Study

Honours Projects

Aquaculture Nutrition

Supervisor team may include:

Dr Louise Adams

Professor Chris Carter

Projects relating to core nutrition and animal performance research themes: Fishmeal replacement, nutrient requirement, digestive physiology or feed assessment in Atlantic salmon, trout, abalone, barramundi or prawns. Links with IMTA Nutrition-Environment and modelling. Please discuss directly with supervisors.

Assessing the role of cultured seaweeds in uptaking nutrients

Supervisory Team:

Primary supervisor: Elisabeth Strain

Co-supervisor: Catriona Hurd, Wouter Visch

Brief project description:

Seaweeds are primarily cultivated for food production. There is however, growing recognition that cultivated seaweeds might also provide other important environmental co-benefits including remediation of pollution through uptake of nutrients or heavy metals, carbon capture, coastal protection and habitat for colonising organisms. To date, research has demonstrated that the environmental co-benefits of cultivated seaweeds differ between species and locations. The project will synthesize the existing literature and test

Specifically, this thesis aims to:

  1. Uptake a literature review/formal meta-analysis testing the efficacy of different cultured seaweeds in uptaking nutrients.
  2. Assess whether different taxonomic or functional groups of cultured seaweeds have different potential benefits in uptaking nutrients.

The results of this thesis will provide new insights into the potential environmental benefits and trade-offs of culturing different species of seaweed in Tasmania and globally.

Skills students will develop during this research project:

The student will learn key analytical skills and conduct data analyses through R gui.

Benchmarking flat oyster reefs restoration outcomes in southeast Tasmania

Supervisory Team:

Primary supervisor: Beth Strain

Co-supervisor: Jeff Ross

Additional supervisors: Sarah Ugalde and Victor Shelamoff

Brief project description:

In the marine environment oysters are ecosystem engineers: they form reef super-structures that significantly influence the surrounding abiotic and biotic conditions. Under suitable environmental conditions oysters can filter, and store nutrients, and enhance bacterially mediated denitrification, which greatly improves the surrounding water quality. The effects of many natural oyster reefs in achieving the ecosystems services are generally inferred through laboratory incubations which have been undertaken for a limited number of species.

In Australia, most of the remaining subtidal flat oyster reefs are in Tasmania. This project represents a unique opportunity to test the effects of remnant flat oyster reefs on the nutrient cycling, by applying three different situ measurement techniques. The fieldwork will be conducted with the support from technical offers, and laboratory processing by the student. The results are expected to inform future restoration and culturing programs for flat oysters being developed in Tasmania and nationally.

Burial of calcium carbonate in deep sea sediments: Does it all add up?

Supervisory Team:

Primary supervisor: Zanna Chase

Co-supervisor: Lennart Bach

Brief project description:

The calcium carbonate cycle in the ocean plays an important role in the global carbon cycle on timescales of decades to millions of years. Production of calcium carbonate in surface waters lowers alkalinity and increases pCO2, thus decreasing the ocean’s uptake of carbon from the atmosphere. The dissolution of CaCO3 on the seafloor will neutralise anthropogenic CO2 additions to the ocean in the coming centuries (Archer et al., 2009; Ridgwell & Hargreaves, 2007). Indeed, a recent study suggests such dissolution has already started in some parts of the ocean (Sulpis et al., 2018). However, an accurate prediction of this effect is hampered by our incomplete understanding of what controls carbonate burial in the deep sea (Sulpis 2019).

The CaCO3 cycle in the ocean is relatively simple (see figure), and one can expect a simple mass balance at the seafloor, where B = P – W – S. That is carbonate burial (B) is equal to the production of carbonate in the upper ocean minus dissolution in the water colum (W) and dissolution in the sediment (S). However, major uncertainties persist in our understanding of CaCO3 cycling in the ocean.

