The Transit Authority of Marine Sediments

These next few weeks look to be rather quiet on the research front, as I am working to get all my materials for my summer experiment, which is a nice change of pace from the busy weeks I had leading up to my departmental seminar. This week, though, I want to talk about the last phase of my dissertation research, which regards the roles that nematodes and other animals play in maintaining ecosystem processes within marine sediments. The title for this week's blog reflects the somewhat complicated network of tubes, holes, and microscopic passageways that many tiny organisms construct within marine sediments, and these tiny transit networks provide passages for nutrient transport between the overlying water and the sediment, and can alter sediment stability at the microscale.

This summer I am working with collaborators to assess how microplastics may change the ability of nematodes and other sediment fauna to construct these transit networks, and how microplastics may increase stress in these organisms by monitoring oxygen turnover within marine sediments. While oxygen availability can change because of natural metabolic activities, increased oxygen availability within marine sediments can mean that organisms are constructing more burrows where oxygen can penetrate deeper into sediments and decreased oxygen availability can mean that organisms in the sediments are consuming more oxygen to try and maintain their metabolisms, possibly indicative of increased stress.

How am I going to manage measuring these microscale activities? Through photographs and microelectrode measurements, of course. I plan to use fluorescent sediment particles to track how deep the animals are burrowing in sediment mesocosms (experimental chambers meant to reflect natural systems) and take pictures throughout the experiment to assess changes in particle depth over time. Additionally my colleagues will be measuring changes in oxygen availability in the sediments using tiny oxygen probes which can measure fluxes on even the smallest of scales. Overall, the setup will look like this artistic rendering, and I am working to quickly get this set up so that I can run some pilot experiments before it's time to run the full setup.

​Tune in next week to learn more about this upcoming project.

---