Effects of climate change and light limitation on Acropora millepora coral recruits (NESP 5.2, AIMS, JCU and AIMS@JCU)

This dataset consists of one spreadsheet, which shows the survival, number of polyps, size, Symbiodinium quantity and photosynthetic efficiency (Fv/Fm) of up to four-month-old Acropora millepora coral recruits while being exposed to three different climate scenarios resembling current climate conditions and conditions expected by mid and end of the century. Coral recruit resilience towards one-month-long light attenuation with five intensities was tested by exposing the recruits either one (experiment 1) or two months (experiment 2) following settlement. Additional tabs show temperature and pCO2 measured throughout the experiment. The experiment had 45 tanks made up from 15 climate (3) - light (5) combinations with 3-times replication. The temperature and pCO2 corresponding to the water going into the main lines feeding the 15 tanks in each climate combination were logged and are available in the dataset. The study was conducted at the National Sea Simulator.

The aim of this study was to 1) identify the survival of coral recruits under simultaneous exposure to climate stress (temperature and pCO2) and light attenuation and 2) identify survival mechanisms (i.e., number of polyps, Symbiodinium quantities, photosynthetic efficiency).

The climate scenarios (average of logged conditions) tested were:
- `Current`: temperature: 28.46 deg C, pCO2: 428 ppm
- `Medium`: temperature: 28.95 deg C, pCO2: 692 ppm
- `High`: temperature: 29.56 deg C, pCO2: 985 ppm

The following light levels were tested for each of the climate scenarios : Maximum day time PAR: 3, 15, 31, 62, 124 (umol photons m-2 s-1) and matching Daily Light Integral of 0.1, 0.5, 1, 2, 4 (mol photons m-2 d-1).

This data will inform the development of water-quality management guidelines, a key aim of NESP project 5.2. The full research report can be found at:

Brunner CA, Ricardo GF, Uthicke S, Negri AP, Hoogenboom MO. 2022. Effects of climate change and light limitation on coral recruits. Marine Ecology Progress Series

# Methods:

Coral recruits of Acropora millepora, a branching coral species abundant in shallow reefs on the Great Barrier Reef, were raised for 4 months in `current` and realistic `medium` and `high` climate scenarios (increased temperature and acidification), and were exposed to five environmentally relevant light attenuation levels typical of flood plumes and dredging operations. The one-month-long light attenuation events were simulated at different recruit ages: (1) one month following settlement, and (2) two months following settlement. After a four-week recovery phase, survival, polyp numbers, size, Symbiodinium quantities and the photosynthetic efficiency (Fv/Fm) were documented, and the data are presented here.

Specific details of the methodology may be found in:
Brunner CA, Ricardo GF, Uthicke S, Negri AP, Hoogenboom MO. 2022. Effects of climate change and light limitation on coral recruits. Marine Ecology Progress Series

# Limitations:

Note that the dataset only includes data for recruits that did not fuse with neighbouring recruits throughout the study. No data gathered where cells are empty. Mortality was observed even in the `Current` (control) climate treatment.

# Format:

Excel Spreadsheet with 3 tables (`Experiment`: 16 columns x 12332 rows, `Temperature`: 5 columns x 26600 rows, `pCO2`: 5 rows x 14544 rows).

# Data Dictionary:

- `experiment`: 1: one-month light attenuation one month after settlement, 2 one-month light attenuation two months after settlement
- `climate`: climate condition that each tank was subjected to: `Current`, `Medium` and `High` conditions.
- `age_month`: age in months following settlement climate = climate treatment based on manipulated temperature and pCO2, see "Temperatures" and "pCO2" tab for details
- `light_PAR`: light attenuation in photosynthetic active radiation (umol photons m-2 s-1) during the attenuation period. The PAR specified corresponds to the maximum light intensity during a day.
- `light_DLI`: light attenuation as Daily Light Integral (mol photons m-2 d-1) during the attenuation period. This corresponds to the total accumulated light received over the day. During the night light was 0. Between 6 am and 9 am light ramped up to the maximum value (light_PAR). It stayed at this level during the day and ramped down to zero from 3 pm to 6 pm.
- `tank_ID`: identification number of climate controllable aquarium
- `disc_ID`: identification number of discs where coral recruits settled on
- `recruit_ID_on_disc`: identification number of each recruit on each disc
- `polyps_alive`: number of alive polyps of each recruit, a dead recruit has 0 alive polyps. Polyps were counted so that we can could standardise the counts of Symbiodinium to Symbiodinium / polyp
- `recruit_alive`: 1: coral recruit is alive, 0: coral recruit is dead
- `recruitarea_tota`: total recruit size in mm² including dead and alive areas
- `recruitarea_alive`: alive recruit area in mm²
- `recruitarea_bleached`: bleached recruit area in mm²
- `recruitarea_cca`: recruit area in mm² overgrown with crustaceous corallin algae (CCA)
- `symbionts_per_polyp`: Symbiodinium cells per alive polyp
- `FvFm`: dark adapted photosynthetic efficiency

# References:

Brunner CA, Ricardo GF, Uthicke S, Negri AP, Hoogenboom MO. 2022. Effects of climate change and light limitation on coral recruits. Marine Ecology Progress Series

Data Location:

This dataset is filed in the eAtlas enduring data repository at: data\custodian\2019-2022-NESP-TWQ-5\5.2_Cumulative-impacts\data\2022-03-23-recruit-climate-light