Seabirds as bioindicators of Southern Ocean ecosystems : concentrations of inorganic and organic contaminants, ecological explanation and critical evaluation

• Main Author: Carravieri, Alice
• Other Authors: La Rochelle, Bustamante, Paco, Cherel, Yves
• Format: Thesis
• Language: English
• Published: 2014
• Subjects: Albatros; Écologie alimentaire; Éléments traces métalliques; Isotopes stables; Mercure; Manchots; Pétrels; Plumes; Polluants organiques persistants; Albatrosses; Feathers; Feeding habits; Mercury; Penguins; Persistent organic pollutants; Stable isotopes; Trace elements; envir; geo; Antarctic; Indian; Kerguelen; Kerguelen Islands; Southern Ocean; Antarc*; Antarctica; Crozet Islands
• Online Access: http://www.theses.fr/2014LAROS026/document

Antarctic and subantarctic marine environments are reached by inorganic and organic contaminants through ocean circulation and atmospheric transport. Yet, environmental contamination is poorly known in the Southern Ocean, in particular in the Indian sector. Among environmental contaminants, mercury (Hg) and persistent organic pollutants (POPs) are primarily of concern, because they are toxic, highly mobile, and they bioaccumulate in the tissues of living organisms and biomagnify up the food web. Seabirds, as upper predators, are exposed to large quantities of contaminants via food intake and have widely served as biomonitors of marine contamination, notably through the non-destructive sampling of their feathers and blood. My doctoral work has focussed on the abundant and diverse seabird species (more than 40) breeding in the French Southern and Antarctic Lands, southern Indian Ocean, in order to describe and explain contaminant concentrations over a large latitudinal gradient, from Antarctica to the subtropics, and to identify the best bioindicator species for contaminant biomonitoring. In a first methodological step, seabirds with synchronous moult of body feathers (adult penguins and chicks of all species) were recognised as good candidates as bioindicators, because, unlike most adult birds, they present low within-individual variation in feather contaminant concentrations. In a second explanatory step, the influence of intrinsic (individual traits) and extrinsic factors (feeding ecology inferred from the stable isotope method) driving variation in contaminant concentrations was evaluated in feathers of the large avian community of the Kerguelen Islands (27 species) and in blood of wandering albatrosses from the Crozet Islands (180 birds of known individual traits). Feeding ecology was the main factor driving variation in contaminant concentrations of blood and feathers, both at the community, population and individual levels, whereas age, sex, phylogeny and breeding status played a minor role. Age-class was ...