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Research OverviewDr. Kohfeld is interested in understanding natural variability and biogeochemical linkages within the ocean and climate system, in order to better assess earth system responses to anthropogenic perturbations. Her research focuses on: Natural and Anthropogenic Changes in the Ocean Carbon Cycle.The goal of this research is to use knowledge of past, natural variations in ocean carbon cycle to better understand how biogeochemical processes operate under widely different physical environmental conditions. This research will help to understand the relationships between the global carbon cycle and climate in the future, provide a vigorous test for our models of the earth system, and provide insights into potential methods of mitigating the effects of global climate change. Current projects include: - Role of dust, climate, and marine biota in glacial-interglacial CO2 cycles - Changes in glacial westerly winds over the Southern Ocean - Ocean CO2injection as a means of mitigating the build-up of atmospheric CO2 - Impact of Coastal Ocean Acidification on Ecosystems Influence of Climate and Land Surface Conditions on Atmospheric Dust in the Past, Present, and Future. Dust production and dust storms affect the global climate
system and can also have tremendous economic and social impacts on
regional scales: dust obscures visibility, impacts agriculture, and
affects respiratory health. The primary objectives of this research are
to (a) quantify changes soil dust on a range of temporal (decadal to
millennial) and spatial (regional to global) scales, (b) determine which
climatic and land-surface conditions influence dust emissions, and (c)
use this information to help predict future changes in dust emissions,
both regionally and globally. Current projects include: Assessing and Adapting to Extreme Weather Conditions in British Columbia. The goal of this research is to understand recent trends and variations in extreme weather events - such as intense winds, precipitation events, and high temperatures - in order to better inform and prepare communities for the future infrastructure, land-use planning, and public safety decisions that may be needed in light of changes resulting from climate change influences on BCs regional weather patterns. Specific projects related to this research area include:
- Secondary effects of climate change on human and ecosystem health: A risk-based approach Research ProjectsRole of dust, climate, and marine biota in glacial-interglacial CO2 cycles
Locations of deep sea sediment cores used to reconstruct past changes in ocean conditions, superimposed on a map of annual surface water silicate (umol/L) (silicate data from World Ocean Atlas, 2005). Understanding the mechanisms controlling biological carbon sequestration in the ocean has been a long-term goal of marine biogeochemical studies, because of its implications for predicting the future changes in atmospheric carbon dioxide concentrations in response to anthropogenic emissions. The goal of this research program is obtain a better understanding of the processes controlling carbon sequestration in the ocean throughout the last full glacial-interglacial cycle by investigating the linkages between dust input, physical oceanography, marine biology. The specific research objectives are: (a) to measure changes in surface water stratification (due to ice melt), dust inputs, and carbon export to the seafloor as archived in marine sediments over the last 140,000 years, specifically in the North Pacific Ocean (b) to develop a global database of paleoceanographic proxies that record biogenic fluxes and ocean characteristics over the past 140,000 years, in order to examine the phasing of physical, chemical, and biological changes as the earth enters a glaciation; and (c) to use a biogeochemistry model in concert with these newly-developed environmental databases to assess the dominant controlling processes (iron flux or stratification) on marine productivity, and how they are expected to affect carbon sequestration and atmospheric CO2 in the past, present, and future.Collaborators: Z. Chase (Oregon State University); A. Ridgwell (University of Bristol); C. Le Quéré (University of East Anglia); Bob Anderson (LDEO) Students: B. Rogers (SFU Environmental Science, 2008) L. Rebar (SFU Geography, 2008), L. Lewis, M. Lane , M. Hershbain (Bronx High School, 2007) Support: NSERC Discovery Grant, SFU President's Research Grant; SFU Work Study Program; NSERC/CFI Grant [Top of Page ] Secondary effects of climate change on human and ecosystem health: A risk-based approach, CCIRC Changes in glacial westerly winds over the Southern Ocean 
Model simulation demonstrating places in the ocean below 800 m where liquidified CO2 might remain sequestered after 1000 years (Figure from A. Ridgwell and T. Rodengen). Anthropogenic CO2 can be sequestered by
means of the injection of CO2 into the ocean, either as liquid CO2 or
by pre-reacting with the mineral CaCO3 to neutralize the acidity prior
to injection. One of the greatest uncertainties in this approach
concerns the time scale over which the carbon will remain sequestered
and where it will outgas, and to what degree it will be "naturally"
neutralized by CaCO3 in deep-sea sediments. Social and economic
constraints, e.g., where carbon dioxide is produced, also provide a
practical constraint in identifying the optimal locations for potential
CO2 injection projects. This study is conducting an ensemble of tracer
release experiments using an Earth System Model (GENIE) to examine the
fate of injected CO2. The fraction of injected CO2 leaked from the ocean
to the atmosphere will be examined on a series of time-frames (1, 10,
100, 1000 years). Trends in Extreme Weather Patterns on the British Columbia
