For the first time it is demonstrated that with the QuikSCAT scatterometer it is possible to detect natural surface films resulting from enhanced biological activity in the ocean. It is shown for two regions in the Norwegian and Baltic Sea that areas of strongly reduced Normalized Radar Cross Section (NRCS) are associated with areas of enhanced chlorophyll-a concentration as evidenced by quasi-simultaneously acquired SeaWiFS data. This result has two implications. Firstly, it opens up the possibility to map globally natural surface film coverage using QuikSCAT data. Secondly, it demonstrates that in ocean areas with high biological activity the presence of natural surface films can give rise to significant errors in wind vector retrieval when using the current QuikSCAT wind retrieval algorithm.