A metatranscriptomic analysis of changing dynamics in the plankton communities adjacent to aquaculture leases in southern Tasmania, Australia

Abstract

Aquaculture releases nitrogen to the marine environment, potentially changing dynamics of local plankton populations and causing adverse impacts. Metatranscriptomics have been used to study planktonic nutrient cycles and community dynamics. We hypothesised that the metatranscriptome could be used to monitor changing phytoplankton physiology near leases. To test this hypothesis, opportunistic samples were collected from one oceanic location in winter and one estuarine location in spring and analysed via RNASeq. Transcriptomes from different locations were found to have little overlap, due to different community compositions in the oceanic and estuarine locations. Transcript function was similar at each location. Proximity to the salmon pen had little influence over the transcriptome at the estuarine location. In the oceanic environment, diatom-based activity decreased near pens and dinoflagellate-based activity increased as demonstrated through the abundance of carbon fixation and nitrogen-acquisition-related transcripts. Our initial results suggest that the use of the metatranscriptome in monitoring is promising.

Keywords: Ammonia; Aquaculture; Diatoms; Dinoflagellates; Nitrate; Transporters.