Tesi sul tema "Ballast water – Environmental aspects – Australia"

Thesis (Ph. D.)--University of Adelaide, Dept. of Botany, 1997.
Errata page is behind title page (p. i). Copies of author's previously published articles inserted. Includes bibliographical references (leaves 121-156).

South Africa, strategically situated at the southern tip of Africa, is edged on three sides by almost 3000 km of coastline surrounded by the Indian Ocean and the Atlantic Ocean (South African Tourism, 2011). This vast ocean expanse is responsible for conveying approximately 96% of South Africa’s exports (Brand South Africa, 2011). Despite the positive economic effects of the shipping industry, translocation of harmful organisms and pathogens via ballast water and sediments inside ballast water tanks has far reaching global environmental (and economic) impacts (Oliviera, 2008:1; David and Gollasch, 2008:1966). Ballast water is the water that is taken on in order to manage the draft of the ship, to help with propulsion, manoeuvrability, trim control, list and stability (Oliviera, 2008:2). The discharge of ballast water into the world’s oceans has resulted in the transfer of ecologically harmful sea-life into non-native environments (IMO, 2011), resulting in major environmental threats to our oceans (Bax, Williamson, Aguero, Gonzalez and Geeves, 2003:313). Various international documents have been developed to deal with the ballast water issue, culminating in the introduction of the International Convention for the Control and Management of Ships’ Ballast Water and Sediments (“the Convention”) in 2004. The Convention aims at achieving a reduction in the transfer and subsequent impacts of aquatic organisms via the ballast water and sediment of ships. On a local level, South Africa does not have direct legislation or regulations dealing with ballast water (Duncan, 2007:34) and relies on the combination of a number of pieces of legislation relating to environmental management, coastal management, biodiversity, alien invasive species control, port control and ship safety (National Environmental Management Act, 1998, National Environmental Management: Biodiversity Act, 2004, National Environmental Management: Integrated Coastal Management Act, 2009, National Ports Act, 2005 and Merchant Shipping Act, 1951). Although the Convention was ratified by South Africa in 2008 (Department of International Relations and Cooperation, 2011) it is still not in force and there still exists no other consolidated legal mechanism through which ballast water is managed. This research has investigated the various roles, responsibilities and mandates of South African competent authorities under the aforementioned legislation in managing ballast water, and has determined that there is definite legislative and institutional fragmentation as well as overlaps. A comparative analysis of management frameworks developed both locally and internationally was conducted in order to develop a management framework for ballast water management in South Africa. Various legislative, institutional and functional aspects were identified and adapted for inclusion in a South African management framework. A co-ordinated approach to ballast water management has been developed in the management framework which is anticipated to result in more definitive roles and responsibilities of the various South African departments involved in the management of ballast water and implementation of the Convention.

[Truncated abstract] Industrial processing to refine alumina from bauxite ore produces millions of tonnes of refining residue each year in Australia. Revegetation of bauxite residue sand (BRS) is problematic for a number of reasons. Harsh chemical conditions caused by residual NaOH from ore digestion mean plants must overcome extremely high pH (initially >12), saline and sodic conditions. At such high pH, manganese (Mn) is rapidly oxidised from Mn2+ to Mn4+. Plants can take up only Mn2+. Thus, Mn deficiency is common in plants used for direct BRS revegetation, and broadcast Mn fertilisers have low residual value. Added to this, physical conditions of low water-holding capacity and a highly compactable structure make BRS unfavourable for productive plant growth without constant and large inputs of water as well as Mn. However, environmental regulations stipulate that the residue disposal area at Pinjarra, Western Australia, be revegetated to conform with surrounding land uses. The major land use of the area is pasture for grazing stock. Hence, pasture revegetation with minimum requirement for fertiliser and water application is desirable. This thesis investigates a number of avenues with potential for maintaining a productive pasture system on BRS whilst reducing the current level of Mn fertiliser and irrigation input. Emphasis was placed on elucidation of chemical and physical factors affecting Mn availability to plants in BRS

