Utilization of shallow-water seagrass detritus by Carribbean deep-sea macrofauna: δ13C evidence

doi:10.1016/0198-0149(85)90028-7

Deep Sea Research Part A. Oceanographic Research Papers

Volume 32, Issue 2, February 1985, Pages 201-214

https://doi.org/10.1016/0198-0149(85)90028-7 Get rights and content

Abstract

Three dives were made using the DSRV Alvin in the deep-sea basin north of St. Croix, Virgin Islands. Detrital seagrasses and macrofaunal distributions at 2455 to 3950 m depth were assessed quantitatively. Counts of the manatee grass Syringodium filiforme (ca. 5 to 100 blades m⁻²) contrasted sharply with those of the turtle grass Thalassia testudinum (ca. 0.1 to 2.0 blades m⁻²), reflecting an abundance proportional to previously reported export rates of the same species from Tague Bay, a nearby shallow source lagoon.

Of the macrofaunal consumers that could potentially utilize this detrital nutrient source, three species of holothurians (Mesothuria verrilli, Psychropotes semperiana, and Benthodytes linqua) and two species of sea urchins (Hygrosoma petersi and Salencidaris profundi) were collected and/or observed. Gut content analyses revealed that all three holothurians deposit-feed on sediment and at least one species of sea urchin (H. petersi) feeds almost exclusively on Syringodium.

Carbon: nitrogen analyses of naturally occurring abyssal Thalassia detritus showed very low nitrogen content (0.21% N) and a high C:N ratio (214.8), thus yielding a loo nutritional value. Fresh Thalassia blades held in a litter bag experiment (by R. D. Turner) at 3950 m changed little in nitrogen content and C:N ratio after four years.

A comparison was made of the stable carbon isotope ratios of ¹³C:¹²C for abyssal seagrass detritus and other potential carbon sources with those for tissues from the holothurian and urchin consumers. The results indicate that a significant proportion of the nutrition of both groups is derived from detrital seagrasses either by direct consumption (sea urchins) or indirectly by deposit-feeding on sediments enriched by decomposed seagrasses (holothurians).

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^†: Present address: Division of Environmental Studies, University of California, Davis, CA 95616, U.S.A.

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Utilization of shallow-water seagrass detritus by Carribbean deep-sea macrofauna: δ13C evidence

Abstract

Geochimica et Cosmochimica Acta

Deep-Sea Research

Geochimica et Cosmochimica Acta

Estuarine and Coastal Marine Science

Aquatic Botany

Deep-Sea Research

Aquatic Botany

Estuarine and Coastal Shelf Science

Deep-Sea Research

Journal of Experimental Marine Biology and Ecology

Deep-Sea Research

Aquatic Botany

Studies concerning the organic matter of the sea bottom

Report of the Danish Biological Station

Natural stable carbon isotope tag traces Texas shrimp migrations

Fishery Bulletin

The association of N2-fixing bacteria with sea urchins

Marine Biology

Nitrogen fixation (acetylene reduction) associated with sea urchins (Strongylocentrotus droebachiensis) feeding on seaweeds and eelgrass

Journal of the Fisheries Research Board of Canada

Food sources of estuarine invertebrates analyzed using 13C/12C ratios

Ecology

Detritus formation from eelgrass (Zostera marina L.): the relative effects of fragmentation, leaching and decay

Limnology and Oceanography

Preliminary studies of the fate of shallow-water detritus in the basin north of St. Croix

Experimental ecology of the feeding of fishes

Microbial life in the deep sea

Scientific American

Microbial degradation of organic matter in the deep sea

Science, Wash.

Detritus decomposition relationships

Changes in carbon, nitrogen, adenosine triphosphate, and chlorophyll a in decomposing Thalassia testudinum leaves

Limnology and Oceanography

Macrophyte production and detritus food chains in coastal waters

Food-web structure and the fractionation of carbon isotopes in the Bering Sea

Marine Biology

Production ecology and physiology of seagrasses

Utilization of shallow-water seagrass detritus by Carribbean deep-sea macrofauna: δ¹³C evidence

The association of N₂-fixing bacteria with sea urchins

Food sources of estuarine invertebrates analyzed using ¹³C/¹²C ratios