This summer my friends and I travelled to Barry Lake, outside of Peterborough Ontario, to conduct field work. We obtained long and short sediment cores, which will enable us to deduce how humans have impacted water quality in Southwestern Ontario and how climate has changed since the last ice age, respectively. We can uncover this information since lake sediments are deposited chronologically. By extracting indicators like stable isotopes and microfossils from the sediments, we can deduce how the environment has changed over time. Stable isotopes of oxygen and hydrogen extracted from the sediment organic matter and carbonates in shelly fauna and marl offer information about regional hydrological changes. Stable isotopes of carbon and nitrogen extracted from the sediment organic matter can show us how plant communities changed over time. Understanding how different aspects of the environment changed over long- and short- timescales is valuable for two main reasons: (i) scientists can gain a historical perspective against which to compare recent changes to the environment by human activities; and (ii) information about past climate can help us to predict how environments will change in response to warming temperatures associated with anthropogenic climate change.