Survival potential of Escherichia coli and enterococci in subtropical beach sand:: Implications for water quality managers
Survival potential of Escherichia coli and enterococci in subtropical beach sand:: Implications for water quality managers
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DOI：
10.2134/jeq2007.0312
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发表时间：
2008-05-01
影响因子：
2.4
通讯作者：
Rogerson, A.
中科院分区：
文献类型：
--
作者：
Hartz, A.;Cuvelier, M.;Rogerson, A.
传统上，粪便细菌被用作指示生物来监测休闲水域的质量。最近的工作对传统指标的稳健性提出了质疑，特别是在海水沐浴海滩。例如，一项对佛罗里达海滩的研究发现，海滩沙滩上的大肠杆菌、粪大肠菌群和肠球菌含量出人意料地高。本研究的目的是通过评估大肠杆菌和肠球菌在海滩沙子中相对于海水的存活率来解释这些丰度。我们使用了定量的实验室中观实验和野外观测相结合的方法。结果表明，与海水相比，大肠埃希菌和肠球菌在沙子中的生存能力和生长能力都有所提高。由于粪便细菌能够在沙子中复制，至少在受控的实验室条件下，结果表明沙子可能是代谢活跃的粪便有机体的重要储存库。对“天然”中游动物(即未灭菌的沙子或富含微型捕食者和本地细菌的水)进行的实验未能显示出与灭菌沙子中相同的粪便指示物的增加。据推测，这是由于捕食和与这些“自然”系统中的本土细菌竞争造成的。尽管如此，在实验期间，与水中注意到的死亡相反，在沙子中保持并恢复了高数量的指示物。在天气和潮汐事件期间，指示性细菌可能会从沙子中冲出进入海岸线水域，从而降低了这些指标作为健康风险预测指标的有效性，并使水质管理人员的解释复杂化。
Fecal bacteria have traditionally been used as indicator organisms to monitor the quality of recreational waters. Recent work has questioned the robustness of traditional indicators, particularly at seawater bathing beaches. For example, a study of Florida beaches found unexpectedly high abundances of Escherichia coli, fecal coliforms, and enterococci in beach sand. The aim of the present study was to explain these abundances by assessing the survival of E coli and enterococci in beach sand relative to seawater. We used a combination of quantitative laboratory mesocosm experiments and field observations. Results suggested that E coli and enteroccocci exhibited increased survivability and growth in sand relative to seawater. Because fecal bacteria are capable of replicating in sand, at least under controlled laboratory conditions, the results suggest that sand may be an important reservoir of metabolically active fecal organisms. Experiments with "natural" mesocosms (i.e., unsterilized sand or water rich in micropredators and native bacteria) failed to show the same increases in fecal indicators as was found in sterile sand. It is postulated that this was due to predation and competition with indigenous bacteria in these "natural" systems. Nonetheless, high populations of indicators were maintained and recovered from sand over the duration of the experiment as opposed to the die-off noted in water. Indicator bacteria may wash out of sand into shoreline waters during weather and tidal events, thereby decreasing the effectiveness of these indicators as predictors of health risk and complicating the interpretations for water quality managers.