Bauxite mining is a major activity in the jarrah (Eucalyptus marginata Donn ex Sm.) forest of south-western Australia. After mining, poor tree growth can occur in some areas. This thesis aimed to determine whether soil constraints, including reduced depth and compaction, were responsible for poor tree growth at low-quality restored bauxite mines. In particular, this study determined the response of jarrah root morphology, leaf-scale physiology and growth/development to soil constraints at two contrasting (low-quality and high-quality) restored bauxite-mine sites. Jarrah root excavations at a low-quality restored site revealed that deep-ripping equipment failed to penetrate the cemented lateritic subsoil, causing coarse roots to be restricted to the top 0.5 m of the soil profile, resulting in fewer and smaller jarrah trees. An adjacent area within the same mine pit (high-quality site) had a kaolinitic clay subsoil, which coarse roots were able to penetrate to the average ripping depth of 1.5 m. Impenetrable subsoil prevented development of taproots at the low-quality site, with trees instead producing multiple lateral and sinker roots. Trees in riplines, made by deep-ripping, at the high-quality site accessed the subsoil via a major taproot, while those on crests developed large lateral and sinker roots. Bauxite mining is a major activity in the jarrah (Eucalyptus marginata Donn ex Sm.) forest of south-western Australia. After mining, poor tree growth can occur in some areas. This thesis aimed to determine whether soil constraints, including reduced depth and compaction, were responsible for poor tree growth at low-quality restored bauxite mines. In particular, this study determined the response of jarrah root morphology, leaf-scale physiology and growth/development to soil constraints at two contrasting (low-quality and high-quality) restored bauxite-mine sites. Jarrah root excavations at a low-quality restored site revealed that deep-ripping equipment failed to penetrate the cemented lateritic subsoil, causing coarse roots to be restricted to the top 0.5 m of the soil profile, resulting in fewer and smaller jarrah trees. An adjacent area within the same mine pit (high-quality site) had a kaolinitic clay subsoil, which coarse roots were able to penetrate to the average ripping depth of 1.5 m. Impenetrable subsoil prevented development of taproots at the low-quality site, with trees instead producing multiple lateral and sinker roots. Trees in riplines, made by deep-ripping, at the high-quality site accessed the subsoil via a major taproot, while those on crests developed large lateral and sinker roots.

Bibliography :leaves 158-171. A monitoring program, funded by the South Australian government (through the former MFP Development Corporation), was established to monitor the quality and quantity of storm water entering and leaving the wetland. This study formed part of the funded program. Simple regression models were developed; and will assist in the monitoring of performance of the wetland to alleviate the pollutant load into the Barker Inlet.

[Truncated abstract. Please see the pdf format for the complete text. Also, formulae and special characters can only be approximated here. Please see the pdf version for an accurate reproduction.] This thesis examines the water use, ecophysiology and hydraulic architecture of Eucalyptus marginata (jarrah) growing on bauxite mine rehabilitation sites in the jarrah forest of south-western Australia. The principal objective was to characterise the key environment and plant-based influences on tree water use, and to better understand the dynamics of water use over a range of spatial and temporal scales in this drought-prone ecosystem. A novel sap flow measurement system (based on the use of the heat pulse method) was developed so that a large number of trees could be monitored concurrently in the field. A validation experiment using potted jarrah saplings showed that rates of sap flow (transpiration) obtained using this system agreed with those obtained gravimetrically. Notably, diurnal patterns of transpiration were measured accurately and with precision using the newly developed heat ratio method. Field studies showed that water stress and water use by jarrah saplings on rehabilitation sites were strongly seasonal: being greatest in summer when it was warm and dry, and least in winter when it was cool and wet. At different times, water use was influenced by soil water availability, vapour pressure deficit (VPD) and plant hydraulic conductance. In some areas, there was evidence of a rapid decline in transpiration in response to dry soil conditions. At the end of summer, most saplings on rehabilitation sites were not water stressed, whereas water status in the forest was poor for small saplings but improved with increasing size. It has been recognised that mature jarrah trees avoid drought by having deep root systems, however, it appears that saplings on rehabilitation sites may have not yet developed functional deep roots, and as such, they may be heavily reliant on moisture stored in surface soil horizons. Simple predictive models of tree water use revealed that stand water use was 74 % of annual rainfall at a high density (leaf area index, LAI = 3.1), high rainfall (1200 mm yr-1) site, and 12 % of rainfall at a low density (LAI = 0.4), low rainfall (600 mm yr-1) site, and that water use increased with stand growth. A controlled field experiment confirmed that: (1) sapling transpiration was restricted as root-zone water availability declined, irrespective of VPD; (2) transpiration was correlated with VPD when water was abundant; and (3) transpiration was limited by soil-to-leaf hydraulic conductance when water was abundant and VPD was high (> 2 kPa). Specifically, transpiration was regulated by stomatal conductance. Large stomatal apertures could sustain high transpiration rates, but stomata were sensitive to hydraulic perturbations caused by soil water deficits and/or high evaporative demand. No other physiological mechanisms conferred immediate resistance to drought. Empirical observations were agreeably linked with a current theory suggesting that stomata regulate transpiration and plant water potential in order to prevent hydraulic dysfunction following a reduction in soil-to-leaf hydraulic conductance. Moreover, it was clear that plant hydraulic capacity determined the pattern and extent of stomatal regulation. Differences in hydraulic capacity across a gradient in water availability were a reflection of differences in root-to-leaf hydraulic conductance, and were possibly related to differences in xylem structure. Saplings on rehabilitation sites had greater hydraulic conductance (by 50 %) and greater leaf-specific rates of transpiration at the high rainfall site (1.5 kg m-2 day1) than at the low rainfall site (0.8 kg m-2 day1) under near optimal conditions. Also, rehabilitation-grown saplings had significantly greater leaf area, leaf area to sapwood area ratios and hydraulic conductance (by 30-50 %) compared to forest-grown saplings, a strong indication that soils in rehabilitation sites contained more water than soils in the forest. Results suggested that: (1) the hydraulic structure and function of saplings growing under the same climatic conditions was determined by soil water availability; (2) drought reduced stomatal conductance and transpiration by reducing whole-tree hydraulic conductance; and (3) saplings growing on open rehabilitation sites utilised more abundant water, light and nutrients than saplings growing in the forest understorey. These findings support a paradigm that trees evolve hydraulic equipment and physiological characteristics suited to the most efficient use of water from a particular spatial and temporal niche in the soil environment.

