Effects of long-term elevated temperature on covering, sheltering and righting behaviors of the sea urchin Strongylocentrotus intermedius.

Lisheng Zhang,Lingling Zhang,Chong Zhao,Jing Wei,Yaqing Chang,Dongtao Shi

doi:10.7717/peerj.3122

Abstract

Increases in ocean temperature due to climate change are predicted to change the behaviors of marine invertebrates. Altered behaviors of keystone ecosystem engineers such as echinoderms will have consequences for the fitness of individuals, which are expected to flow on to the local ecosystem. Relatively few studies have investigated the behavioral responses of echinoderms to long-term elevated temperature. We investigated the effects of exposure to long-term (∼31 weeks) elevated temperature (∼3 °C above the ambient water temperature) on covering, sheltering and righting behaviors of the sea urchin Strongylocentrotus intermedius. Long-term elevated temperature showed different effects on the three behaviors. It significantly decreased covering behavior, including both covering behavior reaction (time to first covering) and ability (number of covered sea urchins and number of shells used for covering). Conversely, exposure to long-term elevated temperature significantly increased sheltering behavior. Righting response in S. intermedius was not significantly different between temperature treatments. The results provide new information into behavioral responses of echinoderms to ocean warming.

Highlights

The Intergovernmental Panel on Climate Change (IPCC) predicts that global mean sea water temperature will increase 2–4.5 ◦C by 2100
The main aim of the present study is to investigate the effects of long-term elevated temperature on covering, sheltering and righting behaviors of S. intermedius in order to provide new information into behavioral responses of echinoderms as ecosystem engineers to ocean warming
Behavioral response of sea urchins is an important concern in climate change biology, because of their susceptibility and ecological importance in the marine ecosystems (Brothers & McClintock, 2015)

Summary

Introduction

The Intergovernmental Panel on Climate Change (IPCC) predicts that global mean sea water temperature will increase 2–4.5 ◦C by 2100 (scenario RCP 8.5, IPCC, 2013). Consistent with theoretical predictions (Poloczanska et al, 2007), empirical studies indicate that elevated water temperature negatively affects physiology (Uthicke et al, 2014), immunity (Brothers et al, 2016), growth (Wolfe, Dworjanyn & Byrne, 2013; Zhao et al, 2015), gonad development (Uthicke et al, 2014), larval development (Kamya et al, 2014; Garcia, Clemente & Hernandez, 2015) and behaviors (Zhao et al, 2014; Brothers & McClintock, 2015; Sherman, 2015) of echinoderms in intertidal and shallow waters Most of these reports were based on short-term perturbation experiments and do not provide enough time to bring about potential acclimation to a new environment (Dupont et al, 2013). Long exposure time studies can provide much more valuable information, the experimental durations (several months) are still relatively short in terms of their life span (Dupont et al, 2013)

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