Bruno John

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Bruno
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John
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  • Dataset
    Experiment testing the temperature dependence of urchin grazing at the Galapagos Science Center on San Cristobal Island from February to March 2018
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2019-08-20) Bruno, John
    This study was conducted from February to March 2018 at the Galapagos Science Center on San Cristobal Island. The rate of Ulva sp. consumption by the two sea urchins, Lytechinus semituberculatus and Eucidaris galapagensis was measured at 10 temperatures: 14°, 16°, 18°, 20°, 22°, 24°, 26°, 28°, 30°, 32°C. L. semituberculatus (green urchin), E. galapaguensis (pencil urchin) and T. depressus (white urchin) are the three most common species in the Galapagos Islands and together make up 91% of the sea urchin biomass. Ulva sp. was used as the prey item because it is one of the most abundant macroalgal species, together with turf, encrusting coralline algae and Sargassum near the Galapagos and coast and because it is highly palatable for herbivores. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/775500
  • Dataset
    Ocean temperature from Onset loggers at 7 sites in the Galápagos archipelago collected from March 2018 to August 2020
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2021-09-07) Bruno, John
    Ocean temperature from Onset loggers at 7 sites in the Galápagos archipelago collected from March 2018 to August 2020. These data are published in Figure 3 of Romero et al., 2021 (doi: 10.1007/s00227-021-03836-9). For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/838851
  • Dataset
    Pencil urchin respiration rates at different temperatures from four sites in the Galápagos archipelago
    (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2021-09-07) Bruno, John
    The responses of ectothermic organisms to changes in temperature can be modified by acclimatization or adaptation to local thermal conditions. Thus, the effect of global warming and the deleterious effects of extreme highs (e.g., heatwaves) on the metabolism and fitness of ectotherms can be population-specific and reduced at warmer sites. We tested the hypothesis that grazer populations at warmer sites in the Galápagos are less thermally sensitive than populations at cooler sites (i.e., potentially due to acclimatization or adaptation). We quantified the acute thermal sensitivity of four populations of the pencil sea urchin, Eucidaris galapagensis, by measuring individual oxygen consumption across a range of temperatures. Thermal performance curves were estimated for each population and compared to the local ocean temperature regime. Results indicated that E. galapagensis populations were adapted and/or acclimatized to local thermal conditions as populations at warm sites had substantially higher thermal tolerance. The acute thermal optimums (Topt) for the warmest and coolest site populations differed by 3°C and the Topt was positively correlated with maximum temperature recorded at each site. Additionally, temperature-normalized respiration rates and activation energy were negatively related to the maximum temperature. Understanding the temperature-dependent performance of the pencil urchin (the most significant mesograzer in this system), including its population-specificity, provides insight into how herbivores and the functions they perform might be affected by further ocean heating. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/838816