A5017529390- Geology and Paleoclimatology Research
- Geological formations and processes
- Isotope Analysis in Ecology
- Pleistocene-Era Hominins and Archaeology
- Peatlands and Wetlands Ecology
- Coastal wetland ecosystem dynamics
- Archaeology and ancient environmental studies
- Aeolian processes and effects
- Geomagnetism and Paleomagnetism Studies
- Groundwater and Isotope Geochemistry
- Aquatic Ecosystems and Biodiversity
- Geochemistry and Elemental Analysis
- Amazonian Archaeology and Ethnohistory
- Plant Water Relations and Carbon Dynamics
- Paleontology and Stratigraphy of Fossils
- Geochemistry and Geologic Mapping
- Ecology and Vegetation Dynamics Studies
- Climate variability and models
- Hydrocarbon exploration and reservoir analysis
- Marine and environmental studies
- Silicon Effects in Agriculture
- Aquatic Ecosystems and Phytoplankton Dynamics
- Evolution and Paleontology Studies
- Geological and Geophysical Studies
- Tree-ring climate responses
Swansea University
2011-2021
University of Wales
1997-2008
Lancaster University
1997
University of Bristol
1997
University of Oxford
1983-1995
Oxford Spires Academy
1985-1994
Oxford Research Group
1984-1992
Mansfield University
1990
Production of biochar (the carbon (C)-rich solid formed by pyrolysis biomass) and its storage in soils have been suggested as a means abating climate change sequestering carbon, while simultaneously providing energy increasing crop yields. Substantial uncertainties exist, however, regarding the impact, capacity sustainability at global level. In this paper we estimate maximum sustainable technical potential to mitigate change. Annual net emissions dioxide (CO2), methane nitrous oxide could...
Although C 4 plant expansions have been recognized in the late Miocene, identification of underlying causes is complicated by uncertainties associated with estimates ancient precipitation, temperature, and partial pressure atmospheric carbon dioxide ( P co 2 ). Here we report isotopic compositions leaf wax n -alkanes lake sediment cores from two sites Mesoamerica that experienced contrasting moisture variations since last glacial maximum. Opposite trends obtained these indicate regional...
Significance Amazonian rainforests once thought to be pristine wildernesses are increasingly known have been inhabited by large populations before European contact. How and what extent these societies impacted their landscape through deforestation forest management is still controversial, particularly in the vast interfluvial uplands that little studied. In Brazil, groundbreaking discovery of hundreds geometric earthworks modern would seem imply this region was also deforested a past,...
Carbon-isotope values of bulk organic matter from high-altitude lakes on Mount Kenya and Elgon, East Africa, were 10 to 14 per mil higher during glacial times than they are today. Compound-specific isotope analyses leaf waxes algal biomarkers show that organisms possessing CO 2 -concentrating mechanisms, including C 4 grasses freshwater algae, primarily responsible for this large increase. Carbon limitation due lower ambient partial pressures had a significant impact the distribution forest...
Abstract On geological time‐scales (≥10 6 years), the global geochemical cycles of carbon and silicon are coupled by drawdown atmospheric CO 2 through chemical weathering Ca‐ Mg‐silicate minerals in continental rocks. Rivers transport soluble products (cations, alkalinity silicic acid) to oceans, where they utilized marine ecosystems. decadal glacial–interglacial time‐scales, however, large biotic fluxes storages Si within terrestrial freshwater ecosystems need be taken into account. Recent...
Oxygen isotopes are sensitive tracers of climate change in tropical regions. Abrupt shifts up to 18 per mil the oxygen isotope ratio diatom silica have been found a 14,000-year record from two alpine lakes on Mt. Kenya. Interpretation tropical-montane records is controversial, especially concerning relative roles precipitation and temperature. Here, we argue that Holocene variations δ O better explained by lake moisture balance than temperature-induced fractionation. Episodes heavy...
A new temperature record from East Africa demonstrates that the tropical lapse rate steepened during last ice age.
ABSTRACT Lake-level and palaeoecological evidence from Africa, Arabia southern Asia for 9000 yBP suggests an intensification increased poleward penetration of the northern monsoons. The vegetation belts shifted north by 4–6° latitude on south side Sahara. In contrast, monsoon over Africa was weaker than today. Calculations based new palaeogeographical map Mali Petit-Maire et al. (1988) indicated that areaaveraged surface albedo decreased 0·10–0·14 in zone 16–24°N total annual precipitation...