Biology subjects

Cavan, E. L.

Publications and source records attributed to Cavan, E. L..

2 recordsLinked to original sources

bioRxiv2023

Valuing carbon sequestration by Antarctic krill faecal pellets

Marine life contribute to carbon stores helping lock carbon away from the atmosphere. Open-ocean pelagic ecosystems are vastly under-reported in terms of carbon sequestration conservation potential, compared to coastal vegetation blue carbon systems. Here we show that a harvested organism, Antarctic krill, has similar carbon sequestration potential through its sinking faecal pellets as coastal blue carbon stores, namely seagrasses, mangroves and marshes. Building upon recent advances in krill abundance and faecal pellet carbon flux data, and combining these with an ocean circulation model, we show that from Austral spring to early autumn Antarctic krill sequester 20 Mt C into the deep ocean for at least 100 years. This equates to USD$ 4 - 46 billion per spring/summer season depending on the price of carbon. The footprint of remineralised krill pellet carbon has a global extent, with some reaching as far as the North Pacific. The vast area of ocean krill inhabit and their high abundance make their total carbon sequestered each year similar to that from coastal vegetated blue carbon stores. As Antarctic krill are being impacted by rapid polar climate change and they are harvested, both krill populations and their habitat warrant protection to preserve this valuable carbon sink.

ecology↗

bioRxiv2020

Commercial fishery disturbance of the global open-ocean carbon sink

Primary production in the global oceans fuels multiple ecosystem services including fisheries, and the open-ocean biological carbon sink, which support food security and livelihoods1, and the regulation of atmospheric CO2 levels2 respectively. The spatial distributions of these two services are driven by primary production and it is likely that ecosystem disturbance from fishing impacts both the carbon sink and atmospheric CO2. Yet the extent of these impacts from past, present and future fishing is unknown. Here we show that 23% of global export and 40% of fishing effort are concentrated in zones of intensive overlap representing 7% of the global ocean area. This overlap is particularly evident in the Northeast Atlantic and Northwest Pacific. Small pelagic fish dominate catches in these regions and globally, and their exploitation will reduce faecal pellet carbon sinks and may cause tropic cascades affecting plankton communities important in sinking carbon. There is an urgent need to address how fisheries affect carbon cycling, and for policy objectives to include protecting the carbon sink, particularly in areas where fishing intensity and carbon export and storage are high.

ecology↗