Food limitation erodes the thermal tolerance of larvae in an ecologically influential marine herbivore
Data files
Nov 19, 2025 version files 795.85 KB
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dpf_stage_temp_food.csv
662 B
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larvae_measurements_scaled.csv
351.54 KB
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README.md
4.87 KB
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roller_density_counts.csv
438.78 KB
Abstract
Biologists often use organismal thermal tolerance to help explain or forecast responses of populations to climate change. Yet many studies quantify thermal tolerance under isolated laboratory conditions despite extreme events, such as heatwaves, often coinciding with other stressors such as nutrient or food limitation. These oversights may be consequential as recent theory suggests thermal tolerance itself can be fundamentally altered by food limitation. Here, we experimentally test how food limitation affects long-term survival, development, and growth across a present-day range of temperatures in the most sensitive life stages of a key marine herbivore, purple sea urchins (Strongylocentrotus purpuratus). We show food limitation substantially erodes thermal tolerance in terms of survival, but when provided ample food, larvae exhibited robust survival across temperatures currently experienced by larvae in nature. Reductions in food however lowered optimal survival temperatures and shifted thresholds of collapse to those conditions observed during recent marine heatwaves. These results are consistent with the “metabolic meltdown” hypothesis - shifting optima and upper limits to cooler temperatures- and illustrate how present day warming with lower productivity may lead to substantial, unexpected declines in larval recruitment. In contrast to survival, developmental rates and time to metamorphic competency were driven largely by temperature with little impact of food concentration. Our findings relate to historical observations of collapses in larval supply at the southern edge of the species range. Overall, these results have broad-reaching implications beyond these sea urchins known to control productivity of kelp forests. We provide a core example of how laboratory derived thermal reaction norms can under-estimate effects of climate change and may explain unexpected vital rate declines of sensitive life-stages in nature.
Dataset DOI: 10.5061/dryad.j9kd51cp2
Description of the data and file structure
We experimentally test how food limitation (500-10,000 cells mL-1) affects long-term survival, development, and growth across a present-day range of temperatures (10-20ºC) in the larval stages of a key marine herbivore, purple sea urchins (Strongylocentrotus purpuratus).
Files and variables
File: dpf_stage_temp_food.csv
Description: Number of days to reach each stage of larval development and metamorphic competency across food and temperature treatments
Variables
- temp: temperature treatment in ºC
- food: microalgal food treatment in cells mL-1
- days_settled: number of days to reach metamorphic competency
- days_prism: number of days to reach prism stage
- days_fourarm: number of days to reach four arm stage
- days_sixarm: number of days to reach six arm stage
- days_eightarm: number of days to reach eight arm stage
- n/a: no data available
- dead: larval culture died before reaching settlement
File: larvae_measurements_scaled.csv
Description: Measurements for body length, stomach area, and postoral arm length across temperature treatments, food treatments, bottle replicates, and 4-, 9- and 15-day timepoints
Variables
- dpf: days post fertilization
- temp: experimental temperature treatment in ºC
- food: experimental microalgal food treatment in cells mL-1
- rep: bottle replicate
- individual: within each bottle replicate, 20 individuals were measured. 'individual' refers to the 1-20 individuals measured
- POA1: measurement of the first postoral arm in µm
- POA2: measurement of the second postoral arm in µm
- BL: measurement of body length in µm
- SW: measurement of stomach width in µm
- SH: measurement of stomach height in µm
- POA: averaged length of the first and second postoral arm measurements in µm
- SA: calculated stomach area using area of a circle with stomach width and length measurements
File: roller_density_counts.csv
Description: Raw counts from the subsets of larval samples taken every other day throughout the experiment.
Variables
- date: calendar day the sample was taken
- temp: experimental temperature treatment in ºC
- food: experimental microalgal food treatment in cells mL-1
- rep: bottle replicate
- count: indicate which count within each replicate 1 through 5
- count_value: number of larval individuals counted in each of the 5 1mL subsamples
- avg_count: average count across the five subsamples
- volume: total volume in which the 5 subsamples were taken from
- avg_bottle: average number of algae scaled from the 5 1mL subsample counts and total volume
- date1: indicator of each day the larvae were sampled
- dpf: days post fertilization
File: TableS1survmort**perbottle_**modeloutput.csv
Description: Estimated survival from model outputs across temperature treatments, food treatments, bottle replicates, and density count days.
Variables
- bottle_id: bottle replicate
- treatment: unique number provided for each distinct treatment combination
- date1: indicator of each day the larvae were sampled
- temp: experimental temperature treatment in ºC
- food: experimental microalgal food treatment in cells mL-1
- dpf: days post fertilization
- obs: binary value to indicate if an observation was made (1) or not made (0)
- est: means for instantaneous mortality
- est_surv: estimates for cumulative survival
File: TableS2_survival15daypairwise.csv
Description: Pariwise comarpisons between all treatment combinations at the 15 day timepoint. Values below 0.05 are considered significantly different survival values between the two paired treatments.
Variables
- variable format: first number_second number
- first number: experimental temperature treatment in ºC
- second number: experimental microalgal food treatment in cells mL-1
File: TableS3_morphometricpairwise.xlsx
Description: Pairwise comparisons of each larval morphometric body measurements (body length, stomach area, and postoral arm length) at each of the timepoints, represented in each tab of the data file.
Variables
- variable format: first number_second number
- first number: experimental temperature treatment in ºC
- second number: experimental microalgal food treatment in cells mL-1
- BL: measurement of body length in µm
- POA: averaged length of the first and second postoral arm measurements in µm
- SA: calculated stomach area using area of a circle with stomach width and length measurements
Code/software
R version 4.4.0 (2024-04-24)
Access information
Other publicly accessible location of the data: DOI: 10.26008/1912/bco-dmo.963415.1