Sources and effects of strontium in waterfowl eggs

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Author
Latty, Christopher J.
Chair
Hollmén, Tuula E.
Committee
Matz, Angela C.
Powell, Abby N.
Hobson, Keith A.
Adkison, Milo D.
Keyword
Birds
Bird eggs
Eggshells
Waterfowl
Strontium
Isotopes
Physiology
Metadata
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URI
http://hdl.handle.net/11122/12558
Abstract
Strontium (Sr) may be a contaminant of concern for wild birds. Because of chemical similarities to calcium (Ca), Sr is readily incorporated into calcified tissues, such as eggshells. My objectives were to determine the potential drivers of both total and radio-Sr in the eggshells of waterfowl, and to assess the relationship between eggshell Sr and thickness. I collected eggs from sympatrically nesting waterfowl species in interior Alaska from 2011-2013. I measured total and radio-Sr in eggshells, environmental chemistry, and eggshell thickness. Local water chemistry explained much of the variation in eggshell Sr for canvasback (Aythya valisineria) and northern shoveler (Spatula clypeata), but not lesser scaup (Aythya affinis). Most of the remaining variation was associated with heterogeneity among eggs in the same nest (intra-clutch variance). General trends in eggshell Sr/Ca among species aligned with what would be expected had diet and/or endogenous reserve use affected eggshell chemistry. Results were similar for radio-Sr, with local water chemistry accounting for far less ⁹⁰Sr in the eggshells of lesser scaup, compared to the other species studied. At the site where water chemistry was stable, canvasback and northern shoveler eggshell thickness was not related to eggshell Sr, but lesser scaup eggshells with more Sr were thicker. At the site where water chemistry was variable, canvasback and northern shoveler eggshells with more Sr were thicker at low to intermediate concentrations, but this effect was moderated when the source of eggshell Sr appeared to be explained by the local environment. In contrast, lesser scaup eggshells with more Sr were consistently thicker, but only at higher concentrations. The different relationships between eggshell Sr and thickness across species, and interactions with apparent Sr sources, suggest the relationship between eggshell thickness and Sr is not a simple dose-dependence. My results show that for some species like lesser scaup, factors associated with the laying hen (e.g., diet or physiology) may have a larger impact on both eggshell total and radio-Sr, as well as how Sr interacts with eggshell quality, than the local environment.
Description
Thesis (Ph.D.) University of Alaska Fairbanks, 2021
Table of Contents
Chapter 1: Introduction -- 1.1 Strontium -- 1.2 Strontium incorporation into biota -- 1.3 Strontium incorporation into eggs -- 1.4 Effects of strontium -- 1.5 Lesser scaup -- 1.6 Objectives -- 1.7 References. Chapter 2: Environmental sources of strontium in waterfowl eggs from Interior Alaska -- 2.1 Abstract -- 2.2 Introduction -- 2.2.1 Objectives -- 2.3 Materials and methods -- 2.3.1 Study site -- 2.3.2 Sample collections -- 2.3.2.1 Eggs -- 2.3.2.2 Water -- 2.3.3 Chemical analyses -- 2.3.3.1 Eggshells -- 2.3.3.2 Water -- 2.3.4 Data treatment and statistical analysis -- 2.4 Results -- 2.4.1 Eggshell Sr/Ca -- 2.4.2 Eggshell Sr/Ca predictors -- 2.4.2.1 Overall model -- 2.4.2.2 Species-specific models -- 2.5 Discussion -- 2.5.1 Potential influence of diet -- 2.5.2 Other potential factors affecting Sr/Ca variance -- 2.5.2.1. Endogenous reserves -- 2.5.2.2 Discrimination of Sr -- 2.5.2.3 Annual water chemistry -- 2.5.2.4 Nest parasitism and laying hen use of other wetlands -- 2.6 Conclusions -- 2.7 Acknowledgements -- 2.8 Figures -- 2.9 Tables -- 2.10 References. Chapter 3: Radionuclide activities in waterfowl eggs in the Alaska boreal forest and relationship to local environment -- 3.1 Abstract -- 3.2 Introduction -- 3.2.1 Objectives -- 3.3 Materials and methods -- 3.3.1 Study site -- 3.3.2 Sample collections -- 3.3.2.1 Eggs -- 3.3.2.2 Lesser scaup ducklings -- 3.3.2.3 Water -- 3.3.3 Chemical analyses -- 3.3.3.1 Eggshells radiochemistry chemistry -- 3.3.3.2 Eggshells elemental chemistry -- 3.3.3.3 Water chemistry -- 3.3.4 Data treatment and statistical analysis -- 3.4 Results -- 3.5 Discussion -- 3.6 Conclusions -- 3.7 Acknowledgements -- 3.8 Figures -- 3.9 Tables -- 3.10 References. Chapter 4: Environmental and eggshell strontium predict waterfowl eggshell thickness -- 4.1 Abstract -- 4.2 Introduction -- 4.2.1 Objectives -- 4.3 Materials and methods -- 4.3.1 Study site -- 4.3.2 Sample collections and analysis -- 4.3.2.1 Eggs -- 4.3.2.2 Water -- 4.3.3 Chemical analyses -- 4.3.3.1 Eggshells -- 4.3.3.2 Water chemistry -- 4.3.4 Data treatment and statistical analysis -- 4.4 Results -- 4.4.1 Eggshell Sr and water Sr/Ca -- 4.4.2 Eggshell thickness -- 4.5 Discussion -- 4.5.1 Differences between species -- 4.5.2 Potential factors leading to greater eggshell thickness and Sr -- 4.5.3 Potential factors leading to lower-quality eggshells from elevated Sr -- 4.6 Conclusions -- 4.7 Acknowledgements -- 4.8 Figures -- 4.9 Tables -- 4.10 References. Chapter 5: Conclusions -- 5.1 References.
Date
2021-05
Type
Thesis
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