Phenology and photosynthetic characteristics of a Japanese seagrass Zostera marina at the southern end of its distribution in the northwestern Pacific

作者：Kawano Takashi^*; Nishihara Gregory N; Terada Ryuta

来源：Nippon Suisan Gakkaishi, 2012, 78(4): 692-704.

The phenology and photosynthetic characteristics of a Japanese seagrass Zostera marina were examined from April 2010 to September 2011 at Yamagawa, Ibusuki City, Kagoshima Prefecture, which is near the southern distributional limit in the northwestern Pacific. A line-transect survey conducted to elucidate its community structure showed that it is distributed at depths of 2-2.5 m. The biomass of this species showed a peak in May accompanying maturation; meanwhile, it disappeared from the substratum from August to October, suggesting that this population has an annual life history. Photosynthesis in this species was determined over a range of temperatures (12-32 degrees C) by dissolved oxygen sensor, and revealed that the net photosynthetic rate was highest at 20 degrees C. An ANOVA analysis indicated that there were no significant differences from 12 degrees C to 24 degrees C. Pulse-amplitude modulated fluorometry was used to demonstrate that the relative electron transport rate (rETR) of photosystem II (water/plastoquinone oxido-reductase) increased quickly with increasing PAR, was highest at 611 mu mol photons m(-2) s(-1), and decreased as PAR further increased. Summer seawater temperature was around 28-31 degrees C in the natural habitat of the community examined, suggesting that respiration and photosynthetic activity might be influenced by the natural conditions.

• 出版日期2012-7