This is a file from the Wikimedia Commons and may be used by other projects. Information from its description page there is shown below. Commons is a freely licensed media file repository.
Summary
DescriptionMeasuring depth of Sargassum weed in rough water.JPG
English: Measuring depth of weed in rough conditions and poor visibility using a one metre scale and two metre diver.
to share – to copy, distribute and transmit the work
to remix – to adapt the work
Under the following conditions:
attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.