Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Parameters
• Instruments
• Project Information
• Funding

This dataset contains initial experimental condition, and concentrations of dissolved inorganic carbon from experiments conducted at the University of Hawaii, Manoa in 2015.

Experiment CRANE (Coral Reef Acclimation to Nutrient Enrichment) identifies a monthlong mesocosm incubation study designed to understand the response of the coral reef community to long-term nutrient exposure.

Parameter
Method

tidal_height
Exact tides at the time of the experiment were retrieved from https://tidesandcurrents.noaa.gov/noaatidepredictions.html?id=1612340

lat
Experimental locations were randomly chosen across a known gradient of submarine groundwater discharge (SGD). The waypoints (latitude and longitude) were inputted in a Garmin GSP 78. 

long
Experimental locations were randomly chosen across a known gradient of submarine groundwater discharge (SGD). The waypoints (latitude and longitude) were inputted in a Garmin GSP 78. 

incubation_time
Time started when benthic chamber was sealed into position and ended when benthic chamber was taken off the benthos.

temp_avg_inside
A HOBO tidbit temperature logger was placed inside the benthic chamber for the duration of the experiment. Temperature readings were taken every 5 minutes. This time series was averaged, resulting in this value.

sal_avg_inside
An Odyssey temperature and conductivity 

ph_amb
A water sample was taken from inside the benthic chamber at the beginning of the experiment (before 13C-sodium carbonate addition). pH was measured using a Thermo Scientific Orion Star A329 portable meter with a pH electrode calibrated against a Tris buffer of known pH from Andrew Dickson’s laboratory at the Scripps Institution of Oceanography.

phosphate_pre
A water sample was collected at the beginning of the experiment from inside the benthic chamber. This water were filtered through a 0.2um filter (GF/F) in situ, and refrigerated for 3 weeks. The samples were brought to room temperature, mixed, and analyzed on a Seal Analytical Segmented Flow Injection AutoAnalyzer AA3HR for soluble reactive phosphate (PO43-).

silicate_pre
A water sample was collected at the beginning of the experiment from inside the benthic chamber. This water were filtered through a 0.2um filter (GF/F) in situ, and refrigerated for 3 weeks. The samples were brought to room temperature, mixed, and analyzed on a Seal Analytical Segmented Flow Injection AutoAnalyzer AA3HR for silicate (SiO).

No3_NO2_pre
A water sample was collected at the beginning of the experiment from inside the benthic chamber. This water were filtered through a 0.2um filter (GF/F) in situ, and refrigerated for 3 weeks. The samples were brought to room temperature, mixed, and analyzed on a Seal Analytical Segmented Flow Injection AutoAnalyzer AA3HR for nitrate + nitrite (N + N; NO2- + NO3-).

ammonia_pre
A water sample was collected at the beginning of the experiment from inside the benthic chamber. This water were filtered through a 0.2um filter (GF/F) in situ, and refrigerated for 3 weeks. The samples were brought to room temperature, mixed, and analyzed on a Seal Analytical Segmented Flow Injection AutoAnalyzer AA3HR for ammonium (NH4+).

PAR_avg_outside
An autonomous Odyssey Submersible Photosynthetic Active Radiation Logger was deployed within the benthic chamber. The scan rate was one per minute and the detected wavelength was cosine corrected photosynthetic irradiance (400_700nm).

adv_mean
A Nortek Vector 3D Acoustic Velocimeter was deployed outside the chamber, within 40cm of the benthos. It was set to sample continuously at a sampling rate of 8 Hz, with a nominal velocity range of 0.30 m/s.

DIC_amb
Right before (within 5 minutes) the 13C sodium bicarbonate spike, water samples for DIC analysis (250 ml) were collected from within the benthic chamber and stored in 300 mL borosilicate bottles. Samples were brought back to the lab and fixed with 200 _l HgCl2 per 250 ml seawater. Samples were analyzed for DIC using the UIC Coulometer and Marianda VINDTA 3D at the S-LAB at the University of Hawai‘i at M_noa.

DIC_2
Right after (within 2 minutes) the 13C sodium bicarbonate spike, water samples for DIC analysis (250 ml) were collected from within the benthic chamber and stored in 300 mL borosilicate bottles. Samples were brought back to the lab and fixed with 200 _l HgCl2 per 250 ml seawater. Samples were analyzed for DIC using the UIC Coulometer and Marianda VINDTA 3D at the S-LAB at the University of Hawai‘i at M_noa.

