NOAA Teacher at Sea: Sue Zupko
NOAA Ship: Pisces
Mission: Extreme Corals 2011; Study deep water coral and its habitat off the east coast of FL
Geographical Area of Cruise: SE United States from off Mayport, FL to Biscayne Bay, FL
Date: June 9, 2011
Time: 1900
Weather Data from the Bridge
Position: 25.4°N 79.5°W
Present weather: overcast
Visibility: 10 n.m.
Wind Direction: 075°true
Wind Speed: 20 kts
Surface Wave Height: 4 ft
Swell Wave Direction: 100° true
Swell Wave Height: 4 ft
Surface Water Temperature:28.5 °C
Barometric Pressure: 1011.8 mb
Water Depth: 308 m
Salinity: 36.5 PSU
Wet/Dry Bulb: 28°/24.8°
This blog runs in chronological order. If you haven’t been following, scroll down to “1 Introduction to my Voyage on the Pisces” and work your way back.
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When I started my journey as a Teacher at Sea, I wondered what scientific research the ship I would be placed on would be doing. Would it be marine mammals in Alaska or Hawaii, hydrography (bottom mapping), a fishery study, buoy placement, or something I’d never heard of. When I was told I was placed on the Pisces and we’d be using an ROV (remotely operated vehicle), I only knew we’d be using the vehicle to go to the bottom and look at corals since it is too deep to scuba dive. I had no real concept of what else would be going on. I did know my students liked the idea of the ROV since I am the Robotics Club advisor at Weatherly Heights Elementary.
We have three missions on the Pisces. One is to look at the bottom through the eyes of the camera lens to see what is actually happening with the coral and its habitat. Another purpose was to update existing maps. The third mission was the most difficult for me to get a grasp of just because it sounds so strange. Benthic grabbing. Benthos means bottom in Greek. Like the soil on land, sediment lying on the bottom of the sea is full of creatures and information needed to fully understand the health of the corals and their habitat. You don’t see the most of the animals living in soil usually either. In soil on land and in the sea sediment, the animals living inside are called infauna, and provide food and nutrients to the epifauna (those living above the surface). What effect has man had on this foundation of the coral reef? What diversity of life is there and how plentiful are they? What size are the lithogenic (of rock origin) particles? It all means something and needs to be studied.
According to Dr. Jeff Hyland, NOAA NCCOS (National Centers for Coastal Ocean Sciences), “People may wonder why scientists want to study the seemingly ‘barren’ sand (or muddy sand) layer that covers vast stretches of the ocean floor. One good reason is because this important habitat is not barren at all! The unconsolidated (loose) bottom that occupies the majority of the sea floor can be teaming with life. The types of animals found can include polycheate worms, mollusks, crustaceans, and fish. Some are large enough to see with the naked eye, but many are so small that you would need to use a microscope to see them. “
The crew of scientists using the Van Veen grab equipment include: Dr. Jeff Hyland, James Daugomah, and Steve Roth (Grab Guys) of NOAA’s NCCOS Laboratory in Charleston, SC. Ocean floor mapping is done prior to an ROV dive to help pinpoint the choicest spots for investigation. After the ROV records the video from its dive, the “Grab Guys” go to work. The science team confers and selects the best spots for study. The beginning spot is relayed to the bridge, which then “makes it so” by taking the ship to those coordinates.
So, now what? Every group on deck must wear hard hats and PFDs (life jackets—Personal Floatation Devices) since the winch will be used and they will be working near the side rail of the ship. The fishermen (deck hands), scientists (both observers and the Grab Guys), and anyone who happens to be nearby must wear this equipment. Safety first.
The fishermen and Grab Guys prepare for the sampling by dragging the 300 pound Van Veen grab close to the side. It sits on a specially constructed table made of 2×4 wood and is painted grey.
Nearby, Steve sets up a smaller table with a sink in it, plus several buckets, a large spoon, and two rectangular plastic tubs nearby. I really wondered what that was all about.
The winch hook is attached to the Van Veer grab and everyone stands ready. When the bridge radios to the fishermen that the ship is over the drop site, they spring into action. The winch operator waits for the signal from the lead fisherman that all is ready and is told by hand signals to raise it up. As the winch lifts up the grab, those working the equipment help steady it over the deck and release it when it’s over the side. The grab is lowered to the bottom as the winch operator monitors the amount of cable deployed. The idea is that when the grab hits the bottom the release bar will pop and close the “grab jaws”. If the grab isn’t going fast enough or lands on an angle it won’t close. Plus, it might not go deep enough into the sediment to get a good sample.
It takes longer than you would think for that grab to hit bottom. Remember, patience is a virtue. The equipment drops 80 meters per minute. Yesterday we were dropping to 320 meters. All eyes are targeted on the winch’s pulley. When the grab hits the bottom, it causes the pulley on the winch cable to swing, meaning that the grab has made contact. Everyone crosses their fingers that the grab not only closed, but also got a large enough sample for an accurate test. The winch driver begins to retrieve the gear. It’s just like doing a science fair project. You must repeat your experiment and have the right amount of sample so your repeated experiments are as similar as possible when you repeat your procedure. They must make three grabs which bring up the correct amount of sediment. Often trial and error comes into play. The current not only made things difficult for the ROV operations, it made the grab go down at an angle so it wouldn’t close (grab or fire) a few times. They had to keep dropping until it worked correctly. At one point the bottom was 370 meters and we had let out 425 meters of cable. That meant that the wind and the current were really strong and pulling the grab out at an angle.
Once the grab gets a sample, they scoop out sediment with a spoon and put it in a blue bin. This is carried over to a sieve bucket and is half submerged and swished around in the sink to get the mud off. This is repeated until all the sediment particles are clean.
The samples are scooped out of the sieve bucket and placed in containers which will be processed back at the laboratory. In general, they are looking for sediment size (grain size), infauna (living organisms from the sediment), and chemicals from man. The containers have been labeled with what tests need to be run. Jeff is recording the numbers on the containers and whether that sediment should be tested for metals, toxicology, total carbon, organics, and sediment size.
A special insert is placed in the grab to measure an exact amount of sediment to determine the amount of the infauna. This sample is cleaned and put in a large container with formalin mixed with rose bengal. The rose bengal had been premixed by Dr. Hyland the first day so that when added to the sediment it will turn the living organisms a pink color, making them easier to find.
After the sediment samples are put in the smaller bottles, the top is screwed on, sealed with electrical tape to make sure it doesn’t open, and stored in the refrigerator or freezer. All these benthic samples will be sent to Barry Vittor, a company specializing in sediment analysis.
I have a new appreciation for the sediment in the ocean. I’ve learned that sediment on the north side of a coral mound in the Gulf Stream usually has less nutrients since the current flows from south to north. The coral and other plankton-consuming animals eat a lot of the food flowing in the current over the mound so the water on the north side contains less food and can support less infauna. I hope my students enjoy learning about the benthos as much as I have. Perhaps with the data we collected, scientists will be able to help determine what we need to do to preserve the corals of the reefs.
