Black carbon. It's a bit different from blue steel!

The coastal environment is where land, sea and air meet making it one of the most biogeochemically active parts of the ocean but also exposes it to many anthropogenic threats, one of these being ‘black carbon’.  This is the aerosols/soot that result from the incomplete combustion of fossil fuels creating carbon-rich compounds which enter the sea through the atmosphere or land runoff.

Paradeep Ram et al. (2018) sampled the surface microlayer and at 1.5m depth in Haloing Bay, Vietnam, Known for its high atmospheric BC levels.  They used solid-phase extraction to measure BC levels and counted abundances of bacteria and virus’ using stains.  Their results showed that the surface layer is significantly more enriched with BC by a factor of 105, and the abundance is significantly higher and more variable of bacteria and virus’.  The virus-to-bacteria ratio was also much higher which suggests that the bacteria may be the main host for these virus’.

The percentage of carbon found to be BC here was the highest reported (32-97%) and the elevated levels in the surface suggested a high holding period here before sampling, which may be attributed to low wind speeds. However, the bacterial and viral elevations were minimal compared to other studies which they put down to potentially being their sampling method as the type of sampler used for the SML greatly effects results.  Despite this the results shed light on a different kind of damage burning of fossil fuels is doing and opens up many more questions for future study.

Pradeep Ram, A.S., Mari, X., Brune, J., Torreton, J.p., Chu, V.T., Raimbault, P., Niggemann, J., Sime-Ngando, T. (2018) Bacterial-viral interactions in the sea surface microlayer of a black carbon-dominated tropical coastal ecosystem (Halong Bay, Vietnam). Elem Sci Anth. (6):13.