Grain sizes retained by diatom biofilms during erosion on tidal flats linked to bed sediment texture

TitleGrain sizes retained by diatom biofilms during erosion on tidal flats linked to bed sediment texture
Publication TypeJournal Article
Year of Publication2015
AuthorsGarwood J.C, Hill P.S, MacIntyre H.L, Law B.A
JournalContinental Shelf Research
Date Published2015/08
Type of ArticleArticle
ISBN Number0278-4343
Accession NumberWOS:000358097600004
KeywordsBiofilms; chlorophyll-a; erosion; estuary; fine sediment; Fine sediment sorting; fundy; Intertidal flats; intertidal sediments; microphytobenthos; Mobility; Size-specific sediment retention; stability; stabilization; transport; upper bay

Size-specific sediment retention by diatom biofilms was measured by eroding intertidal muds at increasing shear stresses (0.01-.0.60 Pa) using a Gust microcosm. The grain sizes eroded from biofilm-covered sediment were compared to those from control cores from which the biofilms were destroyed using bleach. Biofilms were quantified using carbohydrate measurements. Cores from an intertidal mud flat in the Minas Basin of the Bay of Fundy (Canada) showed biofilms preferentially retained clays and very fine silts relative to fine and medium silts. In contrast, prior field observations on an intertidal sand flat indicated that fine and medium silts were preferentially retained by biofilms relative to clays and very fine silts. These contrasting results suggest a link between size-specific sediment retention and sediment texture, where sand biofilms retain coarser, non-cohesive sediment grains, while mud biofilms retain finer, cohesive sediment grains. This relationship implies that biofilms could contribute to a positive feedback that would preserve existing sediment texture. (C) 2015 Elsevier Ltd. All rights reserved.

Short TitleCont Shelf Res
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