How green is my beach? Marine seaweed blooms increasing

2 January 2014

Blooms like this are increasing.

Blooms like this are increasing. Come on in, the water’s lovely! (If you can find it!)


Droplets readers will recall the problems that befell the Olympics in China when the offshore sailing course developed a substantial bloom of the macroalga Enteromorpha.  Problems like this started to occur around 2007 in Qingdao, China and have continued to this day.  Similar problems occur on US, European and African beaches.  A paper published in the December 5th edition of Nature indicates that mass beachings of algal mats, termed “green tides” may be on the increase, fuelled by increasing eutrophication (food for algae) and hydrodynamic processes offshore that bulk up the algal biomass.

As with the problems of algal blooms in freshwater lakes and reservoirs, mostly phytoplanktonic as opposed to the filamentous marine species such as Enteromorpha, the implementation of mitigation measures and management planning are bedevilled by the scale of the problem, an inability to predict when blooms will form and a lack of implementable ‘source of problem’ controls (the ‘having to live with eutrophication’ scenario that is becoming all too ‘in vogue’ these days (a symptomatic treatment akin to liposuction for people who cannot control their eating habits).  Such complexities have led the authors of the Nature article to conclude that harvesting and beneficiation of the algal biomass might be the best solution, at least for now.



Droplets viewpoint:  The problem of water pollution will (globally) become an insurmountable and unpleasant legacy of inaction, a legacy that started in the 1970s and which grows in parallel with population growth and development.  In South Africa the problem is accelerated by infrastructure decay and operational inadequacies of hundreds of wastewater treatment plants, most of which are sub-functional and almost none of which produce effluents that will not impair the waterbody they are so casually dumped into.  So, we find it odd that, while vociferous protests arise about paying for the use of world-class highways, there is a resounding silence on demands for good governance of our natural resources.  The cost of these will be far higher and far more crippling than toll fees.


Source: Green and golden seaweed tides on the rise. Smetacek V and A Zingone.  Nature 504:84-88

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