Fig 1.
Barnacles in the intertidal zone experience a range in emergence time.
A) Abiotic conditions vary with the duration of low tide exposure at each shore height in the intertidal zone. B) Violin plot of daily time emerged (exposed to air) at the three different experimental shore heights representing the low, mid, and upper intertidal zones. The percent of time emerged is calculated at each tidal elevation as the percent of 15-minute timepoints per day in which the water level is greater than the elevation of the experimental plots over the course of a year.
Fig 2.
Flow diagram of the intertidal Numerical Scope for Growth model.
Intertidal animals alternate between submergence under water (A) and emergence in air (B), each with a distinct set of physiological conditions and processes. These can be captured in a Numerical Scope for Growth model (C), if timesteps are high enough resolution to capture the tidal fluctuations.
Table 1.
Summary of model parameters and their sources.
Fig 3.
Model inputs and predicted barnacle growth for 3 shore heights over interval 1 (Feb-Aug 2018).
A-C) Proportion of the day submerged and food availability (f) in the low, middle, and upper intertidal zone during the first interval. D-F) Mean daily temperature during aerial (solid purple line) and aquatic (solid blue line) conditions and daily 75% quantile of temperature (dotted red line). G-I) Daily physiological intake (dark green), aerial cost (purple), and aquatic cost (blue) of a barnacle of 2mm initial operculum length. The aerial cost includes both aerial exposure and aerial recovery costs. J-L) Daily and cumulative Scope for Growth of a representative barnacle of ~2mm.
Fig 4.
Model inputs and predicted barnacle growth for 3 shore heights over interval 2 (Aug 2018- Mar 2019).
See Fig 3 for details.
Fig 5.
Predicted growth from the NSFG model vs. mean observed growth.
The relationship between predicted growth and observed growth in mm at the three elevations (low – blue, mid – orange, upper – grey) in interval 1 (closed circles) and interval 2 (open circles, means ± SE).
Fig 6.
Estimated feeding activity as a function of the proportion of time submerged.
Estimated feeding activity in the upper (square), mid (circle), low (triangle) tidal elevations as a function of the proportion of time submerged over each 6-month interval (interval 1 – open symbols, interval 2 – closed symbols). Feeding activity at each elevation is calculated as an exponential function of the proportion of time submerged (S) over the full 6-month interval, y = Sz (z = 1.16 + 0.04, mean + SE, Table 1).
Fig 7.
Violin plots of weekly energy fluxes for each tidal elevation and interval.
The distribution of cumulative weekly intake (green), aquatic cost (blue) and aerial cost (purple) over interval 1 (A) and interval 2 (B). Aerial cost is the sum of exposure and recovery costs.
Fig 8.
Sensitivity analysis representing the influence of parameter uncertainty on cumulative barnacle SFG (J) over 6 months.
The sensitivities are for the SFG of a representative barnacle in the mid elevations in interval 1 (Feb – Aug), and the PopSE is the population uncertainty among the barnacles in the middle elevation. See Table 1 for parameter definitions.
Fig 9.
The influence of increased body temperatures during aerial and aquatic exposure on barnacle SFG. Change in cumulative barnacle SFG (J) in response to simulated aerial and aquatic warming over 6 months in the upper (A, B), mid (C, D), and low (E, F) elevations in interval 1 (Feb – Aug; A,C,E) and interval 2 (Aug – Feb; B,D,F) for a theoretical barnacle of 2.2 mm initial operculum length. The SFG for the observed environmental temperatures (Δ°C = 0; lower left quadrant of each 3X3 square) ranged from 40 to >100 J.