Researcher Michel Poulin writes from the Arctic hamlet of Resolute, where he has been participating in a research project since May 4, 2011. His previous post described how ice-core samples are collected in the Arctic.
Once we are back at the Resolute base and generally very tired, we have to unload all the gear and samples. Then we have to rinse in fresh water all the equipment used to collect the samples of ice, underlying water and zooplankton. We also rinse the instruments used to take light readings and measure environmental parameters such as the thickness of snow and ice.
The field equipment has to dry before the next excursion out on the ice. And, if any equipment is faulty, now is the time to repair it before the next outing.
In the meantime, all the samples are taken to the Parcoll tent that houses our laboratory.
We then proceed to slowly thaw the core samples before performing a series of physical, chemical and biological analyses on the meltwater.
Sub-samples of the meltwater will be used to determine the pH, temperature and salinity, as well as the concentrations of nutrient-matter that is essential to anything that contains chlorophyll. A parallel can be drawn with terrestrial plants, which also need these nutrients for growth.
Other sub-samples will be used to determine the amount of photosynthetic matter (microscopic algae) contained in the surface water and the subsurface layer of ice. When looking at the microalgal biomass, we are interested in the physiological state of the microalgal cells; what we observe can tell us whether or not they are content in their habitat.
We also study the productivity of microscopic algae in ice. We finish by identifying and counting cells for the algae collected in the surface water and the subsurface layer of ice. So we’ve got a lot of analysis work ahead of us.
This is where the lab team comes in.
A pH meter is used to take pH measurements, and a salinometer is used to take salinity measurements. Nutrient samples are collected and stored in a freezer until it is time for the analyses to be carried out at the Fisheries and Oceans Canada laboratory in Winnipeg, Manitoba.
Biological analyses are done using a filtration tower (see photo). The filtration system has glass funnels of a given volume clamped to a metal filter base, and a pump. Each filtration unit has a valve that regulates filtration flow. It is easy to use:
- place a clean filter on the metal filter base
- clamp the funnel in place
- pour a given volume of the sample into the funnel
- activate the pump
- open the valve
- wait until there is no more water left in the funnel
- retrieve the filter.
The filter gathers the biological material that will be used in the various analyses described earlier.
At this stage, we use different filters of varying porosity, but mostly the filters are very fine so that we can collect microscopic algae from the meltwater and surface water. These filters will be used for the chlorophyll analyses conducted with a fluorimeter in the laboratory.
Other filters will be used later to determine the following parameters: carbon, bacteria, gel substances and fatty acids. Zooplankton samples will also be analyzed for their fatty-acid content.
All in all, busy days ahead for the teams both in the lab and out in the field!