Knauss in Aberdeen – Biodiversity, Fjords, and Climate Change

On the third day of this marine biodiversity extravaganza, one gentleman from the University of Hawaii presented his exciting findings from the hidden fjords of the West Antarctic Peninsula. If you’re wondering what Hawaiian researchers are doing near the South Pole, you wouldn’t be alone, as I was pondering that same question myself when he began explaining that his goals included comparing his research to what they have discovered in the Arctic.  Talk about spanning the globe!  As it turns out, his hard work has led him to conclude that climate change will dramatically alter the kinds and types of creatures that live in fjords, leading to growing similarities between the two poles!

When they first began their research on the peninsula (where climate is changing faster than anywhere on the planet ) near the U.S. Palmer Station Research Base, they had assumptions about what they would find.  However, as so often occurs with scientific exploration, they were greatly surprised by the large abundance and diversity of animals they found in their samples.  One hypothesis for this finding is that Antarctic fjords are in a much earlier melting stage compared to their northern counterparts.  Faster melting in the Arctic leads to larger amounts of heavy, glacial freshwater that causes faster sediment burial and less mixing within the water column.  Without mixing of the nutrients that sink to the bottom, these communities have low biodiversity.

The researchers decided that this alone could not explain the diversity they saw.  They began devising new theories to explain their findings when they made another discovery: sunken krill.  It would seem that an unexpected amount of krill die and “fall out” of the water column down to the benthos, where they decompose and create a feast for the abundant and diverse critters of the deep.  While they noticed these krill deposits in many locations, they have not been able to explain the phenomenon, as the Southern Ocean is not believed to be limited by oxygen or nutrients. 

Taken together, slow melting and krill fall-out create rich and diverse communities.  However, this means that these fjords have not one but two Achilles heels in the face of changing climate: quickening glacial melting and declining krill.  Another factor besides climate putting krill at risk is the growing pressure from fishermen braving the Southern Ocean and high fuel costs in search of this large (and dare I say charismatic?) crustacean species.  In this way, biodiversity hotspots in the Antarctic may shrink over time, eventually resembling Arctic communities.  The impacts of this shift would amplify through the food web in an area already experiencing warming temperatures, melting sea ice, and predator-prey distribution mismatches.  Only time will tell how the peninsula will change, but certainly interesting and important polar research coming from Hawaii!