Changing Arctic Ocean

Arctic ice cave. Photo by Aidan Hunter

Climate change is causing the rapid melting of ice in and around the Arctic Ocean and is radically altering the habitat of humans, animals and marine life alike.

A challenge on this scale requires a major response and researchers from Strathclyde are joining partners from 31 other institutions in the Changing Arctic Ocean programme, run by the UK’s Natural Environment Research Council (NERC) and Germany’s Federal Ministry of Education and Research.

Academics from Strathclyde’s Departments of Physics and Mathematics & Statistics are involved in four of the 16 projects which make up the overall Changing Arctic Ocean programme:

  • PRIZE - aimed at understanding how seasonality, ice cover and ocean properties determine the large-scale ecosystem structure of the Arctic Ocean
  • DIAPOD - developing understanding of how changes in diatom phytoplankton abundance caused by retreating sea ice will affect Arctic zooplankton, particularly the abundance, composition and distribution of the calanus copepod community
  • MiMeMo (Microbes to Megafauna Modelling of Arctic Seas) – using mathematics and computer science to predict flows of nutrient through the marine food web, as the physical environment in the Atlantic Arctic changes. Led by Professor Michael Heath, of Strathclyde’s Department of Mathematics & Statistics 
  • PEANUTS (Primary Productivity Driven by Escalating Arctic Nutrient Fluxes) – investigating whether increases in Arctic net primary productivity – the overall amount of chemical energy produced by plants -  have been accelerated by  changes in the way nutrients are transported towards the ocean surface.

Here, some of our researchers describe their roles in the projects:

PRIZE

Dr David McKee, Department of Physics:

“I’ve been on two expeditions to the Barents Sea for the PRIZE project. One evening during the first expedition, I went out on a dinghy to do measurements of light pollution. I was wearing a survival suit to protect against the elements; despite it being January in the Arctic Ocean, it was raining. For me, that summed up how quickly this ecosystem is changing and why this research is needed.

“We’re monitoring how the ecosystem functions. Seasonality and the timing of algae blooming are very important. The PRIZE team deployed underwater robots for three months at a time to gather data. These have given us valuable insights into how the blooms grow.

“Conditions have been significantly different on each expedition. Phytoplankton, while they are growing, feed on nutrients such as nitrate, phosphate and silicate. In spring, they grow close to the surface of the ocean, where they can get enough nutrition and enough light. Here we can monitor them from space using ocean colour satellites.

“However, as we move into summer they grow at deeper depths where sufficient nutrients can still be found. This is more difficult to observe from space but we are now able to record events using the long-term observations of our underwater robots. Each phase of the programme covers a different stage of the cycle and the robots allows us to be there at exactly the right time the major events are happening.”

Dr Ina Lefering, Department of Physics:

“The PRIZE project examines how the environment reacts to the changes it experiences. One of the most interesting aspects has been the underwater robots, as they gathered data of the Arctic Ocean from January to July.

“The robots surface every few days and send the data to us via satellite, giving us live updates in between research cruises, as the data showed how the phytoplankton began to grow with the return of sunlight in early April.

“Little sunlight gets through the sea ice and we want to know how the phytoplankton will adapt to thinning and retreating ice cover; on the first PRIZE expedition to the Barents Sea in summer 2017, it was full of ice but a year later, there was hardly any.

 “The timing of algal blooms is as significant as the total amount of phytoplankton biomass. Timing is difficult to measure but continuous data from the robots will help us to get some answers.”

Searchlights from the RV Helmer Hansen probe for gaps in the ice. Photo by Emlyn Davies, SINTEF Ocean AS

 

MiMeMo

Professor Michael Heath, Department of Mathematics & Statistics:

“Shrinking sea-ice cover in the Arctic Ocean is already increasing primary production but it’s uncertain, and difficult to predict, how far this could affect bigger species, such as whales, seals and polar bears.

“In this project, we are using mathematics and computer science to predict the likely flows of nutrient through the marine food web, as the physical environment in the Atlantic Arctic changes.

“One of the main objectives is to examine trade-offs between the harvesting of fish and invertebrates to sustain Arctic communities, and cultural values – such as reputation and tourism - arising from the abundance of marine megafauna in the Arctic environment.

“We are developing two contrasting types of mathematical models of marine food webs to quantify seasonal patterns among species, from microbes to the largest animals, in the waters of the Atlantic-Arctic. We will test the models and then use them to predict the impacts of factors associated with a warming climate.”   

 

PEANUTS

Dr Neil Banas, Department of Mathematics & Statistics (lead on computer modelling for PRIZE, DIAPOD, and PEANUTS):

“The main question we’re looking at is: what will follow the loss of ice? There are uncertain consequences; even the direction of change in the food web is uncertain.

“We’re finding that the food web in the western Atlantic sector of the Arctic, from Greenland to Norway, may be more resilient to climate-related shifts in the calanus complex than previously assumed. This is in sharp contrast to other polar regions: for example, the Bering Sea, west of Alaska, is home to some of the richest fisheries in North America, which depend on calanus, other copepods, and krill, and which appear to be highly vulnerable to disruption associated with the loss of sea ice.

“Phytoplankton need light and nutrients but there will be changes in the availability of both that follow from the loss of ice.

“Less ice means more surface light, but also more wind and waves and turbulence, which mix the phytoplankton down into the dark. At the same time more turbulence also means a greater supply of nutrients to the surface waters, so whether it is good or bad for phytoplankton growth depends on whether light or nutrients is more limiting.

“Copepods and krill feed on the phytoplankton, and serve as prey for many fish, birds and even a few mammals, such as bowhead whales. So if we can understand what’s happening with nutrient flux in relation to ice and light, we can better understand the living environment as it’s experienced by birds, fish and mammals.”

 

DIAPOD

Dr Aidan Hunter, Department of Mathematics & Statistics:

“The DIAPOD project is particularly exploring the impact of changes in the Arctic environment on calanus, a family which makes up around 80% of the zooplankton biomass in this region.

“As temperatures increase, ice retreats and the quantity and composition of phytoplankton changes. Diatoms are large phytoplankton that are an important food source for calanus and their abundance is expected to decline with retreating sea ice. I took part in the first leg of the DIAPOD expedition, in May and June; there was more ice than might have been expected.

“We used two types of net designed for gathering plankton. One, the bongo net, goes down to 200 metres, while the other is known as MOCNESS (Multiple Opening/Closing Net and Environmental Sensing System). This net has nine openings which are trawled at various depths down to 1000 metres, so we were taking stratified samples to examine plankton from different depths.             

"The movement of calanus tends to depend on time of year. During summer they move near the surface to feed and typically do this at night when it is dark and there are few of their predators around. But in the Arctic Ocean, where calanus have relatively few visual predators and there is constant daylight in summer, feeding conditions are good day and night. During winter calanus stay at depth in a form of stasis and lower their metabolism to preserve their bodies."

“It’s not known what the effects of the Arctic changing environment on calanus are going to be but we’re aiming to create a realistic mathematical model to predict what’s going to happen.”

 

Numerous other researchers from Strathclyde’s Department of Mathematics & Statistics are participating in Changing Arctic Ocean, including: Dr Douglas Speirs; Dr Robert Wilson; Laura Hobbs; Trevor Sloughter and Euan McRae.