Effects of temperature on the germination of green algae micro-propagules in coastal waters of the Subei Shoal, China

摘要

Since 2007, large-scale green tides that primarily consisted of Ulva prolifera have consecutively invaded the coast of Qingdao (36 degrees 06'N, 120 degrees 25'E, PR China) in summer. The germination of green algae micro-propagules in the Subei Shoal played a significant role in the formation of these green tides. The change in sea temperature might be the key factor that affects the germination of the micro-propagules because the other environmental factors varied only slightly according to previous studies. This study was designed to investigate the effects of temperature on the germination of micro-propagules via laboratory experiments. The results showed the following: (1) five types of green algae micro-propagules, including U. prolifera, U. linza, U. compressa, [Ova sp. (Clade 6) and Blidingia sp., were detected in the seawater samples collected from the Subei Shoal; (2) at 5 degrees C, germinated micro-propagules were not detected in any of the samples; at 10 degrees C, the micro-propagules began to germinate, and the germination quantity markedly changed between 10 degrees C and 30 degrees C; (3) the germination numbers of U. prolifera, U. linza, Ulva sp. (Clade 6) and Blidingia sp. were maximized at 15 degrees C, 10 degrees C, 25 degrees C and 20 degrees C, respectively. This study indicated that the sea temperature played a significant role in the germination of green algae micro-propagules in water and could partly explain the community succession phenomenon of the attached green algae in the Subei Shoal. (C) 2014 Elsevier Ltd. All rights reserved.