, Paul Lavery, Ma Vanderklift

Research outputs pre 2011

This is a retrospective study of shifts in species composition of epiphytic macroalgae that occurred during a period of seagrass loss in Cockburn Sound, Western Australia. Detailed analysis of data on relative abundances of 108 epiphytic taxa collected over 2 yr from 27 widely dispersed sites around Cockburn Sound showed differences in epiphyte composition between sites with loss of seagrasses (Loss sites) and those with no loss in the the long-term (No Loss sites). Future seagrass losses, however, were not predicted by shifts in species composition. Most species were rare and varied with season of sampling. Hence, varying assemblages of …

Effect Of Leaf Movement On Epiphytic Algal Biomass Of Seagrass Leaves, Paul Lavery, Tara Reid, Glenn Hyndes, Beverley Van Elven

Research outputs pre 2011

We tested the hypothesis that the movement of seagrass leaves affects the accumulation and composition of algal epiphytes by comparing the standing crop and composition on tethered (T) and untethered (UT) artificial seagrass units (ASUs) over 4 and 8 wk. We also tested whether any effect of leaf movement on standing crop was dependent on the degree of water movement by repeating the experiment over 8 wk at sheltered and exposed sites. To eliminate the possibility of inter-regional differences between exposed and sheltered sites and to test for interactive effects of light availability and leaf movement on epiphyte biomass, we …

Morphological, Growth And Meadow Characteristics Of The Seagrass Posidonia Sinuosa Along A Depth-Related Gradient Of Light Availability, Cj Collier, Paul Lavery, Rj Masini, Pj Ralph

Research outputs pre 2011

Morphological and growth characteristics of the meadow-forming seagrass Posidonia sinuosa (Cambridge et Kuo), were measured along a depth-related gradient of light to infer its response to long-term differences in light availability. Morphometric measurements were carried out at 6 depths between 1.6 and 9.0 m in summer and winter at Cockburn Sound and summer only at Warnbro Sound in south-western Australia. The minimum light requirement for P. sinuosa of 8.5% sub-surface light was among the lower range reported for seagrasses. Its slow growth rate (0.5–1.5 mgdry shoot–1 d–1), relative to similarly sized species, may contribute to the low light requirements of …

Determining Carbon And Nitrogen Stable Isotope Discrimination For Marine Consumers, Emily N. Gates

Theses : Honours

The application of stable isotope ratios to food web studies is increasing, and the use of generalised discrimination values (0.4±1.4%₀ for δ¹³C and 3.4±1.1%₀ for δ¹⁵N), which are being widely applied to many studies, may not be valid. The broad objective of this study was to evaluate the assumption that these discrimination values are applicable to a range of benthic marine consumers, and therefore appropriate to be used in trophic analyses using carbon (C) and nitrogen (N) stable isotopes in marine food webs. The first aim was to determine if there were differences in …

Automated Photo-Identification Of Cetaceans : An Integrated Software Solution, Daniel Griggs

Theses : Honours

This study investigates current techniques used for automated photo-identification of cetaceans (i.e. dolphins and whales). The primary focus constitutes various techniques that can be applied to identify and extract dorsal fins from digital photographs. A comprehensive analysis of these techniques demonstrates the most effective software solution. To further support this analysis, four prototypes are developed to demonstrate the effectiveness of each technique in a practical environment. The analysis bases its final conclusions on test results generated from these prototype software examples. Final conclusions provide recommendations for an effective, accurate, and practical software solution. This software solution allows dorsal fins to …

The Effects Of Light Reduction Treatments On Mobile Epifaunain An Amphibolis Griffithii (Black) Den Hartog Seagrass Ecosystem, Helen Barwick

Theses : Honours

One of the main anthropogenic disturbances to seagrass meadows in Australia is reduction in light availability, through nutrient enrichment or suspended sediments. Dredging can create suspended sediment plumes from the expulsion of particulates into the water column and in tum reduces light penetration to seagrass ecosystems. Preliminary investigations have demonstrated that light reduction for different intensities and durations results in reduced seagrass and epiphytic algae biomass. The main aim of this study was to determine the effects of different intensities and durations of light reduction on epifaunal assemblages in Amphibolis griffithii seagrass meadows in Jurien Bay, Western Australia. This was …