DIC_postexp
At the end of the 1 hour incubation, water samples for DIC analysis (250 ml) were collected from within the benthic chamber and stored in 300 mL borosilicate bottles. Samples were brought back to the lab and fixed with 200 _l HgCl2 per 250 ml seawater. Samples were analyzed for DIC using the UIC Coulometer and Marianda VINDTA 3D at the S-LAB at the University of Hawai‘i at M_noa.

del_13C_DIC_amb
Right before (within 5 minutes) the 13C sodium bicarbonate spike, water samples were collected from within the benthic chamber and stored in 30 mL borosilicate bottles. Samples were brought back to the lab and fixed with 200 _l HgCl2 per 250 ml seawater. Water samples were sent to the Biogeochemical Stable Isotope Facility at the University of Hawai‘i at M_noa for _13C analysis of dissolved inorganic carbon (Torres et al. 2005).

del_13C_DIC_2
Right after (within 2 minutes) the 13C sodium bicarbonate spike, water samples were collected from within the benthic chamber and stored in 30 mL borosilicate bottles. Samples were brought back to the lab and fixed with 200 _l HgCl2 per 250 ml seawater. Water samples were sent to the Biogeochemical Stable Isotope Facility at the University of Hawai‘i at M_noa for _13C analysis of dissolved inorganic carbon (Torres et al. 2005).

del_13C_DIC_postexp
At the end of the 1 hour incubation, water samples were collected from within the benthic chamber and stored in 30 mL borosilicate bottles. Samples were brought back to the lab and fixed with 200 _l HgCl2 per 250 ml seawater. Water samples were sent to the Biogeochemical Stable Isotope Facility at the University of Hawai‘i at M_noa for _13C analysis of dissolved inorganic carbon (Torres et al. 2005).

BCO-DMO Processing:
- modified parameter names to conform with BCO-DMO naming conventions
- converted date format from d-Mon-yy to yyyy-mm-dd
- reduced precision of ammonia_pre and PAR_avg_outside to 2 digits
- reduced precision of adv_mean to 6 digits
- reduced precision of DIC_amb, DIC_2 and DIC_postexp to 1 digit

NSF award abstract:
Coral reef degradation, whether driven by overfishing, nutrient pollution, declining water quality, or other anthropogenic factors, is associated with a phase shift towards a reefs dominated by fleshy algae. In many cases managing and ameliorating these stressors does not lead to a return to coral dominance, and reefs languish in an algal-dominated state for years. Nearly a decade of research has demonstrated that trajectories toward increasing algal dominance are restructuring microbial community composition and metabolism; the investigators hypothesize that microbial processes facilitate the maintenance of algal dominance by metabolizing organic compounds released by algae thereby stressing corals through hypoxia and disease. The resilience of reefs to these phase shifts is a critical question in coral reef ecology, and managing reefs undergoing these community shifts requires developing an understanding of the role of microbial interactions in facilitating algal overgrowth and altering reef ecosystem function. The research proposed here will investigate the organics produced by algae, the microbes that metabolize the organics, and the impacts of these processes on coral health and growth. This research has implications for managing reef resilience to algal phase shifts by testing the differential resistance of coral-associated microbial communities to algae and defining thresholds of algal species cover which alter ecosystem biogeochemistry. This project provides mentoring across multiple career levels, linking underrepresented undergraduates, two graduate students, a postdoctoral researcher, and a beginning and established investigators.

This project will integrate dissolved organic matter (DOM) geochemistry, microbial genomics and ecosystem process measurements at ecologically-relevant spatial and temporal scales to test hypothetical mechanisms by which microbially-mediated feedbacks may facilitate the spread of fleshy algae on Pacific reef ecosystems. A key product of this research will be understanding how the composition of corals and algae on reefs interact synergistically with complex microbial communities to influence reef ecosystem resilience to algal phase shifts. Emerging molecular and biogeochemical methods will be use to investigate mechanisms of microbial-DOM interactions at multiple spatial and temporal scales. This project will leverage the background environmental data, laboratory facilities and field logistical resources of the Mo'orea Coral Reef Long Term Ecological Research Project in French Polynesia and contribute to the mission of that program of investigating coral reef resilience in the face of global change. The investigators will quantify bulk diel patterns of DOM production and characterize the composition of chromophoric components and both free and acid-hydrolyzable neutral monosaccharides and amino acids from varying benthic algae sources. The team will also characterize planktonic and coral-associated microbial community changes in taxonomic composition and gene expression caused by algal DOM amendments in on-site controlled environmental chambers using phylogenetics and metatranscriptomics, including tracking algal exudate utilization by specific microbial lineages. Field-deployed 100 liter tent mesocosms will be used to examine in situ diel patterns of coupled DOM production and consumption, microbial community genomics and ecosystem metabolism over representative benthic communities comprising combinations of algal and coral species. Together these experimental results will guide interpretation of field surveys of centimeter-scale spatial dynamics of planktonic and coral-associated microbial genomics and metabolism at zones of coral-algal interaction, including boundary layer dynamics of oxygen, bacteria and DOM using planar optodes, high-throughput flow cytometry and fluorescence spectroscopy.