Chasing the Ice in Greenland: How are Lakes Going to be Affected by Earlier Ice-Out?

March 2, 2020 Expeditions 2019

Expedition Date: April 12 – June 3  &  June 22 – July 10, 2019

Field Team Members: Vendy Hazukova1,2, Benjamin Burpee 1,2, Todd Burpee, Robert Northington3, and Jasmine Saros1,2

1 University of Maine – Climate Change Institute
2 University of Maine – School of Biology and Ecology
3 Husson University – College of Science and Humanities

 

Field Expedition Location:  Kangerlussuaq, West Greenland

One of the consequences of changing climate for lake ecosystems is a rapid loss of lake ice and shifts in the timing of major events such as ice-out in the spring and ice-on in the fall. These climate-driven shifts in phenology affect the length of the growing season and thermal structure of lakes—ultimately altering biogeochemical processes, community structure and lake metabolism.

In the Arctic, lakes are covered with ice for a large part of the year; therefore, if we want to understand how changing ice phenology will impact lakes in the future, we need to turn our attention to processes that are happening under the ice. In recent years, it became clear that lakes are not stagnant during the ice-covered period, and that biogeochemical processes continue, including primary production.

Fig.1: On average, ice-out in Greenland lakes happens at the beginning of June. In 2019, ice-out occurred unusually early during mid-May

Project Goals:

The aim of our multi-year research programme is to disentangle how differences in ice-out timing affect community composition, phytoplankton biomass, and lake physical and biogeochemical structure in Greenland lakes. We are mostly focused on changes in phytoplankton communities because alterations at the base of the food web will have cascading effects for the whole ecosystem and consequently for metabolic budget of lakes.

The goal of this expedition was to understand what the drivers of under-ice primary production among selected lakes are, and to what degree do under-ice conditions define open-water processes and community structure.

Fig. 2+3: Moating of lakes at the beginning of May. During this period, it is impossible for us to collect any samples because lake ice has already melted in the littoral zone and is too unstable in the center of the lakes. Fortunately, our sensors that were deployed through the ice at the beginning of April are collecting data even during this period!

 

Fig. 4: Ben is waiting for the ice to melt.
Fig. 5: Dryas integrifolia in bloom. Shifts in phenology are affecting Arctic plants as well.
Fig. 6: Pedicularis dasyantha.

Data collection: 

Our target lakes for this project are located in Kangerlussuq, West Greenland, and they are a subset of lakes that have been systematically studied during the open-water period for more than a decade (e.g.: 2018, 2016, 2014, 2011).

In order to understand seasonal changes in lakes at a high temporal resolution, we use in-situ high-frequency monitoring sensors that record photosynthetically active radiation, dissolved oxygen, and temperature. Over the course of our expedition, we also collect samples for water chemistry and analyses of biotic communities. Given our interest in seasonal dynamics of phytoplankton communities, we employ a variety of methods to characterize them. In order to estimate biomass, we analyze concentrations of pigments using HPLC, and we also count and identify phytoplankton using light microscopy. To further understand qualitative changes in the structure of whole planktic communities, we use next generation amplicon sequencing targeting bacteria and small eukaryotes.

Fig.7+8: Ice has finally melted which allowed us to use inflatable boats and collect more samples! Ben is using a submersible sensor that detects fluorescence of chlorophyll-a and dissolved organic matter—and he loves it!
Fig.9: Zooplankton in the lakes—mostly copepods but you can see a big Daphnia in the middle.

 

Photo credit: Robert NorthingtonFig. 10+11. At the end of our sampling season, we had to find and retrieve buoys with sensors that we deployed in April.
Photo credit: Robert NorthingtonFig. 12: This is our light sensor after being in the lake for over 3 months—the wipers preventing biofouling on top of the white detector work!

Media Outreach:

Please, contact Vendy Hazukova (vaclava.hazukova@maine.edu), Ben Burpee (benjamin.burpee@maine.edu), or Jasmine Saros (jasmine.saros@maine.edu) if you have any questions!