In particular, the following key components of the carbonate cycle are poorly constrained:

  • The rate at which carbonate is produced in surface waters (Krumhardt et al., 2019)
  • The amount of dissolution that occurs during transit through the water column (Berelson et al., 2007; Sulpis et al. 2021)
  • The dissolution rate at the seafloor and whether this is controlled primarily by sediment-side dynamics or water-side dynamics (Boudreau et al., 2020)

This project will take advantage of a number of recently published datasets and model results to test the carbonate mass balance in the ocean. Specifically, the project will use recent estimates of carbonate burial in sediments, carbonate production in surface waters, and dissolution at the seafloor, to test the extent to which carbonate burial can be predicted based on estimates of carbonate production and dissolution.

If a mass balance can be demonstrated, this will be a strong confirmation of the accuracy of current theory and observations. Discrepancies in the mass balance can be used to diagnose any gaps in understanding.

CCAMLR: Conservation and Rational Use

Supervisory Team:

Primary supervisor: Prof Marcus Haward

Co-supervisor:  Dr Valeriya Komyakova

Brief project description:

In the recent decadesMarine plastic pollution has emerged as a major environmental and potential health threat issue. February 2022 will see a meeting of the United Nations Environment Program consider whether to begin negotiations on a global agreement addressing marine plastic litter and plastic pollution. This project aims to explore the potential scope and focus of an international agreement to address marine plastic pollution, including possible challenges in its development and implementation.

Skills students will develop during this research project:

Qualitative  social research methods. Data collection and analysis, Communication skills.

Demographics of recreational fishing participation – understanding the past and looking to the future

Supervisor team may include:

Dr Jeremy Lyle

Dr Sean Tracey

The 2000/01 National Recreational Fishing Survey provided the first comprehensive assessment of recreational fishing in Australia. At the time an estimated 3.4 million Australians fished at least one a year, representing almost 20% of the total population. Participation rates did, however, vary widely by age, gender and area of residence. More recent surveys highlight a trend of declining participation that can be linked in part to changing population demographics. This project will review results of surveys of recreational fishing participation in the context of population demographics and the implications for future participation in recreational fishing.

Evaluating the use of barnacle shells as an archive for reconstructing Southern Ocean oceanography

Supervisory Team:

Primary supervisor: Dr Taryn Noble

Co-supervisor(s) with affiliation and location: Prof Zanna Chase, IMAS Salamanca

Background and Research Aims:

The Southern Ocean plays a major role in moderating climate on short millennial-scale and longer glacial to interglacial timescales through changes in carbon storage and heat redistribution. However, the lack of carbonate preserved in marine sediment records make reconstructing the chemistry and circulation of the past Southern Ocean using existing proxy methods challenging. This project will explore a new approach to reconstructing past ocean chemistry using the chemical and isotopic composition of relic barnacle shells. Barnacles produce calcite shells using the dissolved chemical constituents in the surrounding seawater, and can therefore be analysed to reconstruct the trace metal and isotopic composition of mid-depth (400 -1500 m) paleo-water masses.

High-resolution laser-ablation ICP-MS will be used to analyse the trace metal composition of radiocarbon dated barnacle shells. Different ratios of trace metals will be assessed as potential proxies for reconstructing the temperature and oxygen properties of past water masses. Lower resolution hand-milled sections of calcite will be sampled along the growth axis of the barnacle to reconstruct the oxygen isotope composition of the waters, which reflects the hydrographic properties (temperature and salinity) and the global ice volume signature. Discrete samples will also be analysed for rare earth elements to reconstruct the source of water masses using neodymium isotopes as a circulation tracer.

Required prior learning, licences, training or skills:

A background in chemistry and/or geology will be advantageous

Approach and benefits to student:

The student will gain skills working in the laboratory to prepare samples and purify samples for Nd isotope analysis. The student will also become familiar with a large suite of geochemical data, including the processing and presentation of data.

