At the Mic: Veronica Padula
Birds are fascinating, and I was instantly hooked on studying them in college, especially when thinking about birds’ roles as environmental sentinels. Their health and well-being can tell us so much about what is happening in an ecosystem, and what could potentially be happening to the people in that ecosystem. I first worked with seabirds in Alaska in 2007 (on Marbled Murrelets), and I essentially never left. I love Alaska, and the seabirds that call this place home. I feel a deep connection to and love for the marine environment in Alaska – especially the seabirds.
Seabirds are special creatures. Some soar like kites over vast stretches of ocean, flying almost pole to pole each year, breaking records for the longest known migration of any animal. Others are incredible divers, propelling themselves deep under water, sometimes at speeds of up to 60 mph. There is something that makes each seabird species unique and wonderful, whether it be their showy breeding plumage, brightly colored legs, calls that make you feel like you are at a comedy club (I often feel like murres are laughing at an inside joke I wish I knew the punchline to), or salt-filtering superpowers that allow them to fly great distances over the ocean. Oh, and recent studies report that some seabirds can sleep on the fly, which blows my mind!
No matter how diverse and special, all seabirds have at least one thing in common – they all play important roles in marine ecosystems, and seabird health is a reflection of ocean health overall. Oh, and there’s something else –seabirds are rapidly declining overall, more quickly than any other group of birds on the planet. What are the causes of these declines? The mechanisms for decline likely differ depending on which species or region you are investigating, and seabird biologists across the planet are working hard to get closer to the answers. What does this suggest about ocean health? Scientists are working out those details as well, but I don’t think the news is all that great.
Although Alaska’s marine environment boasts a large number of seabirds, the populations here are not immune to threats and declines. Knowing more about what is happening with seabirds in Alaska and the Arctic overall is especially critical in light of the fact that the Arctic environment is changing rapidly. Scientists are working hard to capture those changes and consider what those changes mean for the future of the Arctic. For example, warming waters may impact prey availability for seabirds, impacting their nutrition, productivity, and long-term survival. Pollution is another critical factor contributing to these changes, especially plastic marine debris pollution.
Marine debris is a global issue with huge environmental impacts. Plastic debris can cause physical harm to wildlife, sometimes resulting in ulcerations, starvation or death. Marine debris affects organisms ranging from microscopic to giant, with tiny microbes hitchhiking across vast distances attached to pieces of debris, to whales dying because their intestines have been impacted by things like plastic bags. Our research investigates the impacts of plastic marine debris on several seabird species breeding in the Bering Sea region, a highly productive and unique ecosystem within the Arctic environment. We initiated a food web study in 2009, collecting seabird specimens from the Western Aleutian Islands for various laboratory analyses. Because we were interested in knowing more about what the birds were eating, we also examined stomach contents in our specimens. We started to notice that some birds had ingested small plastic particles along with their food.
The plastics we found were not giant chunks of plastic like scientists are finding in birds like albatrosses, but the particles were still plastic, adding to the evidence that nearly every seabird on earth will ingest plastic at some point in their lives, and that plastic debris is ubiquitous throughout the oceans. In the marine environment, plastic debris continuously degrades into much smaller “microplastics,” which are more easily carried by ocean currents and more easily mistaken for small prey items such as plankton (Moore 2008). For example, microparticles and nanoparticles fall within the size range of the staple phytoplankton diet of zooplanktons such as the Pacific Krill (Andrady 2011). Since the particles we found were so small, it suggested that birds could ingest plastic without resulting in starvation or internal tissue damage because the small plastics could potentially pass through their system (although that was not always the case).
These observations left us asking more questions than when we began the original project (which is still ongoing). What if the seabirds in the Bering Sea were constantly ingesting plastic, but experiencing no physical consequences as the pieces of plastic were small enough to pass through their bodies? Were the birds at risk of anything during those moments when the plastic was actually inside their bodies? More specifically, were there chemicals that a bird could get exposed to after ingesting plastic? The answer is yes, plastics are often coated in various chemicals, and are also capable of absorbing other environmental contaminants when they are in the ocean. High concentrations of hydrophobic organic contaminants, or persistent organic pollutants (POPs), such as polyaromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) have been measured on plastic debris collected from the environment (Endo et al. 2005,Rios et al. 2007).
