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By Dan Rudy 

Bird Fest presentation highlights plastic peril posed to birds

 

Dan Rudy/ Wrangell Sentinel

Volunteers scour the rocky shoreline of Heritage Harbor on May 2, looking for marine debris.

At last weekend's Stikine River Birding Festival, residents and visitors flocked to the Nolan Center to learn more about their feathery, flighty neighbors.

While there were birding tips, arts shows and craft displays to enjoy, the festival also took on a more serious note regarding threats to the future of species' populations. Of particular concern for marine species are the short term and cumulative effects of discarded plastics.

On Friday evening, University of Alaska Anchorage (UAA) doctoral student Veronica Padula presented findings from her research in the western Aleutian Island. Padula is assisted by Sydney Stewart and the university's biological sciences chair, Douglas Causey.

In the North Pacific Ocean, a convergence zone between oceanic currents has collected hundreds of thousands of tons of plastic, estimated to cover an area the size of Texas. This gyre is just north of the Hawaiian Islands, home to a wide variety of seaborne avians.

Birds and other marine animals often get tangled in debris or mistake it for food. Ingested plastics cannot be digested and can collect in birds' stomachs over time. This can cause them to starve or inflict damage to their digestive tract and linings.

"I get really fired up about the issue of marine debris," Padula commented. Padula has been engaged with the issue since 2009, after being drawn to it during her toxicology work. "I like to say 'the project found me.'"

Her doctoral research with UAA centers on the effects of marine debris on birds found in the western Aleutian Islands. Seabird populations there have been on the decline in the past decade, and she wanted to find out why.

"This started out as a food web study," she explained.

Various bits of plastic were often found in the stomachs of birds harvested for the study, but that did not fully explain the problem of declining population numbers.

"It wasn't an obvious thing that was happening to these birds," Padula said.

Plastic is not a biodegradable substance, but the elements will break it down over time into ever-smaller components. Much of the broken-down plastic content birds ingest is too small for the eye to detect, and Padula explained this "micro-" and "nanoplastic" can reach the point where it passes through cellular lining.

Phthalates are a chemical additive used to give plastic more desirable properties, such as softness or flexibility. Once in the body, they are capable of disrupting hormone reception, due to their chemical similarity to androgens and estrogen.

There are several theories about the effect of endocrine-disrupting compounds on the body. Compounds may contribute to developmental or reproductive problems and trigger false hormonal responses.

During her study in the Aleutians, Padula said tissue samples collected from seabirds were sent to a laboratory to identify and measure the levels of different phthalates commonly found in plastics. Technicians found that all birds in the study had varying levels of phthalates in their systems, even if pieces of plastic were not discovered in their stomachs.

The data indicated that the plastics were affecting the food chain and suggested that birds were being exposed to phthalates whether they were directly ingesting plastics or not. Further testing needs to be conducted, and Padula hopes to continue her research for the next three or four years. She will be in Yakutat this summer collecting blood samples of Aleutian terns.

Solutions to such a pervasive problem will be difficult and costly. However, individuals and communities can begin taking steps to mitigate further damage by properly disposing of refuse and by being more aware of the products they use as consumers.

Striking close to home, several volunteers joined Padula at Heritage Harbor the next day to collect debris on the beach.

Volunteer Kim Powell explained the area has been in persistent need of cleanup. Seasonally, discarded bags, ropes, bottles and styrofoam are discarded in the harbor or collect along the sides of Zimovia Highway. The debris is driven seaward by rain and streams and ends up on the beach.

 

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