If, when and how natural sex ratio bias occurs in Gambusia holbrooki?: consequences for management of pest populations

Supervisory Team:

Primary supervisor: Jawahar Patil

Co-supervisor: Chris Bolch

Additional supervisors: James Haddy

Brief project description:

Understanding the mechanisms of population declines is critical for both conservation of endangered species as well as for implementing sex-ratio biased extinction/eradication strategies for management of pest populations. Regardless of the mechanism that creates a sex ratio bias within a population, increased numbers of one sex over the other can result in behaviors that impose additional fitness costs, such as mating harassment, increasing the risk of population extinctions. Despite, what appears a naturally occurring adult sex ratio bias, the invasive G. holbrooki are known to exhibit normal sex ratios (1:1) at birth and their populations thrive, particularly in invaded habitats. Therefore, it is not clear if the bias is real or reflects observational artifact, on count of size dimorphism. If the former, questions remain as to at what life stage do these differences manifest, what are the drivers and how do G holbrooki populations compensate and thrive? As a first step to address these questions, this honours project will systematically, investigate sex ratio of wild and laboratory reared populations, employing multiple techniques, including molecular markers of sex. The outcome will directly inform the development and implementation of genetic control options to eradicate this invasive species from Tasmania and Australia.

Skills students will develop during this research project:

Management of fish populations and molecular biology. Importantly, student will have opportunity to interact with community volunteers at the Tamar Island Wetland Reserve

Indirect impacts of the range–extending sea urchin, Centrostephanus rogersii: a socioeconomic assessment

Supervisor team may include:

Dr John Keane

Dr Emily Ogier

Professor Caleb Gardner

Centrostephanus are continuing to expand down the east coast of Tasmania, resulting in destructive overgrazing of kelp habitats. While direct biological impacts have been well documented, economic and social implications are less understood. This project looks to define what fisheries/industries are most at risk should barrens continue to expand, and to quantify the social and economic impacts to regional areas, and Tasmania as a whole.

Large salmon nutrition and performance

Supervisor team may include:

Dr Louise Adams

Professor Chris Carter

Nutrition and feeding studies on harvest sized salmon are challenging without specialist experimental facilities. There are opportunities for nutrition related projects investigating aspects of feed digestibility, digestive physiology, product quality and performance under commercial conditions, aligned with large multidisciplinary experiments conducted at the EAF. Laboratory work would begin early (Feb-March) and would require travel between Hobart and Launceston during the project.

Opal preservation and burial efficiency determined using sediment pore water measurements from Cape Darnley, East Antarctica

Supervisory Team:

Primary supervisor: Zanna Chase

Co-supervisor: Taryn Noble

Brief project description:

The Southern Ocean plays a critical role in the oceanic silicon cycle, with Southern Ocean sediments responsible for nearly 50% of silicon burial globally (Treguer and De La Rocha 2013; Chase et al. 2015). The abundant and productive diatoms in the Southern Ocean deliver large amounts of silicon to the seafloor in the form of opal frustules. However, only ~1 - 6% of the silicon that reaches the seafloor escapes dissolution and is preserved long term in the sediment (Chase et al 2015; Pondaven et al. 2002; Nelson et al. 2000). Most of the silicon dissolves in the upper tens of cm of the sediment, and returns as silicic acid to the water column, where it can be reincorporated in the biological cycle. The remaining, buried opal, is incorporated into the sediment record. Paleoceanographers use this buried opal in the form of accumulation rates and preserved diatom assemblages to reconstruct ocean productivity and environmental conditions through time.

Despite its importance to global chemical cycles, and to the integrity of paleoceanographic interpretations, many questions remain about what controls the preservation of opal in Antarctic sediments. There is a growing body of evidence that aluminium plays a central role in opal preservation, with opal preservation increasing with a higher proportion of lithogenic material relative to opal in sinking particles (Van Cappellen and Qui 1997; and see summaries in Martin and Sayles 2003 and Sarmiento and Gruber 2006, chapter 7). The relationship appears to be site specific, although the overall lack of data may be obscuring larger trends.

This project will add to our understanding of opal preservation in Antarctic sediments using data and samples collected on a recent voyage to Cape Darnley, East Antarctica (Jan – Feb 2022). The project will use analyses of sediment and sediment pore waters (e.g. see Gallinari et al. 2008 and Sayles et al. 2001) to evaluate the role of lithogenic material in opal preservation, and to test some proposed algorithms to predict opal burial efficiency (e.g. Sayles et al. 2001). Pore water analyses will be completed at sea, and the student will have access to these data. Sediment solids will be analysed at IMAS for concentrations of opal, Th-232, Al and Th-230. These measurements will enable calculations of fluxes of opal and lithogenic material.

