BIBLIOS

Tipo
Artigos em Revista

Tipo de Documento
Artigo Completo

Título
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

Participantes na publicação
Fatela, F (Author)
Dep. Geologia
IDL
Moreno, J (Author)
IDL
Cabral, MC (Author)
Dep. Geologia
IDL

Resumo
A seasonal study of temperature and salinity of estuarine and sediment interstitial water of tidal marshes was undertaken along three estuaries of W Portuguese coast (Minho, Tejo and Mira).\\nThe climatic N-S transition from wet Atlantic to Mediterranean features appear clearly imprinted in the distribution of tidal marsh assemblages, like foraminifera and ostracoda, mainly reflecting the water salinity gradient control.\\nThe Minho low estuary tidal marsh tends to be flooded by estuarine water ranging from 0.5‰ to 32‰ in each tide cycle, even during dry seasons. However, the marsh hydrological balance sustains a more stable environment where the salinity of interstitial water measurements yielded 8‰ to 16‰. In contrast the Tejo and Mira salt marsh flooding waters record a narrow range between 33‰ and 36‰, in spring, and between 29‰ and 36‰ in autumn. The climatic control of evaporation/ precipitation balance produces an enhanced salinity of marsh interstitial water, that can reach hypersaline conditions, with maximum records of 53‰ in Tejo and 48‰ in Mira lower estuaries.\\nThese environmental differences along the W Portuguese coast are recorded by the tidal marsh assemblages, namely foraminifera and ostracoda. In the low salinity Caminha salt marsh, living foraminifera are essentially composed by the agglutinated species Haplophragmoides manilaensis, Miliammina fusca, Pseudothurammina limnetis Psammosphaera sp. and Trochamminita salsa. The modern ostracoda assemblage includes Leptochytere baltica, Leptochytere psammophila, Leptocythere sp. A and Tuberoloxoconcha sp.1. In the Tejo and Mira salt marsh Ammonia beccarii, Ammonia tepida, Haynesina germanica, Jadammina macrescens, Trochammina inflata, are the dominant foraminifera and Loxoconcha malcomsoni, Terrestricythere cf. elisabethae, Tuberoloxoconcha cf. atlantica and Xestoleberis labiata prevail as well as many other more marine ostracoda species, such as Basslerites teres and Leptocythere fabaeformis.\\nThis study highlights that the knowledge of driven ecological parameters of modern assemblages (usually preserved in fossil record), is fundamental to support reliable paleoclimatic and palaeoenvironmental reconstructions.


Instituição
FACULDADE DE CIÊNCIAS DA UNIVERSIDADE DE LISBOA

Suporte
Estudos do Quaternário

Identificadores da Publicação
ISSN - 0874-0801



Identificadores do Documento
URL - http://www.apeq.pt/ojs/index.php/apeq/article/view/211/241
DOI - https://doi.org/10.30893/eq.v0i14.124

Identificadores de Qualidade
SCOPUS Q4 (2016) - 0.285 - Palaeontology
SCOPUS Q4 (2016) - 0.285 - Earth-Surface Processes