[Truncated abstract] Establishment of vegetation and ecosystem functioning is central to the mitigation of environmental impacts associated with mining operations. This study investigated the ecophysiological functioning of mature plants in natural vegetation and applied this knowledge to diagnose problems affecting plant health and causes of poor plant cover at a mine-rehabilitation site. Ecophysiological parameters, including plant water relations and mineral nutrition, were studied in conjunction with soil physical, hydraulic and chemical properties. The natural ecosystem at the study location in the Great Sandy Desert is characterised by sand dunes and interdunes with distinct plant communities on each. One of the most notable features of the vegetation is the presence of large Corymbia chippendalei trees high on the dunes and relatively small scattered shrubs in the interdunes. Triodia grasses (spinifex), dominate the vegetation in both habitats but different species occur in each; T. schinzii is restricted entirely to the dunes, and T. basedowii occurs only in the interdunes. It was hypothesised that the deep sandy dunes afford greater water availability but lower nutrient supply to plants in this habitat compared with those occurring in the lower landscape position of the interdunes. Water-relations parameters (leaf water potentials, stomatal conductance, d13C) revealed that dune plants, particularly woody species, displayed higher water status and water use than closely related and often congeneric plants in the interdunes. Nutrient concentrations in soils were significantly higher in the interdunes, but concentrations in foliage were similar for related species between habitats. It is concluded that the dunes provide a greater store of accessible water than the soil profile in the interdunes. ... Following an experimental wetting pulse equivalent to a summer cyclone event, A. ancistrocarpa plants displayed significant increases in stomatal conductance, leaf water potential and sap velocity in lateral roots within three days of irrigation at the natural site and two days at the rehabilitation site. Secondary sinker roots originating from distal sections of lateral roots were evidently supplying water to maintain hydraulic function in laterals, thus enabling a fast pulse response. This was accentuated at the rehabilitation site where roots were confined closer to the surface. These results indicate that plants at the rehabilitation site are more dependent on small pulses of water and have less access to deep reserves than plants at the natural site. It is concluded that high runoff losses and insufficient soil depth are major factors contributing to plant water stress, and combined with the direct impacts of erosion, are largely responsible for plant death and ultimately poor plant cover. These issues can be alleviated if cover soil depth is increased to more than 0.5 m and slope angles are reduced to <12o. This study demonstrates the value of an ecophysiological approach for diagnosing problems affecting plant establishment at mine-rehabilitation sites. Furthermore, it has provided recommendations that will improve the rehabilitation strategy and lead to the development of a well vegetated, resilient ecosystem on a stable and non-polluting land form.

