bioturbation in a declining oxygen environment, in situ observations from wormcam生物扰动作用在减少氧气的环境中,从wormcam原位观测.pdf

Bioturbation in a Declining Oxygen Environment, in situ Observations from Wormcam 1,2 ´ 1 3 S. Kersey Sturdivant *, Robert J. Dıaz , George R. Cutter 1Virginia Institute of Marine Science, College of William Mary, Gloucester Pt., Virginia, United States of America, 2 National Oceanic and Atmospheric Administration, Cordell Bank National Marine Sanctuaries Program, Point Reyes Station, California, United States of America, 3 National Oceanic and Atmospheric Administration, Southwest Fisheries Science Center, La Jolla, California, United States of America Abstract Bioturbation, the displacement and mixing of sediment particles by fauna or flora, facilitates life supporting processes by increasing the quality of marine sediments. In the marine environment bioturbation is primarily mediated by infaunal organisms, which are susceptible to perturbations in their surrounding environment due to their sedentary life history traits. Of particular concern is hypoxia, dissolved oxygen (DO) concentrations #2.8 mg l21, a prevalent and persistent problem that affects both pelagic and benthic fauna. A benthic observing system (Wormcam) consisting of a buoy, telemetering electronics, sediment profile camera, and water quality datasonde was developed and deployed in the Rappahannock River, VA, USA, in an area known to experience seasonal hypoxia from early spring to late fall. Wormcam transmitted a time series of in situ images and water quality data, to a website via wireless internet modem, for 5 months spanning normoxic and hypoxic periods. Hypoxia was found to significantly reduce bioturbation through reductions in burrow lengths, burrow production, and burrowing depth. Although infaunal activity was greatly reduced during h