NOAA Teacher at Sea
Onboard NOAA Ship Gordon Gunter
June 5–24, 2013
Mission: Ecosystem Monitoring Survey
Geographical area of cruise: The continental shelf from north of Cape Hatteras, NC, including Georges Bank and the Gulf of Maine, to the Nova Scotia Shelf
Weather Data from the Bridge:
Latitude/longitude: 3853.256 N, 7356.669W
Barometer: 1014.67 mb
Speed: 9.7 knots
Science and Technology Log:
Even before the plankton samples are brought onboard, scientists start recording many types of data when the equipment is launched. The bongos are fitted with an electronic CTD (conductivity, temperature and density) and as they are lowered into the ocean the temperature, density and salinity (salt content) are recorded on a computer. This helps scientists with habitat modeling and determining the causes for changes in the zooplankton communities. Each bongo net also has a flow-through meter which records how much water is moving through the net during the launch and can is used to estimate the number of plankton found in one cubic meter of water.
The plankton collected from the two bongo nets are separated into two main samples that will be tested for zooplankton and icthyoplankton (fish larvae and eggs). These get stored in a glass jars with either ethanol or formalin to preserve them. The formalin samples are sent to a lab in Poland for counting and identification. Formalin is good for preserving the shape of the organism, makes for easy identification, and is not flammable, so it can be sent abroad. However, formalin destroys the genetics (DNA) of the organisms, which is why ethanol is used with some of the samples and these are tested at the NOAA lab in Narragansett, Rhode Island.
When the samples are returned from Poland, the icthyoplankton samples are used by scientists to determine changes in the abundance of the different fish species. Whereas, the zooplankton samples are often used in studies on climate change. Scientists have found from current and historic research (over a span of about 40 years) that there are changes in the distribution of different species and increases in temperature of the ocean water.
At the Rosette stations we take nutrient samples from the different water depths. They are testing for nitrates, phosphates and silicates. Nutrient samples are an important indicator of zooplankton productivity. These nutrients get used up quickly near the surface by phytoplankton during the process of photosynthesis (remember phytoplankton are at the base of the food chain and are producers). As the nutrients pass through the food chain (zooplankton eating phytoplankton and then on up the chain) they are returned to the deeper areas by the oxidation of the sinking organic matter. Therefore, as you go deeper into the ocean these nutrients tend to build up. The Rosettes also have a CTD attached to record conductivity, temperature and density at the different depths.
Another test that is conducted on the Rosettes is for the amount of dissolved inorganic carbon. This test is an indicator of the amount of carbon dioxide that the ocean uptakes from outside sources (such as cars, factories or other man-made sources). Scientists want to know how atmospheric carbon is affecting ocean chemistry and marine ecosystems and changing the PH (acids and bases) of the ocean water. One thing they are interested in is how this may be affecting the formation of calcium in marine organisms such as clams, oysters, and coral.
New word: oxidation – the chemical combination of a substance with oxygen.
This week we headed back south and went through the Cape Cod canal outside of Plymouth, Massachusetts. I had to get up a little earlier to see it, but it was well worth it. The area is beautiful and there were many small boats and people enjoying the great weather.
We also did a small boat transfer to bring five new people onboard, while three others left at the same time. It was hard to say goodbye, but it will be nice to get to know all the new faces.
So now that we are heading south the weather is warming up. I have been told that we may start seeing Loggerhead turtles as the waters warm up – that would be so cool. We had a visit by another group of Common Dolphins the other day. They were swimming along the side of the ship and then went up to the bow. They are just so fun to watch and photograph.
We have been seeing a lot of balloons (mylar and rubber) on the ocean surface. These are released into the air by people, often on cruise ships, and then land on the surface. Sea turtles, dolphins, whales and sea birds often mistake these for jelly fish and eat them. They can choke on the balloons or get tangled in the string, frequently leading to death. Today, we actually saw more balloons than sea birds!!! A good rule is to never release balloons into the air no matter where you live!
Did you know? A humpback whale will eat about 5000 pounds of krill in a day. While a blue whale eats about 8000 pounds of krill daily.
Question of the day? If 1000 krill = 2 pounds, then together how many krill does a humpback and blue whale consume on a daily basis.