University of Southern California

Lovely Seaweeds

Judith Connor, January 27, evening — Seaweeds: the lovely, fluid ocean flora. Each expedition compels me to learn more about them. What makes the Puget Sound in Washington such a rich haven for species of algae? How closely related is the huge kelp Ecklonia in Namibia to the bull kelp back in California? And here in Antarctica, how do photosynthetic seaweeds survive up to 10 long winter months of darkness and cold?

Yesterday, faced with massive chunks of ice against the shore at Cape Evans, I could imagine Carl Skottsberg’s frustration during the Swedish Antarctic Expedition of 1901-1903. He dredged for seaweeds under the ice and ultimately lost most of his collections when the ship sank in pack ice. Some 50 years later, when scuba gave scientists diving access to the seafloor, Skottsberg and Mike Neushul described the algae from the South Shetland Islands and the Antarctic Peninsula.

A few weeks ago, a hole in the sea ice gave our divers a door to the deep. Now that the sea ice has broken up, there is no easy access. I wanted to observe Cape Evans’ sea floor, but a grinding icy barrier serves as an impediment to the dark, cold waters beyond.

broken sea ice.JPGTo the north of us, along the Antarctic Peninsula, Skottsberg’s rich stands of seaweeds extend from the shallows to depths of 30 meters. Large brown algae (but no kelps) dominate a diverse underwater scene. Antarctica has no kelps, so other brown algae (the Desmarestiales) have evolved to fill a similar niche.

seaweedseaurchin.JPG Further south, only a few species survive. In McMurdo Sound, south of 77S, the southernmost seaweeds include Phyllophora antarctica, a red alga endemic to Antarctic waters and thus found nowhere else. Sea urchins here wear a topcoat of Phyllophora cover (see photo above), perhaps as a disguise from predators.

Looking at our seaweed samples under a dissecting microscope, I didn’t think any light could penetrate the heavy cover of diatoms on the older segments. But the growing tips of the branches of Phyllophora were shiny red and clean. Summer sunlight was reaching the seaweeds and stimulating photosynthesis and new growth.

Judith Connor, Ph.D., is one of the instructors for the NSF Antarctic Marine Biology program and serves on the staff of Monterey Bay Aquarium Research Institute.

1 Comment

Dear Sir, i would like to study on taxonomy part of seaweed of antarctica so may you help regarding how i can start and is it different from temperate zone? i have experienced of inter-tidal area of Gujarat India. now i have dream of explore the south pole of the earth. please i request you to give me guidelines for the same project. thanking you, Dr S K Dodia