Ten per cent of the oxygen we breathe comes from just one kind of bacteria in the ocean. Now laboratory tests have shown that these bacteria are susceptible to plastic pollution, according to a new study

Ten per cent of the oxygen we breathe comes from just one kind of bacteria in the ocean. Now laboratory tests have shown that these bacteria are susceptible to plastic pollution, according to a new study

  • These studies have shown that leachates from plastic pollution represent a potential risk to some marine eukaryotic organisms whilst highlighting the high degree of variability in toxicity of leachates from different plastic items5.
  • We report growth, photosynthetic and transcriptomic effects that indicate plastic leachates have the potential to deleteriously affect marine phototrophic bacterial communities, with possible consequences for ocean primary productivity.
  • Both strains of Prochlorococcus showed an overall negative growth rate across the experiment when exposed to HDPE leachate dilutions of 12.5 to 50%. PVC leachate exposure resulted in a markedly greater effect on MIT9312 growth compared to NATL2A. All tested PVC leachate dilutions resulted in negative growth rates for MIT9312, whereas NATL2A was able to maintain a positive growth rate for 0.25 to 1% PVC dilutions.
  • Plastic leachates impair photosynthesis in Prochlorococcus.
  • For both strains exposed to HDPE leachates oxygen production rates started declining from 24 h. A slight increase in the oxygen production rate was observed in MIT9312 after 3 h exposure to 6.25% HDPE leachate, which may imply an initial effort to obtain energy when subjected to stress.
  • Exposure to PVC leachates affected Prochlorococcus to a greater degree than HDPE leachates, reflected in considerably less PVC leachate required to negatively affect Prochlorococcus growth and photophysiological responses.
  • Our results indicate that some concentrations of leachates from common plastic items also have the capacity to impair functioning of photosynthesis in Prochlorococcus and may adversely affect other important marine bacteria.