Occurrence of green macroalgae (Ulva prolifera) blooms in the northern east China Sea in summer 2008

Abstract

This study examined extensive patches of floating green macroalgal (Ulva prolifera) mats in thenorthern East China Sea (ECS) using satellite images from mid May through July 2008 and fieldobservation made during early August 2008 cruise. It was previously reported that the massive macroalgalblooms occurred in the coastal areas of Qingdao in China. During our field survey, researchers noticedwidely distributed floating patches of macroalgal mats ranging in size from tens of centimeters to a fewhundred meters in diameter. Meteorological data in the northern ECS showed high irradiance, high airtemperature,and predominant southerly winds in summer. In the study area during the survey period,surface waters were characterized by the Changjiang Diluted Water (CDW) mass, which contained highconcentrations of nitrate and phosphate. The internal transcribed spacer (ITS) sequence of U. proliferafound in the northern ECS was the same as those of U. prolifera sampled from Qingdao blooms, suggestinga possibility that U. prolifera found in two regions would be derived from the same origin. We suggest thatU. prolifera in the nearshore Jiangsu Province drifted into the northern ECS and proliferated underfavorable meteorological and oceanographic conditions during the summer of 2008.