Phthalates make up another group of plastic-associated chemicals. They are plasticizing chemicals, a group of chemicals added to basic plastic material to impart specific qualities. They are colorless, odorless, oily liquids that are diesters of phthalic acid with low volatility and low water solubility (Lyche et al. 2009), with 25 known types manufactured. Annually, over three million metric tons of phthalates are consumed worldwide (Lyche et al. 2009). Ecological factors such as oceanic and air currents and migratory species have aided the spread of phthalates (Heudorf et al. 2007). They are ubiquitous in the environment, and have been detected in soils (Bauer and Herrmann 1997, Cartwright et al. 2000), surface water (Taylor et al. 1981, Staples et al. 1997, Horn et al. 2004), as pollutants in indoor air (Becker et al. 2004) and in the atmosphere (Thuren and Larsson 1990), the tissue of mammals (Staples et al. 1997), as well as in several aquatic species (Wofford et al. 1981).
Prior to this research, I did not have a very good idea of what phthalates were, simply a group of plastic-associated chemicals that were a growing concern in terms of their environmental contamination. As I learned more about phthalates, I realized they could be extremely harmful for living things, as some phthalate congeners are known endocrine disrupting compounds (EDCs) (Latini 2005,Kamrin 2009, Meeker et al. 2009) (scientists are still working on fully understanding their effects). The chemical structures of EDCs often closely mimic the chemical structures of hormones naturally created within living organisms. When organisms are exposed to EDCs, their bodies get confused, allowing EDCs to interfere with the normal function of natural hormones (for more about EDCs, please see The Endocrine Exchange). Toxin exposure can also negatively alter normal neurodevelopment, and consequently the development of complex brain functions and behaviors (Holahan and Smith 2015). Ultimately, the risk of negative health impacts can be high when organisms are exposed to them.
As our project continues, we are working to better understand the extent of phthalate exposure in seabirds in the Bering Sea, and other scientists are working in places like Australia and Norway to better understand the extent of phthalate exposure in seabirds there. We do not fully understand how phthalates might impact seabird health, but we are getting a start by knowing whether or not they are exposed. To date, we have found detectable levels of at least one phthalate congener (the laboratory analyses can quantify six of the 25 congeners) in each of the 78 individuals we have tested.
Additionally, we are looking at numerous species from this region that sample food from different parts of the marine environment. For example, some species forage near the shoreline while other species forage a bit further offshore, some species stick to eating plankton (which have also been shown to ingest plastic), while other species stick to certain fish, and lots of variations in between. Some species skim the surface of the water for food, while other species dive down into the water column to chase their meal. So this begs the question: is a seabird’s risk of plastic ingestion and phthalate exposure related to how and what it eats? By examining many species from this region, we are able to compare notes from one species to the next, in hopes of getting a clearer picture as to whether or not some seabirds are more at-risk for plastic ingestion and phthalate exposure than others.
Ultimately, what does phthalate exposure mean for seabirds? What does it mean for the ocean environment? What does this mean for human health? We are all part of this planet, and humans rely on the ocean being healthy and functioning just as much as seabirds do, so it is critical that we pay attention to and work toward building a better understanding of what is happening in the ocean environment, so that we might find ways to reverse these patterns and nurse the ocean back to health.
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Veronica Padula is a graduate student at the University of Alaska Anchorage/Fairbanks, where she investigates the impacts of plastic marine debris on seabirds from the Bering Sea. She first fell in love with birds in college when she worked on Black-crowned Night Herons in New York, and since then has spent her time chasing birds, mostly in the Alaskan wilderness, to uncover the secrets of what birds can tell us about the health of the planet.