Metabolic responses of Plectus murrayi across a temperature gradient, McMurdo Dry Valleys, Antarctica, 2016-2017

Summary

Abstract: 

Populations of Plectus murrayi, a mesophilic nematode, have been increasing in the McMurdo Dry Valleys, Antarctica over the past three decades. In contrast, most other Antarctic nematode species, including Scottnema lindsayae, have experienced constant population declines over the same time period due to climate change related increases in summer temperatures and wetting occurrences. To determine why P. murrayi populations are outperforming other Antarctic nematode species, we performed a laboratory experiment to measure their metabolic responses to increasing temperatures. For this experiment, P. murrayi were cultured from soils collected in Taylor Valley during the austral summers of 2016 and 2017 as part of the McMurdo Dry Valleys Long Term Ecological Research (LTER) Project. Using a TAM IV Isothermal Microcalorimeter, we measured the metabolic heat rates of these cultured P. murrayi populations in six sealed 4 mL vials. Three of these vials also contained 200 µl ampoules of 0.4 M NaOH. NaOH reacts with CO2 produced from metabolic processes to release a known amount of heat (108.5 kJ/mol CO2). The difference in metabolic heat rate produced in vials containing NaOH and those without NaOH is proportional to CO2 produced from P. murrayi metabolism. Consequently, this method allowed us to track metabolic heat rates as well as CO2 production rates. O2 consumption was calculated from vials without NaOH using Thornton's rule (455 kJ of metabolic heat/mol O2). P. murrayi metabolic heat rates were compared to C. elegans for reference, and baseline measurements included heat rates of E. coli and blank agar.

Date Range: 

December 20, 2016 to November 25, 2017
Data Citation
Robinson, C.M., Hansen, L.D., Xue, X., Adams, B.J. 2021. Metabolic responses of Plectus murrayi across a temperature gradient, McMurdo Dry Valleys, Antarctica, 2016-2017. Environmental Data Initiative. DOI: 10.6073/pasta/4973e62f9a46674024e41c4f0a3769e9. Dataset accessed 18 May 2022.
Dataset(s)

Description: 

P. murrayi metabolism experiment - sample info

Variables (click to expand): 

DATASET_CODE
  • Label: Dataset code
  • Definition: Internal dataset code.
  • Type: Nominal
  • Missing values: None specified
SAMPLE_ID
  • Label: Sample ID
  • Definition: Sample identifiers, which incorporate species (PM = Plectus murrayi, CE = Caenorhabditis elegans, EC = Escherichia coli, BA = blank agar), sample replicate (1-5), and whether NaOH, NaCl, or H2O were held in a separate ampoule in the presence of the sample throughout the experiment.
  • Type: Nominal
  • Missing values: None specified
REPLICATE
  • Label: Replicate number
  • Definition: Sample replicate number associated with the sample ID. Blank cells = no replicates were associated with that sample ID.
  • Type: Nominal
  • Missing values: None specified
SPECIES
  • Label: Species name
  • Definition: Species name associated with the sample ID.
  • Type: Nominal
  • Missing values: None specified
AMPOULE_CONTENTS
  • Label: Inserted ampoule contents
  • Definition: For each sample ID, indicates media that was added to a separate ampoule (NaOH, NaCl, or H2O) that was held in the presence of the sample throughout the experiment. NaOH = 200 microLiters of .4 Molar NaOH. NaCl = 200 microLiters of .4 Molar NaCl. H2O = 200 microLiters sterile H2O Blank cells = NA.
  • Type: Nominal
  • Missing values: None specified
NEMATODE_COUNT
  • Label: Nematode count
  • Definition: Contains the numbers of nematodes that were present in each sample whether they were Plectus murrayi or Caenorhabditis elegans.
  • Type: Physical quantity
  • Unit: dimensionless
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified

Description: 

P. murrayi metabolism experiment - heat rates

Variables (click to expand): 