Recent regulation mandates that ships conduct mid ocean ballast water exchange (BWE) prior to discharging foreign ballast in territorial waters of Australia, the U.S. and elsewhere. The enforcement of ballast water exchange legislation is undermined, however, by a lack of sensitive and reliable methods for verifying compliance. One way to assess compliance is to compare the concentrations of chemical tracers in ballast tanks with their known distributions in the open ocean. In this work, dissolved organic matter and trace elements are investigated as potential tracers of mid-ocean ballast water exchange on commercial voyages in the North Pacific and Atlantic Oceans. The optical properties of chromophoric dissolved organic matter (CDOM) are frequently used as tracers of water masses in bays and estuaries. Characterization of the underlying fluorescence spectra in seawater dissolved organic matter was performed using parallel factor analysis, allowing the identification of at least nine independently varying fluorescent components present in varying concentrations in the ocean and in ballast water. Two of the humic components were terrestrial in origin and their signals could be traced in the open ocean (Pacific and Atlantic) at levels of approximately 1.5% of riverine concentrations. One humic terrestrial component was sufficient for predicting the coastal vs. oceanic source of most ballast water samples, suggesting that single and dual channel fluorometers could be optimized for verifying ballast water exchange. Barium, manganese and phosphorus were also investigated as potential tracers. Measurements of Ba and P obtained via engine-cooling pipes on commercial vessels were consistent with previous oceanographic measurements. While Ba behaved conservatively in ballast water, concentrations of phosphorus fluctuated and Mn was removed in ballast tanks over time. Ba and P demonstrated considerable promise as ballast water tracers, exhibiting predictable concentrations in exchanged ballast tanks, given a priori knowledge of the ocean (Atlantic versus Pacific) in which BWE was performed.

Ballast water discharged from ships is considered to be one of the four biggest threats to oceans, as alien species, detrimental to the marine ecosystems, are introduced into domestic waters via ballast. Nevertheless, eight years after its adoption, the International Convention for the Control and Management of Ship’s Ballast Water and Sediments of 2004 remains unenforced. In the interim, the IMO has encouraged member countries to implement national ballast water policies in order to reduce the risk of alien invasions into their waters. South Africa was chosen as one of six countries in the world to participate as a pilot country for the GloBallast programme which was conducted in Saldanha Bay between 2000 and 2004. The purpose of the GloBallast programme was to assist developing countries to understand, develop and implement control measures relating to ships ballast water within their ports. The outcome of the risk assessment completed during the programme was that South Africa needed to implement a mandatory ballast water reporting system. The purpose of this study is to examine the status of ballast water management in the ports of South Africa and to determine the progress made since South Africa participated in the GloBallast programme. The methodology used in this study included questionnaires distributed to industry experts and the full population of Ships Agents that are members of the South African Association of Ship Operations and Agents. The findings show that whilst each port is reported to have a ballast water management plan; only three of the eight potential plans could be produced. Two of these plans, belonging to the ecosensitive ports of Ngqura and Saldanha Bay, were proven to be well-known amongst the agents. The other ports, however, reflected a weak 50% and lower level of awareness. It was further determined that the ships agents are largely unaware of the responsibilities placed upon them by these plans. The findings further revealed that these regulations have not been monitored or enforced and presently ballast water management would appear to be merely a paper exercise. Those ships agents who are aware and comply with the requirements report that they have never had a problem with obtaining approval to discharge ballast. Recent developments in July 2012 show that the Department of Transport has assembled a team to further develop legislation and regulations to address ballast water management in South Africa.
Thesis (MBA)-University of KwaZulu-Natal, Durban, 2012.

Includes bibliographical references (leaves [268]-285)
xiv, 285, [85] leaves : ill. (some folded), maps (col., folded) ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Thesis (Ph.D.)--University of Adelaide, Dept. of Geographical and Environmental Studies, 2002

Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library.
"The Lower Murray dairy swamps were once part of a series of freshwater wetlands stretching along the Murray to the Cooring. Of the original 5700 hectares of wetlands only 500 hectares remain today. While the dairy industry that has developed on the swamp has considerable commercial value, it has destroyed the natural water filtration function that the wetlands provided. The industry also causes high levels of dairly effluent to enter the River Murray, contributing to blue-green algae outbreaks and associated economic losses for the local tourism industry. This thesis provides valuable cost-benefit results on a set of three mutually exclusive land use and management options for dealing with the joint problems of water filtration and blue-green algae. The most important options examined involve the return of this area to wetlands for water filtration rather continuing to use it for dairy farming." --p. ix.
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Thesis (Ph.D.) -- University of Adelaide, School of Economics, 2007

