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27 April, 2000

Algae Groups Qeuestion 68: Besides killer whales, are there other whales in the Antarctic that are not "baleen" whales? The macroalgae (seaweed) that we have been working with are primary producers. Like land plants, they use chlorophyll and other pigments to convert the sun's energy, CO2, water and other nutrients into glucose. They are divided into three groups (phyla) that commonly are called by the color names "green algae," "red algae," and "brown algae." Their scientific names are, respectively, Chlorophyta, Rhodophyta, and Phaeophyta. And I will mention a bit of grammar because it is confusing: "algae" is plural, "alga" is singular. Macroalgae have a holdfast which anchors them to the substrate. These are not like roots on a terrestrial plants. Macroalgae can absorb water and nutrients from the marine environment over all surfaces of their bodies. The holdfast is only their attachment point. Some species have a stem-like structure called a stipe. The leaflike part is the blade, and it is where most of the photosynthesis occurs. The area of growth on a macroalga, called the meristem, is located at the base of the blade. The green algae tend to have the fewest defences, either structural or chemical, and therefore are usually preferred by grazers. This is the group most freshwater algae belong to and the group of algae most closely related to land plants. They contain some of the same types of chemicals and structures that terrestrial plants do. Few species of greens live very deep in the ocean. Green algae are some of the species we collect in the intertidal locations on Laggard Island. These include Cladophora and Lambia species. The majority of the brown algae species are marine. Brown carotenoid pigments give this group their color. Browns tend to be large (1-3 meters) and have lots of protective gooey mucus. The brown algae are one of the subjects our science group has been focusing on. In this area that includes Ascoseira, Chordaria, Cystosphaera, three Desmarestia, Himantothallus, and Phaeurus species. Red algae are the most diverse group of all algae world-wide, and we found that to hold true for the Palmer area as well. We have found over 25 species of reds so far. They are smaller in size than the huge browns but make up for that in numbers. They are also the most primitive of algae. The reds include coralline algae which have calcified cell walls (same material as in sea shells) and are found encrusting much of the exposed rock in the underwater area around Palmer with a pink coat. Limpets can scrape away at the hard surface of the encrusting algae for food, but the tough cell wall repels most other grazers. Today was beautifully sunny and calm. Katrin and I decided to take our Zodiac out for an hour of free time squeezed in before lunch. A good thing we did, as the motor had developed a problem. After 15 minutes we gave up trying to start it and called in the Boating Coordinator. When he couldn't get it started either, we switched to the SAR (search and rescue) Zodiac, shoveled out the snow and went out. If we hadn' t checked the Zodiac then, the problem would have come up on our planned afternoon dive! We drove east towards Surge Rocks and Cormorant Island. While circling a berg for photo ops we heard a small exhalation noise. It was hardly noticeable against the sound of the idling engine. Katrin and I looked at each other, recognizing the sound of a seal sneaking a breath at the surface... and close, too! We looked around the boat and spotted a small circle of ripples in our wake just off the end of the boat. Not ten seconds later, the largest leopard seal of the area surfaced right next to us. Three feet away from the boat and nearly as long as our Zodiac, she (most likely) was very impressive. After checking us out, she submerged and appeared again near the berg, swimming away. I got back to the station in time to tend the afternoon dive with Nancy and Allisha from the station crew. Waiting for the divers to swim their transect with video recording equipment was peaceful as we enjoyed the sun glinting off the ice rounds in the water and off the snow cover on the islands. While we were out, we missed the April fire drill. A new scenario for those on the station to practice, as Nancy is one of the fire fighters. Answser 67: Baleen whales have two roughly equal-sized blowholes; toothed whales have only one.


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