TY - JOUR
T1 - How hot for how long? The potential role of heat intensity and duration in moderating the beneficial effects of an ecosystem engineer on rocky shores
AU - CARTWRIGHT, Stephen Robert
AU - Williams, Gray A.
N1 - Funding Information:
Acknowledgments Thanks to Professor CD McQuaid (University of rhodes, South africa) and the Hard rock ecology group (HKU) for comments improving the manuscript and Ms Cecily law for assistance in preparing the experiments. This work was conducted in partial fulfilment of a PhD degree by SrC who was supported by a post-graduate studentship at The University of Hong Kong.
PY - 2014/9
Y1 - 2014/9
N2 - Studies of the importance of ecosystem engineers have focused on their benefit to biodiversity through ameliorating environmental stress, without understanding the exact benefits gained by associated organisms. On monsoonal tropical shores, species experience strong seasonality in environmental conditions from almost temperate winters to tropical summers when mass mortalities can occur during daytime emersion. The limpet, Cellana grata, associates with an ecosystem engineer, the barnacle Tetraclita japonica, in summer, but not in winter. To understand the benefits of this association, physiological responses (heart rates and osmotic responses) of the limpet either amongst Tetraclita or on open rock surfaces were investigated under three environmental conditions in a laboratory mesocosm: awash (non-stressed), low (30 °C) and high thermal stress (40 °C) of varying durations (3 or 6 h). In general, at 30 °C, limpets showed similar physiological responses under all conditions for both exposure durations. After 6 h at 40 °C, however, all limpets on open rock surfaces died, whereas those associated with barnacles survived. The surviving limpets experienced similar levels of stress as those exposed to 40 °C on open rock surfaces for half the time (3 h), showing that both the level and duration of stress were important. Limpets, therefore, gain benefits from engineering species when conditions are extreme or stress is prolonged. Under low temperatures or for short durations (e.g. winter), associating with barnacles does not provide physiological benefits. Understanding how, and to what extent, associates benefit from ecosystem engineers highlights how close the margin between survival and mortality can be when conditions are extreme.
AB - Studies of the importance of ecosystem engineers have focused on their benefit to biodiversity through ameliorating environmental stress, without understanding the exact benefits gained by associated organisms. On monsoonal tropical shores, species experience strong seasonality in environmental conditions from almost temperate winters to tropical summers when mass mortalities can occur during daytime emersion. The limpet, Cellana grata, associates with an ecosystem engineer, the barnacle Tetraclita japonica, in summer, but not in winter. To understand the benefits of this association, physiological responses (heart rates and osmotic responses) of the limpet either amongst Tetraclita or on open rock surfaces were investigated under three environmental conditions in a laboratory mesocosm: awash (non-stressed), low (30 °C) and high thermal stress (40 °C) of varying durations (3 or 6 h). In general, at 30 °C, limpets showed similar physiological responses under all conditions for both exposure durations. After 6 h at 40 °C, however, all limpets on open rock surfaces died, whereas those associated with barnacles survived. The surviving limpets experienced similar levels of stress as those exposed to 40 °C on open rock surfaces for half the time (3 h), showing that both the level and duration of stress were important. Limpets, therefore, gain benefits from engineering species when conditions are extreme or stress is prolonged. Under low temperatures or for short durations (e.g. winter), associating with barnacles does not provide physiological benefits. Understanding how, and to what extent, associates benefit from ecosystem engineers highlights how close the margin between survival and mortality can be when conditions are extreme.
UR - http://www.scopus.com/inward/record.url?scp=84907082151&partnerID=8YFLogxK
U2 - 10.1007/s00227-014-2489-4
DO - 10.1007/s00227-014-2489-4
M3 - Journal article
AN - SCOPUS:84907082151
SN - 0025-3162
VL - 161
SP - 2097
EP - 2105
JO - Marine Biology
JF - Marine Biology
IS - 9
ER -