Excretory products of mobile epifauna as a nitrogen source for seaweeds

Taylor, Richard B.; Rees, Tom ap

doi:10.4319/lo.1998.43.4.0600

Cited by 62 publications

(46 citation statements)

References 28 publications

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“…Similar to that reported for benthic habitats (Taylor & Rees 1998), these dissolved nutrients probably contribute to enhanced growth and, thus, to the longevity of floating or rafting macroalgae and attached micro-organisms. Consequently, primary production may be higher on and around floating items than in the surrounding water bodies.…”

Section: The Rafting Food Websupporting

confidence: 73%

The Ecology of Rafting in the Marine Environment. Ii. the Rafting Organisms and Community

Thiel¹,

Gutow²

2005

Oceanography and Marine Biology - An Annual Review

349

394

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Rafting of marine and terrestrial organisms has been reported from a variety of substrata and from all major oceans of the world. Herein we present information on common rafting organisms and on ecological interactions during rafting voyages. An extensive literature review revealed a total of 1205 species, for which rafting was confirmed or inferred based on distributional or genetic evidence. Rafting organisms comprised cyanobacteria, algae, protists, invertebrates from most marine but also terrestrial phyla, and even a few terrestrial vertebrates. Marine hydrozoans, bryozoans, crustaceans and gastropods were the most common taxa that had been observed rafting. All major feeding types were represented among rafters, being dominated by grazing/boring and suspension-feeding organisms, which occurred on all floating substrata. Besides these principal trophic groups, predators/scavengers and detritus feeders were also reported. Motility of rafting organisms was highest on macroalgae and lowest on abiotic substrata such as plastics and volcanic pumice. Important trends were revealed for the reproductive biology of rafting organisms. A high proportion of clonal organisms (Cnidaria and Bryozoa) featured asexual reproduction, often in combination with sexual reproduction. Almost all rafting organisms have internal fertilisation, which may be due to the fact that gamete concentrations in the rafting environment are too low for successful fertilisation of external fertilisers. Following fertilisation, many rafting organisms incubate their offspring in/on their body or deposit embryos in egg masses on rafts. Local recruitment, where offspring settle in the immediate vicinity of parents, is considered an important advantage for establishing persistent local populations on a raft, or in new habitats. Some organisms are obligate rafters, spending their entire life cycle on a raft, but the large majority of reported rafters are considered facultative rafters. These organisms typically live in benthic (or terrestrial) habitats, but may become dispersed while being confined to a floating item. Substratum characteristics (complexity, surface, size) have important effects on the composition of the rafting community. While at sea, ecological interactions (facilitation, competition, predation) contribute to the community succession on rafts. Organisms capable to compete for and exploit resources on a raft (space and food) will be able to persist throughout community succession. The duration of rafting voyages is closely related to rafting distances, which may cover various geographical scales. In chronological order, three features of an organism gain in importance during rafting, these being ability to (1) hold onto floating items, (2) establish and compete successfully and (3) develop persistent local MARTIN THIEL & LARS GUTOW 280 populations during a long voyage. Small organisms that do not feed on their floating substratum and, with asexual reproduction or direct development, combine all these features appear to be mos...

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Section: The Rafting Food Websupporting

confidence: 73%

The Ecology of Rafting in the Marine Environment. Ii. the Rafting Organisms and Community

Thiel¹,

Gutow²

2005

Oceanography and Marine Biology - An Annual Review

349

394

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“…However, as TKE was strongly dissipated within the A. chauvinii canopy, nutrients from mainstream flows are not likely to be rapidly transferred to the inner regions of the canopy. Therefore inputs of nutrients into the lower half of the canopy may originate from the sediments, fauna and macroalgae (Cowan et al 1996, Taylor & Rees 1998, Tyler et al 2003, Hepburn & Hurd 2005 and are potentially an important source of nutrients for uptake by the older parts of the thallus as well as during periods of low flow and bulk seawater nutrient concentrations.…”

Section: Discussionmentioning

confidence: 99%

Effects of a small-bladed macroalgal canopy on benthic boundary layer dynamics: implications for nutrient transport

Kregting¹,

Stevens²,

Cornelisen³

et al. 2011

Aquat. Biol.

