Epipelic

Epipelic refers to the growth habit of living on mud (sediments, clays, and silt), in other words, residing at the interface of water and sediment.

Dodds, W.K. and Whiles, M.R. (2010) Concepts of Ecology: Concepts and Environmental Applications of Limnology. Second Edition. Elsevier Inc. 829 pp.
Round, F.E., Crawford, R.M. and Mann, D.G. (1990) The Diatoms. Biology and Morphology of the Genera. Cambridge University Press, Cambridge, 747 pp.