The early holocene hydrosere in a small acid hill-top basin studied using crustacean sedimentary remains
The early holocene hydrosere in a small acid hill-top basin studied using crustacean sedimentary remains
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利用甲壳类沉积遗骸研究小型酸性山顶盆地早期全新世水力沉积
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发表时间：
1992
期刊：
影响因子：
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通讯作者：
A. Korhola
中科院分区：
文献类型：
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作者：
A. Korhola
利用亚化石枝角类化石、硅藻、花粉、植物大型化石等沉积资料，研究了芬兰南部前小湖泊的水系发育。硅藻分析表明，该湖在全新世早期明显变得酸性。这反映在枝角类群落中，表现为长吻腹藻等的比例下降，长柄腹足类的比例相对上升，乳突类物种的比例增加，表明酸性，以及某些新的形态类型的出现。随着酸化，浮游物种和滨海物种的浓度和数量都会增加。水生植物群落演替的进展反映在：脊椎动物群落中底栖物种的消失，而植食性物种的显著增加。沉积物的沉积和水位的下降导致了大约6500-7000年前水体上的水生植物和浮叶植物的扩散，并在该地点形成了一个植被覆盖的沼泽。浮游动物几乎灭绝了，但沿海枝角类动物的密度在这一点上达到了顶峰。在亚北部的臭氧年代开始时，盆地变得完全杂草丛生(约.4600-4800B.P.)，与在许多湖泊中观察到的低水位相同时。它被一个Sphagnum摊位覆盖，这反过来又导致分歧者社区完全被摧毁。枝角类之间的浮游/滨海比值密切地反映了开放水域和大型植物带之间的时间关系。气候引起的水位上升和下降被证明在推动水文系列演替的推进方面发挥了重要作用。
The hydroseral development of a former small lake in Southern Finland was studied by means of subfossil cladoceran remains, diatoms, pollen, plant macrofossils and other sediment data. The diatom analysis shows the lake to have become markedly acid during the Early Holocene. This is reflected in the cladoceran communities in the form of a fall in the proportions of Bosmina longirostris etc. and a reciprocal rise in Bosmina (Eubosmina) longispina, an increase in the proportions of the chydorid species indicative of acidity, and the appearance of certain new morphotypes. The concentrations of both planktonic and littoral species and the numbers of such species increase with acidification. Advancement in the hydroseral succession is reflected in the disappearance of benthic species from the chydorid communities and a pronounced increase in exclusively phytophile species. Sedimentation and the drop in water levels are seen to have led to a spread of helophytes and floating-leaved plants over the water body around 6500–7000 B.P., and a vegetation-filled swamp was created at the site. The zooplankton was practically exterminated, but the concentrations of littoral cladocerans reached their peak at this point. The basin became overgrown completely at the beginning of the Subboreal chronozone (approx. 4600–4800 B.P.), simultaneously with the low-water phase observed in many lakes. It became covered with a Sphagnum stand, and this in turn led to complete destruction of the cladoceran communities. The planktonic/littoral ratio among the Cladocera closely reflected the relation between open water and the macrophyte zone as a function of time. Climatically induced rises and falls in water level are shown to have played a significant role in promoting the advancement of the hydroseral succession.