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Field and laboratory velocity profiles were used to quantify boundary layer dynamics within communities of a small (< 0.2 m tall), dense canopy-forming seaweed Adamsiella chauvinii (Rhodophyta) in a soft-sediment habitat and to examine the role of hydrodynamics in modulating nutrient supply. At the 'canopy scale' there was a mixing layer at the fluid−canopy interface where turbulent kinetic energy was greatest, potentially enhancing nutrient uptake in this region. In the lower half of the canopy, a drag-dominated area of very low water velocity (< 0.01 m s −1 ) occurred. Spectral analysis revealed a reduction in energy within the canopy of around 1 Hz. The hydrodynamic parameters obtained from flume measurements were in good agreement with those recorded in the field. To understand the implications of the hydrodynamic environment on nutrient uptake, a flushing ratio was developed that compares the time for macroalgae to remove all nutrients from the canopy volume relative to the timescale for flushing. Results suggest that when nutrient demand is low, the canopy is well flushed and not mass-transfer limited. However when nutrient demand is high, the canopy can deplete nutrients more quickly than they can be replenished by ambient flows and are potentially mass-transfer limited.

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“…Reduction in seaweed production due to diffusion boundary layers in wave-sheltered sites may be offset by a change in nutrient supply to the macroalgae that cannot be detected simply by monitoring the seawater nutrient concentration. For example, in slow flows, localized sources of nitrogen such as ammonium provided by marine invertebrates living on macroalgal surfaces (Gerard & Mann 1979, Taylor & Rees 1998) may be a more important nitrogen-source to macroalgae than nitrate. Similarly, carbon dioxide is considered the primary carbon source in wave-exposed sites while bicarbonate may be more important in slow flows (France & Holmquist 1997).…”

Section: Introductionmentioning

confidence: 99%

Exposure to waves enhances the growth rate and nitrogen status of the giant kelp Macrocystis pyrifera

Hepburn¹,

Holborow²,

Wing³

et al. 2007

Mar. Ecol. Prog. Ser.

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The influence of wave-exposure on the growth and erosion rates of Macrocystis pyrifera was determined in Paterson Inlet, Stewart Island, New Zealand, for each season of 2002. During autumn, following a period of low seawater nitrogen, sites that received significant amounts of oscillatory flow from waves exhibited higher frond growth rates than at wave-sheltered sites. Blade and stipe growth rates at wave-exposed sites were at a yearly maximum during this period, and were 4.3 and 1.6 times higher respectively than at wave-sheltered sites where growth was at a yearly minimum. During this time C:N ratios and nitrogen concentrations of blade tissues indicated that the nitrogen status of frond apices, where the majority of growth occurs, was greater at wave-exposed sites than at wave-sheltered sites. During periods when kelp tissue nitrogen levels are low, but some inorganic nitrogen is available in the water column, oscillatory flow may enhance nutrient uptake by M. pyrifera by increasing the flux of nutrients into kelp canopies and by reducing the size of diffusion boundary layers at the kelp surface. Exposure to waves also modified the seasonal pattern of M. pyrifera growth by ameliorating the negative effect of low seawater nitrogen concentrations during summer and autumn. Blade and stipe growth was relatively steady at wave-exposed sites during the study period, while wave-sheltered sites had distinct seasonal patterns with low growth during summer and autumn, increasing through winter to spring maxima. In this system, water motion influences the growth rates of M. pyrifera only at specific times of year; when tissue nitrogen levels are low but some inorganic nitrogen is available in the water column.

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Excretory products of mobile epifauna as a nitrogen source for seaweeds

Cited by 62 publications

References 28 publications

The Ecology of Rafting in the Marine Environment. Ii. the Rafting Organisms and Community

The Ecology of Rafting in the Marine Environment. Ii. the Rafting Organisms and Community

Effects of a small-bladed macroalgal canopy on benthic boundary layer dynamics: implications for nutrient transport

Exposure to waves enhances the growth rate and nitrogen status of the giant kelp Macrocystis pyrifera

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