Dr Mark Taylor - Research
Ongoing and completed projects plus collaborator contacts
General Research Direction
Fluvial geomorphology
Fluvial geomorphology
A single theme runs through my research interests: fluvial geomorphology and I have published several articles on the relationship between river ecology and habitat availability. In addition, I have also applied my research to practical issues that bridge both my teaching and research and have completed several consultancies for legal firms and environmental companies who have sought to address fluvial-related human impact issues arising from the development or alteration of river catchments. Recent initiatives in the application of fluvial geomorphology to practical issues have been through the development of a Rapid Riparian Assessment (RRA) Tool for Urban Rivers. This is a project that has been conducted with Ku-ring-gai Council through consultancy funding and support of vacation scholarships. The justification for this project is given below:
Land development has caused many urban streams to be in a sub-optimal condition and subject to ongoing environmental degradation. DIPNR has recently developed and implemented a system to classify riparian corridors into three basic categories according to their potential for habitat and biodiversity refugia. Within these general corridor classifications river condition is extremely variable, ranging from pristine to highly degraded. Before any environmental priority programs can be effectively implemented, the condition of the riparian zone and its associated catchment must be determined. We have trialled a range of assessment programs generated by other organisations (Blacktown City Council, Newcastle City Council, River Styles). These were determined to be inadequate for the urban environment because: they failed to discriminate between the diversity of condition and resulted in most reaches being recorded as degraded; they considered only a limited range of variables (such as water quality or bushland) or were too costly and time consuming to implement across all catchments within a council area. Thus, because local councils are required to maintain and protect catchments under local government legislation and as part of the State of the Environment reporting procedure, the acquisition of baseline riparian condition data over space and time is essential if cost effective and accountable integrated catchment management is to occur.
Human impact - environmental pollution
Since 1993, I have worked on various aspects of river related environmental pollution. My interest in the relationship between river sediments and metalliferous contaminant was initially stimulated through the study of Welsh river systems that were variously affected by historic (18th and 19th century) metal mining (principally copper, lead, zinc). However, since my PhD I have expanded my work to examine metalliferous pollution of fluvial systems in the Ouse basin (north of England), Namibia, Broken Hill, Mt. Isa (Leichhardt River) and the Northern Territory (Finniss River) with collaborators from ANSTO. Funding for this work has been provided by a variety of sources: AINSE, BGRG, SoG, University of Oxford, MURG, MUECRGS and NERC (Post-doctoral) funding.
Recent work involves a study of the "The fate, transport, distribution and environmental hazard of heavy metals in arid alluvial systems - legacies of heavy metal mining". The details for this research are presented below:
Heavy metal contamination of stream systems may pose a serious threat to the environment. There is a paucity of knowledge relating to the behaviour and hazard risk of metals in arid river systems. This project will examine and explain the spatial and temporal distribution and bio-availability of heavy metals in streams adjacent to the Mt. Isa mine, Oueensland, the Rum Jungle Mine, NT and downstream of the now closed Khan mine, Namibia. A conceptual model and empirical relationships describing the transport and storage of fluvially transported heavy metals in arid systems will be constructed. The data will be of relevance to similarly polluted arid rivers.
Mining operations and their by-products are known to have seriously contaminated many river systems through the world. In such catchments, as much as 90% of the total load is fluvially transported and thus adjacent urban and agricultural lands and associated water bodies may be negatively impacted by the uptake of metals into the food chain via irrigated crops or animal carcases used for human consumption. Such contaminated sediments can act as significant long-term secondary sources of pollution if they are remobilised via physical entrainment (e.g. floodplain erosion) or chemical processes (pH or Eh changes). Geomorphological-geochemical studies of mining-contaminated river systems these have focussed largely on temperate rather than arid systems. The different physical and chemical controls in arid versus temperate systems may result in different environmental risks due in part to their often extreme climatic regimes. Both Mt Isa and the Gruben River have well documented mining histories and provide an ideal opportunity to assess the relationship between sediment-transport pathways and channel hydraulics and channel and floodplain geomorphology and geochemical and mineralogical metal speciation (Taylor and Kesterton, 2002). At Mt. Isa, there has been no publicly available research conducted on the impact of contamination is despite knowledge of contamination to EPA, Department of Natural Resources and Mines, Qld and the local council. At Rum Jungle mine, NT, despite several studies addressing the biological impact of acid mine drainage and metal contaminants on the East Branch of the Finniss River, there has been a paucity of studies examining how metals are moving through the system e.g. via sediment waves, tied to flood pulses or consideration of the effects of channel hydraulics. These sites along with the known contamination problem at Khan Mine provide an excellent opportunity to examine urban pollution risk coupled to stream hydraulics in an arid or seasonally arid environments.
