Day 7 Hydrochemistry 101: Chantelle Cook

By October 2nd, 2017

water analysis

Today’s tour was the hydochem lab. As soon as you entered the room, your senses were awakened—bleach and acid fill your nostrils and the icy chill of the air conditioner on your skin is a relief from the humidity, for a short while, until you start getting very, very cold!

Of course these smells and the temperature of the room are playing their part in maintaining the integrity of the data in the hydrochem lab. As we were about find out, everything in here is precise, accurate and sterile, for a very good reason—any change in these variables, and the data is compromised!

Our technician today, the talented and very clever chemical science expert Cassie, gives us a mind blowing run down of the intricate work involved in the hydrochem lab. Most of what Cassie talks about today is at a scientific level WAY beyond the chemical science strands taught in primary school. At times, my mind is aching trying to process what she is saying. A layman’s analogy would be this: it’s like when you do a water analysis of your pool or spa, maybe even your fish tank or local waterway. You take a sample, mix some solutions into it and shake it up, maybe leave it for a while. When you come back and it’s a different colour, you know what element is missing, or if it is too high. It’s kind of like that, but with the ocean!

What are they testing the ocean water for? Salinity, conductivity, dissolved oxygen levels and nutrients—mainly nitrate, nitrite, ammonia, phosphate and silica. These things can help scientists predict weather patterns, animal migratory patterns and feeding behaviour, or determine where or why animals or plants in the ocean live where they do. It helps to care for and conserve ecosystems. For example, if there is poor or unhealthy plant life in a particular area of the ocean and ecosystems are not being sustained, scientists will look for what nutrient is missing to help that ecosystem flourish. Perhaps high levels of nitrate and an absence of iron to build chlorophyll means that the proteins cannot form and build healthy plant life.

A big difference in the work in this hydrochemistry lab and your backyard pool testing kit is the level of trace elements they are finding. Here, they are measuring parts per million. Think of how many minutes there are in two years—that is how specific the data they are collecting is. Oceanographers are looking for minuscule changes in the water chemistry.
Analysis of water

For this reason, this is one of the strictest labs for quality control. Not only is the temperature of the room critical, but there can be no contaminants in samples. No smokers are allowed anywhere near or in the lab (the ammonia will contaminate); every test bottle has the volume calibrated and software reads each bottle to give data accuracy; no bubbles can get into the sample, otherwise the oxygen level is compromised; gloves must be worn to stop contamination of samples; glass bottles can only be filled to a certain level so they don’t break under the pressure of heat; and all chemicals are pre-weighted prior to the voyage so that measurements are exact and not affected by movements and gravity changes of the ship.

This work is intricate and precise, and a time consuming process. When you are measuring to parts per million, you have to be! They are aiming for accuracy and precision—hitting the bullseye every single time. Not only are they accurate and precise, but their critical thinking skills need to be on point to question, hypothesise and account for variability and changes in data.

After all this very intense learning, it was time to clock off for the day and enjoy the AFL grand final! My team was not in the top two so I decided to barrack for the Crows, given I have been working in close proximity to birds lately! Alas, as the Crows fell to the Tigers, I ended up being like the bird spotted earlier today, the spangled drongo—a land bird who seemed as perplexed as us to be some 250 nautical miles offshore). Our Saturday evening on board was capped off with a crew BBQ out on deck as we watched the sunset off the Cape York Peninsula.