Absolutely Fabulous Phytoplankton

Now that I’ve confessed I glue tags to the heads of female elephant seals, you must be wondering how I get away with it. Or why for that matter. I’ll tackle these questions in order:

The first thing you should know about me is that I am CRAZY about animals. All of them. Except mosquitos, crocodiles and spiders from Chize (long story).

I love fish!!!
I even love 'not-seal' elephants!!

The adult female elephant seals we select are anaesthetised and then tagged according to approved ethical procedures. While they’re all doped up, they’re also weighed and checked out by dedicated biologists resident on Marion Island. The tags themselves appear to have no negative impact on health or behaviour, and they fall off when the seals moult several weeks later. No problemo!

With regards to my project, it’s all to do with little green cells. Or, more scientifically, phytoplankton. These microscopic, photosynthesising organisms are more important that I can adequately express.

Images copyright Smithsonian Environmental Research Center (http://earthobservatory.nasa.gov/Experiments/ICE/Channel_Islands/)

Phytoplankton form the foundation upon which the entire marine web is based. Without these teeny-tiny wanderer/drifter (plankton) plants (phyto), every food chain in every ocean would collapse.

This amazing SEM picture of a diatom cell is by Dr. Paul Hargraves and Fay Darling (http://www.environmentalgraffiti.com/news-diatoms-art)

Now, elephant seals don’t eat phytoplankton, but zooplankton like krill do. And LOADS of things love krill – from the smallest fish to the largest mammal on the planet, the blue whale.

Photo by George Mobley (http://animals.nationalgeographic.com/animals/invertebrates/krill/)

Bigger fish and squid then feed on the little fish, and it’s these prey species that the starved female seals gorge themselves on. Tah dah! An entire marine food web based on little green cells. So measuring how much phytoplankton is in the Southern Ocean is really, really important… and that’s part of WHY I get away with tagging seals with ‘lasers’.

The ‘lasers’ on my tags actually measure something called fluorescence. Using a scary set of equations painstakingly created by Dr. Christophe Guinet from CEBC-CNRS (Chize), fluorescence can then be utilised to obtain Chlorophyll-a concentration, which is the value satellites give us as a measure of how much phytoplankton they can ‘see’ floating on the surface of the oceans. Which it isn’t, really… But I won’t get into the bio-optics just yet. What I will say is that while satellites are awesome (aside from when they suddenly stop working), they’re also notably inaccurate in the Southern Ocean.

Confused? Alarmed?! Don’t worry, I’ll explain all of this properly over the next few weeks. For the next couple of days, however, I need to concentrate on transporting myself and 40kg of luggage to St. Andrews…

To tide you over (pun intended? no) and ensure you remain you smitten with the microscopic world, I suggest watching this amazing TED(Ed) Talk. I can’t get enough of it! http://www.ted.com/talks/the_secret_life_of_plankton.html


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