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Green and golden seaweed tides on the rise


Sudden beaching of huge seaweed masses smother the coastline and form rotting piles on the shore. The number of reports of these events in previously unaffected areas has increased worldwide in recent years. These 'seaweed tides' can harm tourism-based economies, smother aquaculture operations or disrupt traditional artisanal fisheries. Coastal eutrophication is the obvious, ultimate explanation for the increase in seaweed biomass, but the proximate processes that are responsible for individual beaching events are complex and require dedicated study to develop effective mitigation strategies. Harvesting the macroalgae, a valuable raw material, before they beach could well be developed into an effective solution.

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Figure 1: Green and golden tides.


Figure 2: Ulva green tide development in a shallow coastal environment.
Figure 3: Distribution of drifting Sargassum rafts derived from MERIS satellite images across the central Atlantic Ocean.

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We thank C. Barroca, A. Huckbody, E. Fuller and M. Freling for sharing their photographs and experience, I. Valiela for comments on an earlier draft and P. Kullberg for updates.

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Correspondence to Victor Smetacek or Adriana Zingone.

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Smetacek, V., Zingone, A. Green and golden seaweed tides on the rise. Nature 504, 84–88 (2013).

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