Reconstruction of the past plankton community in Lake Biwa using Daphnia resting eggs

利用水蚤休眠卵重建琵琶湖过去的浮游生物群落

• 批准号: 12440218
• 负责人: URABE Jotaro
• 金额: $ 10.05万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12440218/
• 关键词: Lake Biwa; Zooplankton; DNA; Species Compsition; lake bottom; resting eggs; Sediments; Daphnia; 推積物

To clarify changes in the plankton community for the past 100 years in lake Biwa, we performed paleolimnological analyses on cladoceran remains and genetic analyses on daphnia resting eggs in die lake sediments. Dating of the lake sediments was determined using 137Cs and 210Pb. For genetic analyses, we developed a new method to extract DNA efficiently from the resting eggs of Daphnia species. Identification of Daphnia species was then made based on sequences of mt DNA 12S rRNA and nuclear DNA-ITS regions with PCR-RFLP method.The results revealed historical changes in the zooplankton community. Before 1900, D. mendotae which have been thought as endemic species in Norm America were abundantly occurred and sole Hyalodaphnia species in this lake. After 1990, however, D. galeata was occurred and produced hybrids with D. mendotae. Thus, at present, Hyalodaphnia populations in Lake Biwa compose of D. mendotae, D. galeata and their hybrid. Detailed analysis of the present population showed th … More at D. mendotae were most dominant Hyalodaphnia species and that existence balance of these species (and hybrid) deviated from the Hardy-Weinberg equilibrium, suggesting that D. mendotae and D. galeata are isolated as single species within the lake. Other than these species, D. pulicaria occurred suddenly and abundantly in 1999. Genetic analyses showed that this population is genetically most close to those in lakes at west coast of North America, suggesting that D. pulicaria occurred in Lake Biwa is a recent invader from North America.Paleolimnological analyses on cladoceran remains further revealed that population density of Daphnia species (mainly D. mendotae) has increased, they did not produce resting eggs for the last 20 years. Experimental analysis indicates mat this decrease in resting egg production is not due to changes in water quality. Since Daphnia became to appear abundantly even in winter since 1980, this decrease in resting egg production seems to be due to a results of natural selection caused by changes in food and water temperature regimes in winter. These results suggest that the zooplankton community in Lake Biwa has largely changed for the past 100 years and has received frequently various type of environmental disturbances including eutroophication, species invasions and shift in water temperature regimes. Less

为了弄清过去100年来琵琶湖浮游生物群落的变化，我们进行了古湖泊学分析的枝藻遗骸和水蚤休眠卵的遗传分析。用~（137）Cs和~（210）Pb测定了湖泊沉积物的年龄。为了进行遗传分析，我们开发了一种新的方法来有效地从水蚤属物种的休眠卵中提取DNA。利用PCR-RFLP技术对浮游动物线粒体DNA 12 S rRNA和核DNA-ITS区序列进行分析，揭示了浮游动物群落的历史变迁。1900年以前，D.被认为是北美特有种的门多萨透明水蚤在该湖大量出现，并且是唯一的透明水蚤种。1990年以后，D. galeata与D.门多萨因此，目前在日本琵琶湖的玻璃蚤种群由D. mendotae、黑腹叶蝉D. galeata和它们的杂交种。对现有人口的详细分析表明， ...更多信息 在D. mendotae是最具优势的透明蚤属物种，这些物种（及其杂种）的生存平衡偏离了Hardy-Weinberg平衡，表明D. mendotae和D.盔状珊瑚是湖中孤立的单一物种。除此之外，D. 1999年，疥疮突然大量发生。遗传分析表明，该种群在遗传上与北美西海岸湖泊种群最为接近，表明该种群可能是北美西海岸湖泊种群。通过对枝藻化石的古湖沼学分析，进一步揭示了日本琵琶湖水蚤类（主要是蚤类D. mendotae）增加，但在过去的20年里，它们没有产生休眠卵。实验分析表明，这种休眠蛋产量的下降不是由于水质的变化。自1980年以来，水蚤甚至在冬季也大量出现，这种休眠卵产量的减少似乎是由于冬季食物和水温变化引起的自然选择的结果。这些结果表明，在过去的100年里，琵琶湖浮游动物群落发生了很大的变化，并经常受到各种类型的环境干扰，包括富营养化，物种入侵和水温制度的转变。少

项目成果

J.Urabe: "Facilitation among herbivore animals can mitigate environmental mismatch of energy and material supplies"Ecology Letters. 5. 177-185 (2002)

J.Urabe：“食草动物之间的便利化可以减轻能源和物质供应的环境不匹配”《生态快报》。

J.Urabe: "Daphnia palicaria ; a Zooplankton species that suddenly appeared in 1999 in the offshore zone of Lake Biwa"Limnology. 4・(1)(印刷中). (2003)

J.Urabe：“Palicaria；1999 年突然出现在琵琶湖近海区域的浮游动物”Limnology 4·(1)（出版中）。

Urabe, I., S. Ishida, M. Nishmoto and L. J. Welder: "Daphnia pulicaria; a zooplankton spfecies that suddenly appeared in 1999 in the offshore zone of Lake Biwa"Limnology. in press. (2003)

Urabe, I.、S. Ishida、M. Nishmoto 和 L. J. Welder：“Daphnia pulicaria；1999 年突然出现在琵琶湖近海区域的浮游动物物种”Limnology。

T.Yoshida: "Seasonal Succession of Zooplankton in the north Basin of Lake Biwa"Aguatic Ecology. 35(in press). (2001)

T.Yoshida：“琵琶湖北部流域浮游动物的季节性演替”水生态学。

Makino, W., J. Urabe, J. J. Elser and C. Yoshimizu: "Evidence of phosphorus-limited individual and population growth of Daphnia in a Canadian Shield lake"Oikos. 96. 197-205 (2002)

Makino, W.、J. Urabe、J. J. Elser 和 C. Yoshimizu：“加拿大地盾湖中磷限制水蚤个体和种群生长的证据”Oikos。