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OCEANOGRAPHY and MARINE BIOLOGY: AN ANNUAL REVIEW (Volume 44) - Chapter 3

Đào hang bằng infauna đáy trầm tích hỗn hợp ngũ cốc Cả hai và dịch kẽ, ảnh hưởng đến điều kiện trầm tích oxi hóa khử và số phận của vật chất hữu cơ Xác định và chất gây ô nhiễm. Rõ ràng, định lượng phân tích các đặc tính vật liệu trầm tích, tuy nhiên, chỉ gần đây đã được áp dụng để hiểu cơ chế của đào hang. | Oceanography and Marine Biology An Annual Review 2006 44 85-121 R. N. Gibson R. J. A. Atkinson and J. D. M. Gordon Editors Taylor Francis MACROFAUNAL BURROWING THE MEDIUM IS THE MESSAGE KELLY M. DORGAN1 PETER A. JUMARS1 BRUCE D. JOHNSON2 BERNARD P BOUDREAU2 Darling Marine Center University of Maine 193 Clark s Cove Road Walpole Maine 04573 U.S. E-mail kelly.dorgan@umit.maine.edu jumars@maine.edu Department of Oceanography Dalhousie University Halifax Nova Scotia B3H 4J1 Canada E-mail bruce.johnson@dal.ca bernie.boudreau@dal.ca Abstract Burrowing by benthic infauna mixes both sediment grains and interstitial fluids affecting sedimentary redox conditions and determining fates of organic matter and pollutants. Explicit quantitative analyses of material properties of sediments however have been applied only recently to understand mechanisms of burrowing. Muds are elastic solids that fracture under small tensile forces exerted by burrowers and are dominated by adhesive forces between sediment grains and the surrounding mucopolymeric gel and or by cohesion of this gel. By contrast in clean sands behaving as granular materials gravity is a much more significant force holding grains together than is adhesion or cohesion. Burrowers in muds have diverse structures that act as wedges to propagate cracks and elongate their burrows. In sands increased rugosity on a small and liquefaction on a larger scale facilitate displacement of the grains that carry compressive forces along distinct force chains or arches. The classic dual-anchor system described for burrowers is reinterpreted as having several additional functions. The characteristic dilations or expansions function primarily as wedges that exert lateral tensile forces to propagate cracks forward secondarily as double O-ring seals holding fluid pressure in the advancing burrow maintaining tensile stresses needed to open a crack and thirdly as anchors to pull the shell along in bivalves in particular . Burrowing bivalves .