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Troy Baisden
Qualifications 1993: BA (High Honors), Earth Sciences; 2000: PhD (UC Berkeley), Soil Science Areas of expertise Geochemist: Global Environmental Change
Current Projects in the Terrestial Isotope Biogeochemistry Lab I lead work on terrestrial isotope biogeochemistry at the National Isotope Centre. Currently, there are three main projects (below).Terrestrial Carbon Dynamics (an objective in the Global Change Through Time Programme). Over 8 years, this objective?will develop contemporary data to improve understanding of soil processes used to underpin carbon accounting systems and quantify climate change impacts on productive and natural ecosystems.? Globally, soil contains more carbon than the atmosphere and vegetation combined, and remains a major uncertainty in carbon inventories and climate change feedbacks. Present work has a range of threads, but most focuses on the use of natural abundance radiocarbon as a tracer of carbon cycling on timescales of 5 or more years. A developing focus is the identification of molecular biomarkers appropriate for studying the preservation of carbon in NZ soils and sediments. The objective will also integrate knowledge to identify optimal opportunities for climate change mitigation and adaptation, and minimize risks to the NZ economy. Was Collapse Inevitatible on Easter Island (Rapa Nui)? Reconstructing a Civilisation's Failure is a Marsden Programme. In his book "Collapse", Jared Diamond highlights the spectacular and mysterious collapse of civilisation on Easter Island. Diamond outlines a number of factors leading to success or failure of civilisations. We have identified that one of these factors - fragile soils - allows us to hypothesise that Easter Islanders would have overshot the carrying capacity of their landscape, reaching maximum population as soil nutrient depletion caused declining crop yields. We propose isotope, biomarker and DNA approaches to reconstruct the biogeochemistry of collapse and thereby test whether the timing of nutrient depletion can answer the question: "Why did they cut down the last tree?" Within dormant volcanic craters where settlement occurred, we will obtain carefully located cores to precisely resolve the timing of changes in plant, animal and human populations, as well as soil fertility. We will examine plant microfossils (e.g. pollen, starch grains), nitrogen isotopes, the DNA of native and introduced species, and steroid biomarkers derived from humans and?animal faeces. Plant microfossils from surrounding soils will define the extent of cropping. Collectively, the analyses will enable bio-geochemical modeling to help predict the future of societies around the world where we are stressing carrying capacity of landscapes. (See press release, and listen to audio from Radio NZ). The Isotopic Indicators of Land-to-Water Nitrogen Transfers (FRST Programme) focuses on the development of indicators to define the contribution of pastoral agriculture to declining water quality, and involves Lincoln University, Waikato University, AgResearch, and Environment Canada. The programme is aligned to focus on the science of developing isotopic indicators, with long-term delivery occurring through large ongoing programmes focused on land use and water quality within AgResearch, Landcare Research and the Sustainable Land Use Research Initiative (SLURI). Our proposed indicators are intended to: ??????
Classify the vulnerability of farm units to ongoing losses of N
These indicators recognise that multiple isotopes of N and oxygen (O)
exist naturally, and the relative abundance of these isotopes records
the sources of N and O, as well as the effects of biochemical processes
occurring in soil and water.? Based on a decade of accumulated
knowledge from the use of these isotopes overseas, we have designed a
distinctive and globally significant project that will precisely define
N and O isotope systematics for pasture systems in the absence of the
pollution that obscures relationships in the Northern Hemisphere.
?????? Identify the proportion of river nitrate loads from differing farm types ?????? Quantify the proportion of nitrate lost during transport Selected publications McGroddy, M.E.; Baisden,
W.T.; Hedin, L.O. 2008 Stoichiometry of hydrological C, N and
P losses across climate and geology : an environmental matrix approach
across New Zealand primary forests. Global Biogeochemical
Cycles, 22: GB1026, doi:10.1029/2007GB003005 [link
to electronic copy] Internship, Student and Sabbatical Opportunities I am pleased to be able to support a
range of research opportunities related to global change, climate, land
use with relevance to New Zealand's terrestrial ecosystems. I am able
to offer opportunities to benefit from access to labortories,
appropriate office space, and access to collaborations. Salary is not
(presently) available but can be sought for New Zealanders from a
variety of sources (e.g. FRST post-doc). Suggested topics include but
are not limited to: Links Rafter
Radiocarbon Lab Contact me Please use this link to contact me. ? ?
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