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| Titel |
Seagrasses and sediment response to changing physical forcing in a coastal lagoon |
| VerfasserIn |
J. Figueiredo da Silva, R. W. Duck, J. B. Catarino |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 8, no. 2 ; Nr. 8, no. 2, S.151-159 |
| Datensatznummer |
250005492
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| Publikation (Nr.) |
 copernicus.org/hess-8-151-2004.pdf |
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| Zusammenfassung |
| The Ria de Aveiro is an estuary–coastal lagoon system connected to the Atlantic
Ocean by a channel with a cross-sectional area that, for more than a century, has increased
steadily, partly because of dredging over the last 50 years. Local ocean tides, with amplitudes
of up to 3 m, are today transmitted to the lagoon by the single, engineered inlet channel and
propagate to the end of the lagoon channels as a damped progressive wave. The increase in tidal
amplitude with time has affected the lagoon ecosystem and the water has become more saline.
Seagrass beds are important indicators of ecosystem change; until 1980, much of the lagoon bed
was covered by seagrasses (Zostera, Ruppia, Potamogeton), which were collected in large
quantities for use in agriculture. After 1960, the harvesting declined and the seagrass beds
became covered in sediment, so that the area of seagrasses decreased substantially despite the
decline in the quantity collected. The change in the pattern of seagrass populations can be
related to changes in the physical forcing associated with increased tidal wave penetration.
This has, in turn, induced transport and redistribution of coarser, sandy sediment and
increased re-suspension and turbidity in the water column. However, the initiating cause for
this ecosystem change was dredging, which, since the 1950s, has been used increasingly to
widen and deepen the channels of the system. |
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