Don’t ever let anyone tell you that there are no forests in Antarctica. There are! The forests are forests of large brown macroalgae, also called seaweeds, here along the western Antarctic Peninsula. Pretty much every dive we make at Palmer Station is a dive into a forest, or at least it starts and ends that way.
The biggest “trees” in the forest are four species: Desmarestia menziesii, Desmarestia anceps, Himantothallus grandifolius, and Cystosphaera jacquinotii. Over on the right side of this post you can see still photographs I’ve taken of some of these. But still photos don’t really convey the extent of these forests. Videos do not completely do so either, but come closer.
One new thing we are doing this season here on UAB in Antarctica is putting up videos from our stay here. If you click on the YouTube link that is below the photos on the right you’ll be taken to our UAB in Antarctica YouTube Channel. We’ll try to post short, informal videos of our life here regularly. But we also have two videos there that are a little longer and have information on the undersea life.
If you click on the following link to The Forests of Antarctica it will take you to a new page or tab with the video on the macroalgae. There you will see more still photographs along with underwater video of all four of the main, large brown seaweeds that dominate these communities.
There are three types of macroalgae and they are color coded: brown, red, and green. The difference in color is because they have different types of pigments which capture light and channel it to a pigment they all share, chlorophyll a. Special chlorophyll a molecules bound to special proteins are able to pass the energy from the light to other proteins. These other proteins use it to take carbon from carbon dioxide molecules in the water and convert them into sugars.
The plants then use the energy stored in the sugar and the carbons connected into the sugars themselves to grow. So instead of getting energy and carbon-based molecules for growth from eating other things like animals do, like plants, macroalgae capture their own energy from sunlight. I like to say that algae and plants suntan for a living. Good work if you can get it.
Brown macroalgae dominate the undersea forests here in terms of covering the bottom. In many places, nearly 100% of the bottom is covered by them as you can see in the video. The biomass, or total weight, of all the macroalgae in these locations is comparable to what you would find in a giant kelp forest off the coast of California. When I said these are forests, I wasn’t joking!
Even though brown algae are the kings in terms of biomass, red algae are the kings in terms of numbers of species. There are more species of red macroalgae here than there are browns, so they are very important in terms of the biodiversity of the area. They can be numerically dominant at some places too, although in my experience mostly in very shallow waters. They are often the most abundant macroalgae growing in deeper waters on vertical walls where we also find lots of bottom-dwelling invertebrate animals.
In very deep water – water too deep for us to dive to the bottom in and also too deep for enough sunlight to penetrate to allow the macroalgae to grow – the invertebrate animals take over. If we go to deep (30-40 m, or 100-130 feet) depths on vertical walls the macroalgae do not grow quite as well as otherwise so the animals can grow there with them without getting smothered. We will have another post later on about these animals, but if you would like to see video on them, just click on the YouTube channel link on the right and select the “Invertebrates at Palmer Station” video.
I’m a phycologist, which means that I am a scientist who studies algae (“phycos” is the Greek word for algae). These rich macroalgal forests at Palmer Station are a wonderful place to me! We’ll look forward to telling you about ways these forests are unique compared to undersea communities in other parts of the world in upcoming posts.