Collecting Sinking Particles using a PIT Trap to Visualize and Measure the Vertical Flux of Particles

Abstract

Fjords account for 11 percent of the total marine carbon burial in sediments globally, however there is currently no agreement on how their geological characteristics impact the global cycle. In order to understand the carbon cycling in fjords, an affordable and lightweight particle inceptor trap (PIT) was developed to characterize and measure the mass of sinking particles. Sampling stations were located in Puget Sound, which is an estuary system located in Washington State, that has a large sequestration impact by the Snohomish River. By comparing the sinking particles near and further away from the Snohomish River mouth, the filtered mass of sinking particles furthest from the Snohomish River is 0.678 g and 0.57 g while the filtered masses closest to the river almost tripled in mass with recorded values of 1.637 g and 1.908 g. More particles were observed further away from the river consisting of silts and clays, as well as phytoplankton and small zooplankton due to slower particle sinking velocities, bottom current resuspension and smaller river influence. Closer to the Snohomish River, larger particles such as sands and terrestrial material such as wood were observed. This data signifies that this prototype sinking particle sampler was effective and met expectations by being able to obtain microscopic imagery and sinking particle masses to better understand carbon cycling in a fjord system.