Regional contrasts in Tasmanian cross-shelf fish assemblages recorded from baited-underwater-video surveys

Supervision team:

Associate Professor Neville Barrett

Dr Jacquomo Monk

Baited underwater videos (BRUVs) are now in common use for surveying fish populations on reef systems around Australia. A number of surveys have now been undertaken at locations around Tasmania, but this information has yet to be synthesised to gain an understanding of the general lessons from this with respect to biogeographical patterns, ranges and depth distributions of key species, or the effectiveness of potential indicator species for long-term monitoring programs. A project is available to undertake this synthesis, as well as potentially completing an additional set of BRUV deployments on the Tasmanian west coast to fill in a current biogeographical gap in this regional coverage.

Relationships between seabed complexity and the distribution of key biota

Supervisor team may include:

Dr Neville Barrett

This project uses a comprehensive set of imagery derived from IMOS AUV deployments in Tasmanian shelf waters to examine the spatial distribution of characteristic reef associated species (e.g. particular sponges) and their relationship with significant habitat features. The work will allow future predictions of the distribution of key species based on mapped seabed geomorphology.

A range of similar projects are also available for this image analysis, including description of the spatial distribution of benthic invertebrates and algae within the Flinders Commonwealth Marine Reserve, physical drivers of benthic invertebrate structural height and complexity on deep reefs, the changing distribution of Centrostephanus barrens in eastern Tasmanian waters.

Suitable for February or July start date.

Contact Dr Neville Barrett (neville.barrett@utas.edu.au) for more details.

The Role of Antarctic Tourism in Citizen Science

Supervisory Team:

Primary supervisor: Dr Hanne Nielsen

Brief project description:

This project will investigate the relationship between polar tourism and citizen science. By mapping the existing citizen science activities in the far south and contextualising these within the wider scholarship on citizen science, then investigating perspectives from both tour operators and scientists, the project will identify best practice and suggest future opportunities in the polar citizen science space.

Skills students will develop during this research project:

Qualitative  social research methods. Data collection and analysis, Communication skills.

Two decades of recreational licensing – what has changed and why?

Supervisor team may include:

Dr Jeremy Lyle

Dr Sean Tracey

Marine recreational licences are required for a range of fishing activities in Tasmania. The databases provide an informative insight into the characteristic of those interested in each of the specific fishing methods, including age and area of residence. Not only does this data reveal interesting patterns in the changing demographics of fishing, for example a transition from diving to potting for lobster with age, but also variability in licensing linked to changing management and resource availability.

Use of remote operated vehicles for surveying deep cross shelf habitats and fish assemblages, including improved understanding of fish/habitat relationships

Supervisory Team:

Primary supervisor: Neville Barrett

Co-supervisor: Nick Perkins

Additional supervisors: Jacquomo Monk

Brief project description:

A range of remote-sensing tools are being applied to the survey and description of coastal and shelf habitats and their associated biological assemblages, including multibeam mapping, towed video, drop cameras, Autonomous Underwater Vehicles, Baited Underwater Video and Remote Operated Vehicles (ROVs). ROVs have had great potential in this area but historically the expense and size of vehicles capable of adequately surveying deeper shelf habitats beyond 50 m has significantly constrained research in this area. IMAS has recently acquired a Next Gen ROV called Boxfish, with a custom stereo camera system facing downward and forwards to record benthic cover as well as benthic and epi-benthic fish assemblages. This ROV is currently being deployed at a number of locations in the Freycinet and Huon AMPs for Parks Australia as part of a wider biodiversity survey of these marine parks. This project will assess the extent that the imagery acquired is suitable for describing both benthic and fish assemblages in cross-shelf habitats, as well as providing robust estimates of cover and/or abundance for use in ongoing monitoring programs. This data may be compared with BRUV data from similar areas/habitats for fish assemblages, and with AUV-derived data for benthic sessile fauna such as sponges. Ultimately the project will assist us in informing Parks Australia of optimal and cost-effective ways to undertake inventory of species and habitats in their AMP network, and to monitor core values through time. By extension, it will also greatly assist in our understanding of the offshore habitats and assemblages that underpin important commercial fisheries in our region, including rock lobster, striped trumpeter, jackass morwong.

