Low tide reveals gobs of the alga Ulva hanging from a sampling station on the Skagit tidal flats north of Seattle. In 2009 a team of researchers led by WHOI physical oceanographers Britt Raubenheimer and Steve Elgar set out several stations across the flats to study water and sediment movements. Each station held instruments to measure conductivity (salinity), temperature, and flow speed of the water. As high tide rolled in, so did algae. It fouled the stations, interfering with the instruments and requiring the team to clean almost every station almost every day. "It was back-breaking work," said Raubenheimer.
(Photo by Steve Elgar, Woods Hole Oceanographic Institution)