IDEA   23902
INSTITUTO DE DIVERSIDAD Y ECOLOGIA ANIMAL
Unidad Ejecutora - UE
artículos
Título:
Shorter but thicker: analysis of internal growth bands in shells of intertidal vs. subtidal Antarctic limpets, Nacella concinna, reflects their environmental adaptation
Autor/es:
LOMOVASKY, BETINA J.; DE ARANZAMENDI, M. CARLA; ABELE, DORIS
Revista:
POLAR BIOLOGY
Editorial:
SPRINGER
Referencias:
Lugar: Berlin; Año: 2020 vol. 43 p. 131 - 141
ISSN:
0722-4060
Resumen:
The limpet Nacella concinna is a dominant macroinvertebrate along the coastal Antarctic Peninsula with two ecotypes inhabiting in intertidal (migratory) and subtidal (non-migratory) areas, respectively. The ecological aim of the study is to understand whether higher stress competence and migratory energy expenses in intertidal Antarctic limpets shorten their lifetime and limit the shell growth rate compared to their sublittoral congeners. We evaluated the shell morphometry, age and internal shell growth bands in a large number of intertidal and subtidal N. concinna shells (>180 shells) in Potter Cove, 25 de Mayo/King George Island, South Shetland Islands. Comparisons of the morphometric showed that intertidal limpets are relatively shorter and less wide and have higher shell mass, i.e. at common shell height are relatively thicker and heavier than those of subtidal specimens, showing a distinctive shell allometry between ecotypes. Shell sections revealed internal growth bands, alternating wide opaque (faster growth) with thin translucent bands (slow growth). The maximum age read was close to 20 years for both groups. Comparisons of von Bertalanffy growth curves showed for shell length and shell width lower growth rate k in intertidal animals than in subtidal ones associated to a great variability, with no differences in L∞, W∞ and t0 between the two populations. However, when shell height vs. age is considered, no differences were observed for any growth parameter. Curtailed variability of growth rates in the intertidal population reflects either a limitation of the food reserves or feeding time, or an energy gap for shell growth due to the costs for migration and stress defense. As shell growth and repair are energetically costly, this environmental factors limiting the energy available for growth of shell circumference, whereas at the same time a process must be at work that supports higher shell mass of intertidal limpets.