Investigating the effects of thermal variability and heatwaves on pond zooplankton communities and physiological traits

To understand the impacts of climate change, we must understand the consequences of multiple and interacting timescales of temperature change. While much is known about rising mean temperatures, less is understood about the influence of projected thermal variability and extreme events like heatwaves on biological communities. This study investigates the interaction of short-term (experimental) and long-term (historic) thermal variability with heatwaves on zooplankton communities and physiological traits.
We performed a fully factorial mesocosm experiment with three factors: (1) historic thermal variation (four source ponds with similar average temperature but different daily thermal ranges including 3.7°C, 5.9°C, 9.1°C, and 10.7°C); (2) experimental thermal variation (insulated and non-insulated tanks); and (3) a 4-day heatwave treatment (+3.5°C) halfway through the experiment. We sampled the zooplankton community throughout the experiment and assayed the upper thermal limit (CTmax) and...,

Initial Setup
We carried out this outdoor mesocosm experiment at the Sierra Nevada Aquatic Research Laboratory near Mammoth Lakes, California from 16 July to 14 September 2021. The experiment lasted 61 days with sampling performed weekly and increased to every 4 days from the beginning of the heatwave to 2 weeks after the heatwave. We used 208 L cattle tanks with a randomised array with the following factors: source site (historic thermal history; four ponds), experimental DTR (low and high), and heatwave (heated and non-heated). We used a fully factorial design (16 treatments) with 4 replicates for each treatment for a total of 64 tanks. We covered all tanks with 60% shade cloth, filled them with water from nearby Convict Creek, and added water weekly to counter evaporation. Stream water was not filtered as no zooplankton have been detected in the filtrate of other mesocosm experiments at the same site (Symons et al. 2021). To establish the four different source site communities, w..., , # Investigating the Effects of Thermal Variability and Heatwaves on Pond Zooplankton Communities and Physiological Traits\" Freshwater Biology.

### File: Heatwaves and Thermal Variability Code.R

R script using the below data files to replicate analysis presented in Bonadonna et al. (2024)

### File: \"Temp Variability Meso Data.csv\"

Fields:

* Tank: factor denoting the unique identifier for experimental mesocosms
* Date: date of sampling point in format Date-Month-Year
* SampleTime: factor denoting the sampling time point (T1-T11)
* Site: factor denoting which pond starting zooplankton community came from
* Treatment: factor denoting whether tank was in heated (heat) or nonheated (nonheat) treatment; and low experimental thermal variability (ins) or high experimental thermal variability (nonins) treatment
* Heated: factor denoting whether tank was in heated (heated) or nonheated (nonheated) treatment
* Insulated: factor denoting whether tank was in low experimental thermal variability ...,