22 April, 2000

Benthic Invertebrate Life Question 63: Which whale has the best "song"? I started off the day somewhat unpleasantly with a problem-plagued dive. The problems were minor but still uncomfortable! Andy and I started our dive at Christine easily, but as soon as I started descending, I could feel an icy trickle into my glove. I signaled to Andy that we needed to resurface. The tenders did a beautiful job of removing the glove with the hole and regloving me with a spare while I stayed in the water. It takes a lot of effort to get one of the dry gloves properly attached. Two tenders held me and my arm up while one of the other divers still in the boat put the glove on. Unfortunately, the effort needed to reglove me in the water dislodged the hose leading to my drysuit, and when we started to descend I couldn't add air to my suit. As I descended I felt the suit compress around me, and my descent went faster and faster. When I found that the hose was no longer connected, I switched to using my BC to increase my buoyancy and control my descent. My suit was pinching me painfully anyplace that there was excess material to form wrinkles. Fortunately we had descended in a location with a depth of around 40 feet , so we were on the bottom very soon and my buddy could reconnect the hose. The rest of the dive was uneventful except for three passing Gentoo penguins, but I will have long lines of bruises for several days from the suit squeeze! Diving around the islands, the only benthic (ocean floor) environments we have seen are rocky ones. Some are vertical walls of rock, some are long slopes of loose rock, some have steps of large boulders. In areas near the glacier there are soft bottom environments with a unique group of invertebrates and algae, but these are not our focus. We collect both invertebrates (animals without spinal columns) and macroalgae while diving. Most algae and invertebrates have certain depth zones that they are most often found in. There are also definite differences in the species found at different sites at the same depth. With the large quantities of macroalgae, we often have to push it aside to look closely at the substrate for invertebrates. Some of the benthic invertebrates we have found I mentioned in earlier journal entries, such as tunicates or the starfish Odentaster sp. We see lots of sea stars underwater; two other species that we see frequently are Neosmilaster sp. and Perknaster fuscus. There are six or seven other sea star species we see occasionally. At certain sites we see several species of sea cucumber; the most common is black in color. Sea anemones and nudibranchs are similarly present but not abundant. The primary species of sea urchin is the purple, spiny Sterechinus sp. There are also shelled animals. Gastropods, like the limpet Nacella concinna, and a variety of snails are the most common. I saw one small orange octopus on our first dive but none since. Bivalves (like clams) protrude above the sediment in softer bottom areas. There are various worms and crustaceans also. One of the most surprising invertebrates for me is the large insect-like isopod Glyptonotus which frequently comes into the lab on macroalgae. Isopods live in marine evironments elsewhere around the world, but they are tiny. Those here are five to six centimeters long! The most common invertebrates are sponges. We find them at every site and have recorded nearly 100 species. We are still finding new ones on our dives! Answer 62: The blue whale is the biggest animal ever. At the end of the summer, a well-fed blue whale could weigh as much as 150-200 tons. Maximum length is about 30.5 meters. A 100-ton blue whale eats 3 to 4 tons of krill each day during the peak feeding season.