RefDoc
Haut

Faire une nouvelle recherche
Make a new search
Lancer la recherche


Titre du document / Document title

Strength, drag, and dislodgment of two competing intertidal algae from two wave exposures and four seasons

Auteur(s) / Author(s)

PRATT Marney C. (1 2) ; JOHNSON Amy S. (1) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) Biology Department, Bowdoin College, 6500 College Station, Brunswick, ME 04011, ETATS-UNIS
(2) Biology Department, Duke University, Box 90338, Durham, NC 27708, ETATS-UNIS

Résumé / Abstract

Intertidal macroalgae often experience greater risk of dislodgment with increasing size because of underscaling of breaking force of their stipes relative to drag on their thalli. This ratio (breaking force/drag) indicates safety from breakage at a given flow speed, with values greater than one indicating safety from breakage and values lower than one indicating danger of breakage. We examined this force ratio for the largest thalli of two species of co-dominant, red algae, Chondrus crispus Stackhouse and Mastocarpus stellatus Stack. In With. (Guiry), in four seasons at two wave exposures. During fall and winter, the largest thalli in both populations were dislodged resulting in a decrease in mass of the largest thalli found. This decrease was greater for Chondrus than for Mastocarpus, but their mass-specific force ratios (at 0.55 m s-1) were equal indicating similar size-specific risk of dislodgment. The equality of force ratios was underlain by two similarities: (1) breaking force was independent of mass and not different between species; (2) mass-specific drag was not different between species. These similarities were underlain by dissimilar causes: (i) similarity in breaking force (the product of cross-sectional area and material strength) occurred because greater material strength of Mastocarpus compensated for greater mass-specific cross-sectional area of Chondrus; (ii) similarity in mass-specific drag (a function of planform area and the coefficient of drag) occurred because greater drag coefficients for Mastocarpus compensated for greater mass-specific planform areas of Chondrus. The similarity in force ratio, if it held at season-and site-relevant flow speeds, would suggest that during seasons of minimal growth and high wave exposure, the mass of the largest thalli of both species should be the same. Chondrus, however, had a greater mass at both sites in all seasons. Chondrus experienced greater decreases in mass probably because it grew larger and larger thalli are less safe. Extrapolation of a site-relevant force ratio for Chondrus in the fall revealed (1) that the site-relevant force ratio did not differ between exposures even though the mass-specific force ratio was greater at the protected site, and (2) a paradoxical result that all Chondrus thalli studied ought to have dislodged, but had not. This paradox may be resolved by consideration of the protection conferred by canopies of Chondrus: a canopy may effectively raise its site-relevant force ratio. Perhaps differences in protection conferred by different canopies explain why larger Chondrus persist with Mastocarpus even given a similarity in mass-specific force ratio.

Revue / Journal Title

Journal of experimental marine biology and ecology    ISSN  0022-0981   CODEN JEMBAM 

Source / Source

2002, vol. 272, no1, pp. 71-101 (2 p.1/4)

Langue / Language

Anglais

Editeur / Publisher

Elsevier, Kidlington, ROYAUME-UNI  (1967) (Revue)

Mots-clés anglais / English Keywords

Marine plant

;

Florideophyceae

;

Thallophyta

;

Algae

;

Rhodophyta

;

Environmental factor

;

Marine environment

;

America

;

North America

;

United States

;

Chondrus crispus

;

Maine

;

Island

;

Interspecific competition

;

Seasonal variation

;

Wave effect

;

Hydrodynamic drag

;

Tear strength

;

Shear strength

;

Morphology

;

Pruning

;

Intertidal zone

;

Habitat

;

Phytoplankton

;

Mots-clés français / French Keywords

Plante marine

;

Florideophyceae

;

Thallophyta

;

Algae

;

Rhodophyta

;

Facteur milieu

;

Milieu marin

;

Amérique

;

Amérique du Nord

;

Etats Unis

;

Ile Bailey

;

Mastocarpus stellatus

;

Chondrus crispus

;

Maine

;

Ile

;

Compétition interspécifique

;

Variation saisonnière

;

Action vague

;

Résistance hydrodynamique

;

Résistance déchirement

;

Résistance cisaillement

;

Morphologie

;

Taille plante

;

Zone intertidale

;

Habitat

;

Phytoplancton

;

Mots-clés espagnols / Spanish Keywords

Planta marina

;

Florideophyceae

;

Thallophyta

;

Algae

;

Rhodophyta

;

Factor medio

;

Medio marino

;

America

;

America del norte

;

Estados Unidos

;

Chondrus crispus

;

Maine

;

Isla

;

Competencia interespecífica

;

Variación estacional

;

Acción onda

;

Resistencia hidrodinámica

;

Resistencia a la desgarradura

;

Resistencia cizallamiento

;

Morfología

;

Poda planta

;

Zona intertidal

;

Habitat

;

Fitoplancton

;

Localisation / Location

INIST-CNRS, Cote INIST : 7185, 35400010132711.0050

Nº notice refdoc (ud4) : 13657537



Faire une nouvelle recherche
Make a new search
Lancer la recherche
Bas