Salinity and water temperature assessment of the tidal marshes from the W Portuguese coast, as an ecological tool to palaeoenvironmental reconstructions based on Foraminifera and Ostracoda assemblages

摘要: A seasonal study of temperature and salinity estuarine sediment interstitial water tidal marshes was undertaken along three estuaries W Portuguese coast (Minho, Tejo Mira).The climatic N-S transition from wet Atlantic to Mediterranean features appear clearly imprinted in the distribution marsh assemblages, like foraminifera ostracoda, mainly reflecting gradient control.The Minho low estuary tends be flooded by ranging 0.5‰ 32‰ each tide cycle, even during dry seasons. However, hydrological balance sustains a more stable environment where measurements yielded 8‰ 16‰. In contrast Mira salt flooding waters record narrow range between 33‰ 36‰, spring, 29‰ 36‰ autumn. The control evaporation/ precipitation produces an enhanced water, that can reach hypersaline conditions, with maximum records 53‰ 48‰ lower estuaries.These environmental differences are recorded namely ostracoda. Caminha marsh, living essentially composed agglutinated species Haplophragmoides manilaensis, Miliammina fusca, Pseudothurammina limnetis Psammosphaera sp. Trochamminita salsa. modern ostracoda assemblage includes Leptochytere baltica, psammophila, Leptocythere Tuberoloxoconcha sp.1. Ammonia beccarii, tepida, Haynesina germanica, Jadammina macrescens, Trochammina inflata, dominant Loxoconcha malcomsoni, Terrestricythere cf. elisabethae, atlantica Xestoleberis labiata prevail as well many other marine species, such Basslerites teres fabaeformis.This highlights knowledge driven ecological parameters assemblages (usually preserved fossil record), is fundamental support reliable paleoclimatic palaeoenvironmental reconstructions. Keywords: salinity, marshes, foraminifera, Avaliacao da salinidade e temperatura agua nos sapais costa Oeste de Portugal, na perspectiva reconstrucao paleoambiental com base ecologia Foraminiferos Ostracodos O registo sazonal dos estuarios intersticial sedimentos sapal rios Minho, Mira, durante enchente, integram o estudo das associacoes foraminiferos ostracodos actuais Portugal. Nestes trabalhos podemos observar transicao entre padrao climatico humido do NO Peninsula Iberica mediterrâneo SO.O baixo estuario rio tende ser inundado por aguas grande amplitude salinidade, em cada ciclo mare, que persiste mesmo nas estacoes mais secas. No entanto balanco hidrologico contribui para um ambiente relativamente estavel, onde os valores variam 16‰.No inundam preia mar varia apenas Primavera, no Outono. evaporacao/ precipitacao contexto Sul, produz aumento ate hipersalinidade, atinge Mira.Estas diferencas condicoes ambientais ao longo Portugal estao reflectidas composicao organismos sapal, nomeadamente ostracodos. Sob baixa registadas Caminha, biocenose composta essencialmente pelas especies carapaca aglutinada associacao inclui 1. Nos A. dominam foraminiferos, enquanto se destacam numa diversidade caracteristicas marinhas, como fabaeformis.A relacao encontrada ostracodos, mostra caracterizacao factores ecologicos biocenoses (dos grupos fossil) analogos actuais, sao determinantes reconstituicao fiavel evolucao paleoclimatica paleoambiental. Palavras-Chave: sapais, Costa