Grabbing the Sea's Bottom

SEDIMENT GRAB

It’s not all about water! Studying the cycle of carbon in the sea is a huge undertaking. There are so many parts to look at all the way from the sea surface to the deepest depths.  

Some places in the Ross Sea reach down to 1200 meters while most depths have only been ~500m. Scientists on board wanted a closer look at the sea’s bottom.

We have cameras that are able to take photos of the sea floor. There are many creatures living down there and they have NO idea what is happening at the surface. All they see are the remains of the organisms that once lived at the surface and sank to the bottom when they died.

The floor is scattered with sea stars, anemones, slug-like creatures, centipede-like creatures, worms and the occasional fish.

A claw was sent down to do a sediment grab. This instrumet grabs the top surface of the sea floor as well as the water sitting right above it. The whole grab is brought back on the deck of the ship and everyone is excited to see what it holds.

The water contains many things we cannot see with the naked eye. In order to visualize these microscopic living creatures we want to get rid of the water but keep the “bugs”. To do this we send the water through a filter. A filter is a tiny piece of paper that has tiny holes. These holes allow the water to go through but everything else is stuck on to the paper. These filters are then put onto glass slides and then taken to the microscope for a closer inspection.

This image shows algae from the layer of dirt at the bottom of the sea.

These images are from that thin layer of water above the sea floor. The microscope uses a mercury lamp to shine blue light on to the sample. When blue light shines on algae they glow red because of their chlorophyll. Chlorophyll is unique to plants and algae and is involved in photosynthesis—fixing carbon dioxide in to oxygen using sunlight and water.  Note that the copepod (left photo) does not glow red because it is an animal and does not have the plant chlorophyll.  The photo to the right is a mixed population of many different types of algae.

These are happy scientists! Allison Lee (Research Technician at Institute for Systems Biology), Rachel Stevens (Undergraduate at College of Charleston) and Jack DiTullio (Principal Investigator at College of Charleston).