|CWR Presents : Hydrological and biogeochemical pathways in hillslopes of coastal plain catchments: How does seasonality affect phosphorus fate and transport processes?
Nutrient loss from terrestrial ecosystems causes nutrient enrichment in receiving waterways (eutrophication) threatening their water quality and biodiversity values. The Peel-Harvey estuary (WA), RAMSAR-listed wetlands and their contributing waterways in coastal plain catchments in the Peel-Harvey area are an example of the above issues. Fertilizer application on sandy soils has been targeted for Best Management Practices (BMPs) for phosphorus (P) due to their poor nutrient retention ability. Traditionally, conceptual and numerical models for catchment hydrology and P transport processes have been used to assess and implement BMPs that achieve “targeted P loading” at the catchment’s outlet. Validity of the model results is often questioned as model internal structures and process representations cannot be contrasted due to lack of comprehensive datasets.
New field sampling strategies, based on eco-hydrological concepts, have recently become a stepping stone in unlocking key first-order control processes in nutrient cycling (nutrient availability, pathways and transport mechanisms) in catchments by simultaneously monitoring water movement and nutrient cycle processes along a topo-sequence (from uplands to riparian and stream zones). In this talk, I will present results of the implementation of such approaches to investigate the effect that the seasonality on rainfall inputs, plants, and soil types exert on hydrological and biogeochemical pathways for P within hillslopes of coastal plain landscapes (Mayfield drain catchment, Harvey River, WA). Detailed documentation of water movement in surface and shallow subsurface pathways, passive tracers, biogeochemical parameters and P concentrations (total, total dissolved, and soluble reactive P) was undertaken from April 2011-October 2012 at several hillslopes representative of different land uses and soil types in the area.
The preliminary results highlighted: 1) significant differences in the way and timing at which the hydrological connectivity of upland-riparian zones via shallow subsurface flow takes place in different landscapes, 2) seasonal changes on the interaction of shallow subsurface flow in riparian zones with surface water in the drains, and 3) changes on biogeochemical functioning of upland and riparian zones in relation to P cycle and P forms (organic or inorganic). The implications of the findings for our current understanding and previously proposed conceptual models for hydrological and P pathways in coastal plain catchments in the Peel-Harvey area will be discussed.
This work was conducted within a trans-disciplinary project (plant-soil-water sciences) during 2011-2012 founded by Greening Australia-ALCOA Foundation US to investigate the use of novel plants to mitigate P losses towards sustainable landscapes in the Peel-Harvey catchment, and it will continue (2012-2015) under an ARC Linkage Project “Farming in a biodiversity hotspot – harnessing native plants to reduce deleterious off-site phosphorus flows” (J. Lambers and M Ryan, School of Plant Biology, UWA).
Dr Carlos Jorge Ocampo is a Research Assistant Professor at the Centre for Ecohydrology (UWA). Carlos holds an Engineering Degree in Water Resources (Hydrology/Hydraulic) from the Universidad Nacional del Litoral (UNL, Argentina) and a PhD in Environmental Engineering from UWA on the topic of hydrological and biogeochemical controls on catchment nitrate response.
On completion of his PhD, Carlos returned to Argentina where he was an Assistant Professor at UNL and a Research Scientist at the National Research Council (CONICET). He returned to UWA in 2010. Carlos is a field-oriented hydrologist (hillslope-catchment hydrology) but he has a strong background in numerical modelling in urban hydrology, catchment hydrology, and historical flood reconstruction in large river systems.
His research interests lie in linking hydrology and biogeochemistry (nutrient cycles) at catchment scale, by using a combined approach of hydrometric, passive and isotopic tracers, and numerical modelling. He has conducted field work in a number of sites in Australia and Argentina on nitrogen and phosphorus cycling, hydrological connectivity of shallow-transient groundwater systems, and surface/groundwater interactions.
PS* This seminar is free and open to the public & no RSVP required.
Carlos Ocampo,Research Assistant Professor-Ecohydrology Centre of Excellence & Environmental Systems Engineering School of
Blakers Lecture Room, Ground Floor, Mathematics Building, The University of Western Australia
: 6488 7565
Wed, 07 Nov 2012 16:00
Wed, 07 Nov 2012 17:00
Askale Abebe <[email protected]>
Fri, 05 Apr 2013 09:34
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