Effects of ocean acidification and shading on growth, exoskeleton calcification and behavior of hermit crabs

• Grant number: 15/02727-0
• Support Opportunities: Scholarships in Brazil - Master
• Start date: June 01, 2015
• End date: February 28, 2017
• Field of knowledge: Physical Sciences and Mathematics - Oceanography - Biological Oceanography
• Agreement: Coordination of Improvement of Higher Education Personnel (CAPES)
• Principal Investigator: Alexander Turra
• Grantee: Marilia Nagata Ragagnin
• Host Institution: Instituto Oceanográfico (IO). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 11/50317-5 - Biodiversity and functioning of a subtropical coastal ecosystem: a contribution to integrated management, AP.BTA.TEM

Abstract

Anthropogenic activities release high carbon dioxide concentrations in the atmosphere, which is absorbed by the oceans and cause Ocean Acidification (OA) due to a pH reduction. This process affects marine calcifying organisms due to changes in dissolution and deposition of calcium carbonate in their tissues. Hermit crabs are an example of these organisms and may present variations in growth rate, behavior and exoskeleton calcification. Furthermore, environmental shading is induced by coastal constructions (e.g. harbors and docks) and may also originate negative effects in growth and behavior of hermit crabs as well as reduce the adaptability of animals in relation to changes in pH. Hermit crabs are abundant in Araçá Bay, which is threatened by shading due to the project of Port of São Sebastião expansion. As these animals are appropriate models to evaluate acute and synergic effects of OA and shading, the present study aims to evaluate OA and shading effects on the growth rate, calcification rate and behavior of hermit crabs with juveniles of Pagurus criniticornis collected in Araçá Bay. The experiment will be maintained for six months with four treatments: pH=7.6 and photoperiod of 12:12h; pH=7.6 and photoperiod of 0:24h; pH=8.1 and photoperiod of 12:12h (control); and pH=8.1 and photoperiod of 0:24h. Hermit crabs' molts will be collected over the six months. Analysis of Variance (ANOVA) will be applied to compare the shield length of the first and the last molts of each individual and evaluate growth rate. To evaluate calcification rate, the density of the last molt of each individual will be measured by micro tomography and ANOVA will be applied to compare the density among the treatments. At the end of the experimental period, the same hermit crabs will be used in behavior tests with presence of predator odor (danger signal) and gastropod odor (new shell available signal). ANOVA will be used to compare the response behavior between the treatments. In this context, the present study aims to provide information about synergic effects of OA and shading in marine organisms, which will allow understanding the potential impacts of global climate changes in association with local human impacts. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

TURRA, ALEXANDER; RAGAGNIN, MARILIA N.; MCCARTHY, IAN D.; FERNANDEZ, WELLINGTON S.. The effect of ocean acidification on the intertidal hermit crab Pagurus criniticornis is not modulated by cheliped amputation and sex. MARINE ENVIRONMENTAL RESEARCH, v. 153, JAN 2020. (13/19826-6, 14/12879-0, 13/50197-5, 15/02727-0)

MCCARTHY, IAN D.; WHITELEY, NIA M.; FERNANDEZ, WELLINGTON S.; RAGAGNIN, MARILIA N.; CORNWELL, TOMAS O.; SUCKLING, COLEEN C.; TURRA, ALEXANDER. Elevated pCO(2) does not impair performance in autotomised individuals of the intertidal predatory starfish Asterias rubens (Linnaeus, 1758). MARINE ENVIRONMENTAL RESEARCH, v. 153, JAN 2020. (14/12879-0, 13/50197-5, 15/02727-0)

RAGAGNIN, MARILIA NAGATA; MCCARTHY, IAN DONALD; FERNANDEZ, WELLINGTON SILVA; TSCHIPTSCHIN, ANDRE PAULO; TURRA, ALEXANDER. Vulnerability of juvenile hermit crabs to reduced seawater pH and shading. MARINE ENVIRONMENTAL RESEARCH, v. 142, p. 130-140, NOV 2018. (15/02727-0)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

RAGAGNIN, Marilia Nagata. Effects of multiple stressors on the impact of ocean acidification on marine biota. 2017. Master's Dissertation - Universidade de São Paulo (USP). Instituto Oceanográfico (IO/DIDC) São Paulo.