My current research interests focus on the use of light stable isotopes in hopes of developing records of climate change. The importance of this research is the development of paleoclimate records that will better constrain modern climate change and will hopefully help to determine whether this change is antropogenically driven. I am in the process of developing records of climate change from lake sediments and tree rings. I have also been studying modern precipitation/meteorology and surface waters in Ireland to better interpret past climate change.

Recently, I completed a MSc researching the paleoclimatic history of Ireland using stable isotopes from a variety of sources. Bill Patterson and I generated a record of climate change over the past 18,000 years that can be used to better constrain future climate change. Climate during the this time period was once thought of as a period of climatic stability. However, research over the past few decades has shown that this is actually a period of rapid climatic change. Recently, this has best been seen during the summer of 2003, when Europe experienced some of the highest temperatures since the implementation of meteorological records.

Lakes in Ireland are excellent recorders of past climate change .Western Ireland in particular is excellent because of the abundance of lakes that precipitate calcite. I am in the process of developing a record of climate change/variability during the Holocene and Late Glacial periods of western Ireland from several lakes.

The main lake of interest is Loch Inis Ui Chuinn (Lough Inchiquin) which lies ~2km to the northwest of the town Corofin, County Clare. In 2002, we recovered a 7.5m sediment core. Isotopes of carbon and oxygen (d13C and d18O) from calcite precipitated during the summer months by charaphytes record significant variation. The variation in oxygen isotopes suggests that major variations in atmospheric circulation have occurred in the past 14,500 years. Changes in carbon isotopes reveal that may changes have occurred in the lake ecosystem.

Lithology, weight percent total calcite, weight percent total organic matter, oxygen isotope values of lacustrine calcite from Lough Inchiquin. Click here for the full story.

In addition to calcite in lake sediment, I have also been developing records of nitrogen and carbon isotopes and weight percentages from the organic fraction of the lake sediment. These records will help to answer questions in the nutrient cycling of the lake as well as changes lake productivity and source of organic materials.

Before we can gain a better understanding of paleoclimate records derived from lake carbonate we must understand mechanisms that produce variation in isotope values of modern surface waters first. To accomplish this we sampled 144 locations across ireland to determine the spatial distribution of d18O and dD values. The focus of this project is to provide insight into the behavior of lakes and rivers in Ireland, including source, recycling and loss through evapotranspiration. The short duration of sampling in this project provides a snapshot of modern isotope variability to be applied towards long-term climate change in Ireland and provide a basis of comparison for other proxy records.

This study provides a first regional survey of surface water isotope values for Ireland that are useful for characterizing modern meteorological behavior and providing a template for comparison on lake sediment-based paleoclimate records. Significant variation in isotope values suggest that climate records derived from sediment isotope values need to be evaluated in a regional context if applications to global models are to be realistic. In the Burren region of county Clare, variation in lake values suggest that factors in addition to precipitation are significant in determining the values of individual lakes. These factors likely include differences in residence times, catchment size, evaporation, etc. Therefore, future studies of climate change would provide the most comprehensive record by using several different types of lakes each of which shows differential sensitivity to different meteorological parameters.

Sample values were separated into lakes, rivers unrelated to lakes (not downstream), rivers downstream of lakes, reservoirs and samples that may represent mixing with seawater. All slopes are lower than the Global Meteoric Water Line (GMWL) and a majority of the data plot below the GMWL. Slopes are lower than the GMWL because surface waters are affected by evaporation resulting in values plotting with lower slopes. Lakes have the lowest slope of all the surface waters due to significant evaporation. Lakes have lower slopes than rivers in part because of increased residence time that permits greater evaporation, that increases values. Downstream rivers plot with the same slope as lakes.

In addition to research in Ireland, I am working on a project with Greg Wiles to develop a record of climate change during the Medieval Warm Period in Alaska. It is our hope that we can determine such parameters as humidity, temperature, and source of precipitation in this region of Alaska. I am in the process of developing a yearly record of oxygen, hydrogen, and carbon isotopes from alpha-cellulose over the life span of the tree. The figure to the left is the preliminary oxygen isotope data so far.

In October of 2004, I will have the opportunity to travel to Ireland again to collect several modern trees and bog wood samples. It is my goal to developing a record of atmospheric circulation from isotopes in the tree rings and modern climate records. Then it may be possible to apply these records to the bog wood samples.

Bill Patterson and I at The Quay's, Galway.

I am currently working on the development of a new isotopic paleothermometer for lake sediment. It is my hope to develop a record of absolute temperatures for the past 14,500 years in western Ireland. If this works, it will be the first record of its kind employing this technique. Stay tuned for more...

At some point, Dr. Antoine Zazzo and I would also like to conduct research on charaphytes to constrain isotopic fractionation in a controlled environment.

I'm also interested in other isotope proxies, as well as radiogenic isotopes.

To the Saskatchewan Isotope Laboratory