Changes in 50th percentile, 95th percentile, and monthly max wind speeds at Abbotsford, BC. How is global climate change affecting British Columbia's regional weather patterns and the frequency and severity of extreme wind events? The west coast of Canada is rapidly urbanizing and the concentration of infrastructure increases our society's vulnerability to extreme weather events and the potential costs resulting from damage. Despite the large uncertainties that exist, we must make forecasts of extreme wind speeds that are as dependable as possible to inform management objectives and future planning decisions. This research project examines recent trends and variations in wind intensity and frequency for the British Columbia coast using available wind speed and weather data from the past ~60 years (e.g. Griffin et al., 2010). In addition to determining the dominant climate controls on wind speed behavior in the Pacific Northwest (Griffin et al., in prep), this project evaluates the performance of regional climate models and re-analysis datasets at predicting changes in the spatial and temporal patterns in winds (work by B. Cross). This project also investigates seasonal changes in wind speeds from different directions along the west coast (work by B. Bylhouwer). Changes in coastal winds can have implications for the timing of the Spring transition between upwelling and downwelling wind regimes, as well as changes in the intensity of winds in these regimes.Students: Brad Griffin, Ben Cross, Brian Bylhouwer Support: NSERC Graduate Fellowship (BG); SFU Graduate Fellowships (BG); CCIRC (BG), SFU Startup funding and NSERC Discovery and CFI grants (KEK) [Top of Page ] Air Quality Impacts of Climate Change in the Lower Fraser Valley of British Columbia Paleotempestology of the Pineapple Express
Satellite image of a Pineapple Express storm that hit the coast of BC on January 8, 2009 (image courtesy of US National Weather Service, http://www.wrh.noaa.gov/). Almost every winter, the west coast of North America is impacted by storm events bring extensive warm rain, creating massive flood events and some cases causing hazardous debris flows and landslides. These storms have been dubbed "the Pineapple Express" because of the tropical origin of the water vapor that is rapidly transported to the coast. The historical record has afforded study of these 'atmospheric rivers' over the past 50-70 years, but how has the frequency of Pineapple Express varied further back in time? The goal of this project is to to investigate past changes in the frequency of the Pineapple Express by measuring the isotopic signature of the rain that is archived in local tree rings.Co-Supervisor: Ken Lertzman (REM) Students: Christie Spry Support: SFU Graduate Fellowships (CS), NSERC Discovery Grant (KEK), SFU CCIRC (CS) [Top of Page ] Climate change impacts on storm-induced debris flow hazards near Chilliwack, British Columbia
Locations of 37 debris flows (red circles) identified in the Chilliwack region between 1980-2009. Green triangles show locations of nearest Environment Canada and ISH meteorological stations (Figure courtesy of L. Sutton). Debris flows are fast moving saturated sediment flows that are often triggered by high volumes of precipitation, and can present challenges to communities through their hazards to infrastructure, development sites, and public safety. The area surrounding Chilliwack, BC, frequently experiences damage from landslides and debris flows, and faces issues with land use planning and safety. In January, 2009, a state of local emergency in Chilliwack was called when debris flows and flooding forced several residents from their homes. Future climate change poses an additional threat to this region because of potential changes in the frequency and intensity of severe precipitation events that are likely to impact the Lower Fraser Valley. The goal of this research is twofold: (1) to ascertain the meteorological conditions that are most conducive to debris flows, and (2) to assess possible changes in these meteorological conditions in the future.Students: Liz Sutton Support: SFU Graduate Fellowship (LS), CTEF/CCIRC Graduate Fellowship (Spring 09) (LS), PICS Graduate Fellowship (LS), 2009-2010 Canada Public Safety Research Fellowship in Honour of Stuart Nesbitt White (LS) [Top of Page ] Changes in the frequency of extreme wind events during the Dust Bowl Several studies have examined the climatic and land-use
controls on drought and precipitation during the Dust Bowl. But
not many studies have focused on the near-surface and synoptic
meteorological conditions that are needed to raise dust into the
atmosphere in
Impact of Coastal Ocean Acidification on Ecosystems Anthropogenic CO2 emissions are driving significant decreases in ocean pH and are projected to cause mean surface ocean pH to decline by 0.3-0.5 pH units by 2100. This change in pH is 100 times greater than changes experienced over the past four million years, and may have profound ecological and socio-economic ramifications. Ocean acidification has been shown to inhibit calcification of molluscs, echinoderms, and other heavily calcified marine invertebrates, yet its effects on coastal ecosystems and their associated goods and services remain poorly understood. The Strait of Georgia is a large, coastal estuarine ecosystem on the west coast of Canada that supports a multi-million-dollar shellfish industry and is home to people who harvest wild growing shellfish for food. The goal of this proposal is to investigate spatial and temporal changes in the acidification of the Strait of Georgia, and to determine the potential impacts on coastal ecosystems. We propose to (a) quantify spatial and temporal changes in biogeochemical variables relevant to calcifying organisms using contemporary, historical and paleo-data; (b) assess impacts of pH on the survival and growth rates of key species in the laboratory; (c) examine how these impacts may alter ecosystem dynamics using complementary field studies, and (d) assess the vulnerability and adaptive capacity of coastal human communities to changing pH in the Strait of Georgia. This project will provide the first quantification of past and currently changing pH in the Strait of Georgia. Laboratory and field experiments will assess the influence of coastal acidification on different life stages of species relevant to shellfish fisheries and aquaculture, and the ecosystems in which they are embedded. Finally, we hope to identify key vulnerabilities for subsistence, commercial, and aquaculture harvesters, recommend mitigative actions, and communicate means by which these communities might adaptively plan for the future.Collaborators: A. Salomon (REM), C. Harley (UBC-Zoology), D. Lepofsky (SFU-Archeology), D. Ianson (DFO-IOS), J. Silver (U. Guelph-Geography) Students: B. Bylhouwer, C. Duckham [Top of Page ] |
