A Sailor's Life for Me

Well, I am back home in Mount Pleasant. I apologize for the tardiness of this post, but I have been sick the last week. Last Monday Anthony and I drove to Cleveland to meet the R/V Lake Guardian. If you follow the link, you will find that the Lake Guardian is a research vessel owned by the EPA. We were lucky enough to be invited to come along and conduct our own research alongside EPA scientists. The Lake Guardian is equipped with many different types of sampling equipment as well as lab space for processing samples at sea.

Lake Erie bathymetry. The eastern basin is the deepest and the western basin the shallowest. Image from http://www.ngdc.noaa.gov/mgg/greatlakes/erie.html

The EPA conducts regular monitoring surveys of the Great Lakes, and this cruise was focused on Lake Erie. Many of you will know that the Great Lakes have been heavily stressed by human activity, with Lake Erie probably the most impacted. It is the smallest of the Great Lakes by volume and the shallowest, having an average depth of only 62 feet (19 meters). (Also check out the EPA's Great Lakes Atlas.) Lake Erie is divided into three basins which are visible in the image above: the eastern, central, and western basins. We began our cruise by transiting to a site in the eastern basin. Here we used a rosette sampler to collect water samples from various depths.

Rosette sampler

Me doing something um, important, with the rosette sampler. My new hat is the coolest!

From left to right: Two of our fabulous marine techs, Owen and Meredith, and Anthony. Owen is sporting a cup of coffee, which is absolutely essential to the success of any research cruise.

We made two casts to collect water samples, one for data about water chemistry and one for dissolved organic matter (DOM) samples. The samples were filtered onboard ship and stored for later analysis at CMU.

Set up and ready to go in the chemistry lab

We also attempted to take some sediment cores from the eastern basin, but a storm blew through and we were unable to get good cores. Below is a picture of the multicorer, which is one type of coring device. A multicorer is good for taking several cores at once, as the name implies. The device takes relatively short cores, but preserves the sediment-water interface, which other types of coring device do not. With the larger coring devices, the top of the sediment package--the newest sediment deposited--is usually lost.

Multicorer

In my limited experience, sediment coring devices are deployed off the fantail, or back of the boat. The picture below is from a different cruise I took with my Ph.D. advisor in 2009, but it is easier to see the architecture of the working parts of the ship. The Lake Guardian is similarly designed.

R/V R.G. Sproul

Fortunately, we were able to get good cores and water samples from both the central and western basins. As soon as the cores are retrieved, they have to be extruded from the plastic tubes and sliced at regular intervals for storage and transport.

Cores before they have been extruded

After three days of bizarre sleep and work schedules, we returned to Cleveland, offloaded, and returned home. Now the real work begins because we will spend the next several months analyzing our new samples. As I mentioned before, we are hoping to get some basic data about the chemistry of Lake Erie's water and sediments, including trace metals. Trace metal data especially is lacking or absent for the Great Lakes, and the GEM lab would like to fill this gap. Trace metals are an integral part of the lake ecosystem as well as pollutants. All organisms require metals such as iron as micronutrients, and currently we have very little information about the relationship between the lake's biota and trace metals, and what this means for the health of the Great Lakes.