海洋微塑料作为生物载体的生态效应

The ecological effect of marine microplastics as a biological vector

随着海洋塑料垃圾的不断增多,海洋微塑料作为一种新型的海洋污染物逐渐受到重视。目前关于微塑料来源分布及分析方法的认识较为普遍,大部分研究注重于海洋生物误食微塑料、微塑料吸附及释放有毒物质的环境及生态效应,而微塑料作为微生物、附生动植物的载体作用仍有待研究。文章综述了微塑料作为生物载体的三个作用:1)聚集作用。微塑料表面易覆盖生物膜形成微型生物群落,为基因水平移动提供场所,可能引发致病基因、抗生素抗性基因(antibiotic resistance genes,简称ARGs)的转化、转导。2)扩散作用。来源于污水的微塑料上可能附着生长着有害藻种、致病菌耐药菌或其他生物,随水流移动到适宜区域,可能引发赤潮或导致致病菌及耐药菌的传播扩散,形成生物入侵。3)首次提出微塑料的"捕食增强作用"概念,即有机物、营养盐、生物群落聚集在微塑料颗粒上可提高捕食者的捕食效率,从而促进海洋动物摄食微塑料,进而加剧微塑料颗粒对海洋生物的毒理病理作用。文章着重阐述了"微塑料+生物"的生态效应。

With the increase of marine plastic waste,marine microplastics have attracted more and more attention as a new type of marine pollution.At present,studies of the source,distribution and analytical approach of microplastics are well recognized.Most research focuses on plastic ingestion by marine organisms,and on the effects of microplastics adsorbing and releasing toxic chemicals.However,the role of microplastics as a vector for pelagic microorganism,phytoplankton and micozooplankton is poorly understood.In this review,we address three functions of microplastics as a biological vector.1)Aggregation,it is easy for biofilms to form a microbial community on the surface of microplastics,which provide the means for horizontal transfer of organisms and genes,and may lead to the transformation or transduction of pathogenic gene,antibiotic resistance gene(ARGs),called genetic exchange.2)Dispersal,the spread of harmful algal species,pathogenic bacteria and drug-resistant bacteria as well as other microorganisms may happen when the microplastics are freshly from the waste water flow,which potentially poses a risk of invasion when arriving in a new habitat with favorable condition.3)A feeding enhancement concept,we propose this concept because a piece of microplastics is full of the attached biofilms,nutrients and organisms,which may attract large grazers or predators and can also improve their predation efficiency.As a result,these grazers/predators may seek pieces of microplastic as foods,which may cause more serious toxicological effects.The review focuses on the ecological effects of“microplastic+biology”.