This is a simple system that can be deployed on rocky reefs to measure environmental variables such as sea temperature, light intensity, sedimentation rates and water flow during short periods of times (5 to 60 days). This station can be constructed with different materials, here we present the system used on rocky reefs from Patagonia Argentina. Variables measured:Water temperature and light intensity were registered by HOBO® Pendant® Temp/Light (MX2202) Loggers. The logger measures light intensity in units of lumens/ft2 or lux and has a range of 0 to 167,731 lux (15,582 lum/ft2). The temperature sensor accuracy is ± 0.5°C from -20° to 70°C with a resolution 0.04°C. See HOBO manual for more specifications. Light and temperature was recorded once every 10 min.PVC tube traps (open-ended containers) were used to collect and retain sediment that settles from the water column to acquire information of the sedimentation rates on different rocky reefs. The PVC tubes of 50 mm mouth diameter and 200 mm height had an aspect ratio > 3 as recommended by Hakanson et al. (1989) to avoid losing the trapped sediment because of water flux.Dissolution rates of alabaster blocks (plaster of Paris) was used to investigate differences in water motion. This low-cost method has been used in several studies for measuring water motion in subtidal habitats (e.g. Watson, 1976; Leichter and Witman, 1997; Irving and Connell, 2002; Connell, 2005). All measures were made simultaneously at all rocky reefs while one alabaster block was deployed inside a 20 L recipient to serve as control as recommended byJokiel and Morrissey (1993). PVC tube traps (open-ended containers) were used to collect and retain sediment that settles from the water column to acquire information of the sedimentation rates on different rocky reefs. The PVC tubes of 50 mm mouth diameter and 200 mm height had an aspect ratio > 3 as recommended by Hakanson et al. (1989) to avoid losing the trapped sediment because of water flux.Dissolution rates of alabaster blocks (plaster of Paris) was used to investigate differences in water motion. This low-cost method has been used in several studies for measuring water motion in subtidal habitats (e.g. Watson, 1976; Leichter and Witman, 1997; Irving and Connell, 2002; Connell, 2005). All measures were made simultaneously at all rocky reefs while one alabaster block was deployed inside a 20 L recipient to serve as control as recommended byJokiel and Morrissey (1993). References: Connell, S. D. (2005). Assembly and maintenance of subtidal habitat heterogeneity: Synergistic effects of light penetration and sedimentation. Marine Ecology Progress Series, 289, 53–61. https://doi.org/10.3354/meps289053 Hakanson, L., Floderus, S., & Wallin, M. (1989). Sediment trap assemblages a methodological description. In P. G. Sly & B. T. Hart (Eds.), Sediment/Water Interaction (pp. 481–490). Dordrecht, Netherlands: Springer. Irving, A., & Connell, S. (2002). Sedimentation and light penetration interact to maintain heterogeneity of subtidal habitats: algal versus invertebrate dominated assemblages. Marine Ecology Progress Series, 245, 83–91. https://doi.org/10.3354/meps245083 Jokiel, P., & Morrissey, J. (1993). Water motion on coral reefs: evaluation of the “clod card” technique. Marine Ecology Progress Series, 93(1–2), 175–181. https://doi.org/10.3354/meps093175 Leichter, J. J., & Witman, J. D. (1997). Water flow over subtidal rock walls: relation to distributions and growth rates of sessile suspension feeders in the Gulf of Maine Water flow and growth rates. Journal of Experimental Marine Biology and Ecology, 209(1–2), 293–307. https://doi.org/10.1016/S0022-0981(96)02702-5 Watson, A. L. (1976). Preliminary observations on the influence of water movement on population structure in Ancorina corticata (Carter) (Choristida: Demospongiae). Proceedings of the New Zeland Ecological Society, 21(1), 45–50.