DATASET_CODE
  • Label: Dataset code
  • Definition: Internal dataset code.
  • Type: Nominal
  • Missing values: None specified
SAMPLE_ID
  • Label: Sample ID
  • Definition: Sample ID. Additional information about each sample can be found in another table in this data package.
  • Type: Nominal
  • Missing values: None specified
AGGREGATION
  • Label: Aggregation factor
  • Definition: Determines whether metabolic heat rate values were aggregated per sample or per nematode.
  • Type: Nominal
  • Missing values: None specified
TEMP_15C_1
  • Label:
  • Definition: Metabolic heat rate of the sample or nematode at 15 degrees C, averaged across four hours. Measurement #1 in the sequence of measurements.
  • Type: Physical quantity
  • Unit: microWatts
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified
TEMP_10C_2
  • Label:
  • Definition: Metabolic heat rate of the sample or nematode at 10 degrees C, averaged across four hours. Measurement #2 in the sequence of measurements.
  • Type: Physical quantity
  • Unit: microWatts
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified
TEMP_5C_3
  • Label:
  • Definition: Metabolic heat rate of the sample or nematode at 5 degrees C, averaged across four hours. Measurement #3 in the sequence of measurements.
  • Type: Physical quantity
  • Unit: microWatts
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified
TEMP_15C_4
  • Label:
  • Definition: Metabolic heat rate of the sample or nematode at 15 degrees C, averaged across four hours. Measurement #4 in the sequence of measurements.
  • Type: Physical quantity
  • Unit: microWatts
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified
TEMP_20C_5
  • Label:
  • Definition: Metabolic heat rate of the sample or nematode at 20 degrees C, averaged across four hours. Measurement #5 in the sequence of measurements.
  • Type: Physical quantity
  • Unit: microWatts
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified
TEMP_25C_6
  • Label:
  • Definition: Metabolic heat rate of the sample or nematode at 25 degrees C, averaged across four hours. Measurement #6 in the sequence of measurements.
  • Type: Physical quantity
  • Unit: microWatts
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified
TEMP_30C_7
  • Label:
  • Definition: Metabolic heat rate of the sample or nematode at 30 degrees C, averaged across four hours. Measurement #7 in the sequence of measurements.
  • Type: Physical quantity
  • Unit: microWatts
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified
TEMP_35C_8
  • Label:
  • Definition: Metabolic heat rate of the sample or nematode at 35 degrees C, averaged across four hours. Measurement #8 in the sequence of measurements.
  • Type: Physical quantity
  • Unit: microWatts
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified
TEMP_40C_9
  • Label:
  • Definition: Metabolic heat rate of the sample or nematode at 40 degrees C, averaged across four hours. Measurement #9 in the sequence of measurements.
  • Type: Physical quantity
  • Unit: microWatts
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified
TEMP_45C_10
  • Label:
  • Definition: Metabolic heat rate of the sample or nematode at 45 degrees C, averaged across four hours. Measurement #10 in the sequence of measurements.
  • Type: Physical quantity
  • Unit: microWatts
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified
TEMP_50C_11
  • Label:
  • Definition: Metabolic heat rate of the sample or nematode at 50 degrees C, averaged across four hours. Measurement #11 in the sequence of measurements.
  • Type: Physical quantity
  • Unit: microWatts
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified
TEMP_15C_12
  • Label:
  • Definition: Metabolic heat rate of the sample or nematode at 15 degrees C, averaged across four hours. Measurement #12 in the sequence of measurements.
  • Type: Physical quantity
  • Unit: microWatts
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified

Description: 

P. murrayi metabolism experiment - metabolic rates

Variables (click to expand): 

DATASET_CODE
  • Label:
  • Definition: Internal dataset code.
  • Type: Nominal
  • Missing values: None specified
TEMPERATURE
  • Label:
  • Definition: Temperatures and measurement sequence that samples were held at for 4 hours in the order listed. E.g., 15C_1 indicates the sample was held at 15 degrees C and was first in the measurement sequence.
  • Type: Physical quantity
  • Unit: celsius
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified
PM_WITH_NAOH
  • Label: P. murrayi with NaOH
  • Definition: Average metabolic heat rate per Plectus murrayi individual in the presence of NaOH at each experimental temperature. This was calculated by averaging the average metabolic heat rate per nematode for samples PM1_NaOH, PM3_NaOH, and PM5_NaOH at each experimental temperature.
  • Type: Physical quantity
  • Unit: microWatts
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified
PM_WOUT_NAOH
  • Label: P. murrayi without NaOH
  • Definition: Average metabolic heat rate per Plectus murrayi individual in the absence of NaOH at each experimental temperature. This was calculated by averaging the average metabolic heat rate per nematode for samples PM2_NaCl, PM4_NaCl, and PM6_H2O at each experimental temperature.
  • Type: Physical quantity
  • Unit: microWatts
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified
CO2_PROD_RATE
  • Label: Co2 production rate
  • Definition: The rate of CO2 production by the average Plectus murrayi individual at each of the experimental temperatures.
  • Type: Physical quantity
  • Unit: picoMolesCO2perSecond
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified
O2_CONS_RATE
  • Label: O2 consumption rate
  • Definition: The rate of O2 consumption by the average Plectus murrayi individual at each of the experimental temperatures.
  • Type: Physical quantity
  • Unit: picoMolesO2perSecond
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified
RESP_QUOTIENT
  • Label: Respiratory quotient
  • Definition: The rate of CO2 production divided by the rate of O2 consumption yields the respiratory quotient.
  • Type: Physical quantity
  • Unit: dimensionless
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values: None specified

Short name: 

PMMET

Dataset ID: 

265
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