A study published in ScienceAdviser investigated the physiological effects of plastic ingestion in seabird chicks, specifically the sable shearwater (Ardenna carneipes), using data-independent acquisition mass spectrometry (DIA-MS). The primary objective is to assess how varying levels of plastic ingestion influence physiological responses in free-living seabird chicks. This is achieved by analyzing plasma samples from live chicks and validating results through proteomic analysis of brain tissue and quantitative PCR (qPCR) of stomach and liver samples from necropsied individuals that did not successfully fledge.
The study was conducted on Lord Howe Island, Australia, between April and May 2023. Chicks aged 80 to 90 days were captured at night, measured for morphometrics, and lavaged to determine their ingested plastic load. Birds were classified into two groups based on their plastic exposure: low exposure (<5 pieces or <0.5 g) and high exposure (>8 pieces or >0.65 g). A total of 31 blood samples were collected (18 from high-exposure chicks and 13 from low-exposure chicks). Plasma was separated from whole blood and stored at -80°C for further analysis.
Plastic ingestion was assessed using stomach lavage, with plastic pieces being dried, counted, and weighed. Due to the increasing volume of plastic found in some chicks, lavage was sometimes incomplete, and impacted birds were categorized based on observable plastic presence. One chick, for instance, had 403 pieces of plastic in its stomach, with 398 items only identified postmortem. This underscores the severe impact of plastic pollution on seabird physiology.
This study presents crucial insights into the physiological impact of plastic ingestion on seabirds. The presence of plastic-induced physiological stress was evident in the proteomic alterations observed in plasma and brain tissue. The high-exposure group showed distinct molecular changes indicative of metabolic stress, inflammation, and potential disruptions in normal physiological function. The findings suggest that plastic ingestion not only affects digestion but also has broader systemic effects, potentially influencing survival rates and fitness in seabird populations.
This research underscores the detrimental effects of plastic pollution on marine wildlife. By leveraging advanced proteomic techniques, the study provides evidence that seabird chicks exposed to high levels of plastic undergo physiological stress at the molecular level. These results highlight the urgent need for marine conservation efforts to mitigate plastic pollution, as well as further studies to explore long-term consequences on seabird health and population dynamics.
Sources: ScienceAdviser
