Since returning from Summit, we have had some time to transition into the next exciting phase of our trip here in Greenland: Arctic Ecology…
We began our explorations by heading into our own backyard, that is, the valleys and lakes around Kangerlussuaq. Led by Ross Virginia and Matt Ayers, we headed to a couple sites about 5-10 miles out of town, where we familiarized ourselves with some of common local flora.
We quickly became acquainted with some of the major players, or foundation species, in this ecosystem. One of the most abundant species we noticed was a low, shrubby plant called Northern Willow (Salix glauca). They have oblong leaves about 4-6cm long and these plants are dioecious, indicating that each plant is either male or female. These guys were easy to recognize as they produce small clusters of flowers, called catkins, which appear as fuzzy cylindrical stems.
Our next common heath plant was slightly smaller, with rounded leaves, and closer to the ground than the Willow, called the Dwarf Birch (Betula nana). As we walked around, it was clear that Willow and Birch were the two dominant woody species in this landscape.
Other common plants in the area included the bright green, highly branched Field Horsetail (Equisetum arvense), and the beautiful blue Arctic Bellflower (Campanula uniflora).
We’ve also learned the calls and visual markers of the most common birds in this area, including the bright flash of white rump distinguishing the Wheatear (Oenanthe oenanthe), and the red forehead and lightly rosey breast of the Common Redpoll (Carduelis flammea). We’ve also become WELL acquainted with the loud nasal honks and squawks of the ravenous Ravens that guard our dumpster. Species biodiversity in the Arctic is quite low compared with ecosystems that have more tolerable abiotic conditions, less geographic isolation, and more complex food webs. So one of the most satisfying things about working here is how quickly we can have a handle on identifying species!
Next, we tested our reflexes and dexterity through catching fish with our bare hands (yes, we all succeeded!), after which Matt proceeded to shock, amaze, (and test our gag reflexes) as he carefully sliced open the bellies of the Sticklebacks to reveal the slender, pink, squirming parasites living inside. Almost the entire Stickleback population in this lake is infected by this flatworm, observable by the large, distended abdomens displayed by these parasitized fish. The biology of these Schistocephalus worms are fascinating – Stickleback are actually just one of three different hosts necessary to complete their life cycle! In fact, these parasites take full advantage of the food web: they start by infecting zooplankton in the water, are then passed onto a planktivorous fish host (like the Stickleback), and are eventually snapped up and passed into their final host stage, a bird!
But perhaps one of highlights of our adventures thus far…has been meeting infamous sea tomatoes firsthand! At the end of the day, Ross and Matt took us to one of the highest sea tomato abundance lakes in the area, and it blew away all of our expectations. These orange-to-brownish gelatinous spheres are actually colonies of cyanobacteria of the genus Nostoc. Cyanobacteria have a fascinating and unique biology, including the ability to execute three different complex metabolic processes, that is photosynthesize, respire, and fix atmospheric nitrogen! However, while this particular lake bed is covered in sea tomatoes, neighboring lakes appear to have little to none at all. Are they dispersal limited? Nutrient limited? This remains one of the biggest mysteries surrounding their abundance and distribution in this area…and one which we are hoping to tackle as we brainstorm these next couple weeks!
Last (but certainly not least), we used our investigative power to assess the effectiveness of chocolate cake on happiness and satiation in Arctic scientists. Results – it is highly effective!
Happy Birthday, Stephanie!!