This month, evidence that the microbiome is controlling blood pressure - so will we treat hypertension with probiotics in future? Also, plastic is everywhere and an urgent environmental threat, but is the public aware, or do they care? We also consider the economics of animal extinction and species conservation, the price we pay for water, and the role of the "blue carbon" in keeping CO2 in check... Get the references and the transcripts for this programme from the Naked Scientists website