Publikationsdatum:
2017-06-29
Beschreibung:
Parameterizations of surface ocean isoprene concentrations are numerous, despite the lack of source/sink process understanding. Here we present isoprene and related field measurements in the mixed layer from the Indian Ocean and the East Pacific Ocean to investigate the production and consumption rates in two contrasting regions, namely oligotrophic open ocean and coastal upwelling region. Our data show that the ability of different phytoplankton functional types (PFTs) to produce isoprene seems to be mainly influenced by light, ocean temperature, and salinity. Our field measurements also demonstrate that nutrient availability seems to have a direct influence on the isoprene production. With the help of pigment data, we calculate in-field isoprene production rates for different PFTs under varying biogeochemical and physical conditions. Using these new calculated production rates we demonstrate that an additional, significant and variable loss, besides a known chemical loss and a loss due to air sea gas exchange, is needed to explain the measured isoprene concentration. We hypothesize that this loss, with a lifetime for isoprene between 10 and 100 days depending on the ocean region, is attributed to heterotrophic respiration mainly due to bacteria.
Print ISSN:
1810-6277
Digitale ISSN:
1810-6285
Thema:
Biologie
,
Geologie und Paläontologie