Responses of All Size-fractionated Chlorophyll-a Contents to Bioremediation Ineutrophic Water

27 Mar Responses of All Size-fractionated Chlorophyll-a Contents to Bioremediation Ineutrophic Water

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Abstract

通过对富营养小水体叶绿素 a分粒级分析 ,探讨了生态修复对水体粒径分级叶绿素 a的影响以及各粒级叶绿素 a对修复 的响应 , Na no -粒级叶绿素 a为本水体的第 1贡献者 , N et-粒级也占有较高的比例 ,处于第 2位 , Pico-粒级所占份额最小;环境因 子 BO D5和 T N T P与 N et- Chla% 和 N ano-Ch la% 分别呈非常显著负和正相关;生物修复实施前后 N et-chla% 和 Nano -ch la% 均有非常显著变化 ,生态修复工程后网采浮游植物相对生物量明显增多 ,微型浮游植物相对生物量显著减少 ,而微微型浮游植 物相对生物量仅有小幅度的升高 ,修复前后并无显著差异。

English Abstract

Using the relationships between organism and it’s surroundings have been widely adopted as the the way to evaluate if ecosystem is healthy or not by experts. Many of scholars are attempting to erect a biologic method so that the water quality could be quickly assessed. Provided that a method can be established to quickly assess the presumptive effect for water body. As with the process of bioremediation, it can not only provide the solid proof for scientific management and for selecting correct presumptive plan, but can also facilitate subsequent decision-making process as well. In the process of bioremediation, by testing all size-fractionated chlorophyll-a in eutrophic water, the article explores how size-fractionated chlorophyll-a is in response to the bioremediation, in a hope to reflect the effect of bioremediation in accordance with the response of all size-fractionated chlorophyll-a, so as to provide biological proof for illustrating the efficiency of measures taken for the bioremediation. This test water is: water area(350m~2), water dept(60cm), water volume(210m~3). Before testing, spot survey was conducted and found to be in a condition of hypereutrophic. Comprehensive measures concerning ecology are taken including the way of adding Bioenergizer, biologic algaecide, effective microbe into water, and planting Macrophyte. Beforehand, background was sampled twice on 11th and 27th of April. The experiment began from April 29,2002. And after the engineering project, sampling work was done on 16th, 24th and 30th of May, 06th,13th, 20th and 27th of June, 04th,11th, 12th,13th,14th,15th, 17th, 25th and 31th of July respectively. Water samples for phytoplankton analyses were collected at the depth of 0锝2 m, 0.5m with length Niskin bottles (for a total final volume of 10L). Next, the samples were divided into pico (0.2锝2.0 渭m), Ultra (0.2~5 渭m), Nano (2~20渭m), Net (20~200渭m) size fractions by filtration. Chlorophyll-a was determined by spectrophotometry following the methods proposed by Lorenzen. Samples for water quality analyses were collected at the integrated depths of 0m with a 0.5 m for determination of temp, DO, pH, SD, CODmn, BOD_5, TN, NH_4-N, NO_2, PO_4 and TP. Within the periods of time in this survey, the average value of the content of the following elements involving Net-, Nano- and Pico-Chla amounts to be 51.486, 83.491, 6.056 and 2.622 mgm~3 respectively. The average value of contribution rates of Net-, Nano-, Ultra- and Pico-Chla occupied 32.250%, 65.240%, 4.721% and 2.091% respectively. Nano-phytoplankton is the highest contribution to bulk chlorophyll-a contents, Net-phytoplankton also occupies the higher rate, being placed in the second, while Pico-phyplankton occupies the least. Bivariate correlate analyze was done between the content of all size-fractionated chlorophyll-a, the percentages of all size fractionated chlorophyll-a contents to bulk chlorophyll-a contents with all environmental factors. The result showed only the percentages of net-chla and nano-chla obviously correlated to the temperature.Considering the influence of temperature, thus, by controlling temperature, partialcorrelate analysis was redone. The result showed that the percentage of Net-Chla correlated negatively with BOD_5 and TNTP while the percentage of Nano-Chla correlated positively with BOD_5 and TNTP. As both BOD_5 and COD are indexes reflecting the level of the water contamination, results of the above analysis signified that thepercentages of Nano-and Net-chla were closely correlated on the level of water contamination. By conducting ANOVE on the percentages of all size fractionated chlorophyll-a before and after the bioremediation, it was found that the percentages of Net-Chla銆丯ano-Chla were significantly different after the bioremediation than before.The relative biomass of Netphytoplankton increased and the relative biomass of Nanophytoplankton decreased obviously after bioremediation,but the relative biomass of Picophytoplankton only contained small range of going up, there were