NOAA Teacher at Sea Jennifer Fry Onboard NOAA Ship, Oscar Elton Sette March 12 – March 26, 2012
Mission: Fisheries Study Geographical area of cruise: American Samoa Date: March 19, 2012
5.Once the crane operator lifts the unit out of the water, scientists guide the C.T.D. onto the deck.
2. The C.T.D. is ready to be deployed into the ocean. Using a team of scientists, a crane, and crane operator the heavy unit is carefully guided into the water.
CTD Operations: Conductivity, Temperature, and Depth
The CTD Operations onboard the Sette are conducted by Evan Howell, Pacific Islands Fisheries Science Center, Megan Duncan, Joint Institute for Marine and Atmospheric Research at the University of Hawaii, and Scott Allen, NOAA survey tech. The CTD platform, which resembles a giant wedding cake constructed of painted steel, contains multiple instruments that can measure water characteristics including pressure, temperature, salinity, oxygen levels, and chlorophyll concentration.
It takes 30 readings per second as it sinks towards the seafloor.
The CTD records data as it sinks and ascends, but only data from the downcast is used, insuring the instruments are recording data in an uninterrupted “profile” of the water column. All data collected helps capture ocean characteristics. The acquired data will be shared with the American Samoa Department of Marine and Wildlife Resources scientists and compared with the data they have collected previously.
Using prior data, current CTD data, and acoustic Doppler current profiler, a type of sonar detecting water currents, scientists can determine patterns in the oceans of American Samoa and compare them.
NOAA Teacher at Sea Jennifer Fry Onboard NOAA Ship, Oscar Elton Sette March 12 – March 26, 2012
Mission: Fisheries Study Geographical area of cruise: American Samoa Date: March 9, 2012
With the morning light, the island’s landscape came into view. Looking back toward land was the single road, a variety of buildings, consisting of numerous churches, restaurants, schools, and hotels. I have come to learn that each small village has its own church and outdoor meeting hall. Behind the buildings the topography extended upward forming a steep hillside covered with green, lush tropical plants, including a variety of palms and fruit trees laden with mangoes and papayas.
After a hearty Samoan breakfast with ten of the scientists that will be on the research vessel, we met with representatives from the local marine sciences community at the American Samoan government building. Chickens, chickens, and a small clutch of baby chickens happily pecked on the lawn in front of the building which put a smile on my face.
The chief scientist, Dr. Donald Kobayashi, began by introducing the team of scientists and gave a brief overview of the upcoming mission aboard NOAA Ship Oscar Elton Sette.
The variety of investigations that will be conducted during these next 2 weeks which include:.
Midwater Cobb trawls: Scientists, John Denton, American Museum of Natural History, and Aimiee Hoover, acoustics technician , Joint Institute for Marine and Atmospheric Research of the University of Hawaii, will conduct nighttime tows that will focus on epipelagic and pelagic juvenile reef fish and bottomfish species.
Bot Cam: Using a tethered camera that is later released to float to the surface, and using acoustics–a.k.a. sonar readings–scientists Ryan Nichols, Pacific Islands Fisheries Science Center , Meagan Sundberg, Joint Institute for Marine and Atmospheric Research of the University of Hawaii, and Jamie Barlow , Pacific Islands Fisheries Science Center, will collect samples of fish at selected sites during the cruise.
CTD experiments: “Conductivity, Temperature, and Depth.” At predetermined locations scientists Evan Howell, Pacific Islands Fisheries Science Center, and Megan Duncan, Joint Institute for Marine and Atmospheric Research at the University of Hawaii, will collect water samples called “profiles” taken of the water column at different depths. This data is very important in determining the nutrients, chlorophyll levels, and other chemical make-up of the ocean water.
Plankton tows: Using plankton and Neuston nets, scientists Louise Giuseffi, Pacific Islands Fisheries Science Center, and Emily Norton,University of Hawaii, Manoa, Biological Oceanography department, will conduct day and nighttime plankton tows focusing on plankton and microplastic marine debris. Scientists will be looking at a specific species of plankton called the copepod. This study will also be collecting microplastic pieces, some of which are called “nurdles” which are small plastic pellets used in the manufacturing process. Unfortunately most plastic debris will never degrade and just break into smaller and smaller pieces potentially working their way into the food web, making this research and its findings very important to environmental studies.
Handline fishing using a small boat, the Steel Toe: Scientists Ryan Nichols, Pacific Islands Fisheries Science Center, Meagan Sundberg, Joint Institute for Marine and Atmospheric Research at the University of Hawaii, and Jamie Barlow, Pacific Islands Fisheries Science Center, will conduct daily fishing expeditions obtaining scientific data on bottomfish, grouper and snapper species. They will be focusing on life history factors including age, growth, male/female ratios, length and weight. This is very exciting research since the last data collected from this region was from the 1970s and 80s.
I am very excited and fortunate to be part of this important scientific research project, and the significant data collected by the scientists.
Did You Know?
