Novel techniques for collection of sinking particles in the ocean and determining their settling rates

Michael L. Peterson, Stuart G. Wakeham, Cindy Lee, Meaghan A. Askea,Juan Carlos Miquel

Limnol. Oceanogr. Methods 3:520-532 (2005) | DOI: 10.4319/lom.2005.3.520

ABSTRACT: Three new approaches for collecting and processing sinking particles for biogeochemical studies are presented. They include (1) a modification of our existing indented rotating sphere carousel (IRSC) sediment trap design from its conventional time-series function to one that collects particles based on discrete particle settling-velocity ranges; (2) development of a large, free-floating NetTrap based on the design of a closing plankton net capable of collecting large amounts (~1 g) of very fresh sinking particulate material in short time periods (24-36 h) to facilitate microbial decomposition experiments; and (3) an elutriation system to fractionate particles from the NetTrap into settling-velocity classes using countercurrents of varying speeds. These approaches were recently tested in the Mediterranean Sea and appear to provide new opportunities to characterize fluxes of carbon and other elements of interest and to investigate mechanisms of sinking.