High water temperature tolerance in photosynthetic activity of Zostera japonica Ascherson & Graebner seedlings from Ago Bay, Mie Prefecture, central Japan

Climate Change Impacts on Seagrass Meadows and Macroalgal Forests: An Integrative Perspective on Acclimation and Adaptation Potential

“…Likewise, experiments with Z. japonica seedlings showed a thermal limit of 29 • C above which seedlings die (Abe et al, 2009), similar to the thermal limit for P. oceanica seedlings. Seagrass seedling mortality at temperatures around 30 • C are likely to constrain the extant distribution of seagrasses (e.g., Abe et al, 2009), and their capacity to accommodate to future, warmer regimes.…”

“…Experimental simulated heat waves and warming at projected levels in the NW Mediterranean led to reduced growth, increased mortality, leaf necrosis, and respiration in Posidonia oceanica seedlings (Herman and Sultan, 2016;Guerrero-Meseguer et al, 2017), and also increased their susceptibility to consumption by grazers (Hernán et al, 2016). Likewise, experiments with Z. japonica seedlings showed a thermal limit of 29 • C above which seedlings die (Abe et al, 2009), similar to the thermal limit for P. oceanica seedlings. Seagrass seedling mortality at temperatures around 30 • C are likely to constrain the extant distribution of seagrasses (e.g., Abe et al, 2009), and their capacity to accommodate to future, warmer regimes.…”

“…These contrasting results reflect either local adaptation to particular spring regimes or the fact that the response of seagrass seed germination to temperature is likely to be best represented by a Gaussian distribution, with minimal and maximum thermal tolerances and an optimum temperature for germination. Abe et al (2009) determined that optimal water temperature for seed germination of a Japanese Z. marina stand was in the range from 10 to 15 • C, with optimal temperature for seedling growth ranging from 20 to 25 • C; and seedling mortality observed at water temperatures exceeding 28 • C. Based on these results, they predicted that Z. marina stands would be lost from areas exceeding maximum temperatures of 28 • C (Abe et al, 2009), thereby leading to the expectation of losses with warming in the lower latitudinal limit of the species in Japan (Abe et al, 2009). Seed abortion following marine heat waves has been documented in Posidonia species, both in the Mediterranean (P. oceanica, Balestri and Cinelli, 2003) and Australia (P. australia, Shark Bay, Thomson et al, 2015).…”

Temperature characteristics in seed germination and growth of Zostera japonica Ascherson & Graebner from Ago Bay, Mie Prefecture, central Japan

“…Then cultures were conducted at water temperature at 5°C intervals from 5 to 35°C and at 1°C intervals from 27 to 30°C under light conditions of 100 lmol photons/m 2 /s and 12L:12D for 1 week. Water temperatures were controlled by using an improved type of temperature-gradient culture apparatus [18,19,29,30] between 10 and 35°C and by using COOLPIPE 150LF (TAITEC) and THERMAL ROBO TR-1A (AS-ONE) to keep the temperature of 5°C.…”

“…Among the various environmental factors, water temperature is one of the most important factors that determine the seasonal growth and the distributional patterns of marine plants [17][18][19]. There are several reports that the maximum biomass of Zostera japonica population appeared during summer [4,[11][12][13][14][15]20], whereas that of Z. marina population appeared during spring [21][22][23][24][25][26].…”