Supershrimp: Deep Bioturbation in the Strait of Canso, Nova Scotia

Pemberton, George; Risk, Michael J.; Buckley, Dale E.

doi:10.1126/science.192.4241.790

Cited by 97 publications

(48 citation statements)

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“…Burrows continue vertically into the sediment and often exhibit several galleries of interconnected chambers at distinct sediment depths (for example, Ziebis et al, 1996a). The deepest burrows reported to date reached 3 m (Pemberton et al, 1976). Most known species remain subsurface their entire life and maintain semi-permanent burrows that are constantly reworked.…”

Section: Study Sitementioning

confidence: 99%

Biodiversity of benthic microbial communities in bioturbated coastal sediments is controlled by geochemical microniches

2009

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We used a combination of field and laboratory approaches to address how the bioturbation activity of two crustaceans, the ghost shrimp Neotrypaea californiensis and the fiddler crab Uca crenulata, affects the microbial diversity in the seabed of a coastal lagoon (Catalina Harbor, Santa Catalina Island, CA, USA). Detailed geochemical analyses, including oxygen microsensor measurements, were performed to characterize environmental parameters. We used a whole-assemblage fingerprinting approach (ARISA: amplified ribosomal intergenic spacer analysis) to compare bacterial diversity along geochemical gradients and in relation to subsurface microniches. The two crustaceans have different burrowing behaviors. The ghost shrimp maintains complex, deepreaching burrows and permanently lives subterranean, supplying its burrow with oxygen-rich water. In contrast, the fiddler crab constructs simpler, J-shaped burrows, which it does not inhabit permanently and does not actively ventilate. Our goal was to address how varying environmental parameters affect benthic microbial communities. An important question in benthic microbial ecology has been whether burrows support similar or unique communities compared with the sediment surface. Our results showed that sediment surface microbial communities are distinct from subsurface assemblages and that different burrow types support diverse bacterial taxa. Statistical comparisons by canonical correspondence analysis indicated that the availability of oxidants (oxygen, nitrate, ferric iron) play a key role in determining the presence and abundance of different taxa. When geochemical parameters were alike, microbial communities associated with burrows showed significant similarity to sediment surface communities. Our study provides implications on the community structure of microbial communities in marine sediments and the factors controlling their distribution.

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Section: Study Sitementioning

confidence: 99%

Biodiversity of benthic microbial communities in bioturbated coastal sediments is controlled by geochemical microniches

2009

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“…Burrowing shrimp inhabit a broad range of sediments, excavating elaborate burrow structures to depths >3 m (Pemberton et al, 1976). Fiddler crabs also excavate mud from burrows, which they leave as compacted balls on the sediment surface.…”

Section: Other Mechanisms Of Burrowing In Mudmentioning

confidence: 99%

The biomechanics of burrowing and boring

Dorgan

2015

Journal of Experimental Biology

134

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Burrowers and borers are ecosystem engineers that alter their physical environments through bioturbation, bioirrigation and bioerosion. The mechanisms of moving through solid substrata by burrowing or boring depend on the mechanical properties of the medium and the size and morphology of the organism. For burrowing animals, mud differs mechanically from sand; in mud, sediment grains are suspended in an organic matrix that fails by fracture. Macrofauna extend burrows through this elastic mud by fracture. Sand is granular and non-cohesive, enabling grains to more easily move relative to each other, and macrofaunal burrowers use fluidization or plastic rearrangement of grains. In both sand and mud, peristaltic movements apply normal forces and reduce shear. Excavation and localized grain compaction are mechanisms that plastically deform sediments and are effective in both mud and sand, with bulk excavation being used by larger organisms and localized compaction by smaller organisms. Mechanical boring of hard substrata is an extreme form of excavation in which no compaction of burrow walls occurs and grains are abraded with rigid, hard structures. Chemical boring involves secretion to dissolve or soften generally carbonate substrata. Despite substantial differences in the mechanics of the media, similar burrowing behaviors are effective in mud and sand.

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“…In contrast, wave action and bioturbation enhance solute fluxes through advective fluid exchange between permeable sediments and the water column. Wave-induced orbital motions flush (and in the extreme can fluidize) the uppermost sediment layers (Riedl & Machan 1972, Rutgers van der Loeff 1981, while ventilation or feeding currents created by endobenthic organisms, pumping water through individual burrows, can reach locally to depths > 100 cm (Pemberton et al 1976, Aller & Yingst 1985, Reichardt 1988, Huettel 1990). …”

Section: Introductionmentioning

confidence: 99%

Impact of bioroughness on interfacia solute exchange in permeable sediments

Huettel

Gust²

1992

Mar. Ecol. Prog. Ser.

263

205

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We demonstrate the contribution of biogenic sediment microtopography, termed bioroughness, comprising all surface relief created by benthic organisms, on interfacial solute fluxes in permeable beds. Rhodamine-WT dye injected in sandy intertidal sediments revealed strong advective porewater replacement down to 5 cm sediment depth caused by small aggregates of mussel shells exposed to boundary layer flows. In a set of laboratory flume experiments we quantify the impact of various types of bioroughness elements on interfacial solute exchange and ident~fy small-scale horizontal pressure gradients of < 1 Pa cm-' as the driving force for the advective processes. Roughness size, sediment permeability, and characteristics of the boundary layer flow determined magnitude and depth range of the resulting advective porewater flows, which provided a fast, conveyor-belt-type link between sediment layers as deep as 15 cm and the water column. Simulated bioroughness elements in natural sizes and abundances increased porewater fluxes in sandy sediment up to 7-fold at subcritical flows (friction velocity U. < 0.8 cm S-') compared to smooth-bed fluxes. Advective porewater flows were associated with structures as small as 700 pm at water flows as low as 3 cm S-' and sediments with permeabilities of K > 3 Darcy (D). Interfacial fluxes associated with protruding bioroughness exceeded those with recessed structures of comparable size. Elevated biogenic structures just above an undisturbed smooth surface, such as rest~ng crabs, produced pressure patterns similar to those recorded for small mounds, and at an abundance of 17 m-' increased dye flux up to 5-fold relative to smooth control runs. Moving on 3-dimensional streamlines, bioroughness-driven advection is an important structuring process in permeable sediments, increasing the surface area of geochemical reaction zones and creating a variety of microenvironments for interstitial life. We conclude that roughness-related advective porewater processes play a key role in permeable sediments.

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Supershrimp: Deep Bioturbation in the Strait of Canso, Nova Scotia

Cited by 97 publications

References 1 publication

Biodiversity of benthic microbial communities in bioturbated coastal sediments is controlled by geochemical microniches

Biodiversity of benthic microbial communities in bioturbated coastal sediments is controlled by geochemical microniches

The biomechanics of burrowing and boring

Impact of bioroughness on interfacia solute exchange in permeable sediments

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