American Samoa pronunciation: The first syllable of “Samoa” is accented.
Pago Pago (capital of American Samoa): The “a” pronunciation uses a soft “an” sound as in “pong.”
Animals Seen Today
“Flying Foxes” Fruit bats
Brown tree frog
NOAA TEACHER AT SEA STEVEN WILKIE ONBOARD NOAA SHIP OREGON II JUNE 23 — JULY 4, 2011
Mission: Summer Groundfish Survey Geographic Location: Northern Gulf of Mexico Date: June 26, 2011
Surf. Water Temp.
Surf. Water Sal.
Science and Technology Log
After two days of travel we are on site and beginning to work and I believe the entire crew is eager to get their hands busy, myself included. As I mentioned in my previous post, it is difficult if not impossible to separate the abiotic factors from the biotic factors, and as a result it is important to monitor the abiotic factors prior to every trawl event. The main piece of equipment involved in monitoring the water quality (an abiotic factor) is the C-T-D (Conductivity, Temperature and Depth) device. This device uses sophisticated sensors to determine the conductivity of the water, which in turn, can be used to measure salinity (differing salinities will conduct electricity at different rates). Salinity influences the density of the water: the saltier the water the more dense the water is. Density measures the amount of mass in a specific volume, so if you dissolve salt in a glass of water you are adding more mass without much volume. And since Density=Mass/Volume, the more salt you add, the denser the water will get. Less dense objects tend to float higher in the water column than more dense objects, so as a result the ocean often has layers of differing salinities (less salty water on top of more salty water). Often you encounter a boundary between the two layers known as a halocline (see the graph below for evidence of a halocline).
Temperature varies with depth in the ocean, however, because warm water is less dense than cold water. When liquids are cold, more molecules can fit into a space than when they are war; therefore there is more mass in that volume. The warm water tends to remain towards the surface, while the cooler water remains at depth. You may have experienced this if you swim in a local lake or river. You dive down and all of a sudden the water goes from nice and warm to cool. This is known as a thermocline and is the result of the warm, less dense water sitting on top of the cool more dense water.
Temperature also influences the amount of oxygen that water can hold. The cooler the temperature of the water the more oxygen can dissolve in it. This is yet another reason why the hypoxic zones discussed in my last blog are more common in summer months than winter months: the warm water simply does not hold as much oxygen as it does in the winter.
The CTD is also capable of measuring chlorophyll. Chlorophyll is a molecule that photosynthetic organisms use to capture light energy and then use to build complex organic molecules that they can in turn be used as energy to grow, reproduce etc. The more chlorophyll in the water, the more photosynthetic phytoplankton there is in the water column. This can be a good thing, since photosynthetic organisms are the foundation of the food chain, but as I mentioned in my earlier blog, too much phytoplankton can also lead to hypoxic zones.
Finally the CTD sensor is capable of measuring the water’s turbidity. This measures how clear the water is. Think of water around a coral reef — that water has a very low turbidity, so you can see quite a ways into the water (which is good for coral since they need access to sunlight to survive). Water in estuaries or near shore is often quite turbid because of all of the run off coming from land.
So, that is how we measure the abiotic factors, now let’s concentrate on how we measure the biotic! After using the CTD (and it takes less time to use it than it does to describe it here) we are ready to pull our trawls. There are three different trawls that the scientists rely on and they each focus on different “groups” of organisms.
The neuston net (named for the neuston zone, which is where the surface of the water interacts with the atmosphere) is pulled along the side of the ship and skims the surface of the water. At the end of the net is a small “catch bottle” that will capture anything bigger than .947 microns. The bongo nets are nets that are targeting organisms of a similar size, but instead of remaining at the surface these nets are lowered from the surface to the seafloor and back again, capturing a representative sample of organisms throughout the water column. The neuston net is towed for approximately ten minutes, while the bongo nets tow times are dependent on depth. Once the nets are brought in, the scientists, myself included, take the catch and preserve it for the scientists back in the lab to study.
The biggest and baddest nets on the boat are the actual trawl nets launched from the stern (back) of the boat. These are the nets the scientists are relying on to target the bottom fish. This trawl net is often referred to as an otter trawl because of the giant heavy doors used to pull the mouth of the net open once it reaches the bottom. As the boat moves forward, a “tickler” chain spooks any of the organisms that might be lounging around on the bottom and the net follows behind to scoop them up. This net is towed for thirty minutes, and then retrieved and we spend the next hour or so sorting, counting and measuring the catch.
I thought that adjusting to a 12 hour work schedule would be tough, but with a 5-month old son at home I feel I am more prepared than most might be for an extended day. I might go as far as to say that I have more down time now than I did at home! Although the ship’s crew actually manages the deployment of the majority of the nets and C-T-D, the science team is always involved and keeping busy allows the hours to tick away without much thought. Before you know it you are on the stern deck of the ship staring at a gorgeous Gulf of Mexico sunset.
The sun has long since set. As I write this it is well after midnight and my bunk is calling.