A Q&A with Expert Michael Lang
Q: How did your interest in shallow sea bottom dwelling octopi develop? How often do you see such octopi on your polar dives?
A: Growing up in Belgium, our family spent much time at our summer home in Liguria (Italian Riviera) which was less than one hour from the Oceanographic Museum/Aquarium in Monte Carlo, Monaco. The most interesting aquarium there was always the one with octopus, amazing, intelligent creatures with problem-solving and color-changing capabilities. You wouldn't want to study a boring creature if marine biology was your interest, right? Marine organisms need to be studied in their environment, hence under water, the reason for my interest in octopus ecology and scientific diving. On polar dives in Antarctica we routinely see large octopi, although most populations occur in deeper waters beyond diving depths.
Q: When one ordinarily thinks of the "White Continent," it is as an austerely beautiful yet cold and barren place. Is there a particular cold adaptation that is common to birds and sea mammals alike that enables them to flourish there, at least part of the year?
A: Behavioral and physiological adaptations allow diving birds (such as penguins) and marine mammals (such as Weddell seals) to inhabit this extreme perennially ice-covered environment. Because there is no food topside, they have evolved as expert breath-hold divers to forage for prey in the water column or deep on the sea floor. Minimizing loss of body heat is equally important when temperatures are well below freezing most of the time. Either a layer of blubber or fine, densely packed feathers that capture air (a good insulator) create a thermal protection layer to keep birds and seals warm.
Q: Can our travelers expect to see sun dogs and diamond dust?
A: Viewing sundogs (aka parhelia) should be possible while we are in cold Antarctica especially as we are approaching winter toward the end of the austral summer and the sun is lower on the horizon. Sundogs appear on either side of the sun because of refraction of light by ice crystals (aka diamond dust). When the crystals are randomly distributed a circular halo may appear around the sun, if they are vertically oriented, a diamond-shaped sundog may appear on either side of the sun.
Q: If Antarctica is mostly deeply ice-covered, how and where do the tenacious lichens and fungi manage to grow?
A: Lichens and fungi grow predominantly on exposed rock that is wind blasted or melted clear of ice and snow. About 2% of Antarctica is actually ice free. There are also dry valleys on the continent that have not seen precipitation in hundreds of years. Only the hardiest species survive in Antarctica and lichens are highly tolerant of drought and cold. Lichens are a symbiosis of two different organisms, a fungus and an alga. The fungus supplies the plant with water and nutritious salt, and the algal part organic substance, like carbohydrates. There is also very little competition for growing on exposed surfaces. The Antarctic Peninsula contains the highest diversity of about 150 species of lichens.
Q: Can you give us a sneak peek at the Census of Antarctic Marine Life findings during the International Polar Year? Did scientists find new species in the Antarctic in the course of the survey?
A: In 2010, the first global Census will relate range maps for known Antarctic marine species and maps of species richness, showing hotspots and the extent of biodiversity. The Census will also offer a complete list of named marine species as well as fresh estimates of species yet to be discovered. Web pages for the great majority of the named species are erected, compiled in cooperation with the Encyclopedia of Life and DNA identifiers (barcodes) assembled for many species. There will also be new estimates of biomass at various levels in the food chain and for selected species and estimates of abundance that has been or might be lost soon. Interestingly, one of the top highlights of the fourth progress report of the Census of Marine Life reported on the Antarctic ancestry of many deep-sea octopuses worldwide. There is now published the first molecular evidence that a large proportion of deep-sea octopus species worldwide evolved from common ancestor species that still exist in the Southern Ocean. Octopuses started migrating to new ocean basins more than 30 million years ago when, as Antarctica cooled and a large ice sheet grew, nature created a "thermohaline expressway", a northbound flow of frigid water with high salt and oxygen content. Isolated in new habitat conditions, many different species evolved; some octocpuses, for example, lose their defensive ink sacs, which are pointless at perpetually dark depths.
Q: Our program will take place in February, at the end of the austral summer (November – March), which is said to be the best whale watching of the season. Can you please explain why this is so?
A: This is the time of year when the sea ice has retreated to its maximum extent and Antarctic krill (shrimp-like creature) populations explode forming large size-specific schools of millions of krill. This amount of prey species is the mainstay diet of baleen whales. At this time of year, it is quite common to spot Minke, Blue and Humpback whales, killer whale pods, but also Fin, Sei and Beaked whales. Before the whales head north for the winter, they gorge on krill.
Q: As the Smithsonian Scientific Diving Officer, you direct one of the nation's largest civilian scientific diving programs. Can you please share with us some of the projects that are currently being carried out by that program?
A: The Smithsonian Marine Science Network and Smithsonian Scientific Diving Program provide the research support and infrastructure for our scientists, collaborators and post-doctoral fellows to accomplish their underwater studies. In Panama we conduct numerous long-term studies examining the evolution and divergence of marine organisms in the Caribbean and the Pacific, such as tropical reef fish diversity, black sea urchin populations throughout the Caribbean, Panamanian coral reef monitoring, effects of oil spills and behavioral responses of marine organisms. In Belize and Florida we study biological, geological and chemical ecology of coral reef, seagrass and mangrove systems. In the Chesapeake Bay we study population dynamics and life histories of commercially important species such as blue crabs and oysters, hypoxia in marine systems, and impacts of non-native, invasive species on the marine ecosystem.
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