Skills students will develop during this research project:

The student will gain extensive experience in image annotation and associated software, an intimate knowledge of Tasmanian coastal/shelf fish species and cover forming sessile invertebrates, as well as the quantitative analytical approaches to analysing these datasets. The student will be engaging with a number of national image-related programs and developing skills in an emerging field of marine science.

Using Electrolysed Oxidising (EO) water as a pre-treatment sanitiser for chilled fish stored on ice

Supervisor:

Mike Williams

(Please contact the supervisor for further information)

Using ship-based measurements and profiling floats to estimate net community production and air-sea CO2 flux from the Southern Indian Ocean

Supervisory Team:

Primary supervisor: Zanna Chase

Co-supervisor: Christina Schallenberg

Additional supervisors: Elizabeth Shadwick       

Brief project description:

The Southern Ocean plays an important role in the global carbon cycle (Gruber et al. 2009). This region is responsible for the uptake of about 40% of anthropogenic CO2 emissions (Frolicher et al. 2015), and is believed to play a key role in glacial-interglacial climate change (Sigman et al. 2010).  Large-scale upwelling in the Southern Ocean delivers waters rich in nutrients and natural carbon from the deep ocean to the sunlit surface waters. This upwelled water has the potential to release large amounts of natural carbon dioxide to the atmosphere, and to take up anthropogenic CO2 from the atmosphere (Gruber et al. 2009). While biological productivity can consume CO2 before it is released to the atmosphere, a lack of the micro-nutrient iron generally inhibits biological productivity in the Southern Ocean (Boyd et al. 2000; Coale et al. 2004).

Biological consumption of carbon in the southern-most part of the Southern Ocean, the Antarctic Zone, is particularly important in the carbon cycle. In this region, south of the so-called “biogeochemical divide” (Marinov et al. 2006), upwelled waters flow south after reaching the surface, and are ultimately incorporated into the deepest water mass in the ocean- the Antarctic Bottom water. Biological productivity in this region therefore has the potential to lock carbon away in the deep ocean for up to a thousand years.

Despite the importance of the Antarctic Zone in the global carbon cycle, this region remains poorly studied, due to its remoteness and the inhospitable conditions over winter. The recent development of autonomous profiling floats, instrumented with chemical and optical sensors (biogeochemical Argo floats; BGC-Argo), is changing our view of Southern Ocean carbon cycling: float-based estimates of carbon flux suggest sparse ship-based measurements have underestimated the release of carbon to the atmosphere in the Antarctic Zone (Gray et al. 2018), particularly over autumn and winter.  However, even the float-based study is based on a relatively small number of floats, covering a small fraction of the waters around Antarctica.

This project will estimate the biological productivity and air-sea CO2 flux using data collected from a Jan-Feb 2022 voyage to the Cape Darnley region, East Antarctica. This is one of only 4 regions around the continent where AABW is formed (Ohshima et al. 2013). The area has recently been identified as a strong CO2 sink in summer (Murakami et al. 2020). The voyage will be collecting oceanographic data, including nutrient and carbon measurements, and deploying BGC-Argo floats over the continental slope. The student will work with these data sets and make measurements of particulate organic carbon, biogenic silica and chlorophyll, in order to address the following objectives:

  • Summarise nutrient, carbon and biomass parameters encountered during the voyage
  • Calculate Net Community Production (NCP) from nutrient depletion relative to winter water characteristics, and examine the stoichiometry of nutrient depletion
  • Calculate air-sea CO2 flux from underway pCO2 data
  • Compare the ship-based estimates of NCP and CO2 flux with estimates based on BGC-Argo floats
  • Use the float data through winter to extend observations of the seasonal cycle of NCP and pCO2 flux

Skills students will develop during this research project:

Data analysis and visualisation; lab work.

