ORCID Profile
0000-0003-0692-8347
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Physical Geography | Geology | Sedimentology | Environmental Chemistry (Incl. Atmospheric Chemistry)
Physical and chemical conditions | Estuarine and lagoon areas |
Publisher: Canadian Center of Science and Education
Date: 22-07-2013
DOI: 10.5539/IJB.V5N4P1
Publisher: Elsevier BV
Date: 05-2019
Publisher: CSIRO Publishing
Date: 2004
DOI: 10.1071/EN04011
Abstract: Environmental Context.Dating estuary sediments provides insights into the materials entering the estuary and can pinpoint when the contamination occurred. Heavy metal contamination is a known health risk but attributing it to a source can be contentious. For a s le sourced downstream of a city and a mining region, lead-210 dating and stable lead isotope analyses uncovered the sources of lead inputs. These methods quantified the extent that upstream mining activities and, for the first time, the extent that non-mining inputs (vehicles, industry) contributed to the estuary’s pollution. Abstract.210Pb dating and heavy metal analyses (Cd, Cu, Pb, Zn) have been combined to establish an historical profile of pollutant levels in sediments in the Tamar Estuary (Tasmania, Australia) over the past century. Heavy metal profiles through the core show a strong correlation with mining activities and industrialization during the past century, reflecting catchment disturbance in one of Australia’s earliest settled areas. A source apportionment of Pb in the sediment core using stable Pb isotope ratios (204Pb, 206Pb, 207Pb, 208Pb) shows that mine pollution has been contributing 10–25 mg kg–1 to Tamar Estuary sediments since the start of mining in the early 1890s, whilst non-mining inputs were not significant until post-1930 and became increasingly significant post-World War II. Since the 1950s–1960s, non-mining anthropogenic Pb inputs have become as significant as Pb from mining activities, although there does appear to be a decline in non-mining inputs during the past 20 years, which is consistent with findings elsewhere where reductions in atmospheric Pb levels have been observed and are attributed to the phasing-out of leaded gasoline. The source apportionment does, however, suggest that Pb from mine pollution at Storys and Aberfoyle Creeks continues to impact upon upper Tamar Estuary sediment quality.
Publisher: Elsevier BV
Date: 2020
Publisher: Springer Science and Business Media LLC
Date: 11-05-2022
DOI: 10.1007/S11273-022-09878-0
Abstract: Climate change threatens global mangroves, which are already among the world’s most impacted ecosystems. Vulnerability components of exposure, sensitivity and adaptive capacity were evaluated on mangroves of atoll settings on Jaluit Atoll, in the Marshall Islands, assessing spatial changes of mangrove cover 1945–2018/19, sea-level trends 1968–2019, and reviewing available information. Inland mangrove depressions occur on Jaluit, as well as coastal lagoon margin mangroves, and both were assessed using the same methods. Spatial analysis results showed both inland and coastal mangroves have increased in area. Inland mangroves on eight of Jaluit’s islands mostly expanded after 1976 from 40 to 50 hectares, with progradation and tidal creek infill closing lagoon connections. Shoreline mangroves showed 88–100% of transects prograding 0.1–0.51 m year −1 and 0–11.5% of transects eroding 0–0.18 m year −1 . Assessment of a combination of aerial/satellite images, literature and on-the-ground photos indicated that the mangroves are in healthy condition. Vulnerability assessment results showed both inland and coastal mangroves to have similar strengths and weaknesses in resilience, with intrinsic areas of vulnerability persisting during increased future sea level rise, limited sediment supply and extremely low elevations.
