Methodology:
High-intertidal pools are common in all three regions, allowing us to work at two spatially separated sites in each region. At each site, we identified 18 tide pools, marking each pool and quantifying physical attributes, including surface area, volume, and height on the shore. We also anchored TidbiT temperature datalogger (Onset; Bourne, Massachusetts, USA) in most pools. In the fall of 2017, we identified tide pools and conducted initial surveys and measurements. We repeated surveys every three months until immediately prior to the establishment of grazing experiments at each site in the summer of 2018. These surveys provided insights into the natural temporal variability in community and ecosystem metrics and provided baseline information on relationships between grazer abundances and producer biomass.

Sampling and analytical procedures:
During the quarterly surveys, we quantified consumer abundances, nutrient fluxes, oxygen fluxes, and photosynthetic biomass in each tide pool. Organism abundances were measured by pumping the water from each pool into a bucket, spreading a flexible mesh quadrat over the bottom of the pool, and censusing the algae and invertebrates present in each pool. Nutrient and oxygen fluxes were measured during whole-pool incubations in the dark and in the light.

Seasonal survey data:
Surveys include information on pool attributes by date as well as ecological survey data for each seasonal survey. Abundances of algae and mobile invertebrates were measured by delineating the perimeter of each pool with a transect tape then pumping the water from each pool into a bucket. A flexible mesh quadrat (Bracken and Nielsen 2004) was spread over the bottom of each pool. The mesh was composed of 10 centimeter x 10 centimeter squares, and total square counts (also used to estimate pool percent cover) and squares per species (to the nearest ¼ square) were used to estimate cover of seaweeds and sessile invertebrates. All mobile invertebrates in each pool were counted and identified to the lowest possible taxonomic unit, usually species. Values for other pool attributes (e.g., volume, depth, perimeter) were often measured during seasonal surveys, and those were recorded in the Survey dataset as well as in Pool Characteristics (see related dataset "Tide Pool Characteristics").

This work was conducted at sites located in three regions along the California (USA) coast: (1) Bodega Head, Sonoma County (38.31°N, 123.07°W); (2) Kenneth Norris Rancho Marino Reserve and Hazards Canyon Reef, San Luis Obispo County (35.54°N, 121.09°W and 35.29°N, 128.88°W, respectively); and (3) Corona del Mar State Beach, Orange County (33.59°N, 117.87°W).

Known Problems/Issues:
Some environmentally-related (e.g., tides, darkness) issues caused gaps in the data. These are indicated by "nd".

seasonal_surveys.csv