NSF Award
0086229
The contribution of midwater appendicularians to particle dynamics remains understudied in marine food webs. This project will develop in situ submersible-based techniques that will lead to more detailed, long-term investigations of the ecological role of species with relatively large houses (1-30 cm diameter). These species are poorly known but ubiquitous in water column environments on a global scale, are often numerous, and are tractable targets for in situ documentation of rates of feeding, house production, and house flux. The limited but compelling amount of field information about these omnivorous, non-selective filter feeders suggests that they may have a central role in the flux of material throughout the water column, especially in particle-rich layers. First, appendicularians are capable of rapid generation times. Second, most species are capable of high grazing rates on a wide spectrum of particles, including microbial phytoplankton, bacteria, and detritus. The rate of export or recycling of biogenic carbon from particle-laden appendicularian houses depends upon several factors. For example, the investigator believes that particle loading on houses in the epipelagic and epibenthic zones will vary in relation to surface production and resuspension, respectively. Rates (of particle selection, feeding, house-fecal pellet production, and house-fecal pellet sinking) will also vary with species, particle selection, and house age. Therefore, developing reliable field methods will be essential to better understand how behavioral and environmental parameters interact to influence the fate of particulate matter.
