Periodic swarms of the salp Salpa aspera in the Slope Water off the NE United States: Biovolume, vertical migration, grazing, and vertical flux

Madin, Laurence P.; Kremer, Patricia; Wiebe, Peter H.; Purcell, Jennifer E.; Horgan, E.H.; Nemazie, D. A.

doi:10.1016/j.dsr.2005.12.018

Cited by 85 publications

(67 citation statements)

References 49 publications

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“…For example, the widely distributed Salpa democratica has occurred in dense aggregations in Australia, New Zealand, Japan, and South Africa (Gibbons 1996). Populations of the same species and Salpa fusiformis have been reported in the Mediterranean Sea, and Salpa aspera in the Carolina Slope (Madin et al 2006). Dense populations of Pegea confoederata have been widely recorded in the Arabian Sea (Ramaswamy et al 2005).…”

Section: Discussionmentioning

confidence: 99%

Mass deposition event of Pyrosoma atlanticum carcasses off Ivory Coast (West Africa)

Lebrato

Jones

2009

Limnology & Oceanography

142

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Thousands of moribund thaliacean carcasses (Pyrosoma atlanticum) were deposited between February and March 2006 at the seafloor in the Ivory Coast area (West Africa). Remotely operated vehicle surveys were conducted in a continuous depth gradient between 20 and 1275 m along an oil pipeline. Video and still photography were used to estimate the carcass distribution, density, and size on the seabed, as well as recording the local megafauna interactions with the gelatinous material. Large patches of dead pyrosomids covered extensive areas on the continental slope, whereas minor aggregations were found on the shelf. The carcasses were in many instances trapped along the pipelines, accumulating extensively in troughs and furrows in the slope, and especially in soft sediment channels. Pyrosoma atlanticum dried samples were used to calculate the carbon content, enabling the extrapolation to the densities and sizes recorded in the video surveys. The average standing stock of organic carbon associated with the carcasses was .5 g C m 22 in the whole slope and canyon, with values as high as 22 g C m 22 in certain areas. Eight megafaunal species from three different phyla were observed 63 times directly feeding on the decomposing carcasses. The gelatinous carbon may have contributed substantially to the detrital food web including microbes at the seabed, and certainly to the diet of larger benthic organisms. The organism-level carbon measurements and documented fate of pyrosomid organic carbon is new evidence of the importance of gelatinous material in large-scale processes and elemental cycling.

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Section: Discussionmentioning

confidence: 99%

Mass deposition event of Pyrosoma atlanticum carcasses off Ivory Coast (West Africa)

Lebrato

Jones

2009

Limnology & Oceanography

142

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“…Salps achieve higher rates of filtering and efficiently retain smaller particles (1 μm -1 mm) than most other planktonic grazers (Madin and Deibel 1998) and therefore play a key part in pelagic ecosystems, particularly when they form dense swarms (Alldredge and Madin 1982). Due to their efficient removal of small particles from surface waters, salps are capable of packaging and exporting primary production to deeper waters, thus influencing biogeochemical cycling (Madin 1982;Madin et al 2006;Phillips et al 2009). Some species are vertical migrators, accelerating the transport of fecal material and biomass to deeper water.…”

Section: Introductionmentioning

confidence: 99%

A comparison of filtration rates among pelagic tunicates using kinematic measurements

Sutherland

Madin

2009

Mar Biol

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Salps have higher filtration rates than most other holoplankton, and are capable of packaging and exporting primary production from surface waters. A method of kinematic analysis was employed to accurately measure salp feeding rates. The data were then used to explain how diverse body morphologies and swimming motions among species and lifecycle stages influence salp feeding performance. We selected five species, representing a range of morphologies and swimming styles, and used digitized outlines from video frames to measure body-shape change during a pulse cycle. Timevarying body volume was then calculated from the digitized salp outlines to estimate the amount of fluid passing through the filtering mesh. This non-invasive method produced higher feeding rates than other methods and revealed that body volume, pulse frequency and degree of contraction are important factors for determining volume filtered. Each species possessed a unique combination of these three characteristics that resulted in comparable filtration (range: 0.44 -15.33 ml s -1 ) and normalized filtration rates (range: 0.21 -1.27 s -1 ) across species. The convergence of different species with diverse morphologies on similar normalized filtration suggests a tendency towards a flow optimum.

