Herbicides: a new threat to the Great Barrier Reef

The runoff of pesticides (insecticides, herbicides and fungicides) from agricultural lands is a key concern for the health of the iconic Great Barrier Reef, Australia. Relatively low levels of herbicide residues can reduce the productivity of marine plants and corals. However, the risk of these residues to Great Barrier Reef ecosystems has been poorly quantified due to a lack of large-scale datasets. Here we present results of a study tracing pesticide residues from rivers and creeks in three catchment regions to the adjacent marine environment. Several pesticides (mainly herbicides) were detected in both freshwater and coastal marine waters and were attributed to specific land uses in the catchment. Elevated herbicide concentrations were particularly associated with sugar cane cultivation in the adjacent catchment. We demonstrate that herbicides reach the Great Barrier Reef lagoon and may disturb sensitive marine ecosystems already affected by other pressures such as climate change.农业用地产生的农药径流（涵盖杀虫剂（insecticides）、除草剂（herbicides）与杀菌剂（fungicides）），是澳大利亚标志性大堡礁（Great Barrier Reef）健康面临的核心关切之一。即便是浓度相对较低的除草剂残留，也会降低海洋植物与珊瑚的生产力。然而，由于缺乏大规模数据集，此类农药残留对大堡礁生态系统构成的风险迄今仍未得到充分量化。本研究针对三个集水区（catchment）内的河流与溪流中的农药残留开展溯源分析，并追踪其向邻近海洋环境的迁移路径，现将相关研究结果公布于此。研究在淡水与近岸海水中均检出多种农药（以除草剂为主），且其分布与集水区内特定土地利用方式密切相关。高浓度的除草剂残留与邻近集水区的甘蔗种植活动存在显著关联。本研究证实，除草剂可抵达大堡礁潟湖，并可能对已受气候变化等其他压力因素影响的脆弱海洋生态系统造成干扰。