Ask an Explorer
Questions were sent to the science party during this expedition. Selected questions and answers are offered below.
Question from: Kathleen, Cedar Key, Florida
I am conducting research in the Lower Suwannee National Wildlife Refuge in Cedar Key, Florida. Specifically, I am working with horseshoe crabs. Have you been able to map the northeastern quadrant of the Gulf? The map on the Web site of the Sigsbee Escarpment is awesome. I would like to know if there is geology map of my region.
Answer from: Harry Roberts, Louisiana State University
The map you viewed on our Web site was a computer-enhanced multibeam bathymetry map. The original data for this map was acquired by NOAA. Similar maps are available for continental shelf areas, but the relief on the shelf is not so spectacular. It sounds as if you are interested in shallow-water, reef environments. Good bathymetric, geologic sediment, and habitat maps as well as photo mosaics exist for this area of Florida. Thanks for your interest in our Gulf of Mexico Web site.
Question from: Kathleen, Cedar Key, Florida
Also, were you doing any plankton tows? Did you find Limulus larvae? I'm looking for data from the loop current and areas north of the loop in my area.
Answer from: Nicole Morris, NOAA Office of Ocean Exploration
During last year's Expedition to the Deep Slope, we did not perform any plankton tows. The primary purpose of last year's mission was to discover and characterize the sea-floor communities that live in association with hydrocarbon seepage and on hardground in the deep Gulf of Mexico. There were two sampling operations that occurred last year. Since the Alvin submersible can only dive during daytime hours, we performed separate nighttime operations which were an essential part of the mission. These nighttime operations included bottom trawling, conductivity-temperature-depth (CTD) casts, multibeam mapping, and box coring.
This year’s Expedition to the Deep Slope mission includes two types of activities: revisiting and completing our characterization of about half of the sites discovered last year and exploring and characterizing three to five new areas. And also for this year’s mission, we will not be performing any plankton tows.
Question from: Tanya, Monroe, Louisiana
Has there been any determination of a symbiotic relationship between the polychaete worms and the mussels?
Answer from: Stéphane Hourdez, Researcher, Station Biologique de Roscoff, France
There is one group of polychaetes that is found living inside the mantle cavity (along the gills) of the mussels. However, their relationship is unclear. Some people think the polychaetes are parasitic, snatching small pieces of gills from the mussels. Others think they may be too big to be truly parasitic, and if they do harm the mussels it is a rare occurrence. Even though the mussels are symbiotic with bacteria, they are still able to filter, and the worm may divert some of the filtered food for their needs (this is called cleptoparasitism).
Question from: Cindy, Wilmington, North Carolina
Can you visually distinguish male and female chemosynthetic tubeworms?
Answer from: Stéphane Hourdez, Researcher, Station Biologique de Roscoff, France
Male and female tubeworms look exactly the same in their tubes, so there is no way to distinguish between them on the bottom of the ocean. But if you remove the worms from their tubes, you can visually distinguish between male and female worms. For male tubeworms, there is a pair of raised grooves that are nearly 1 inch (2.5 centimeters) long on the dorsal side, between the two wings of the vestimentum (the part of the worm located right below the opening of the tube). For females, this same area appears smooth and no grooves are present.
Question from: Bruce, Arden, North Carolina
I was fascinated to learn that the cold seep tubeworms are classified as annelids. Are they segmented (like earthworms) as adults? Or as larvae?
Answer from: Stéphane Hourdez, Researcher, Station Biologique de Roscoff, France
It took a very long time for the scientists to agree on where to place the tubeworms. They once were considered to be in a phylum of their own. Their larvae are segmented and look pretty much like any other annelid larvae. The adults are very strange and appear
unsegmented. However, if you look at the end of the body (a part that is very often broken off in the collected worms), there are segments and bristles. These characters and others were used to justify placing them in the annelids. Modern molecular analyses of their DNA has also confirmed they are annelids.
Question from: Bruce, Arden, North Carolina
Since the cold seep tubeworms form such "twisty" tube casings, how do you measure their length? Do you use the old-fashioned string method, or do you have a more sophisticated approach?
Answer from: Stéphane Hourdez, Researcher, Station Biologique de Roscoff, France
After considering other methods, the best, fastest, cheapest is the good-old string method. We simply run the string along the length of the tube, then align the string on a meter stick, and get the measurement. The whole process usually takes about a minute. In some cases, though, the tubes are so twisty that they make loops (one tube had nearly two turns in its loop); and, in these cases, it may take longer to measure.
