In the sea ice the base of the food web is the algae, the ice algae which grow generally
at the bottom of the ice so where the ice meets the water.
And that's because the algae need two things mainly, they need sunlight which comes in
from above, and they need nutrients which come from below.
So that feeds them the bacteria within the ice and you see a lot of different types of
bacteria that you find either rarely or not at all in the water underneath the ice.
And it also feeds the water column and the benthos the sediment organisms below.
And so, there's a very high abundance of organisms in those regions because of this connection
between the ice and the sediment.
We study psychrophiles which are extremophilic organisms that live at cold temperatures and
psychrophiles live only at cold temperatures so if you bring them to room temperature they
die.
Here we go, what we do is we get ourselves onto
the ice.
And once we get to the ice flow, we pick a suitable site, somewhere fairly level.
And we have an ice auger that takes a core that is about this big around and up to a
meter long.
We have several extensions so that once we pull out one meter we can go down again, and
the longest one we've got so far is four meters long.
The ice that we are studying is only a couple of years old.
So maybe the oldest ice that we've collected on this expedition, is five to ten years old.
And that's most of the ice in the Arctic is less than two years in fact.
So then once we get the ice back to the lab we've taken it to the freezer room so it doesn't
melt while we are working with it.
And we lay it out, and look for any variations in it.
Whether there is air bubbles usually in the surface or whether there is a band of algae
growing at the bottom.
Then we start cutting it into sections.
So we'll cut maybe a five centimeter section to melt for the ice salinity.
With that we can learn about the history of the ice, and we cut other sections to look
at the biology in the core, so for those we will add filtered sea water so we'll take
natural sea water and we'll filter all the organisms out of it and then use that to melt
this ice so that when the organisms come out of the brine channels that they live in they
are not shocked by the low salinity.
So then once we've melted all the ice, which usually takes overnight, then we put it through
a very small filter that has a pore size of zero point two micrometers.
So a human hair is about a hundred micrometers across so this filter catches things that
are five hundred times smaller than a human hair.
We catch all the bacteria on these filters, and then we freeze them at ultra low temperature
to preserve them until we get back to shore.
And then once we are on shore, we'll take them and extract the DNA from them and then
sequence that on a DNA sequencer.
And from that we can learn about the diversity and evolution of these organisms.
We know that the ice is decreasing, but we don't know what effect that is going to have
on the biology, there's different options that people have considered, one is that the
algae in the surface water will be more productive because there is more light because the ice
isn't blocking the light, and you can imagine that would rain down and perhaps increase
the total productivity of the system, or they might decrease in productivity because there
will be more meltwater on the surface stronger stratification which means that there is less
nutrients coming up from below to feed the algae then we would actually have less productivity
and that would cause a decline in the total ecosystem.
And both of those are options and we don't know which one is correct, so what we're doing
is finding out what the system is like now so that we can track it as it changes into
the future.