Effects Of Long-term High Temperature Stress On Behaviours,growth And Offspring Traits Of Sea Urchin Strongylocentrotus Intermedius

Sea urchin Strongylocentrotus intermedius belongs to echinoidea of echinodermata,which occurs round lithoherm,dinas and gravel in inter-tide and shallow seas.S.intermedius is in a middle status in marine ecosystem as both customer and prey for many marine organisms.Hence,changes in the ecological function of sea urchins can affect the stability of the whole marine ecosystem.It also shows that sea urchins are ideal organism for studying the changes in the marine environment.Temperature is an important factor that affects the growth and survival of marine life.In the context of the continuous rise of global oceanic temperature,it is of great ecological significance to study the effects of long-term high-temperature environment on marine biological fitness,intergenerational adaptation and physiological behavior for our understanding of the effects of global climate change and the sustainable development of aquaculture and marine species protection provides the basis for information.In our present research,sea urchin S.intermedius are cultured respectively in laboratory water temperature and long-term high temperature condition(always + 3 °C higher than laboratory water temperature)for 17 months.The effects of long-term high-temperature environment on the suitable traits,reproductive intergeneration and behavioral activities of the sea urchin were studied at different time nodes.The main research contents were as follows:Ocean warming greatly impacts marine organisms,ecosystem structure and humanity.It is essential to investigate fitness related consequences of ecologically important marine organisms in response to long-term high temperature.Here,we compared the effect of short-term(?4 months)and long-term(?10 months)exposure to elevated temperature on a series of fitness related traits of the sea urchin S.intermedius.Test diameter,body weight and test weight were significantly affected by long-term exposure(?10 months)of elevated temperature,but not by short-term exposure(?4 months).This indicates that the evaluation of the effect of ocean warming on growth of S.intermedius requires long-term exposure,which is probably underestimated by the investigations of short-term exposure.A significantly higher test height:test diameter(H:D)was found in S.intermedius exposed to elevated temperature for both ?4 and ?10 months.This result enriches our understanding of morphological plasticity of test shape of sea urchins.In the present study,we found the robustness of lantern and the sensitiveness of gut of sea urchins in ocean warming.A significant increase in HSP70 expression of S.intermedius with exposure to elevated temperature is an important physiological response of sea urchins to high temperature and suggests the importance of HSP70 in the thermal acclimation of sea urchins in ocean warming.The current results also highlight the importance of long-term acclimation of test thickness of sea urchins to elevated temperature.The present study provides new insights into the thermal acclimation of sea urchins in ocean warming.Transgenerational acclimation is important for the evolutionary adaptation of echinoderms in the changing ocean.Here,we investigated the effects of water temperature for offspring,breeding design,dam and sire on egg size,fertilization,hatchability,larval survival,size,abnormality and metamorphosis of the sea urchin S.intermedius.Transgenerational acclimation to ocean warming is much more complex than previously thought in sea urchins.There was transgenerational acclimation on fertilization,post-oral length and metamorphosis in S.intermedius,while negative carryover effects were found in hatchability and most traits of larval size.Dam and sire effects were highly trait and developmental stage dependent.This study indicates that sea urchins can transgenerationally acclimate long-term elevated temperature provided their offspring lives at an optimal temperature,in spite of negative carryover effects in a few traits.However,sea urchins(at least S.intermedius)probably cannot achieve transgenerational acclimation to long-term elevated temperature for survival provided their offspring is exposed at an elevated temperature(+?3 °C).The dangerous status of S.intermedius conversation to ocean warming should be highlighted,because their larvae cannot survive no matter directly exposed to high temperature or even given a long-term parental thermal acclimation.The present study enriches our understanding of transgenerational acclimation to ocean warming in sea urchins and clarifies their potential applications to conversation and aquaculture.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 individuals fitness,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 S.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.