My research has focused on three main areas
stable isotopes for cetacean research: a guide
Are you new to stable isotopes and interested in applying this tool to investigate cetaceans' foraging and movement ecology? We have recently published a paper, led by my colleague and friend, Dr. Clarissa Teixeira, that provides a useful guide for students and researchers new to this method. In this paper, we talk about everything you need to know, from planning your research, to carrying out the lab work, and analysing and interpreting your data.
A few examples of what you will find in this paper include a description of the temporal resolution that the different tissues offer, how to choose the ideal tissue, depending on the research question you want to address, how to store and preserve the different tissue types, sample treatment (e.g., lipid extraction, decalcification), and processing for stable isotope measurements in the Isotope Ratio Mass Spec. We also present the different tools to analyse isotope data, including the different packages developed for use in R.
The article is published in the journal Marine Mammal Science, and can be accessed here.
case study for franciscana dolphins
Our recent study published in the journal Marine Environmental Research showed that the isotopic signal from the nursing period that occurred during the first few months of life still affects the whole tooth stable isotope values in juvenile franciscanas (up to 3 years old). Why does it matter? Tooth tissue is frequently used for stable isotope measurements to assess the feeding ecology of marine mammals, including franciscana dolphins.
By measuring stable isotopes in different tooth portions, including the center which excludes the dentin layer deposited during the nursing period, we demonstrated the effect of the dentin deposition patterns on the whole tooth isotope values of franciscana dolphin, and how it can affect dietary assessments.
Isotope mixing models showed that dietary estimates were different when using the isotope measurements of the whole tooth in comparison to using only the center tooth portion, affecting dietary inferences for juvenile franciscanas.
With this, we call for caution when using stable isotope measurements from the whole tooth of this and other small-toothed dolphins. We recommend, when possible, to exclude the dentin layer deposited during the nursing period, remove juveniles from analysis when only whole tooth isotopic analysis is feasible, or choose another tissue for isotopic measurements.
The full paper can be accessed in the here.
research groups
Pelagic ecosystems lab - PEL
Led by Prof. Dr. Brian Hunt and situated at the Institute for the Oceans and Fisheries, University of British Columbia.
Oceanic ecology research group
Dedicated to conducting objective science based research to better understand the ecology of marine life inhabiting the California Current Large Marine Ecosystem (CCLME). This includes dedicated research, conservation, and education initiatives.
Find us on Facebook!
partners
EComega - furg
Laboratory of Ecology and Conservation of the Marine Megafauna (Laboratório de Ecologia e Conservação da Megafauna Marinha), at Universidade Federal do Rio Grande, southern Brazil. Led by Professors Dr. Eduardo Secchi, Dr. Silvina Botta and Dr. Luciano Dalla Rosa.