Polar microbial responses to man-made DOC.

Anthropogenic dissolved organic carbon (ADOC) is composed of thousands of organic pollutants from hydrocarbon emissions and synthetic compounds. Yet its effects on marine microbial communities has barely been assessed.

The study investigated responses in Arctic and Antarctic coastal bacterial communities to ADOC concentrations over a 24hr period. Using methods such as CARD-FISH, Flow cytometry, High-throughput sequencing and Bioinformatics, Cerro-Gálvez et al (2019) assessed cell abundance, community composition, gene frequencies and transcriptional responses to ADOC exposures.

ADOC had no effect on community structure however, increased the abundance of rare biosphere bacteria, such as Nocardioides sp. (Arctic), Psuedomonas sp. (Antarctica) associated with hydrocarbon degradation. Gene frequencies and transcriptional activity revealed increased transcriptional activity of ubiquitous Flavobacteria in both communities to ADOC. ADOC further enriched Transcripts in cell function and protein coding, differing between polar communities. Gene expressions, revealed cellular adaptations and detoxifying mechanisms in some bacterial communities, assumed to detoxify ADOC concentrations.

The paper highlights change in community composition, transcriptional response and detoxifying mechanisms under ADOC. However, it gives an important contribution to the responses and impacts associated with ADOC expressing changes in polar bacterial communities, before emphasising the importance for further studies of ADOC on microbial communities in oceanic ecosystems.

Cerro‐Gálvez, E., Casal, P., Lundin, D., Piña, B., Pinhassi, J., Dachs, J., & Vila‐Costa, M. (2019). Microbial responses to anthropogenic dissolved organic carbon in the Arctic and Antarctic coastal seawaters. Environmental microbiology, 21(4), 1466-1481.