The Albufera de València coastal lagoon is one of the largest oligohaline lagoons in the Iberian Peninsula. Highly polluted and threatened by plans for urban development, it has been protected as a Natural Park since 1986 to preserve its environment and surroundings, mostly consisting of ricefields and a forested coastal sand bar. Restoration plans focus on recovering the water quality and submerged macrophyte cover that occupied most of the lagoon in the 1950’s. Until recent studies, little was known about the wetland’s palaeoenvironmental history. To improve this knowledge, we analysed the Holocene evolution of the lagoon based on sedimentology, geochemistry and microfossils (foraminifera, diatoms, ostracods and pollen remains) from four cores. Two were collected in the sand bar, and two from the central lagoon. In combination with previous work, our new data show that the lagoon remained brackish for most of its history since 8700 cal BP, with the frequent presence of accompanying freshwater taxa from 7000 to 3400 cal BP. Notwithstanding chronological uncertainties, some episodes of decline in the abundance of microfossils seem to match aridity events Bond 5 (8.2 ky BP) and Minorca 7 (7.5-7.2 ky BP), the latter marking the switch from a dominance of arboreal vegetation to grasses. The most important change in the water body consisted of a sharp change at the beginning of the 19th century from a brackish to an oligohaline lagoon, driven by anthropogenic hydrological control associated with the expansion of ricefields. Later on, by the 1960-1970’s, the growing population impacts of agricultural, wastewater and industrial effluents launched a major eutrophication process that would eventually sharply reduce the benthic vegetation and invertebrate communities and promote the phytoplankton dominance of the ecosystem in a turbid state. Although our multiproxy study has increased understanding of the lagoon’s history, somewhat supported by documentary evidence, further palaeoecological research in different parts of the wetland would help define the causes of heterogeneous timing of changes in this large, shallow, complex system. Notwithstanding the need for further research, there is a clear priority for managers and the society to work on restoration efforts to drive the Albufera wetland towards one of the previous, less impacted, states of this worn-out and neglected ecosystem.
Bibliographical noteFunding Information:
The former Spanish Ministry of Education and Technology funded this research through the project VARECOMED (REN2002-03272). JMB acknowledges the funding from a fellowship (BES-2003-2759) as part of the VARECOMED project. We thank also Blas Valero and Ana Moreno and the people from University of Minnesota, Limnological Research Centre and Lac Core who helped on the laboratory core descriptions. M.A. Rodrigo assisted in the interpretation of macrophyte changes. JMB wants to dedicate the paper to the memory of his grandparents, Carmen Polo and Jose Barba, for their support and advice, and who died during the development of this work. Patrícia Llàcer-Manri-que collaborated in the palynological analysis. We would like to thank two anonymous reviewers for their thoroughly effort in suggesting improvements to an early version of the manuscript. Finally, all living authors would like to acknowledge the great interest of the deceased senior author, Maria Rosa Miracle, for her perseverance in pursuing understanding of natural phenomena and for the conservation of nature.
© Asociación Ibérica de Limnología, Madrid. Spain.
Copyright 2019 Elsevier B.V., All rights reserved.
- Climatic events
- Coastal lagoon evolution
- Iberian Peninsula
- Pollen analysis
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