Surface water quality of the Liverpool Plains (NSW), a series of floodplains comprising the floodplain of the Mooki River, is poor despite the introduction of conservation tillage that has reduced soil erosion and, with it, the transport of sediment, nutrients and chemicals to streams.The aim of this thesis was to provide a basis for recommending the possible wider use of biofilters, by determining their effectiveness in reducing pollutant (mainly atrazine) transport at multiple scales in the Liverpool Plains, quantifying the importance of relevant processes, including the capacity of soil biofilters to degrade the retained pollutants, and evaluating the effect of pollutants on the biofilter vegetation. These objectives were explored in two sub-catchments within the Liverpool Plains, namely Big Jacks Creek and the Blackville.Soils are predominantly vertosols that crack deeply on drying, resulting in initially high infiltration rates on wetting and high water holding capacity. Field monitoring revealed that biofilters such as grassed waterways, natural grasslands or vegetated filter strips (VFS) positioned at multiple catchment scales can significantly reduce pollutant concentrations in runoff. The use of biofilters is discussed, along with other best management practices that will be needed to manage pesticide loads both at source and in the transport pathway.
Doctor of Philosophy (PhD)

Includes list of publications issued during the candidature.
Bibliography: leaves 176-197.
iii, ix, 197, [22] leaves : ill., maps ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Phosphorus retention was measured in five pilot-scaled constructed wetlands with different configurations in terms of macrophyte species and substrates in order to evaluate the phosphorus removal efficiency of water plants and substrates in experimental ponds; assess the contribution of macrophytes to phosphorus removal through direct uptake, modification of water chemistry and impacts on the phosphorus adsorption characteristics of substrate; and, contribute to the optimal design and operation of constructed wetlands for the treatment of agricultural drainage water.
Thesis (Ph.D.)--University of Adelaide, Dept. of Soil and Water, 2002?

The decline of floodplain vegetation along the Lower River Murray, South Australia, has evoked recommendations for ‘environmental flows’ to restore and maintain the health of the ecosystem. To assist managers to maximize benefits from environmental flows, this thesis considers the significance of water for germination and recruitment in key floodplain plant species. Three dominant species are considered, including two trees, river red gum (Eucalyptus camaldulensis) and black box (E. largiflorens), and an understorey shrub, tangled lignum (Muehlenbeckia florulenta). The soil seed bank was dominated by terrestrial annual native plants. Among 1400 seedlings, a single river red gum was found, and no black box or lignum, suggesting that these species do not contribute to the persistent soil seed bank and rely instead on aerial seed banks (serotiny). Sampling of the soil seed bank was continued to determine when seed fall might coincide with appropriate soil moisture conditions. Responses of the soil seed bank to varied water regimes were compared to determine requirements for seedling survival. The results indicated that species richness, rapidity of response and survival time were all promoted by sustained soil moisture. Stands of eucalypts in various states of health (from very stressed to very healthy) were monitored to identify seasonal patterns in bud crops, flowering, fresh leaves and volumes of seed released from the aerial seed bank. Distinct seasonal phenological patterns were apparent, and suggested alternating flowering among individual trees (biennial for red gum, bi-annual for black box), producing an annual peak in summer. Peak seed rain occurred in summer (December–March) in healthy trees for both red gum and black box, with light seed rain continuing throughout the year. Seed fall from stressed trees was much reduced. Stressed trees responded after a second watering event, with much more varied and extended annual seed fall patterns. Lignum showed a spring peak in flowering and seed production. There was a prolific response of flowering and seeding to rainfall, but few seedlings survived. Vigorous vegetative growth occurred in existing plants in response to rainfall and watering but no new cloned plants were found during the study. An investigation of chromosomes as a potential tool to appraise the balance between sexual and asexual reproduction in lignum proved inconclusive, although a previous report of octoploidy in lignum was confirmed. Seeds from all three species and lignum cuttings were tested for their responses to varied watering regimes, based on combinations of simulated rain and flood conditions. The optimal soil moisture for continued growth and survival in all seeds and cuttings was 10 25%, with moisture values <10% causing wilting and death. The results also suggested that red gum and black box seeds which germinate in water under flooded conditions need to be stranded onto moist soil at the water’s edge within 10 days, for the seedling to continue to grow. It was also concluded that germination on rain-moistened soil is a key supplementary mechanism for recruitment, particularly between irregular flood events. For greatest benefit, the timing of environmental flows should complement any seasonal rainfall and irregular flooding that may occur. Extension of suitable soil moisture conditions (10-25%) for as long as possible after >5 mm rainfall, or after over-bank flows, would increase chances for survival of seedlings. December is the most likely month for maximal benefit from watering in the Lower Murray Valley, for germination and recruitment, based on regional rainfall and flooding patterns.
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Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2008