Reconstruction of the environmental history of a coastal insular system using shallow marine records: the last three millennia of the Cíes Islands (Ría de Vigo, NW Iberia)
| Autor: | Tania L. Insua, Irene Alejo, Iria García-Moreiras, Castor Muñoz Sobrino, Pablo Ramil-Rego, Natalia Martínez-Carreño, Javier Ferreiro da Costa, Víctor Cartelle, Carlos Fernández Rodríguez, Soledad García-Gil |
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| Rok vydání: | 2016 |
| Předmět: |
Palynology
010506 paleontology Archeology geography geography.geographical_feature_category 010504 meteorology & atmospheric sciences Sediment Geology Structural basin 01 natural sciences Oceanography Downwelling Archipelago Facies Upwelling Sedimentary rock Ecology Evolution Behavior and Systematics 0105 earth and related environmental sciences |
| Zdroj: | Boreas. 45:729-753 |
| ISSN: | 0300-9483 |
| Popis: | The coastal lagoon-beach complex at the Cies Islands located at the opening of the Ria de Vigo (NW Iberia) is an important ecosystem currently threatened by anthropogenic impacts and climate variations. We used multiproxy marine sediment analyses to reconstruct the millennial environmental dynamics of this insular system and, in particular, the recent history of its coastal lagoon. Geophysical surveys were used to obtain bathymetry and identify the major sedimentary units of its closest submarine basin as well as their sediment sources. Core samples were taken in the middle and distal parts of the sedimentary body, where several prograding sedimentary units are thinner, allowing continuous sampling of the facies. Lithological, textural, elemental and chronological analyses were carried out on two cores. The detailed palynological studies on one of the cores included the analyses of the pollen, non-pollen palynomorphs and dinocysts dating back three millennia. Our results revealed noticeable environmental changes affecting this area during the last 3000 years, due mainly to changing climate and oceanic conditions but also to the impact of historic human occupation of the islands. Several cold events (the 2.8 ka BP event and the Little Ice Age) characterized by enhanced upwelling alternated with warmer stormy periods of prevailing downwelling conditions in the ria. These circumstances altered the balance amongst the lacustrine, marsh, dune and lagoon systems, opening ephemeral inlets and modifying the trophic stage of the shallow waters surrounding the archipelago. Here we provide a background of the human and climatic impacts affecting these highly sensitive habitats, which may serve to improve their future management strategies. |
| Databáze: | OpenAIRE |
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