Water flows through mussel rafts and their relationship with wind speed in a coastal embayment (R铆a de Ares-Betanzos, NW Spain)

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• 作者：S. Piedracoba ; X.A. 脕lvarez-Salgado ; U. Labarta ; M.J. Fern谩ndez-Reiriz ; B. G贸mez ; C. Balseiro
• 关键词：Subtidal currents ; Tidal currents ; Coastal winds ; Mussel rafts ; Rí ; a
• 刊名：Continental Shelf Research
• 出版年：1 March, 2014
• 年：2014
• 卷：75
• 期：Complete
• 页码：1-14
• 全文大小：3583 K

文摘

Knowledge of water flows through mussel rafts and their controlling factors is required for an ecosystem approach to the sustainable management of this culture in the Galician r铆as. With this aim, 4 acoustic 2D-ACM current meters were hung from the bow of 4 rafts located in the mussel cultivation areas of the R铆a de Ares-Betanzos (NW Spain) during autumn 2007. Simultaneously, an Aanderaa DCM12 Doppler profiler was moored in an area free of rafts in the middle r铆a. There were differences in the subtidal and tidal dynamics of the middle channel and mussel farm areas. The tide explained 51.5% of the total variance of the surface current in the middle r铆a. The explained variance in the seed collection areas of Redes (inner r铆a) and Miranda (outer r铆a), where only 2-3 rafts are anchored, were 64.1% and 16.8%, respectively. In the cultivation areas of Arnela (inner r铆a) and Lorb茅 (middle r铆a), where 101 and 40 rafts are anchored, 14.3% and 53.4% of the total variance was explained by the tide. These disparities in the contribution of the tide are likely due to a combination of topographic and bathymetric differences among sites and distortions of the natural flow by the rafts and their hanging ropes. Furthermore, there was a marked influence of winds on the subtidal currents within the rafts; contrasting correlation coefficients and lag times between wind speed and currents were observed for the outer and inner sides of the embayment. The filtration rate of the growing mussels and the number of mussels per raft allow an efficient clearing of the particles transported across the hanging ropes by the measured subtidal currents of 2-3 cm s^-1 characteristic of the cultivation areas of Arnela and Lorb茅.