文档介绍：第六讲海洋底栖藻类生态
近海底栖植物区系
Benthos 海底生物(包括底栖动、植物)
近海底栖植物包括:
red algae, brown algae, green algae, blue-green algae, diatoms,
seagrass, mangroves, marsh grass
海洋底栖植物生存于陆地与大洋之间的交界地带,具有高生产力、栖息地类型多变、人类和动物影响大等特点。
海洋底栖植物分布范围:
上限: This region extend on to the land until the effect of seawater is negligible and the flora indistinguishable from that of typical freshwater habitats.
下限: The lowermost point seaward must be the point below which growth of benthic flora ceases due to lack of light for photosynthesis, and this may be close to land on steep slope and out on the continental shelf on gentle slope.
底栖植物分布的下限会随着季节和水体混浊度的变化而变化,这些都和水体中阳光的透射强度变化有关。
底栖植物区系通常都是light limited(光限制), 由于浮游藻类、海草甚至陆源植物的遮荫作用,导致水体的光线透射率降低;例如,如果大型海藻密集生长,其叶状体(algal frond)就会形成一个遮蓬,阻挡光线透射下去,对于小型底栖藻类而言,光就成为限制其生长的关键因子;
海流、波浪运动、陆地径流输入、动物活动等,都会增加水体混浊度,甚至翻起的泥沙会覆盖藻体,造成光线不足,限制底栖植物生长;
Estuarine waters carry high concentrations of silt in suspension and this may restrict light ration to such and extent that phytoplankton and benthic production is severely reduced.
底质为底栖植物提供了适宜的附着场所;
沉积物及丰富的异养生物(动物、微生物等),使得底层水体具有丰富的营养盐,一般认为,与外海浮游植物的营养盐限制相比较,近海底栖植物区系受到营养盐限制的可能性比较小;
浅海水体中,波浪运动、海流和上升流等都能产生搅动,阻止水体的热力学分层(except for brief period at least in the temperate zone),因此,营养盐很少能成为底栖植物生长的限制因子,与外海相比较,近岸具有更高的生产力。
陆源径流输入和水体中营养盐再循环,使得近海水体中营养盐含量丰富。
空间的竞争
In densely populated munity, competition for space is likely to be severe, and biotic interactions among algae, and between algae and other groups anisms like bacteria, fungi, seagrasses, grazing animals are plex.
Spores(孢子) of seaweeds germinates(萌发) only when they adheres to substrate.
Crowding lead shading petition for nutrients and there is an inverse relationship between density and individual size.
两种不同的底栖环境
Intertidal zone 潮间带 in anisms are subject at intervals to ation (干燥), direct solar heat, rain, snow, freshwater runoff, wind, frost, etc.
Subtidal zone 潮下带 which is strictly aquatic and more uniform, but has nevertheless marked variables of light intensity and