Quaternary geomorphology and sedimentology
My studies relating to the evolution of geomorphic systems have encompassed a large temporal spectrum covering the recent (last few tens to hundreds of years) to studies of Quaternary tufa (freshwater calcium carbonate) systems (~500,000 years) that are present along the Barkly rivers in northwest Queensland, with specific attention to the rivers around Riversleigh. A common thread of this work has been my interest in the sedimentology of ancient fluvial systems. I have been able to combine my sediment-contaminant and Quaternary studies through the use of chemostratigraphy to identify the age and specific depositional environments of depositional units. Recent research work at Riversleigh has involved collaborating with Dr. Russell Drysdale, University of Newcastle, NSW to supervise Karen Carthew (Macquarie University) who has just completed her PhD study of the modern and ancient facies (sediment) associations of the tufa. Carthew's PhD represents the first systematic attempt to produce a facies model for tropical tufa.
Climate changes and geomorphological signals in Namibia
This new project (2004) is being conducted with the School of the Environment and Geography, Oxford University with Drs Heather Viles and Kathleen Nicholl. The background and justification for this project is provided below:
Namibia is an arid country with large areas of hyper-arid desert however throughout the Quaternary the relative wetness of the Namibia climate has fluctuated. The nature and extent of those fluctuations is subject to debate, particularly over the last 125 ka BP. Some researchers suggest that increased wetness was confined to the inland escarpment areas where other state that the increased precipitation also affected desert areas towards the coast more directly, as opposed to indirectly via the delivery of flood waters from rivers that drain the uplands. This project is investigating geomorphological evidence for changes in wetness in the desert zone and will focus on a series of extensive tufa deposits which now fringe the ephemeral Tsondab River system that passes through the Naukluft Mountains in central southern Namibia. This research will build upon a field and sampling program conducted in July 2004 to investigate the age and environmental context of tufa deposition which should indicate more precisely if the timing of the wetter conditions, their environmental context and their relationship to known changes in Botswana and Southern Africa. This research is significant because it examines climate change over the recent geological past and will provide some data into the fragility of the Namibian desert with respect to climate change. Namibia experiences precipitation from only the edges of the southern African rain-bearing systems and since the Miocene it is thought that this aridity has been enhanced by the presence of the cold Benguela current. Many biophysical ecosystems as well as human ecosystems are dependent on the precipitation that results from the advective fog that forms when warm tropical air masses pass over the cool upwelling waters of the Benguela current. Variations in rainfall patterns (in particular droughts which are common) are closely related to anomalies in sea surface temperature which in turn are believed to be linked in part, to the El NiÑo/Southern Oscillation (ENSO) phenomenon.
Changes in global temperature as a consequence of global warming in the 21st century are also predicted to cause changes in spatial and temporal patterns of precipitation. As a result, ENSO conditions are likely to intensify and naturally dry areas in southern Africa are expected to become drier during El Niņo events.
Key to Granting Agency Acronyms AINSE - Australian Institute of Nuclear Science and Engineering; ARC - Australian Research Council; BGRG - British Geomorphological Research Group; MURG - Macquarie University Research grant; MUECRGS - Macquarie University Early Career Research Grants Scheme; NERC - Natural Environmental Research Council (UK)