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. (2018). Mercury exposure and short-term consequences on physiology and reproduction in Antarctic petrels (Vol. 237).
Keywords: Antarctica Bioaccumulation Body condition Breeding success Stable isotopes Trophic position
Programme: 388
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. (2022). Quantitative meta-analysis reveals no association between mercury contamination and body condition in birds (Vol. 97). Bachelor's thesis, , .
Keywords: blood body mass energetics fat feather feeding habitat metabolism species
Programme: 109,330,388,1036,1210
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. (2020). Trace elements and persistent organic pollutants in chicks of 13 seabird species from Antarctica to the subtropics (Vol. 134). Bachelor's thesis, , .
Keywords: Albatrosses; Mercury; Penguins; Petrels; Selenium; Stable isotopes
Programme: 109
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. (2023). Carryover effects of winter mercury contamination on summer concentrations and reproductive performance in little auks (Vol. 318).
Keywords: Blood Chick growth Feathers Migration Reproduction Seabird Telomeres
Programme: 388
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. (2017). From Antarctica to the subtropics: Contrasted geographical concentrations of selenium, mercury, and persistent organic pollutants in skua chicks (Catharacta spp.) (Vol. 228).
Keywords: Bioaccumulation Blood Chick HCB Southern Ocean Stable isotopes
Programme: 109
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. (2017). From Antarctica to the subtropics: Contrasted geographical concentrations of selenium, mercury, and persistent organic pollutants in skua chicks (Catharacta spp.) (Vol. 228).
Keywords: Bioaccumulation Blood Chick HCB Southern Ocean Stable isotopes
Programme: 109
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. (2017). Lagrangian analysis of multi-satellite data in support of open ocean Marine Protected Area design (Vol. 140).
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. (2018). Intrathalline Metabolite Profiles in the Lichen Argopsis friesiana Shape Gastropod Grazing Patterns (Vol. 44).
Abstract: Lichen-gastropod interactions generally focus on the potential deterrent or toxic role of secondary metabolites. To better understand lichen-gastropod interactions, a controlled feeding experiment was designed to identify the parts of the lichen Argopsis friesiana consumed by the Subantarctic land snail Notodiscus hookeri. Besides profiling secondary metabolites in various lichen parts (apothecia, cephalodia, phyllocladia and fungal axis of the pseudopodetium), we investigated potentially beneficial resources that snails can utilize from the lichen (carbohydrates, amino acids, fatty acids, polysaccharides and total nitrogen). Notodiscus hookeri preferred cephalodia and algal layers, which had high contents of carbohydrates, nitrogen, or both. Apothecia were avoided, perhaps due to their low contents of sugars and polyols. Although pseudopodetia were characterized by high content of arabitol, they were also rich in medullary secondary compounds, which may explain why they were not consumed. Thus, the balance between nutrients (particularly nitrogen and polyols) and secondary metabolites appears to play a key role in the feeding preferences of this snail.
Keywords: Chemical ecology Herbivory Lichen-gastropod interactions Notodiscus hookeri Snail Stereocaulaceae Subantarctic islands
Programme: 136
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. (2019). Overcoming deterrent metabolites by gaining essential nutrients: A lichen/snail case study (Vol. 164). Bachelor's thesis, , .
Abstract: Specialised metabolites in lichens are generally considered repellent compounds by consumers. Nevertheless, if the only food available is lichens rich in specialised metabolites, lichenophages must implement strategies to overcome the toxicity of these metabolites. Thus, the balance between phagostimulant nutrients and deterrent metabolites could play a key role in feeding preferences. To further understand lichen-gastropod interactions, we studied the feeding behaviour and consumption in Notodiscus hookeri, the land snail native to sub-Antarctic islands. The lichen Usnea taylorii was used because of its simple chemistry, its richness in usnic acid (specialised metabolite) and arabitol (primary metabolite) and its presence in snail habitats. Choice tests in arenas with intact lichens versus acetone-rinsed lichens were carried out to study the influence of specialised metabolites on snail behaviour and feeding preference. Simultaneously, usnic acid and arabitol were quantified and located within the lichen thallus using HPLC-DAD-MS and in situ imaging by mass spectrometry to assess whether their spatial distribution explained preferential snail grazing. No-choice feeding experiments, with the pure metabolites embedded in an artificial diet, defined a gradual gustatory response, from strong repellence (usnic acid) to high appetence (D-arabitol). This case study demonstrates that the nutritional activity of N. hookeri is governed by the chemical quality of the food and primarily by nutrient availability (arabitol), despite the presence of deterrent metabolite (usnic acid).
Keywords: D-arabitol; Feeding choice; Lichen; Mass spectrometry imaging; Parmeliaceae; Snail; Usnic acid
Programme: 136
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. (2020). Mass Spectrometry Imaging of Specialized Metabolites for Predicting Lichen Fitness and Snail Foraging (Vol. 9).
Abstract: Lichens are slow-growing organisms supposed to synthetize specialized metabolites to protect themselves against diverse grazers. As predicted by the optimal defense theory (ODT), lichens are expected to invest specialized metabolites in higher levels in reproductive tissues compared to thallus. We investigated whether Laser Desorption Ionization coupled to Mass Spectrometry Imaging (LDI-MSI) could be a relevant tool for chemical ecology issues such as ODT. In the present study, this method was applied to cross-sections of thalli and reproductive tissues of the lichen Pseudocyphellaria crocata. Spatial mapping revealed phenolic families of metabolites. A quantification of these metabolites was carried out in addition to spatial imaging. By this method, accumulation of specialized metabolites was observed in both reproductive parts (apothecia and soralia) of P. crocata, but their nature depended on the lichen organs: apothecia concentrated norstictic acid, tenuiorin, and pulvinic acid derivatives, whereas soralia mainly contained tenuiorin and pulvinic acid. Stictic acid, tenuiorin and calycin, tested in no-choices feeding experiments, were deterrent for N. hookeri while entire thalli were consumed by the snail. To improve better knowledge in relationships between grazed and grazing organisms, LDI-MSI appears to be a complementary tool in ecological studies
Keywords: Notodiscus hookeri Pseudocyphellaria crocata Chemical Ecology Lichens Lobariaceae Mass Spectrometry Imaging Optimal Defense Theory Specialized Metabolites
Programme: 136
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