Publisher: Wiley
Date: 22-05-2023
DOI: 10.1111/BTP.13231
Abstract: Here, we investigate Mid‐ to Late‐Holocene vegetation changes in low‐lying coastal areas in Tonga and how changing sea levels and recurrent volcanic eruptions have influenced vegetation dynamics on four islands of the Tongan archipelago (South Pacific). To investigate past vegetation and environmental change at Ngofe Marsh (‘Uta Vava’u), we examined palynomorphs (pollen and spores), charcoal (fire), and sediment characteristics (volcanic activity) from a 6.7‐m‐long sediment core. Radiocarbon dating indicated the sediments were deposited over the last 7700 years. We integrated the Ngofe Marsh data with similar previously published data from Avai’o’vuna Sw on Pangaimotu Island, Lotofoa Sw on Foa Island, and Finemui Sw on Ha’afeva Island. Plant taxa were categorized as littoral, mangrove, rainforest, successional/ disturbance, and wetland groups, and linear models were used to examine relationships between vegetation, relative sea level change, and volcanic eruptions (tephra). We found that relative sea level change has impacted vegetation on three of the four islands investigated. Volcanic eruptions were not identified as a driver of vegetation change. Rainforest decline does not appear to be driven by sea level changes or volcanic eruptions. From all sites analyzed, vegetation at Finemui Sw was most sensitive to changes in relative sea level. While vegetation on low‐lying Pacific islands is sensitive to changing sea levels, island characteristics, such as area and elevation, are also likely to be important factors that mediate specific island responses to drivers of change.
Publisher: SAGE Publications
Date: 11-11-2021
Abstract: Geo ersity assessment is recent and is passing through a stage of methodological development and consolidation. With rapid environmental change, improving the developmental states of geo ersity assessment is of paramount importance. A scientometric analysis is presented to identify knowledge gaps, current trends and avenues for future research in quantitative geo ersity assessment literature. The study is categorised into three areas of analysis: (a) methodological intentions of geo ersity assessment, (b) current trends in geo ersity assessment methods and (c) current geographic trends. A ranking tool was developed to determine whether the current methodological intentions of geo ersity assessments trend towards combined geo ersity and bio ersity assessments or towards the independent assessment of geo ersity. Results showed that about 50% of publications independently assessed geo ersity with no consideration for bio ersity, 32% discussed or reviewed geo ersity by mentioning potential links to bio ersity and 12% more strongly linked geo ersity assessment to bio ersity assessment. Tools used by scholars to determine geo ersity values varied from statistical through to the more frequently adopted geographic information systems (GIS) and spatial analytical software approaches. Study sites selected for geo ersity assessments were predominantly terrestrial at the state-wide scale. Marine assessments, or seabed geo ersity, were mostly absent from the literature, with only two publications found. Brazil in South America had many geo ersity assessments and European scholars have played crucial roles in the development of quantitative geo ersity assessment in recent years. Subsequent research will benefit from developing a unified geo ersity assessment approach, reaching a consensus on an accepted definition and standardising the geo ersity concept, broadening research site environment types and developing strategies to promote further international and intranational collaboration.
Publisher: Wiley
Date: 10-02-2023
DOI: 10.1002/RRA.4115
Abstract: Bedrock influence on river channel form is difficult to assess, with many catchments dominated by glacial erosion and with blanketing sediments from both pluvial and fluvial sources. The Scamander catchment in Tasmania lacks glacial history and features two bedrock‐confined sub‐catchments of similar area and maximum flow length, but one dominated by Mathinna Group sedimentary rocks, and the other with large areas in granite lithology. Lithology types, stream network parameters and near stream slope angles were analysed using geographical information systems, and results of stream cross sections, channel form and planforms were compared for each lithology. Results showed that granite features low gradient, shallow streams with channel slope cross sections of °. Granite channels are irregular and dominated by large boulders that create channel roughness and resist incision. Weathering products of coarse quartz sand provide anchorages for in‐channel vegetation. By contrast, sedimentary Mathinna Group rocks feature steeply incised trough‐like channels, with near‐channel hillslope gradients mostly between 30° and 50°. Rectangular blocks disintegrate to gravel cobbles on the channel bed, providing poor anchorage for vegetation. Mathinna lithology influences steep, low roughness channels, and stable, incised recurved meanders formed by river interaction with vertical layers of resistant rock. The resistant bedrock lithology is demonstrated in this study to influence varied river planforms, near‐channel slope gradients, channel sediments and cross sections.
