RT Journal Article T1 Biodiversity of diatom assemblages in a Mediterranean semiarid stream: implications for conservation A1 Ros, María Dolores A1 Aboal, Marina A1 Marín Murcia, José Pedro AB Many semiarid streams are threatened both by human demands and climatic effects (global warming), but little is known about their algal biodiversity and their conservation value, especially in Mediterranean areas. The aim of the present study was to evaluate annual changes in the structure and species richness of diatom communities in runs and pools of an oligohaline, semiarid stream in south-eastern Spain, and their relationship with nutrients and hydrology. The pool substrate was covered most of the time by a yellow-brown coat, mainly composed of diatoms and a few cyanophytes (Leptolyngbya). In the runs, cyanophytes were dominant (Rivularia) and diatoms occurred as epiphytes. The diversity of these diatom assemblages was high, particularly in the pools. Some species were present throughout the year, whereas others showed a bimodal growth pattern. Maximum biomasses were reached in summer in the pools and in autumn in the runs, when levels of phosphorus increased as a result of flooding. Species richness and diversity were correlated with hydrology and sulfate concentrations, whereas biomass (as chlorophyll a and ash-free dry weight) was associated with variations in temperature, conductivity and ammonium. These semiarid streams are refuges of biodiversity, representing habitats reliant on cycles of drought and floods, which should be considered in proposals for their conservation. PB CSIRO Publishing SN 1323-1650 YR 2009 FD 2009-01-29 LK https://hdl.handle.net/20.500.14352/98599 UL https://hdl.handle.net/20.500.14352/98599 LA eng NO Ros M. Dolores, Marín-Murcia José Pedro, Aboal Marina (2009) Biodiversity of diatom assemblages in a Mediterranean semiarid stream: implications for conservation. Marine and Freshwater Research 60, 14-24. NO Ministerio de Educación. Gobierno de España. DS Docta Complutense RD 1 sept 2024