SBC LTER: Kelp Removal Experiment: Daily photon irradiance at the surface and seafloor

These data are total daily photon irradiance in mol quanta m-2 d-1 at the sea surface and reaching the sea floor at SBC LTER kelp removal experiment sites. Sensors record instantaneous irradiance at one minute intervals, and data are averaged hourly and integrated over a 24 hour period. Sensors are mounted on the sea floor at one kelp-control and two kelp-removal plots at four sites (Arroyo Quemado, Carpinteria, Naples Reef and Mohawk Reef). At Mohawk Reef and Arroyo Quemado, sensors are also mounted above the sea surface on a spar buoy. No surface sensor was deployed at Naples Reef, and at Carpinteria, a surface sensor was deployed only for the period January 2008 to April 2010. Data are collected with MkV/L Light Intensity Recorders manufactured by Alec Electronics Corporation. The kelp removal experiment was initiated in 2008 at selected reef sites along the mainland coast of the Santa Barbara Channel. The following three giant kelp manipulations are maintained in sampling plots at each site: Control: Macrocystis pyrifera is left intact in a 2000 m 2 plot. Annual removal: Macrocystis pyrifera is removed from an adjacent 2000 m 2 plot once each winter and allowed to re-colonize over the course of the year. Continuous removal: Macrocystis pyrifera is removed from a 200 m 2 area within the 2000 m 2 plot on each sampling date.