Publisher: SAGE Publications
Date: 03-09-2023
DOI: 10.1177/03091333221122292
Abstract: Bio ersity assessment is constitutive in establishing conservation priorities and outcomes, and geo ersity complements species richness as a surrogate in the absence of species data, improves statistical modelling and can facilitate prediction of species distribution and abundance. Yet, geo ersity is frequently excluded, and bio ersity prioritised in conservation endeavours such as ecosystem-based management. Therefore, combined geo ersity and bio ersity assessment approaches present practical benefits to conservation such as improved collaboration between biologists and geoscientists, efficacious indicators of conservation value, and abatement of bio ersity partialities and wider inclusion of geo ersity in conservation literature. This study scientometrically analysed 240 bio ersity assessment publications to investigate geo ersity inclusiveness, methodological trends, geographic trends, environment-type trends and future directions in bio ersity assessment methods. Results showed these species richness articles frequently included geo ersity-relevant terms such as hydrological, soil, geological and geomorphological components, but the all-encompassing ‘geo ersity’ term was absent entirely. Geographic trends showed many potential economic, social, cultural and political factors influencing geo ersity inclusiveness in bio ersity assessment. For ex le, Australia’s relatively resource exploitative approach to geology and early involvement in the inception of the geo ersity concept could explain the high frequency of geological-related terms in Australian bio ersity assessments. Methodological trends showed dominance by field-based bio ersity assessments such as trapping methods, followed transects, quadrats, net methods and observations. Given the specific s le size of literature analysed, inferences from this study relate only to bio ersity assessment methods and not bio ersity discourse in its entirety. Subsequent research could investigate specific factors, such as social, economic or political, and their influence on geo ersity inclusiveness in bio ersity assessment methods.
Publisher: Smithsonian Institution
Date: 20-03-2019
Abstract: Sandy beaches are critical resources for low-lying Pacific atoll communities, providing protection during storms, and land area for many coastal villages. Information on the nature of atoll beach sediment, its geochemistry and composition, can help to establish priorities to effectively protect the sources of Pacific island beach sediment. To understand sand sources, this study evaluated its physical characteristics including grain-size, geochemistry and composition, from windward and leeward beach profiles around Abaiang Atoll, Kiribati. Beach sand was % carbonate, averaging 37% coral fragments, 30% mollusc shells, 12% foraminifera, and 20% calcareous algae. Significant differences were found between reef and lagoonal sites in proportions of coral and mollusc fragments and foraminifera tests, with lagoon beaches having higher mollusc and coral proportions and lower foraminifera relative to reef beaches. This is attributed to high foraminiferal productivity offshore of reef beaches, and taphonomic durability of coral fragments in longshore drift into the lagoon. Mean sediment diameter increased from the upper to lower beaches at all sites, but fine sediment was lacking, attributed to its dissolution by rainfall and groundwater outflow. Geochemical analysis showed a mean of 84% Ca-Mg carbonates, of which 80% was calcium carbonate. There was no significant difference in the mean calcium percentage or calcium carbonate composition of the sediment between lagoon and reef beach sediment sources. Magnesium and magnesium carbonate content were significantly higher at reef sites relative to lagoon sites, attributed to higher proportions of foraminifera. Sediment-producing near shore habitats are critical to village protection through provision of beach sand, and this study shows the need to better conserve and manage coral reefs and habitats such as lagoon seagrass beds, to ensure continued atoll beach sand supply.
Publisher: Public Library of Science (PLoS)
Date: 08-04-2010
Publisher: Springer Science and Business Media LLC
Date: 14-12-2007
DOI: 10.1007/S10661-006-9212-Y
Abstract: We predict the decadal change in position of three American Samoa mangroves from analysis of a time series of remotely sensed imagery, a geographic information system, tide gauge data, and projections for change in sea-level relative to the mangrove surface. Accurate predictions of changes to coastal ecosystem boundaries, including in response to projected relative sea-level rise, enable advanced planning to minimize and offset anticipated losses and minimize social disruption and cost of reducing threats to coastal development and human safety. The observed mean landward migration of three mangroves' seaward margins over four decades was 25, 64, and 72 mma(-1), 12 to 37 times the observed relative sea-level rise rate. Two of the sites had clear trends in reductions in mangrove area, where there was a highly significant correlation between the change in position of the seaward mangrove margin and change in relative sea-level. Here it can be inferred that the force of sea-level rise relative to the mangrove surface is causing landward migration. Shoreline movement was variable at a third site and not significantly correlated with changing sea-level, where it is likely that forces other than change in relative sea-level are predominant. Currently, 16.5%, 23.4%, and 68.0% of the three mangroves' landward margins are obstructed by coastal development from natural landward migration. The three mangroves could experience as high as a 50.0% reduction in area by the year 2100. A 12% reduction in mangrove area by the year 2100 is possible in the Pacific islands region.
