The role of carbon dioxide in the initiation and maintenance of blue-green dominance in lakes
The role of carbon dioxide in the initiation and maintenance of blue-green dominance in lakes
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DOI：
10.1046/j.1365-2427.1997.00164.x
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发表时间：
1997-04-01
影响因子：
2.7
通讯作者：
Shapiro, J
中科院分区：
文献类型：
--
作者：
Shapiro, J
1. 1993年，美国威斯康星州斯阔湖南部盆地，人工循环并注入二氧化碳，试图消除夏季通常存在的大量蓝绿色。未混合、未注入的北部盆地为对照。尽管两个盆地的二氧化碳浓度和pH值有很大差异，但它们的蓝绿色最大值同时开始，最终达到相同的大小。两个流域的优势藻类均为水华束丝藻和水华鱼腥藻。从5月13日至9月9日，进行了实验，以确定光合作用（产氧）的浮游植物群落在两个流域的pH值的变化在7-9的范围内的响应。南北两个流域的光合作用对pH值的响应斜率都经历了两次明显的变化，这两次变化反映了植物光合产物中蓝绿色比例的变化。添加KHCO_3或NaHCO_3的实验表明，对pH的响应实际上是对CO_2浓度的响应。因此，在光合作用实验中获得的数据被用于计算动力学参数K-s* 和V-max*。的K-S* 值的变化与蓝绿色的比例，较低的值在蓝绿色占主导地位的时期。V-max* 值没有显示出这样的系统性变化。CO2补偿和零光合作用浓度证实，当蓝绿色占主导地位时，CO2的吸收比浮游植物主要由非蓝绿色组成时更有效。即使在pH值为10.0.5时，也没有证据表明直接使用碳酸氢盐。从其他四个湖泊季节性收集的水的实验表明，斯阔湖并不是唯一的。在每种情况下，响应斜率（因此K，* 值）在春季非蓝绿色占主导地位时很高，但在蓝绿色最大值开始时下降。对个别藻类物种的实验证实，蓝绿色通常比绿色具有更好的CO2动力学。它的结论是，蓝绿色的最大启动不依赖于条件下的低CO2浓度或高pH值。然而，一旦蓝绿色变得丰富，他们确保其优势，通过减少CO2浓度的水平，只有自己。
1. In 1993 the south basin of Squaw Lake, Wisconsin, U.S.A., was artificially circulated and injected with CO2 in an attempt to eliminate the massive quantities of blue-greens normally present during summer. The unmixed, uninjected north basin was the control. Despite a great difference in CO2 concentration and in pH between the two basins, their blue-green maxima began simultaneously and eventually reached the same size. The predominant algae in both basins were Aphanizomenon flos-aquae and Anabaena flos-aquae.2. From 13 May to 9 September, experiments were done to determine the responses of photosynthesis (oxygen production) of the phytoplankton communities in both basins to changes in pH over the range 7-9. Both the north and south basins underwent two distinct shifts in the slopes of their photosynthetic responses to pH. These shifts paralleled changes in the proportion of blue-greens in their phytoplankton.3. Experiments with additions of KHCO3 or NaHCO3 showed that the responses to pH were really responses to CO2 concentration. Therefore, the data obtained in the photosynthesis experiments were used to calculate the kinetic parameters K-s* and V-max*. The K-s* values varied in relation to the proportion of blue-greens, with lower values during the period when blue-greens predominated. The V-max* values showed no such systematic changes.4. CO2 compensation and zero photosynthesis concentrations confirm that when the blue-greens dominated, CO2 was taken up much more efficiently than when the phytoplankton comprised mostly non-blue-greens. No evidence appeared suggesting direct use of bicarbonate even at pH values of 10.0.5. Experiments with water collected seasonally from four other lakes show that Squaw Lake is not unique. In each case the response slopes (and therefore K,* values) were high during spring when non-blue-greens were dominant, but decreased when the blue-green maximum began.6. Experiments with individual species of algae confirm that blue-greens generally have better CO2 kinetics than do greens.7. It is concluded that initiation of the blue-green maximum does not depend upon conditions of low CO2 concentration or high pH. However, once the blue-greens become abundant they ensure their dominance by reducing concentrations of CO2 to levels available only to themselves.