Expedition Blog- Microbe Hunting: What’s bubbling under the ice?

by Lydia Hayes-Guastella, Kiel Reese Lab
dressed for safety
Dr. Katie Howe (Post-doctoral Researcher) and Lydia Hayes-Guastella (PhD Student Researcher) dressed in safety gear and ready to collect a core from on deck.

Greetings from the Ross Sea, Antarctica! We are aboard the Research Vessel Ice Breaker (RVIB) Nathaniel B. Palmer, and we have been keeping busy. Between the three different science groups on board the ship studying everything from geophysics and geology, to sediment chemistry, microbiology, and crustaceans there is alway plenty to learn and do.

gravity core
A gravity core on deck before being brought inside to be processed.

We have successfully collected 13 gravity cores full of Ross Sea sediments taken from water depths of approximately 900 meters below sea level, and reaching up to 2.5 meters below the seafloor. A gravity corer consists of a metal barrel with a core catcher at the bottom and a removable (clear) plastic liner inside the barrel to collect the sediments. Gravity corer gets its name because gravity (aided by heavy weights) carries it to the bottom of the water and the weight of the barrel drives it into the seafloor.

collecting gas samples from sediment core
Undergraduate researchers Antares Hofmann, and Lorine Salel from Texas A&M University- Corpus Christi, and Graduate Researcher Lydia Hayes-Guastella form University of South Alabama and Dauphin Island Sea Lab collecting gas samples from a sediment core.

Our team has been describing these sediment cores by looking at colors and sediment textures, as well as looking for any shells or visual signs of life from the outside of the cores. Then we dig deeper and start collecting a wide variety of subsamples to allow us to understand the chemical makeup of the sediment and pore water, and the microbial community that exists and is active in these environments.

calibrating oxygen optodes
Dr. Katie Howe (Postdoctoral Researcher) and Kristen Lamprecht (Graduate Researcher) calibrating oxygen optodes for core oxygen measurements.

We are on a mission to uncover the vertical migration patterns of methane from methane gas hydrates (frozen methane crystals) through sediments and the overlaying water column, where methane can be produced and transformed both biotically and abiotically. Our team from the Kiel Reese Lab is specifically looking at the microbial communities associated with these methane hydrate bearing sediments and asking questions like “who are the members of the microbial community?”, and “what they are doing? (are they producing or utilizing methane?)” and “how are they doing it?”.

team inspects gravity core
Coring team members inspecting a gravity core on deck: Dr. Hao Yu (Left, Texas A&M University-Corpus Christi), Lydia Hayes-Guastella (Middle, University of South Alabama and Dauphin Island Sea Lab), Dr. Ingo Pecher (Right, Texas A&M University-Corpus Christi).

The water is now becoming more steadily covered in ice, with higher winds and stronger currents, but we are very hopeful that we can continue to collect cores and accomplish our scientific mission.

This research expedition is funded by the National Science Foundation Office of Polar Programs (award number 2044453 to Dr. Brandi Kiel Reese).