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Effects of salinity on survival of the exotic seagrass Zostera japonica subjected to extreme high temperature stress
Citation:
KALDY, III, J. E. AND D. Shafer. Effects of salinity on survival of the exotic seagrass Zostera japonica subjected to extreme high temperature stress. BOTANICA MARINA. Walter de Gruyter GmbH, Berlin, Germany, 56(1):75-82, (2012).
Impact/Purpose:
Zostera japonica is a non-indigenous seagrass that is expanding along the Pacific Coast of North America.
Description:
Zostera japonica is a non-indigenous seagrass that is expanding along the Pacific Coast of North America. The ecophysiology of this seagrass is poorly studied and management of the species is fragmented. We collected Z. japonica plants from Padilla Bay, WA., Yaquina Bay and Coos Bay, OR, USA and exposed them to a constant water temperature of 35 °C at three different salinities (5, 20 and 35). After 7 d exposure, shoot mortality ranged between 58 and 94% and after 9 d exposure only a few plants from the Yaquina Bay population survived. There were statistically significant differences between salinities, with mortality greater at salinity 5 than at either salinity 20 or 35. Additionally, there were statistically significant population differences, with Padilla > Coos > Yaquina ranked highest to lowest mortality. Consequently, it appears that the Z. japonica plants from the two southern populations were better adapted to handle high temperature stress as indicated by the lower mortality of plants from these populations. We suggest that, Z. japonica will continue to spread to the south until it reaches systems that regularly exceed the temperature tolerances.
