长江口及邻近海域夏、冬季浮游病毒丰度分布

应用荧光显微计数法,对2006年夏季和2007年冬季长江口浮游病毒丰度(virus direct count,VDC)进行了检测.结果表明:夏季该海域VDC在2.22×106～9.97×107个·ml-1,高值分布在近海B区(122.5°-123.5°E)的表层海域;冬季VDC在1.99×106～2.66×107个·ml-1,高值分布在近岸A区(120.5°-122.5°E)海域,且由近岸向外海逐渐降低.夏季VDC与浮游细菌生物量、叶绿素含量关系密切,与营养盐相关性不显著(P＞0.05);冬季VDC与浮游细菌、营养盐含量关系密切,与叶绿素a含量相关性不显著(P＞0.05).夏季VDC显著高于冬季(P＜0.01),且两季的分布特征存在不同,此种差异主要与浮游细菌、浮游植物等病毒寄主的分布有关.冬季的营养盐含量也是影响其浮游病毒分布的重要因素.

Abundance distribution of virioplankton in Yangtze River estuary and its adjacent East China Sea in summer and winter

An investigation was made on the abundance distribution and its variation of virioplankton in the Yangtze River estuary and its adjacent East China Sea in summer 2006 and winter 2007. The virus direct count (VDC) was quantified by fluorescent microscopy. In summer 2006, the VDC was from 2.22 x 10(6) to 9.97 x 10(7) ind x m(-1), being higher in the surface sea water of B area (122.5 degrees-123.5 degrees E); in winter 2007, the VDC was from 1.99 x 10(6) to 2.66 x 10(7) ind x mh(-1), being higher in coastal A area (120.5 degrees-122.5 degrees E) and decreased from nearshore waters to offshore waters. In summer, the VDC had close relationships with bacteriaplankton biomass and chlorophylla concentration but less relationship with nutrients concentration (P > 0.05); in winter, the VDC was closely related to bacteriaplankton biomass and nutrients concentration but less related to chlorophyll-a concentration (P > 0.05). The abundance distribution pattern of virioplankton showed significant seasonal variability, with the VDC significantly larger in summer than in winter (P < 0.01), which was mainly decided by the distribution of the viral host, and partly by the nutrients concentration in wintertime.