The role of light for fish-zooplankton-phytoplankton interactions during winter in shallow lakes - a climate change perspective
The role of light for fish-zooplankton-phytoplankton interactions during winter in shallow lakes - a climate change perspective
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DOI：
10.1111/j.1365-2427.2008.02156.x
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发表时间：
2009-05-01
影响因子：
2.7
通讯作者：
Jeppesen, Erik
中科院分区：
文献类型：
--
作者：
Bramm, Mette Elisabeth;Lassen, Majbritt Kjeldahl;Jeppesen, Erik
1. 光照条件的变化会影响浮游动物食草动物的食物供应和质量以及它们遭受鱼类捕食的机会。在北部湖泊，冬季光照特别低，并且随着气候变暖，一些现今浮游生物群落的北界可能会进一步向北移动，浮游生物将因此接收到较少的冬季光照。2．我们跟踪了冬季（11 月至 3 月）清澈和浑浊的浅湖中浮游动物和浮游植物的生物量和群落结构的变化，在有鱼和无鱼的围栏中以及四种不同的光照处理（入射光的 100%、55%、7% 和 < 1%）3。在这两个湖泊中，浮游动物总生物量和叶绿素-a 均受到光照和鱼类存在的影响。无论光照水平如何，鱼类的存在都会导致甲壳类生物量低、轮虫生物量高以及桡足类生活史的变化。鱼类对浮游动物生物量影响的强度随着光照的减弱而减弱，有鱼存在时光照的影响最强。4．当有鱼存在时，光照减少导致清澈的湖水从轮虫转向桡足类桡足类动物，而在浑浊的湖水则从轮虫转向桡足类桡足类动物。光影响浮游植物生物量，并在较小程度上影响浮游植物群落的组成和规模。但鱼类对浮游植物的影响总体较弱。5．我们对典型丹麦浅层富营养化湖泊的研究结果表明，冬季光照条件需要发生重大变化，才能对浮游生物群落产生重大影响。当这些浮游生物群落因全球变暖而向北移动时，所发生的光照变化对于这种湖泊类型来说大多是不太重要的，至少在IPCC A2情景中的本世纪剩余时间里是这样，而在深湖中可能会观察到更强的影响。
1. Variations in the light regime can affect the availability and quality of food for zooplankton grazers as well as their exposure to fish predation. In northern lakes light is particularly low in winter and, with increasing warming, the northern limit of some present-day plankton communities may move further north and the plankton will thus receive less winter light.2. We followed the changes in the biomass and community structure of zooplankton and phytoplankton in a clear and a turbid shallow lake during winter (November-March) in enclosures both with and without fish and with four different light treatments (100%, 55%, 7% and < 1% of incoming light).3. In both lakes total zooplankton biomass and chlorophyll-a were influenced by light availability and the presence of fish. Presence of fish irrespective of the light level led to low crustacean biomass, high rotifer biomass and changes in the life history of copepods. The strength of the fish effect on zooplankton biomass diminished with declining light and the effect of light was strongest in the presence of fish.4. When fish were present, reduced light led to a shift from rotifers to calanoid copepods in the clear lake and from rotifers to cyclopoid copepods in the turbid lake. Light affected the phytoplankton biomass and, to a lesser extent, the phytoplankton community composition and size. However, the fish effect on phytoplankton was overall weak.5. Our results from typical Danish shallow eutrophic lakes suggest that major changes in winter light conditions are needed in order to have a significant effect on the plankton community. The change in light occurring when such plankton communities move northwards in response to global warming will mostly be of modest importance for this lake type, at least for the rest of this century in an IPCC A2 scenario, while stronger effects may be observed in deep lakes.