M. Vanni, J. Andrews, W. Renwick, María González, S. Noble
{"title":"Nutrient and light limitation of reservoir phytoplankton in relation to storm-mediated pulses in stream discharge","authors":"M. Vanni, J. Andrews, W. Renwick, María González, S. Noble","doi":"10.1127/0003-9136/2006/0167-0421","DOIUrl":null,"url":null,"abstract":"We investigated the dynamics of nutrient and light limitation of phytoplank- ton in a reservoir ecosystem in relation to storm-mediated variation in stream dis- charge, and how dynamics differed at a shallow site near stream inflows versus one in deep water near the lake outflow. Storm-mediated discharge events reduced the sev- erity of nutrient limitation and increased the severity of light limitation, as predicted by a model of reservoir resource limitation developed by Kimmel et al. (1990). The sev- erity of nutrient limitation was negatively correlated with discharge to the lake; the correlation was strongest with discharge over the preceding 10-14 day period and wea- ker at shorter and longer time scales. However, discharge events also flushed phyto- plankton from the lake and enhanced light limitation, so it is not clear by which mech- anism(s) discharge events mediate phytoplankton resource limitation. Phytoplankton near stream inflows were less nutrient limited than phytoplankton at the lake outflow, consistent with predictions of the Kimmel et al. (1990) model. However, this was true even when streamflow was negligible, suggesting alternative mechanisms for reduced nutrient limitation near stream inflows. In contrast to predictions of the model, phyto- plankton were not more light limited near stream inflows than at the outflow; shallo- wer depth near inflows compensated for higher turbidity, in terms of the light climate experienced by phytoplankton. Our results show that the mechanisms by which dis- charge events mediate phytoplankton resource limitation are complex and require fur- ther study in reservoirs as well as other aquatic systems subject to a high degree of temporal variation in discharge.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2006-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"60","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Archiv Fur Hydrobiologie","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1127/0003-9136/2006/0167-0421","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 60
Abstract
We investigated the dynamics of nutrient and light limitation of phytoplank- ton in a reservoir ecosystem in relation to storm-mediated variation in stream dis- charge, and how dynamics differed at a shallow site near stream inflows versus one in deep water near the lake outflow. Storm-mediated discharge events reduced the sev- erity of nutrient limitation and increased the severity of light limitation, as predicted by a model of reservoir resource limitation developed by Kimmel et al. (1990). The sev- erity of nutrient limitation was negatively correlated with discharge to the lake; the correlation was strongest with discharge over the preceding 10-14 day period and wea- ker at shorter and longer time scales. However, discharge events also flushed phyto- plankton from the lake and enhanced light limitation, so it is not clear by which mech- anism(s) discharge events mediate phytoplankton resource limitation. Phytoplankton near stream inflows were less nutrient limited than phytoplankton at the lake outflow, consistent with predictions of the Kimmel et al. (1990) model. However, this was true even when streamflow was negligible, suggesting alternative mechanisms for reduced nutrient limitation near stream inflows. In contrast to predictions of the model, phyto- plankton were not more light limited near stream inflows than at the outflow; shallo- wer depth near inflows compensated for higher turbidity, in terms of the light climate experienced by phytoplankton. Our results show that the mechanisms by which dis- charge events mediate phytoplankton resource limitation are complex and require fur- ther study in reservoirs as well as other aquatic systems subject to a high degree of temporal variation in discharge.
我们研究了水库生态系统中植物的营养和光照限制动态与风暴引起的水流变化的关系,以及在靠近水流流入的浅水地点与靠近湖泊流出的深水地点的动态差异。正如Kimmel等人(1990)开发的水库资源限制模型所预测的那样,风暴介导的排放事件降低了养分限制的严重程度,增加了光照限制的严重程度。养分限制的严重程度与入湖量呈负相关;在前10-14天内,其相关性最强,在较短和较长的时间尺度上相关性较弱。然而,排放事件也会使浮游植物从湖中流出,并增强对光的限制,因此,排放事件介导浮游植物资源限制的机制尚不清楚。与Kimmel et al.(1990)模型的预测相一致,河流流入附近的浮游植物比湖泊流出处的浮游植物营养受限更少。然而,即使在水流可以忽略不计的情况下,这也是正确的,这表明了在水流流入附近减少营养限制的其他机制。与模型的预测相反,浮游植物在水流流入处并不比在水流流出处受到更多的光照限制;就浮游植物所经历的轻度气候而言,靠近流入的浅水深度补偿了较高的浊度。我们的研究结果表明,放电事件介导浮游植物资源限制的机制是复杂的,需要在水库和其他受高度时间变化影响的水生系统中进行进一步研究。