David S. McLagan

An Antarctic Research Station as a Source of Brominated and Perfluorinated Persistent Organic Pollutants to the Local Environment

This study investigated the role of a permanently manned Australian Antarctic research station (Casey Station) as a source of contemporary persistent organic pollutants (POPs) to the local environment. Polybrominated diphenyl ethers (PBDEs) and poly- and perfluoroalkylated substances (PFASs) were found in indoor dust and treated wastewater effluent of the station. PBDE (e.g., BDE-209 26-820 ng g(-1) dry weight (dw)) and PFAS levels (e.g., PFOS 3.8-2400 ng g(-1) (dw)) in dust were consistent with those previously reported in homes and offices from Australia, reflecting consumer products and materials of the host nation. The levels of PBDEs and PFASs in wastewater (e.g., BDE-209 71-400 ng L(-1)) were in the upper range of concentrations reported for secondary treatment plants in other parts of the world. The chemical profiles of some PFAS samples were, however, different from domestic profiles. Dispersal of chemicals into the immediate marine and terrestrial environments was investigated by analysis of abiotic and biotic matrices. Analytes showed decreasing concentrations with increasing distance from the station. This study provides the first evidence of PFAS input to Polar regions via local research stations and demonstrates the introduction of POPs recently listed under the Stockholm Convention into the Antarctic environment through local human activities.

The transport of polycyclic aromatic hydrocarbons during rainfall and snowmelt in contrasting landscapes

Though it has been established that stream concentrations of polycyclic aromatic hydrocarbons (PAHs) in urban watersheds can be much greater than those in less developed watersheds, knowledge of transport mechanisms is lacking, particularly in temperate, Northern climates with seasonal snow packs. We combine high-resolution stream water sampling with air, suspended solid and stream flow monitoring to investigate the source to stream transport of PAHs during rainfall and snowmelt in paired watersheds with contrasting land use. Despite similar particle loads, contamination of particles that is 8-48 times higher in the urban watersheds leads to area-normalized loads of PAHs that are 6-82 times greater than in the agricultural watersheds. In the urban watershed, average volumetric storm flow concentrations increase with longer antecedent dry period that allows build-up of PAHs on watershed surfaces. Cluster analysis suggests road dust is a minor source of suspended solid-bound PAHs in more agricultural watersheds during rainfall. During snowmelt, earlier peaks in concentration in the urban watershed are likely due to melt from snow packs and snow banks travelling quickly to the stream network via impervious surfaces and sewer drains. While road-derived inputs also appear to be important during snowmelt in the agricultural watershed, relatively delayed peak concentrations result from delayed inputs from snow packs in more pervious areas of the watershed.

Signals from the south; humpback whales carry messages of Antarctic sea-ice ecosystem variability

Southern hemisphere humpback whales (Megaptera novaeangliae) rely on summer prey abundance of Antarctic krill (Euphausia superba) to fuel one of the longest-known mammalian migrations on the planet. It is hypothesized that this species, already adapted to endure metabolic extremes, will be one of the first Antarctic consumers to show measurable physiological change in response to fluctuating prey availability in a changing climate; and as such, a powerful sentinel candidate for the Antarctic sea-ice ecosystem. Here, we targeted the sentinel parameters of humpback whale adiposity and diet, using novel, as well as established, chemical and biochemical markers, and assembled a time trend spanning 8 years. We show the synchronous, inter-annual oscillation of two measures of humpback whale adiposity with Southern Ocean environmental variables and climate indices. Furthermore, bulk stable isotope signatures provide clear indication of dietary compensation strategies, or a lower trophic level isotopic change, following years indicated as leaner years for the whales. The observed synchronicity of humpback whale adiposity and dietary markers, with climate patterns in the Southern Ocean, lends strength to the role of humpback whales as powerful Antarctic sea-ice ecosystem sentinels. The work carries significant potential to reform current ecosystem surveillance in the Antarctic region.