Toxicity of seabird guano to sea urchin embryos and interaction with Cu and Pb

Abstract

Guano is an important source of marine-derived nutrients to seabird nesting areas. Seabirds usually present high levels of metals and other contaminants because the bioaccumulation processes and biotic depositions can increase the concentration of pollutants in the receiving environments. The objectives of this study were to investigate: the toxicity of seabird guano and the joint toxicity of guano, Cu and Pb by using the sea urchin embryo-larval bioassay. In a first experiment, aqueous extracts of guano were prepared at two loading rates (0.462 and 1.952 g L(-1)) and toxicity to sea-urchin embryos was tested. Toxicity was low and not dependent of the load of guano used (EC50 0.42 ± 0.03 g L(-1)). Trace metal concentrations were also low either in guano or in aqueous extracts of guano and the toxicity of extracts were apparently related to dissolved organic matter. In a second experiment, the toxicity of Cu-Pb mixtures in artificial seawater and in extracts of guano (at two loadings: 0.015 and 0.073 g L(-1)), was tested. According to individual fittings, Cu added to extracts of guano showed less toxicity than when dissolved in artificial seawater. The response surfaces obtained for mixtures of Cu and Pb in artificial seawater, and in 0.015 g L(-1) and 0.073 g L(-1) of guano, were better described by Independent Action model adapted to describe antagonism, than by the other proposed models. This implied accepting that EC50 for Cu and Pb increased with the load of guano and with a greater interaction for Cu than for Pb.

Multi-level analysis of reproduction in an Antarctic midge identifies female and male accessory gland products that are altered by larval stress and impact progeny viability

“…These GO terms are related to digestion and detoxification of ingested materials by the growing larvae-neither of which would be relevant issues for the non-feeding adults. One cytochrome p450 (CYP6Z2), up-regulated in larvae, has been implicated in chemical resistance in Anopheles mosquitoes 109 and therefore may be critical for larval survival in a potentially toxic microhabitat, such as seabird guano 110 .…”

Inputs of seabird guano alter microbial growth, community composition and the phytoplankton–bacterial interactions in a coastal system

“…These seabirds release a large amount of N (32.7 ± 12.7 mg kg −1 ) and P (16 ± 7.9 mg kg −1 ) into colony soils, mainly through excrements and pellets (De La Peña‐Lastra et al, 2019; Otero & Mouriño, 2002). In addition, seabird excrements have large amounts of Zn, Cu and As (Otero et al, 2018; Rial et al, 2016).…”

Assessing the Risk of Metals and Their Mixtures in the Antarctic Nearshore Marine Environment with Diffusive Gradients in Thin-Films

“…In this study, four sites (Sites 4, 8, 10, and 11) were in close proximity to large Adélie penguin colonies, and had large volumes of melt stream runoff from the colonies to the marine sites (personal observation). This could imply that the metal contaminants were insoluble, remain complexed in guano, or were bound to other organic carbon rendering them less labile 44 .…”

“…This could imply that the metal contaminants were insoluble, remain complexed in guano, or were bound to other organic carbon rendering them less labile. 44 Predicted Toxicity. For most Antarctic marine organisms, including the microalgae and echinoid examined in this study, copper is the most toxic metal investigated.…”