small wave ripples or giant current ripples) Turbidity currents Bed consolidation Biological processes Interactions between sediments and organisms living within sediments can also alter the fluxes of oxygen and other dissolved components in and out of the sediment-water interface. Animals like worms, mollusks and echinoderms can enhance resuspension and mixing through movement and construction of burrows. Microorganisms such as benthic algae can stabilize sediments and keep the sediment-water interface in a more stable condition by building mats. These microalgal mats' stabilizing effect is in part due to the stickiness of the exopolymeric substances (EPS) or biochemical "glue" that they secrete. Biological processes that affect the sediment-water interface include, but are not limited to: Bioturbation Biofilms Bacterial use of different chemical "food" (see Redox reactions) Remineralization of organic carbon and detritus Chemical processes There are several chemical processes that happen abiotically (chemical reactions), as well as biotically (microbial or enzyme mediated reactions). For example, oxidation-reduction (redox) reactions can occur simply through the reactions of elements, or by oxidizing/reducing bacteria. The transformations and turnover of elements between sediments and water occur through abiotic chemical processes and microbiological chemical processes. Abiotic Chemical reactions can occur at the sediment-water interface, abiotically. Examples of this would include the oxygenation of lake sediments as a function of free iron content in the sediment (i.e. pyrite formation in sediments), as well as sulfur availability via the sulfur cycle. Sedimentation is often the final scavenging process that takes trace chemicals and elements out of the water column. Sediments at this interface are more porous and can hold a larger volume of pore water in the interstitial sites due to high organic matter content and lack of settling. Therefore, chemical compounds in the water can undergo two main processes here: 1) diffusion and 2) biological mixing. Chemical diffusion into and out of the interstitial sites occurs primary through random molecular movement. While diffusion is the primary mode through which chemicals interact with the sediments, there are a number of physical mixing processes which facilitate this process (see Physical Processes section). Chemical fluxes are dependent on several gradients such as, pH and chemical potential. Based on a specific chemical's partitioning parameters, the chemical may stay suspended in the water column, partition to biota, partition to suspended solids, or partition into the sediment. In addition, Fick's first law of diffusion states that the rate of diffusion is a function of distance;