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“…These pellets remain intact for days (4) and have sinking speeds (200-3,646 m·d −1 ) (5, 6) that are higher than most copepod or krill pellets (3). Furthermore, diurnal vertical migration by some species may accelerate vertical export (7,8). The combination of high filtration rates, small mesh size, and rapid pellet sinking implies that salps have the potential to shift particle distributions toward larger sizes, contribute to vertical transport, and remove substantial amounts of primary production from surface waters.…”

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confidence: 99%

Filtration of submicrometer particles by pelagic tunicates

Sutherland

Madin

Stocker

2010

Proc. Natl. Acad. Sci. U.S.A.

138

135

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Salps are common in oceanic waters and have higher per-individual filtration rates than any other zooplankton filter feeder. Although salps are centimeters in length, feeding via particle capture occurs on a fine, mucous mesh (fiber diameter d ∼0.1 μm) at low velocity (U = 1.6 ± 0.6 cm·s −1 , mean ± SD) and is thus a low Reynoldsnumber (Re ∼10 −3 ) process. In contrast to the current view that particle encounter is dictated by simple sieving of particles larger than the mesh spacing, a low-Re mathematical model of encounter rates by the salp feeding apparatus for realistic oceanic particle-size distributions shows that submicron particles, due to their higher abundances, are encountered at higher rates (particles per time) than larger particles. Data from feeding experiments with 0.5-, 1-, and 3-μm diameter polystyrene spheres corroborate these findings. Although particles larger than 1 μm (e.g., flagellates, small diatoms) represent a larger carbon pool, smaller particles in the 0.1-to 1-μm range (e.g., bacteria, Prochlorococcus) may be more quickly digestible because they present more surface area, and we find that particles smaller than the mesh size (1.4 μm) can fully satisfy salp energetic needs. Furthermore, by packaging submicrometer particles into rapidly sinking fecal pellets, pelagic tunicates can substantially change particle-size spectra and increase downward fluxes in the ocean.biofiltration | low Reynolds number | salps | colloids | carbon cycle F ilter feeding is a common strategy among marine plankton for collecting small food particles from a suspension. Pelagic tunicates in the class Thaliacea, order Salpida, have the highest perindividual filtration rates of all marine zooplankton filter feeders (1). Weight-specific clearance rates (70-4,153 mL·mg C −1 ·h −1 ) (2) are higher than most copepod and krill species. Salps filter feed by rhythmically pumping water into the oral siphon, through the pharyngeal chamber, and out the atrial siphon (Fig. 1A). This pumping action, generated by circular muscle bands, also creates a propulsive jet for locomotion. Food particles entering the pharyngeal chamber are strained through a mucous net that is continuously secreted and rolled into a food strand that moves posteriorly toward the esophagus. The bag-like net is secreted by the endostyle and fills much of the pharyngeal chamber (Fig. 1A). This feeding mechanism results in ingestion of any particles that enter the atrial siphon and adhere to the filtering mesh.After digestion, particles are packaged into dense fecal pellets, which often contain undigested or partially digested plankton (3, 4). These pellets remain intact for days (4) and have sinking speeds (200-3,646 m·d −1 ) (5, 6) that are higher than most copepod or krill pellets (3). Furthermore, diurnal vertical migration by some species may accelerate vertical export (7,8). The combination of high filtration rates, small mesh size, and rapid pellet sinking implies that salps have the potential to shift particle distributions toward larger sizes, con...

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Periodic swarms of the salp Salpa aspera in the Slope Water off the NE United States: Biovolume, vertical migration, grazing, and vertical flux

Cited by 85 publications

References 49 publications

Mass deposition event of Pyrosoma atlanticum carcasses off Ivory Coast (West Africa)

Mass deposition event of Pyrosoma atlanticum carcasses off Ivory Coast (West Africa)

A comparison of filtration rates among pelagic tunicates using kinematic measurements

Filtration of submicrometer particles by pelagic tunicates

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