Evaluation of effective shore level as a method of characterizing intertidal wave exposure regimes

Abstract

Wave splash modifies the duration and timing of aerial exposure of intertidal organisms, influencing patterns of vertical zonation, thermal stress, and the consequences of climate change. Harley and Helmuth (Limnol. Oceanogr. 48:1498-1508) described a method for measuring effective shore level (ESL), a metric that combines the influence of wave splash and tidal regime on patterns of emersion and immersion. They identified immersion events as sharp drops in temperature recorded by submersible dataloggers and compared the tide height at the time of the temperature drop to the wave height recorded by an offshore buoy. Here we explore the generality of this method at 10 sites along the Pacific coast of North America spanning 14°of latitude. We deployed miniature temperature loggers at fixed intertidal heights at each site and recorded temperatures at intervals of 5 to 15 min for periods of up to 5 years. We use these data to explore the effects of different approaches to calculating temperature drops and wave heights, as well as variation in the buoy location, on ESL calculations. We present a software program (SiteParser) that can be used to identify temperature drops in a datalogger time series and also calculate daily and monthly summary statistics of temperature. We show that ESL parameters provide a useful metric for comparing the effects of wave action on immersion patterns within sites. We also introduce a metric of average wave run-up that can be used to compare the effect of wave action on immersion patterns among more distant locations.

Heat Stress in the Intertidal: Comparing Survival and Growth of an Invasive and Native Mussel Under a Variety of Thermal Conditions

“…Although water temperatures tend to follow a latitudinal cline, the body temperatures of intertidal species when measured at low tide do not always follow a similar pattern. Thermal stress during low tide is determined by a complex interaction involving factors such as timing of low tide, terrestrial climate, and wave splash, all of which fluctuate along a coastline (Helmuth et al, 2002(Helmuth et al, , 2006Gilman et al, 2006). Thus, some northern sites with cool water temperatures may experience warmer low tide body temperatures than southern intertidal sites.…”

Physiologically grounded metrics of model skill: a case study estimating heat stress in intertidal populations

“…For each study site, observed tidal height data were obtained from the nearest National Oceanic and Atmospheric Administration (NOAA) Center for Operational Oceanographic Products and Services observing station ( ). The effect of wave splash was estimated using metrics of significant wave height and shore slope data presented by Gilman et al . (2006a) .…”

Upstream—Downstream Shifts in Peak Recruitment of the Native Olympia Oyster in San Francisco Bay During Wet and Dry Years

“…Loggers, like settlement tiles, were placed at 0 m MLLW. For each site, we processed logger data as daily mean values of air and water temperatures using the SiteParser program (Gilman et al 2006). We calculated daily mean salinity values for each site using data from nearby continuous water-quality monitoring stations that were maintained by the US Geological Survey (USGS 2015) and the SF Bay NERR (NERR 2015), and compared these daily means with measurements that were taken during biweekly or monthly site visits using a YSI-85 multimeter (YSI, Yellow Springs, Ohio; Online Resource 1).…”