Inter-species and inter-colony differences in elemental concentrations in eggshells of sympatrically nesting great cormorants Phalacrocorax carbo and grey herons Ardea cinerea

Abstract

We compared the concentrations of 17 heavy metals and essential elements in post-hatching eggshells of two waterbirds, the obligate piscivorous great cormorant Phalacrocorax carbo (GCM) and the more omnivorous grey heron Ardea cinerea (GHR), breeding sympatrically in eight mixed colonies in Poland. We found significant inter-species and inter-colony differences in the levels of most of the elements. GHR had significantly higher concentrations of Al, which can be explained by its very low stomach pH: an acidic environment favours the release of Al compounds. Differences in Mn, Ni, Cu, Se and Hg concentrations can be attributed to the various contributions of fish and other aquatic organisms to the diet, and to the exploration of different habitats (GCM exclusively aquatic, GHR a wider range) and microhabitats (GCM, in contrast to wading GHR, dive for food, exploring the whole depth range of water bodies), differently exposed to contamination by those elements from sediments. Inter-colony differences were related to the level of industrialisation. We recorded higher levels of some elements in the eggshells (Fe, Mn in both species and Cr, Ni and Zn in GCM) collected in industrialised areas, which may be associated with the negative environmental impact of industrial areas.Electronic supplementary materialThe online version of this article (10.1007/s11356-018-3765-5) contains supplementary material, which is available to authorized users.

Identification of Factors Affecting Environmental Contamination Represented by Post-Hatching Eggshells of a Common Colonial Waterbird with Usage of Artificial Neural Networks

“…Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) was used to estimate concentrations of elements in the eggshells according to the procedure described previously [ 7 , 34 ]. The elemental concentration (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sc, Se, Sr, V, and Zn) was analyzed in 4–12 eggshells per colony.…”

“…The elemental concentration (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sc, Se, Sr, V, and Zn) was analyzed in 4–12 eggshells per colony. Data on elemental concentration for 7 colonies were also presented [ 7 ].…”

“…Biomaterials, such as various avian tissues, are widely used for sensing and monitoring the levels of environmental pollution as a biological data storing media [ 1 , 2 ]. Eggshells of different species of waterbirds, including herons Ardeidae, are often used to determine the health of aquatic ecosystems [ 3 , 4 , 5 , 6 , 7 ]. The grey heron Ardea cinerea is a highly opportunistic predator, with a diet varying widely according to habitat and season; depending on location, it may be dominated by fish, crustaceans, or mammals [ 8 , 9 ].…”

“…Since the grey heron adopts the income breeder strategy for acquiring nutrients for egg production [ 13 , 14 ], their maternal investments (including eggshells) correspond to the contamination of the herons’ foraging areas on breeding grounds [ 15 ]. The existence of the unique mechanism of deposition of the harmful elements in the eggshells makes them good sensors of the quality of the environment at nesting sites as the composition of an eggshell represents a relatively short exposure time from a very strictly defined area exploited by the birds during the initiation of the breeding season [ 7 , 16 , 17 ].…”