Publisher: Elsevier BV
Date: 03-2016
Publisher: Proceedings of the National Academy of Sciences
Date: 19-12-2022
Abstract: Beginning ~3,500 to 3,300 y B.P., humans voyaged into Remote Oceania. Radiocarbon-dated archaeological evidence coupled with cultural, linguistic, and genetic traits indicates two primary migration routes: a Southern Hemisphere and a Northern Hemisphere route. These routes are separated by low-lying, equatorial atolls that were settled during secondary migrations ~1,000 y later after their exposure by relative sea-level fall from a mid-Holocene highstand. High volcanic islands in the Federated States of Micronesia (Pohnpei and Kosrae) also lie between the migration routes and settlement is thought to have occurred during the secondary migrations despite having been above sea level during the initial settlement of Remote Oceania. We reconstruct relative sea level on Pohnpei and Kosrae using radiocarbon-dated mangrove sediment and show that, rather than falling, there was a ~4.3-m rise over the past ~5,700 y. This rise, likely driven by subsidence, implies that evidence for early settlement could lie undiscovered below present sea level. The potential for earlier settlement invites reinterpretation of migration pathways into Remote Oceania and monument building. The UNESCO World Heritage sites of Nan Madol (Pohnpei) and Leluh (Kosrae) were constructed when relative sea level was ~0.94 m (~770 to 750 y B.P.) and ~0.77 m (~640 to 560 y B.P.) lower than present, respectively. Therefore, it is unlikely that they were originally constructed as islets separated by canals filled with ocean water, which is their prevailing interpretation. Due to subsidence, we propose that these islands and monuments are more vulnerable to future relative sea-level rise than previously identified.
Publisher: IUCN, International Union for Conservation of Nature
Date: 02-09-2016
Publisher: Resilience Alliance, Inc.
Date: 2016
Publisher: Elsevier BV
Date: 08-2008
Publisher: CSIRO Publishing
Date: 2020
DOI: 10.1071/PC19016
Abstract: Temperate Australian saltmarshes, including those in the southern island state of Tasmania, are considered to be a threatened ecological community under Australian federal legislation. There is a need to improve our understanding of the ecological components, functional relationships and threatening processes of Tasmanian coastal saltmarshes and distil research priorities that could assist recovery actions. A semisystematic review of the literature on Tasmanian coastal saltmarshes supported by expert local knowledge identified 75 studies from 1947 to 2019. Existing understanding pertains to saltmarsh plants, soils, invertebrates and human impacts with ongoing studies currently adding to this knowledge base. Several knowledge gaps remain, and the present review recommends six key priority areas for research: (1) citizen science–organised inventory of (initially) saltmarsh birds, plants and human impacts with the potential for expansion of datasets (2) use of saltmarsh by marine transient species including fish and decapods (3) use of saltmarsh by, and interactions with, native and introduced mammals (4) invertebrates and their interactions with predators (e.g. birds, fish) and prey (e.g. insects, plants, detritus) (5) historic saltmarsh loss and priority areas for conservation (6) monitoring changes to saltmarsh due to both localised human impacts (e.g. grazing, eutrophication, destruction) and global change factors (e.g. climate change, sea-level rise). Addressing these research priorities will help in developing a better understanding of the ecological character of Tasmanian coastal saltmarshes and improve their conservation management.
Publisher: MDPI AG
Date: 02-05-2018
Publisher: JSTOR
Date: 1998
DOI: 10.2307/2997695
No related organisations have been discovered for Joanna Ellison.
Start Date: 02-2002
End Date: 08-2005
Amount: $67,635.00
Funder: Australian Research Council
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