title: Effects of Bt-transgenic rice cultivation on planktonic communities in paddy fields and adjacent ditches.
abstract: The non-target effects of transgenic plants are issues of concern; however, their impacts in cultivated agricultural fields and adjacent natural aquatic ecosystems are poorly understood. We conducted field experiments during two growing seasons to determine the effects of cultivating Bacillus thuringiensis (Bt)-transgenic rice on the phytoplankton and zooplankton communities in a paddy field and an adjacent ditch. Bt toxin was detected in soil but not in water. Water quality was not significantly different between non-Bt and Bt rice fields, but varied among up-, mid- and downstream locations in the ditch. Cultivation of Bt-transgenic rice had no effects on zooplankton communities. Phytoplankton abundance and biodiversity were not significantly different between transgenic and non-transgenic rice fields in 2013; however, phytoplankton were more abundant in the transgenic rice field than in the non-transgenic rice field in 2014. Water quality and rice type explained 65.9% and 12.8% of this difference in 2014, respectively. Phytoplankton and zooplankton were more abundant in mid- and downstream, than upstream, locations in the ditch, an effect that we attribute to water quality differences. Thus, the release of Bt toxins into field water during the cultivation of transgenic crops had no direct negative effects on plankton community composition, but indirect effects that alter environmental conditions should be taken into account during the processes of management planning and policymaking.
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China. Electronic address: liuyb@craes.org.cn.
authors.forename: Yongbo
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Liu
authors.affiliation: Pearl River Fisheries Research Institute, Chinese Academy of Fishery Science, Guangzhou 510380, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Zhanjun
authors.initials: Z
authors.lastname: Quan
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China. Electronic address: lijsh@creas.org.cn.
authors.forename: Junsheng
authors.initials: J
authors.lastname: Li
mesh_terms: D000383:Agriculture / Q000379:methods; D001413:Bacillus thuringiensis / Q000235:genetics; D044822:Biodiversity; D012275:Oryza / Q000235:genetics*; D010839:Phytoplankton / Q000187:drug effects*; D030821:Plants, Genetically Modified / Q000009:adverse effects*; D012987:Soil / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D012987:Soil; D014867:Water
keywords: Aquatic ecosystems; Biodiversity indices; Bt-transgenic rice; Non-target effects; Plankton community