NOAA Teacher At Sea
Aboard NOAA Ship Nancy Foster
September 14 – 27, 2014
Mission: Deep Habitat Classification
Geographical area of cruise: Tortugas Ecological Reserve and surrounding non-reserve area
Date: September 21 & 22, 2014
Weather: September 22, 2014 20:00 hours
Latitude 24° 25.90 N Longitude 83° 80.0 W
Few clouds, clear
Wind speed 10 knots
Air Temperature: 28.5° Celsius (83.3° Fahrenheit)
Sea Water Temperature: 29.9° Celsius (86° Fahrenheit)
CLICK ON THE SMALL PHOTOS TO MAKE THEM LARGER
All week we have had the privilege of using the Remotely Operated Vehicle. This model is the Mohawk 18. It has two cameras, one that provides still photographs and the other takes high-definition video. Both are geo-referenced so we know exactly which latitude and longitude we are working.
It has an amazing maneuverability and gets around, over and under things quite quickly. The footage is sent back up aboard in real time via a long fiber optic umbilical cord.
This amazing piece of equipment has allowed us to see down to depths that the divers would not have been able to reach. It has also allowed us lengthy bottom times that the divers would not have been able to sustain. Most of the divers have been trained to dive with double air supply tanks, which affords them more bottom time, but the ROV can stay down for hours and hours at a time. The only limitation is the stress it puts on the pilots. Jason and Lance, our pilots, said that a four hour dive is about all they can run at a time without getting extremely crossed-eyed and need a break! However, they are troopers and we have been doing multiple ROV dives each day, some lasting up to 4 hours.
Here are some fun things we have seen.
The last ROV dive of our day (& this cruise) was to a 56’ shrimp boat wreck which was down 47 meters (154 ft) just along the boundary of the North Reserve. We saw nine Goliath Groupers (Epinephelus itajara) all at once. Groups of these fish are often seen on wrecks, but the scientists were a bit surprised about the high density on such a small boat. Due to over fishing of the Goliath Grouper, about twenty years ago, a moratorium was placed on fishing them and they were being considered for Endangered Status. After just 10 years, a significant increase in population size was observed. It’s still illegal to bring them over board but they are not on the Endangered Species list. Juveniles live in the mangroves but adults live in deeper waters where our scientists were able to observe them with the ROV.
During the last 6 days we spent 14 hours and 20 minutes underwater with the ROV. The entire time was recorded in SD and the scientists recorded the most significant events in HD. They also sat at the monitors the entire time snapping still shots as often as they saw things they wanted photos of. 957 digital stills were taken. The longest dive was 4 hours and 10 minutes. Our deepest dive was 128 meters (420 feet!)
The screen on the left shows the map of the area the ROV is surveying.
These maps were created by the Multibeam Echo Sounder (MBES) The ROV depends on the MBES as do the fish scientists. Without these maps, the ROV would not know where to dive and the fish scientists would not know where to conduct their research. The MBES gives the fish scientists a wider view of the terrain than they can get on their own by SCUBA diving in smaller areas.
The Multibeam Echo Sounder (MBES) uses SOund NAvigation and Ranging (Sonar) to create high-definition maps of the sea floor and it’s contours (as well as other objects such as shipwrecks) by shooting sound waves (from 512 sonic beams) down to the seabed and then listening as they reflect back up to the ship.
This is very similar to the way a topographic (topo) map represents the three-dimensional features (mountain and valleys) of the land above water. Instead of using contour lines to show variations in relief, MBS uses color to depict the bathymetry (submarine topography) Red shows the shallowest areas, purple the deepest.
Another important element of the MBES for the fish researchers is called backscatter. This byproduct of the sonar action wasn’t always collected. Not until advances in technology allowed for an understanding of how to gather useful information from the backscatter did technicians realized how valuable it can be. Backscatter is the amount of acoustic energy being received by the sonar after it is done interacting with the seafloor. It is now recognized that the information from backscatter can determine substrate type. Different types of substrate will “scatter” the sound energy differently. For example, a softer bottom such as mud will return a weaker signal than a harder bottom, like rock.
Layering together the multibeam data (which provides seafloor depth information and is computed by measuring the time that it takes for the signal to return to the sonar) with the backscatter, provides information which is especially helpful to fish researchers as it can assist them in classifying habitat type. This allows them to know where they might find the species of fish they are looking to study.
Tim Olsen, Chief Engineer, toured Camy and I through the engine room. It was overwhelming how many wires, cranks, moving parts and metal pieces there were. Tim and the other engineers are brilliant. I can not fathom what it takes to keep this 187 foot ship going with it’s multiple cranes, winches, engines, thrusters, small boats, air conditioners, toilets, kitchen appliances, etc.
I was most interested in the water systems. The ship makes all its own drinking water since salt water is non-potable and it would take a lot of storage space to carry fresh water (space its tight on a ship!) They have two systems. One is a reverse osmosis system which, using lots of pressure, moves sea water through a membrane to remove the salts. This system produces 1500 gallons of potable water a day. The second one is a flash distiller. In this system, seawater is heated by the engine and then pumped into a vacuum chamber where it is “flashes” into water vapor which is condensed and collected. The distilling system makes 1800 gallons a day aboard the Nancy Foster. Distillers, in some form, have been used on ships since the 1770s.
The other thing that caught my attention was the sewage treatment system. Earth Campers, this one is a bit smaller than the one we toured!
Of course, I also took a ride out in one of the small boats to assist the divers. Sometimes all I do is fill out the dive log and pull the buoys back into the boat but I really enjoy being out in the open ocean, feeling the sea spray in my face and watching the light move across the top of the water.
This week Tim has been coming around every now and then wearing his Domino King’s crown and cape, reminding us all to come challenge him to a game of Mexican Train (a fun dominos game).
Tim has won every tournament game on the Nancy Foster in the last three months and has the bling to show for it! Then tonight, to the surprise of all, one of the scientists, Mike, dethroned the king! This was the first time ever that a member of the science team has won the championship game.
Today was a fairly quiet day. Not too much science was done except setting out a few more fish traps.
The big news was that we steamed back to Key West and made a science crew change. We said goodbye to Jason, Lance & the ROV as well as Sean, Brett, Linh, Alejandro, Ariel, Ben and Camy. They will all be missed. Be sure you see Camy’s Miami Herald news articles–the first: (http://www.miamiherald.com/news/local/community/florida-keys/article2113805.html); and second: (http://www.miamiherald.com/news/local/community/florida-keys/article2500074.html)
We welcomed aboard NOAA’s Mary Tagilareni, Deputy Superintendent for Operations & Education and Beth Dieveney, Deputy Superintendent for Science & Policy as well as Lonny Anderson, our new dive master. From the FWC, Bill Sympson, Biological Scientist, as well as our conch biologists Bob Glazer, Associate Research Scientist and Einat Sandbank, Biological Scientist.
Also while in port, a few of the crew dived under the ship to check for any calcium carbonate secreting critters that may be growing on the transducer. While down there, they found some lobster pot line that had caught on the propeller.
To end the evening, a pod of dolphins can by again and Ensign Conor Maginn caught this video.
WORD OF THE DAY: Extirpated
BONUS QUESTION: Tell me about any Sonoran Desert species which were once being listed as Threatened or Endangered (or were being considered to be listed) and then had their populations recover.
Answer to the quiz from the last blog: Lion Fish are INVASIVE.