Validating a new proxy for iron fertilization in the Southern Ocean

Supervisor:

Dr Taryn Noble

Project Description:

The input and dissolution of continental material to high nutrient surface waters of the Southern Ocean plays an important role in biogeochemical cycling of carbon because it alleviates iron limitation and stimulates phytoplankton growth. In remote subantarctic regions dust is an important source of dissolved iron, but close to Antarctica, dissolved iron sources include melting sea ice, icebergs calved from glaciers, and upwelled deep waters.

The Antarctic Ice Sheet is experiencing rapid changes in response to anthropogenic climate warming. Melting ice shelves and glacier retreat will increase the input of freshwater and dissolved continental material to the surface ocean, but the biological response to these changes (and therefore impact on the global carbon cycle) is unknown. However, we can study the biological and chemical response to past changes in ice sheet retreat recorded in ocean sediments to improve our understanding of how the system might change in the future.

The aim of this Honours project is to test the reliability of a geochemical method (Robinson et al. 2008) for quantifying the dissolved iron flux along the continental margin of East Antarctica. This method uniquely targets the input of dissolved material, rather than the input of total continental material. The distinction is biologically important, because phytoplankton take up dissolved iron from seawater.

Chemical leaching experiments will be carried out on surface seafloor sediments, which preserve the most recent period of sediment deposition. Two isotopes of thorium will be measured in the leachates, Th-232 which only enters the ocean from continental inputs, and Th-230 which is produced mainly from the decay of U-234 dissolved in seawater. Thorium is very insoluble in seawater and as is dissolves from continental material it rapidly adsorbs to the surface of particles, making it an excellent tracer of dissolved components. 

The leaching is designed to recover only the Th that is adsorbed to the sediment particles, which should represent the 232Th/230Th ratio in the overlying seawater. The results of the leaching experiments will be compared to existing measurements of the dissolved 232Th/230Th in the overlying water column in order to assess the reliability of this method.

What spatial information is used to address socio-cultural objectives in marine spatial planning?

Supervisory Team:

Primary supervisor: Myriam Lacharité

Co-supervisor: Maree Fudge

Additional supervisors:

Brief project description:

Marine spatial planning (MSP) is increasingly used to manage ocean resources in complex and crowded socio-ecological systems. MSP aims to meet general and specific objectives to ensure a balance is struck between fair and sustainable economic development and the conservation of the marine environment. The outcome of an MSP process is a ‘plan’ which can be refined according to evolving needs and stakeholder sentiment. This plan then becomes the basis for the management and regulation of the socio-ecological system.

The MSP process relies on the availability of relevant and accurate spatial information on marine ecosystems and biodiversity, ocean uses and the delineation of zones under regulatory frameworks, as well as threats and pressures. Over the past decade, socio-cultural objectives have been increasingly explicitly included in MSP; however, Australian marine spatial plans examined in a recent study do not explicitly include socio-cultural objectives, instead focusing on the distribution of ecosystems and biological communities (Zurcher et al. 20221). To address this gap in Australian MSP processes we pose the following research question: if socio-cultural objectives are to be more broadly included in future Australian marine spatial plans, what information is relevant and could be used to meet these needs? The aim for this honours project is to draw on examples from overseas to determine: 1) the information and data used in the development of and/or monitoring of marine spatial plans specifically to address socio-cultural objectives, 2) if this information is spatially explicit and if so, in what ways or formats, and 3) to what extent this information and data are applicable in the Australian context.

1Zurcher, R., Motzer, N., Magris, R.A., Flannery, W. 2022. Narrowing the gap between marine spatial planning aspirations and realities. ICES Journal of Marine Sciences, 0: 1-9.

Skills students will develop during this research project:

Systematic literature review, spatial analysis, marine management.

Authorised by the Executive Director, Institute for Marine and Antarctic Studies
29 September, 2021