By Sara Pedro
I became interested in contamination of the polar regions during my master’s while researching mercury concentrations in Antarctic Gentoo penguins (Pygoscelis papua). This species spends their complete life cycle in many of the sub-Antarctic islands, such as South Georgia and the Kerguelen Islands, and reproduce in colonies of about 320 000 breeding pairs (Borboroglu and Boersma 2013). Because of their large numbers, wide distribution in the Antarctic Ocean, and easy access, Gentoo penguins are good biomonitors of local contaminant concentrations; a major reason we studied this species. We found that mercury concentrations in Gentoo penguins were not at concerning levels (Pedro et al. 2015). Nevertheless, the fact that mercury accumulates in species in the Antarctic, one of the most remote regions in the world, indicates the widespread contamination of pollutants released mostly in industrialized areas.
In transitioning to my PhD, I switched poles to focus on the Arctic. Like in the Antarctic, the Arctic region is impacted by global pollution. At the same time, the Arctic has been facing marked sea-ice loss associated with increasing temperatures. The Arctic is more susceptible to these changes in climate than other regions around the globe (Screen and Simmonds 2010) due to the albedo effect: less sea-ice to reflect solar radiation leads to more absorption by the ‘darker’ ocean surface. Because contaminants are transported by air and oceanic currents, climate change will likely alter contaminant dynamics and pathways into Arctic ecosystems (Macdonald et al. 2005). One situation that leads to this change in contaminant dynamics is the alteration of Arctic food web structure, such as the replacement of native with invasive prey fish.
My current PhD project at the University of Connecticut focuses on legacy persistent organic pollutants (POPs) and mercury in invasive versus native prey fish in the Eastern Canadian Arctic, and consequent levels in ringed seals (Pusa hispida). Legacy POPs include several pesticides and polychlorinated biphenyls (PCBs) that can travel long distances, often by atmospheric transport, eventually accumulating in remote regions. These POPs take a long time to break down in the environment, and can accumulate in animals to potentially cause toxic effects (Letcher et al. 2010). Mercury is released mainly during gold mining and coal burning and is transported to remote regions where, similarly to POPs, it can accumulate in the food web and cause toxic effects (Dietz et al. 2013).
With the recent increases in average temperatures in the Arctic, some fish species have expanded their habitat ranges from boreal areas to more northern regions and are now found more frequently in the Canadian Arctic. Studies on Arctic seabird and marine mammal diets suggest that invasive fish such as capelin (Mallotus villosus) and sand lance (Ammodytes sp.) are replacing Arctic cod (Boreogadus saida) as the most important prey species in lower Arctic regions (Provencher et al. 2012; Chambellant et al. 2013; Hop and Gjøsæter 2013). Although POPs and mercury are transported to the Arctic, they are still at higher environmental levels closer to the direct sources (e.g. intense agricultural areas, waste incineration). A switch in diet from native to invasive fishes may therefore change ringed seal contaminant burdens. My PhD research will compare contaminant levels in invasive capelin and sand lance to Arctic native fish species, including Arctic cod. I will also determine contaminant levels in ringed seals to better understand how climate change impacts contaminant transfer in Arctic food webs. The results of this project are also important for local communities because, although they do not eat these invasive and native Arctic fishes in particular, locals eat Arctic marine mammals, such as ringed seals that feed on these fishes.
Part of this project includes visiting the local communities in the Arctic that are the most affected by these habitat changes. Arviat, Nunavut is one of the communities collaborating in this project and participated in collecting fish samples. This was my opportunity to visit the Arctic! Last spring, I flew up to Arviat (Figure 1) and gave a few talks regarding preliminary results of my research at the high school, the Arctic College, and the Hunters and Trappers Association.
Figure 1: Town of Arviat, Nunavut (left) in the Eastern Canadian Arctic (right).
My visit in April was short and sweet, consisting of 4 different flights each way… 8 flights in three days (luckily, none of the flights were delayed)! Given the thaw doesn’t happen until June/July in Arviat, late April means snow boots and warm coats. Hudson Bay was a beautiful, expansive white plain (Figure 2)! However, I could tell that it was the spring for them. The locals were walking on the streets, kids were out playing and the roads were clear enough to easily drive through. Everyone looked happy and they were very welcoming. At the high school, I gave a few talks to different classes about my research. The students were interested and engaged, and I even got the wise question “So why does this matter?” from a 12-year-old. Another girl told me that she didn’t like fish and when I asked what she eats instead, she told me about how her father hunts caribou. She invited me to join them on a hunt. If it weren’t for my tight schedule, I would have definitely gone out for a caribou hunt! In this region, they mostly depend on caribou (Rangifer tarandus), seals, and Arctic char (Salvelinus alpinus) for subsistence. High school students will often miss classes and come in tired because the main priority for many of them is to help their families hunt and fish.
After visiting the high school, I went to the Arctic College (Figure 3). Most of the students were gone for the summer but I met a few that stick around and volunteer for research projects. Getting locals involved in environmental research in these remote regions is very important given their sensitivity to climate change and environmental pollution. Fishers and hunters at the Hunters and Trappers Association are concerned about having contaminants in their food, since they depend largely on local food sources. The Arctic Monitoring and Assessment Program (AMAP) has been monitoring contaminants in the Canadian Arctic for over twenty years. The levels of some POPs, such as DDT and PCBs have been declining or have stabilized in the Arctic, mostly since the Stockholm Convention to ban these contaminants (Stockholm Convention 2008). However other contaminants such as mercury have been increasing in some Arctic animals (Riget et al. 2010; McKinney et al. 2015). As a polar environmental scientist, it is my duty to continue researching the impacts of climate change on contaminant levels in these remote regions and to address the communities’ questions and concerns.
Being able to visit one of the most fascinating regions in the world while doing environmental research is why I enjoy being a scientist!
Sara Pedro has a Master’s in Ecology and is currently a PhD student in the Natural Resources and the Environment department of the University of Connecticut, CT.
Borboroglu PG, Boersma PD (2013) Penguins: Natural History and Conservation. University of Washington Press, Seattle
Chambellant M, Stirling I, Ferguson SH (2013) Temporal variation in western Hudson Bay ringed seal (Phoca hispida) diet in relation to environment. Mar Ecol Prog Ser 481:269.
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Pedro S, Xavier JC, Tavares S, et al (2015) Mercury accumulation in gentoo penguins Pygoscelis papua: spatial, temporal and sexual intraspecific variations. Polar Biol. doi: 10.1007/s00300-015-1697-9
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Stockholm Convention (2008) Listing of POPs in the Stockholm Convention. http://chm.pops.int/TheConvention/ThePOPs/ListingofPOPs/tabid/2509/Default.aspx. Accessed 28 May 2015