A slightly different talk this time on the fascinating biodiversity of the Antarctic seabed by Dr Huw Griffiths of British Antarctic Survey. The talk summarised the wide range of life that lives under the water around Antarctica.
Only 0.4% of the Antarctic is completely free of snow and
ice, with the ice sheet being up to 4km thick in some parts. This makes living on the
continent extremely difficult however, some species do make this their
permanent home such as mites, tardigrades, springtails and even some wingless
insects. These creatures live in the range of mosses, liverworts, lichens and
tussock grasses that are able to survive.
Compared to the land,
the waters around Antarctica are less harsh and more life can persist. That
said compared to the other seas and oceans, the Southern Ocean is a much more
inhospitable place with strong clockwise moving currents, extreme West-East
winds and sea temperatures that rarely get above 0 degrees (In some parts the
surface and seafloor temperature is almost the same!).
However, over 20,000 species have been found in the water
around Antarctica! Of these species only c90 are the traditional Antarctic
birds and mammals that many people will first think off such as penguins,
seals, whales and albatrosses. The next layer of species in the sea are the
plankton and mesopelagic fish that make up c700 species. Out of these 700
species the most important and numerous is the Antarctic krill which feeds on
plankton and are an important food source for larger animals. Also, the amount of dead plankton due to the krill and the faeces of the krill help life much deeper as it sinks to the seafloor
providing vital nutrients. The final section is the seabed contains an
astonishing c19,000 species!
It may come as a surprise to many that the Antarctic seafloor is so rich in life. The seabed contains large numbers of corals, sponges and the like which has been suggested to be due to a lack of crushing predators (sharks, rays, crabs etc) that normally damage these species and may give us an insight into what the seafloor looked like in the time of the dinosaurs.
However, not all of the seafloor is covered in coral reefs with large areas covered in a substance called diatomaceous ooze (a diatom rich sediment). Here different species live such as sea snails, sea spiders, anemones, hydrozoans, star fishes and some sponges on any rocks.
The shallower areas of the sea floor look more familiar with species like limpets, bivalves, cephalopods and more fish species. Unfortunately, the shallower seafloors are at risk of icebergs scrapping the floor and destroying the life there; with this becoming a greater threat as global temperatures continue to rise resulting in more and more ice bergs. As a result species rich reefs are mainly found on cliffs in shallow water where they are protected.
Personally, I would not call myself a marine biologist with my interests much more focused around ornithology and entomology. However, this talk was extremely interesting and definitely filled a gap I didn’t know I had in my knowledge. This talk has also helped to spark an interest in marine biology.
The research that is currently happening into Antarctic marine
life is defiantly exciting with so much still to learn about life on the
seafloor however, there is only a limited number of scientists that are ever
lucky enough to work in Antarctica and though it is a dream job to many
including myself unfortunately it may just be that.
However, this talk has defiantly helped to inspire me to follow my dreams; as the saying goes ‘you only live once’ so why not spend it working in amazing places.
Want to know more?
Watch this video by BBC Earth for seven worlds one planet which shows some of the creatures found under the Antarctic ice! With divers diving through a small whole made in an ice shelf.
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