Detached Macrophyte Accumulations In Surf Zones: Significance Of Macrophyte Type And Volume In Supporting Secondary Production, Karen Ruth Crawley

Theses: Doctorates and Masters

Detached macrophytes (sea grass and macroalgae) are transported from more offshore areas and accumulate in large volumes in surf zones, where they are commonly called wrack. In coastal regions in other parts of the world, wrack transported from one habitat to a second habitat can be considered as a "spatial subsidy" for the recipient habitat with significant consequences for community dynamics and food webs. The primary aim of this study was to determine the significance of the different components of wrack (i.e. sea grass and brown, red and green algae) as a direct and indirect food source and habitat for …

Effects Of Temporary Par Reduction On The Seagrass Amphibolis Griffithii (Black) Den Hartog, Paul R. Mackey

Theses : Honours

Declines in seagrass health and distribution are commonly caused through human induced reductions in the availability of photosynthetically active radiation (PAR). These reductions can result from a variety of human-induced perturbations, including channel dredging. The impetus for the research was driven by the broad-scale degradation of the ecologically important southern-Australian endemic seagrass Amphibolis griffithii (Black) den Hartog in Champion Bay, Geraldton, Western Australia. The study investigated the affects of reduced PAR on A. griffithii and identified responses that may be useful in developing management triggers to minimise the impact of PAR limitation events. The study was carried out during late …

Does Plant Morphology Influence Fish Fauna Associated With Seagrass Meadows?, Michael C. Burt

Theses : Honours

Three distinct seagrass habitats were sampled to determine whether fish assemblages differed between meadows comprising of different seagrass species with different morphological characteristics and whether plant morphology influences species assemblages. Three seagrass habitats consisting of Posidonia sinuosa, Posidonia coriacea and meadows of a mixture of P. coriacea and Heterozostera tasmanica in the Success Bank region, off the coast of Fremantle, Western Australia were selected. For each habitat, sampling was carried out using a 1m wide beam trawl over a distance of 50m at six replicated locations, on three occasions between June and September 2002. Seagrass samples were collected at each …

Analysis Of Increases In Fishing Power In The Western Rock Lobster (Panulirus Cygnus) Fishery, John Fernandez

Theses: Doctorates and Masters

The western rock lobster, Panulirus cygnus, fishery represents a significant commercial asset to Western Australia, and it is therefore important that appropriate strategies are developed to effectively manage it. Because the fishery has a very high level of exploitation, researchers and managers rely significantly on annual stock assessments which are based on catch and effort data. This study will identify and assess the effects that changes in fishing power factors (e.g. advances in fish-finding technology) have had on estimates of catch and effort. The fishing power increases can be used to adjust nominal fishing effort to produce a time series …

The In Vitro Propagation Of Seagrasses : Halophila Ovalis, Ruppia Megacarpa And Posidonia Coriacea, Melissa Grace Henry

Theses : Honours

Seagrass communities are of high ecological and economic significance. They provide a nursery area for commercial and recreational juvenile fish and crustacea. Seagrasses also play an important role in influencing the structure and function of many estuarine and nearshore marine environments. Unfortunately, the decline of seagrasses, as a result of human impact, has increased in recent years. This decline has become a major problem throughout the world. Current methods used to restore degraded seagrass beds are limited, the most promising being transplanting material from healthy donor beds. This approach is expensive because it is labor intensive and damages the donor …

The Filtration Rate, Oxygen Consumption And Biomass Of The Introduced Polychaete Sabella Spallanzanii Gmelin Within Cockburn Sound : Can It Control Phytoplankton Levels And Is It An Efficient Filter Feeder?, Geordie Clapin

Theses : Honours

Sabella spallanzanii, a filter feeding, sabellid polychaete worm which is common in the Mediterranean Sea, was recently discovered in Cockburn Sound, Western Australia. The species has been in Port Phillip Bay, Victoria for about 10 years, where it has spread widely, competes with native species and has economic impacts on the local scallop fishery. In Cockburn Sound, S. spallanzanii has colonised a shallow, sandy area known as the Southern Flats, reaching a mean biomass of 258 gDW m² , as well as almost all artificial structures such as jetties and navigational marker pylons. A large biomass of this introduced …