Effect of burrowing by the crab Helice crassa on chemistry of intertidal muddy sediments

• Published in: Environmental toxicology and chemistry 1999-09, Vol.18 (9), p.2078-2086
• Main Authors: WILLIAMSON, R. B, WILCOCK, R. J, WISE, B. E, PICKMERE, S. E
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Ecotoxicology, biological effects of pollution; Fundamental and applied biological sciences. Psychology; Marine and brackish environment
• ISSN: 0730-7268; 1552-8618
• DOI: 10.1897/1551-5028(1999)018<2078:EOBBTC>2.3.CO;2

In highly bioturbated muds where the main bioturbator was the burrowing mud crab Helice crassa, the effect of burrowing on intertidal muddy sediment chemistry was assessed. The study was conducted at Manukau Harbor, New Zealand, where sediment cores were taken on the intertidal sediments at low tide from the tidal flats and from the sides of banks. Results are presented in terms of sediment structure and color, DO, organic carbon and nitrogen, sulfides, acid-extractable divalent iron, acid-extractable trivalent Fe, manganese, and zinc. The results show that most of the sediments in the bioturbated layer were anoxic and contained no sulfidic layer. Acid-volatile sulfides and iron sulfide were consistently present throughout the core profile. The surface oxic layer was thinner in the burrows than on the sediment surface. The burrows appeared to exert a strong influence on the concentrations of acid-volatile sulfide, acid-extractable Fe(II), acid-extractable Fe(III), and Mn, but no effect on TOC, total organic N, or acid-extractable Zn.