exam 4

biologically produced structures that include tracks, trails, burrows, borings, fecal pellets and other traces made by organisms

what burrowers use to burrow

watery sediment with high silt clay content have this, become more viscous with more movement

fluid fills hydrostatic skeleton, circular muscles contract elongating the body while longitudinal muscles contract to bring body together

opposite end of organism that is most likely the shell that anchors the body from moving backward

the head of the foot, that anchors into sediment once stretched to allow for the remaining body to be pulled further into sediment

using spade-shaped digging tools to burrow into sediment powered by muscular force

-burrowing in mud increases water content of sediment -increases grain size -alters vertical and 3D mechanical, chemical structure

ingests small particles deep in sediment and expels them on surface of sediment

elongated worm like form, live in water between sand grains

strong vertical chemical gradients -gradient is strongly affected by biological activity

boundary between oxygenated zone and anoxic zone

particulate organic matter derived from sedimenting phytoplankton, seaweeds, and sea grasses

ingest organic and inorganic matter then release as fecal pellets

head down-feed within sediment depth and defecate on surface surface-feed on surface microorganisms such as diatoms

deposit feeders are most efficient at digesting and assimilating benthic microbes like diatoms and bacteria

creates watery surface layer, large grain size, microbial growth and transfer of POM

feed on small particles, low Re within chamber (bivalves) higher Re outside

utilize natural flow of water to bring particles to their feeding structures -needs orientation in current, pressure drag, and particles concentration may be low

use ciliary or muscular activity to create feeding currents to bring particles to mouth -high saturation and possible clogging of particles, ability to create current and keep siphon erect

cilia on gills allow for interception of non-nutritional particles to be removed before entering the gut. adaptation to allow for more valuable particles

-low pop size-move to prey patches -capture of prey -limitations on depth, sensory etc. -feeding while avoiding predation themselves

vision and odor detection

phyrangeal jaw and sharp teeth to pull prey down throat