Depth attenuation of organic matter export associated with jelly falls
Limnol. Oceanogr., 56(5), 2011, 1917-1928 | DOI: 10.4319/lo.2011.56.5.1917
ABSTRACT: We explore the attenuation in the export ratio of jelly-POM (particulate organic matter) with depth as a function of the decay rate, temperature, and sedimentation rate. Using data from the Vertical Transport In the Global Ocean project, we compare ratios computed with the Martin-curve, with a particle-based parameterization, and with sediment-trap data. Owing to the temperature dependence of the decay rate (Q10 = 4.28), the jelly-POM export ratio below 500 m is 20–45% larger in subpolar and temperate areas than in the tropics. Vertical migration of gelatinous zooplankton leads to a variable starting depth of a jelly fall (death depth), which governs the start of remineralization, and the fate of the biomass. Owing to the absence of observations, we employ a sinking speed matrix ranging from 100 m d-1 to 1500 m d-1 to represent slow- and fast-sinking carcasses. The assumption of a constant decay rate k independent of temperature in other particle-based models may not be appropriate. These results provide information for including jelly-POM in global biogeochemical model formulations.