Effects of dietary phosphorus deficiency on the abundance, phosphorus balance, and growth of Daphnia cucullata in three hypereutrophic Dutch lakes
Effects of dietary phosphorus deficiency on the abundance, phosphorus balance, and growth of Daphnia cucullata in three hypereutrophic Dutch lakes
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DOI：
10.4319/lo.2001.46.8.1871
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发表时间：
2001-12-01
影响因子：
4.5
通讯作者：
Van Donk, E
中科院分区：
文献类型：
--
作者：
DeMott, WR;Gulati, RD;Van Donk, E
我们研究了三个相互关联的、富营养化的荷兰湖泊的种群动态、磷平衡和个体生长，以评估摄食磷(P)对大型水蚤的限制。与磷限制假说一致，三个湖泊的产蛋量和种群密度的下降与Seston C：P比从300增加到400-500(摩尔)的季节性增加相一致。在实验室取食富磷饲料的前36h内，从Breukleveen湖采集的成体水蚤体内的特定磷含量呈线性增加(r(2)=0.99)，这证实了野外水蚤组织中存在磷缺乏。实验室实验测试了在天然菌种对照和添加磷酸盐或富磷蓝藻聚球藻的菌种中葫芦巴幼体的生长情况。以栅藻(2 mg C L-1)为食物的过滤湖水中的生长也被估计。这种设计使我们能够将对照和栅栏藻生长速度之间的差异划分为磷、能量和残留因素的限制。在10个实验中的每一个实验中，葫芦巴都表现出对磷酸盐和聚球藻补充剂的反应促进了生长。与预测一致的是，C/P比最高的湖泊中，水蚤的控制生长速度最低，对磷添加的响应最强。然而，Seston中C：P比例非常相似的两个湖泊中的动物在生长反应上有所不同。我们的结果证实了饲料磷的限制，但也表明能量限制和残留因素也是造成大型水蚤生长的湖间差异的原因。
We studied population dynamics, phosphorus balance, and individual growth to evaluate limitation of Daphnia cucullata by dietary phosphorus (P) in three interconnected, hypereutrophic Dutch lakes. Consistent with the P-limitation hypothesis, declines in egg production and population density coincided with seasonal increases in the seston C:P ratio from 300 to 400-500 (molar) in all three lakes. Adult Daphnia collected from Lake Breukeleveen exhibited a linear increase in specific P content during the first 36 h of feeding on a P-rich diet in the laboratory (r(2) = 0.99), which confirms that field Daphnia experienced P deficits in their tissues. Laboratory experiments tested the growth of juvenile D. cucullata in controls with natural seston and in seston supplemented with phosphate or the P-rich cyanobacterium Synechococcus. Growth was also estimated in filtered lake water with Scenedesmus (2 mg C L-1) as food. This design allowed us to partition differences between the control and Scenedesmus growth rates into limitation by phosphorus, energy and residual factors. In each of 10 experiments, D. cucullata exhibited improved growth in response to the phosphate and Synechococcus supplements. In agreement with predictions, Daphnia exhibited the lowest control growth rate and the strongest response to P addition in seston from the lake with the highest seston C:P ratio. However, animals in seston from two lakes with very similar seston C:P ratios differed in their growth responses. Our results confirm dietary P limitation but show that energy limitation and residual factors also contributed to between-lake differences in Daphnia growth.