The Tiny Algae That Fuel The Marine Food Chain

Omega-3 nutrients are essential for our health, and for many of us, a major source of these fatty acids is the fish we eat. But these nutrients actually originate much further down the food chain, with the microscopic plant-like organism known as phytoplankton. “Omega-3 are so important for all animals, including humans,” says Dr Eleonora Puccinelli of NIOZ, the Royal Netherlands Institute for Sea Research. “We need them to function well, but we can’t produce them in big enough quantities. We rely on phytoplankton.” Her research is devoted to understanding how Omega-3 is transferred from these tiny algae to humans, and how they’ll be impacted by a changing climate.

One of Eleonora's focuses is on upwelling systems, where water rises to the surface from the bottom of the ocean, bringing lots of nutrients with it. “I really think that upwelling areas are an underestimated source of Omega-3,” she says. Crucially, higher levels of Omega-3 point to better food quality. “There are two major upwelling systems off the African continent, where the local community relies extensively on food from the sea, especially small-scale fisheries. Taking samples over time will provide enormous knowledge about the region’s food quality and food security.”

But as sea water temperatures rise, there’s a risk that phytoplankton will suffer, and as a result, production of Omega-3 will wane. However, so far a lack of data makes it difficult to clearly pinpoint how climate change is affecting Omega-3 production. Through the samples she takes throughout her research, Eleonora hopes to bridge this knowledge gap. “I started with the approach of getting baseline information, but we also have students looking at it in a laboratory set up. So we're going to run experiments with increasing temperatures, and then we can see if and how the production of Omega-3 may change.”

Some major clues also emerged from an expedition she took to the North Sea last year. “We were at sea during the most intense marine heatwave recorded in the North Atlantic, and a few months later we observed unusual bird behaviours, with some species along the coast found in general poor health. One of the possibilities is that the food they were eating was not of good quality,” she says. “With the kind of measurements I'm able to do, we can help determine whether food quality is a main factor affecting higher trophic levels,” she says. The research is a work in progress, but could demonstrate the knock-on effect a reduction and change in the phytoplankton community will have on every being in the food chain, including humans.

This cruise was part of the ACTNOW project, coordinated by NIOZ. “The strength of our cruise was this very holistic overview of the food web, which is not very common, because it's logistically quite challenging, and it's expensive to organise.” The cruise focused on the nearby North Sea, but had strong collaborations with partners who produced different case studies from all across Europe. NIOZ’s unique access to its own fleet, its international partnerships, and its seaside location on the island of Texel are just some of the strengths that set it apart from other institutions. 

“It has so many different kinds of facilities - we can do any kind of measurement we want in-house,” says Eleonora. “And not just facilities, but we have the technical support to help us, and the students actually receive direct training. If you need to process a sample multiple times, you can just run into the lab and do it.” The open lines of communication between the different scientists at NIOZ are also a benefit that Eleonora highlights. “We have four scientific departments, and the research is really varied, we don't focus on one line of research. There are possibilities for collaborating with each other.” 

Eleonora also mentions her positive experience as a woman in science at NIOZ. After successfully interviewing for the job at seven months pregnant, she was later encouraged to apply for the Women In Science Excel grant, which she was awarded. “I feel really supported personally, and my head of department is really understanding.” 

“There are a lot of possibilities. I'm still relatively new to the place, but NIOZ is really setting  the ground for people to expand their horizons as much as possible.”

Header picture courtesy of Morgan Trimble