Changes in the stygobiont polychaete community of the Jameos del Agua, Lanzarote, as a result of bioturbation by the ech
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ORIGINAL PAPER
Changes in the stygobiont polychaete community of the Jameos del Agua, Lanzarote, as a result of bioturbation by the echiurid Bonellia viridis M. Carmen Brito & Alejandro Martínez & Jorge Núñez
Received: 24 March 2009 / Revised: 24 July 2009 / Accepted: 27 July 2009 / Published online: 15 August 2009 # Senckenberg, Gesellschaft für Naturforschung and Springer 2009
Abstract The Jameos del Agua is a natural anchialine cave lagoon that has been developed as a tourist attraction. It is semi-illuminated due to a partial collapse of the ceiling (known as “jameo”). A fine carpet of benthic diatoms covers the bottom, in 0.5–2 m depth of water, of the tidally influenced and fully marine lagoon. Interstitial polychaetes inhabit this diatomean carpet and the lava rubble mixed with sand and gravel. During the last decades, the echiurid Bonellia viridis became very abundant and its bioturbation activities have changed the natural bottom conditions. The whitish fecal material from B. viridis formed sediment mounds that sharply contrast with the black volcanic rock. This new habitat have been colonized by several endemic species (e.g., Fauveliopsis jameoaquensis), but also by abundant stygoxene macro- and meiofaunal opportunistic species that compete with the endemic stygobities. The most recent colonizers are mainly deposit-feeding polychaetes that take advantage of the high amount of trophic resources available (e.g., Notomastus spp., Trichobranchus glacialis, Aphelochaeta marioni, Cirrophorus lyra). As a result of the recent colonizations, it is necessary to establish monitoring of the communities and to evaluate the viability of controlling the population of B. viridis in the lagoon, since these alterations can also affect the endemic populations living in the water column. Keywords Megafauna . Meiofauna . Marine caves . Annelida . Atlantic Ocean
M. C. Brito : A. Martínez : J. Núñez (*) Departamento de Biología Animal, Universidad de La Laguna, 38206 La Laguna, Tenerife, Canary Islands, Spain e-mail: [email protected]
Introduction The Jameos del Agua marine cave lagoon is a section of a 7,600-m-long volcanic lava tube, which originated from the activity (21±6.5 ka) of the Corona volcano on Lanzarote, Canary Islands (Carracedo et al. 2003). The natural lagoon within the cave has been developed as a popular tourist attraction and is semi-illuminated due to a partial collapse of the ceiling (so-called “jameos” in the Canary Islands). The tidally influenced, fully marine, lagoon is 50 m long and 10 m wide, with a maximum depth of 11 m. Incident light through the skylights permits the growth of a benthic diatomean carpet, primarily in 0.5–2 m water depths. Submarine caves have been considered to be oligotrophic environments with limited fauna and flora and low biomass (Fichez 1990). The high diversity of species in the Jameos del Agua cave lagoon is thus unusual, and contrasts with the scarce fauna which inhabits the adjacent Cueva de los Lagos, a series of totally dark, anchialine cave pools situated in the most in
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