Under the sea everything is better (specially water quality measurements)

Under the sea everything is better (specially water quality measurements)

Water quality measurements and equipment installment is a mouthful and may sound boring, but believe me, it is the opposite. Within the Fish and Wildlife Inventory and Monitoring Program division of the natural resources management team, there is the water quality team that is in charge of taking measurements of the quality of the water, specifically dissolved oxygen, salinity, temperature, conductivity, temperature, and depth. For the whole process, the team uses different methodologies that are divided into different consecutive processes. The water quality team also works with the Rosenstiel School of Marine, Atmospheric and Earth Science doing in-water fish surveys, seagrass surveys, and epifauna surveys. This interdisciplinary study is called Integrated Biscayne Bay Ecological Assessment and Monitoring (IBBEAM), and it offers more than one perspective for solutions towards conservation, the possible problems that raised salinity poses in the bay, and the main sources and reasons for this. In this blog, I will explain what a day with the water quality team looks like. 

Hold on tight!

Equipment installment in the bay

To be able to collect water quality measurements, there is a special equipment that is put underwater in areas that are neither too deep or to shallow, with an average between 1 – 2.5 meters, along Biscayne Bay. This is useful and more practical for equipment installment and retrieve. The equipment, as shown in the picture, is similar to a CTD (conductivity, temperature, and depth) machine called YSI 6600 that records data every 15 min. It is basically a multi-parameter water probe/sonde that is design to retrieve various components in water. Only one single probe can cost as much as $500, which is why it is so important to check the state of the instrument before installing it in the water and after retrieve. The process of installing and retrieving has to be done between 1-3 days because of the amount of different spots along the bay (north to south) where they are located.  Generally, the equipment is left underwater on specific sites for about a month not only to be able to process data more easily, and to avoid great quantities of living organisms from being able to attach to the instrument, but to also be able to continuously examine the data.

Now, to the fun part...

For instrument installment in the different areas along the bay (north to south), I got into a boat loaded with five YSI 600s to replace with the ones that had been in the water for 1 month, and 1 more YSI 600 used for calibration. When we get to the site, we put our snorkels and fins, the new YSI 600 and the one used for calibration, along with zip cable ties and a lock. Both instruments are placed along with the one already in the water (that had been there for about a month), and the new instrument is tighten with tie to a concrete structure which is where the instrument lies. While we are tiding the new instrument and placing the lock, the calibration one, which takes recordings every 1 min., is gathering data which is analyzed in the lab later to make sure that the old and the new are functioning correctly, and overlaps the data to make sure no recordings are lost in the process. After, the calibrating instrument is removed, the old instrument is left next to the new instruments to remove in our way back, for both to completely record data for the whole 15 min. Finally, in our way back, we collect the old instruments in every site by cutting the zip tides on it and opening the old lock. Also, while doing all this process, I had the chance to see different species of fish like yellow stripe grunts, and yellow tail snappers, as well as different types of jellyfish and corals.

Sites where the YSI 6600 instrument is along the bay

Red and Black dots are sites. Blue lines are canals that run into the Bay. This canals contain freshwater and are operated by the South Florida Water Management District, which is the agency that regulates water flow into the bay and in all South Florida. 

Data Download, Calibration, and Interpretation

When this is done, and all the old instruments are retrieved, we head back to the lab in the park headquarter to download the data collected for that whole month, and calibrate the instruments. The calibration is important to establish a reference point for accurate readings. Calibration involves comparing the readings of the instrument with known standards or reference. The purpose is to adjust or verify the accuracy of the instrument’s measurement values, and it is useful to guarantee accuracy, environmental variations, quality control, and traceability. In addition, the data is also downloaded into the computer by using a cable that connects directly from the instrument to the computer. The data is then translated into a software system which analysis the data into graphs. This data is interpreted by the water quality team, and pass along to the rest of the partners to create interdisciplinary pathways to contribute to conservation.

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