by Christina Kellogg, USGS
I clearly remember going through a phase when I was about 3 years old where I didn’t want any of my foods touching each other. I ate dry cereal and then drank the milk. I ate plain spaghetti and then ate the sauce separately with a spoon. I’m sure the other scientists on this ship are thinking that microbiologists are a lot like 3-year olds, because we are constantly reminding everyone that our samples can’t be touched by anyone or anything. This is because microorganisms are EVERYWHERE and we can never be too careful about keeping our samples free of outside contamination. That is why we have to be a bit obsessive about how our samples are collected.
We mark our quivers with distinctive duct tape to make sure the ROV pilots and the other scientists don’t forget which containers are specifically for our samples. We clean our sample quivers carefully each night to make sure there are no particles of sample from the previous day or anything smeared on the inside walls, and sterilize them by wiping down the inside surfaces with alcohol (like when a nurse wipes your arm with alcohol before giving you an injection, to sterilize your skin). We also send our quivers down on the ROV filled with freshwater when most of the other quivers are filled with seawater. Why? Well the surface seawater has different microbes in it than the water at the bottom where the corals we are collecting live and we don’t want to accidentally pick up some bacteria from it. Freshwater is less dense than seawater, so when the quiver is opened deep under water, the freshwater rushes out and is replaced by ‘local’ seawater from the exact depth where the sample is being collected. The coral is already bathed in that water all the time, so we don’t worry about contamination from it.
Corals that are being collected for microbiology have to be placed in a quiver alone. The researchers studying coral genetics can put several different corals into a single quiver together and it doesn’t matter because they can tell them apart by how they look. But since different corals have different microbes (and we can’t see them), we can’t have more than one coral in a quiver because bacteria could be transferred between the samples by their rubbing together in the quiver and we could mistakenly think one coral’s bacteria really belong to the other coral. Similarly, we can’t use corals that are collected in a biobox and are touching sediment, water from different depths (every time the box is opened) and other invertebrates…because all those things have different microbes.
It’s not really that microbiologists are like 3-year olds who don’t want anything to be touching. We’re more like surgeons who are operating on a patient and constantly have to be aware of the microorganisms that could be on their hands, surgical instruments, etc., knowing that if they aren’t careful, those microbes could get into the patient and cause a deadly infection. Luckily, in the case of environmental microbiology, the consequence of a contaminated sample is that we can’t use it rather than that somebody dies. However, when you consider how expensive and difficult it is to get these samples from the deep sea, we feel like we can’t afford to lose even one…and that’s why we’re a bit obsessive/compulsive about “No Touching!” our samples.