INVESTIGADORES
IRIBARNE Oscar Osvaldo
artículos
Título:
Between-habitats differences in burrow characteristics and trophic modes in the southwestern Atlantic burrowing crab Chasmagnathus granulata
Autor/es:
O. IRIBARNE,; BORTOLUS, A.; BOTTO, F
Revista:
MARINE ECOLOGY PROGRESS SERIES
Editorial:
INTER-RESEARCH
Referencias:
Lugar: Oldendorf/Luhe; Año: 1997 vol. 155 p. 132 - 145
ISSN:
0171-8630
Resumen:
ABSTRACT Burrow characteristics, food type, and feeding h a b ~ t sof the SW Atlantlc burrowing crab
Chasmagnathus grdnulata were compared between ~ n d i v ~ d u allisv ing in mud flats and In Spartinadominated
marshes. Burrows were shorter (X - 19.7 cm, SD = 5 8, n = 54) and more dynamlc (entrance
displacement: X = 3 2 cm d-l, SD = 1 7, n = 21) in mud flats than In Spartlna-dominated areas (length
X = 41 cm, SD = 12, n = 78, no entrance displacement). Sediment turnover rate was much higher in mud
flats (X - 5 9 kg m-' d-l) than in Spartlna-dominated areas ( X = 2 4 kg m-' d.'). Burrow shape differed
between areas, being straight, near-vert~catlu nnels in the vegetated area, but oblique (average angle
to vertical = 60'. SD = 16", n = 110), and having a funnel-shape entrance and a much large]- diameter in
mud flats Stomach contents also differed between habitats. Pleces of plants dominated contents in the
vegetated area, while sediment (with polychaetes, diatoms, ostracods, and nematodes) dom~na t edin
the mud flats, lndicatlng that crabs are mainly deposit feeders In the mud flats and herb~vorousin the
Spart~na-dominateda reas. This pattern suggests that the heuristic model relatlng burrow arch~tecture
to trophic modes prev~ouslyp roposed for fossorial thalassinidean shrimps applies to individuals of a C
granulata populat~on The burrow content showed higher organic content and vegetal parts in the vegetated
area than in the other area. Burrows in the mud flat showed a significantly higher abundance of
nematodes and ostracods. Due to their hydrodynalnic characteristics and content, burrows in the mud
flats may work as passive traps for sediment and organic matter. Given the extensive intertidal area
inhabited by C granulata in SW Atlantic estuanes, and the locatlon of their burrows (between marshes
and the open estuary), these burrows may work as traps for detritus, thus reduclng the export rate of
organic matter from marshes.