Seawater chemistry and benthic metabolic rates as a function of coral cover from a mesocosm experiment conducted at the Hawaii Institute of Marine Biology in June 2016

Data Type: Other Field Results, experimental
Version: 1
Version Date: 2021-01-29

» CAREER: Biogeochemical Modification of Seawater CO2 Chemistry in Near-Shore Environments: Effect of Ocean Acidification (Nearshore CO2)
Andersson, AndreasUniversity of California-San Diego (UCSD-SIO)Principal Investigator
Page, HeatherUniversity of California-San Diego (UCSD-SIO)Student, Contact
Rauch, ShannonWoods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager

Seawater chemistry and benthic metabolic rates as a function of coral cover from a mesocosm experiment conducted at the Hawaii Institute of Marine Biology in June 2016.


Spatial Extent: Lat:21.433019 Lon:-157.786461
Temporal Extent: 2016-06-14 - 2016-06-17

Acquisition Description

General study design:
Coral communities with different benthic cover (0, 40, 80%) were created in flow-through mesocosms exposed to natural environmental variations. The experiment was designed to examine how benthic metabolism influence diurnal seawater carbonate chemistry and how this scales with varying coral cover. The experiment was conducted at the Coral Reef Ecology Laboratory at the Hawaii Institute of Marine Biology in Kaneohe, HI, USA.

Methods description:
Coral communities with planar surface area coverage ranging 0, 20, 40, 60, 80 and 100 percent were created within flow-through mesocosms. Diurnal seawater chemistry was measured for communities during June 2016 by taking hourly water measurements (T, S, DO_sat, DO_conc, and pH) and collecting water samples for dissolved inorganic carbon (DIC) and total alkalinity (TA) every 3 hours over 24-hour time periods. Seawater chemistry data were used to calculate diurnal net community production (NCP) and net community calcification (NCC) rates using modified standard equations (Langdon et al. 2010).

Analytical Methods:
Seawater samples were collected by hand using 250 ml Pyrex glass bottles and fixed with 100 µL HgCl2 as per standard protocols (Dickson et al. 2007). Handheld YSI multi-meter instrument was used to measure temperature, salinity, dissolved oxygen, and pH at the time of sampling. All seawater samples were transported to the Scripps Coastal and Open Ocean Biogeochemistry lab and analyzed for TA via an open-cell potentiometric acid titration system developed at Scripps Institution of Oceanography (SIO) by A. Dickson (Dickson et al. 2007) and DIC via an automated infra-red inorganic carbon analyzer (AIRICA, Marianda Inc).

Quality Control:
Standard protocols were followed for sampling and analysis of seawater TA and DIC (Dickson et al. 2007). YSI multi-meter instrument was calibrated prior to each sampling period with accuracies of 0.2 °C for temperature, 1% for salinity, ±2% for dissolved oxygen saturation, 0.2 mg/L for dissolved oxygen concentration, and 0.2 for pH. The accuracy and precision of TA (0.33 ± 2.21 μmol/kg) and DIC (-1.31 ± 2.98 μmol/kg) measurements were evaluated using certified reference materials (CRM) provided by the laboratory of A. Dickson at SIO and analyzed every 5 samples for DIC and ~15-20 samples for TA.

For additional information please see Page et al. (2017).

Known Problems:
Rows for Mesocosm_IDs of "Header 1"," 9", and "10" on Date 14-06-16 and Time 00:00 (lines 56, 60, 62 in original Excel file): TA did not pass QAQC and therefore were omitted. Consequently, NCC and NCP could not be calculated for these data.

Processing Description

Data Processing:
Carbonate chemistry (pH_calc, pCO2_calc, and omega_calc) was constrained using CO2SYS software (Lewis and Wallace 1998). Data were processed and statistically compared using R Software (v 3.2.0).

BCO-DMO Processing:
- added UTC date/time field in ISO8601 format.

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Related Publications

Page, H. N., Courtney, T. A., Collins, A., De Carlo, E. H., & Andersson, A. J. (2017). Net Community Metabolism and Seawater Carbonate Chemistry Scale Non-intuitively with Coral Cover. Frontiers in Marine Science, 4. doi:10.3389/fmars.2017.00161

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DateDate of measurements (local time; HST); format: DD-MM-YY unitless
TimeTime of measurements (local time; HST); format: hh:mm unitless
ISO_DateTime_UTCDate and time of measurements (UTC) in ISO8601 format: YYYY-MM-DDThh:mmZ unitless
MesocosmIDMesocosm identification unitless
TreatmentEach mesocosm acted as inflow or contained a coral community. 0=0% coral cover; 20 = 20% coral cover; 40 = 40% coral cover, 60 = 60% coral cover, 80 = 80% coral cover, and 100 = 100% coral cover. unitless
TempTemperature degrees Celsius
SalinitySalinity unitless
DO_satdissolved oxygen percent saturation unitless (percent)
DO_concdissolved oxygen concentration milligrams per liter (mg/L)
pH_ysipH unitless
DICdissolved inorganic carbon micromoles per kilogram (umol/Kg)
TAtotal alkalinity micromoles per kilogram (umol/Kg)
pH_calcpH (total scale) calculated from in situ temperature, salinity, TA, and DIC unitless
pCO2_calcpCO2 calculated from in situ temperature, salinity, TA, and DIC microatmospheres (uatm)
omega_calcSeawater saturation state with respect to aragonite calculated from in situ temperature, salinity, TA, and DIC unitless
NCCNet community calcification rate millimoles per square meter per hour (mmol/m^2/h)
NCPNet community primary production rate millimoles per square meter per hour (mmol/m^2/h)

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Dataset-specific Instrument Name
YSI Professional Plus (Pro Plus) Handheld Multiparameter
Generic Instrument Name
Water Quality Multiprobe
Dataset-specific Description
YSI Handheld Multiparameter Instruments were used to monitor in situ temperature (accuracy ± 0.2°C), salinity (accuracy ± 1%), DO_mg (accuracy ± 0.2 mg/L), and DO_% (accuracy ± 2%), and pH (accuracy ± 0.2).
Generic Instrument Description
An instrument which measures multiple water quality parameters based on the sensor configuration.

Dataset-specific Instrument Name
Open-cell potentiometric acid titration system
Generic Instrument Name
Automatic titrator
Dataset-specific Description
The open-cell potentiometric acid titration system was developed by the laboratory of A.G. Dickson. Briefly, a known amount of seawater is added to an open cell beaker where hydrochloric acid as acidified to a pH of 3.5-4.0 and allowed to stabilize to remove CO2 gas formed by the addition of acid. Small aliquots of hydrochloric acid are then added to pH of ~ 3.0. The titration is monitored by a glass electrode and the total alkalinity of the sample is calculated using a non-linear least-squares method following Dickson et al. (2007).
Generic Instrument Description
Instruments that incrementally add quantified aliquots of a reagent to a sample until the end-point of a chemical reaction is reached.

Dataset-specific Instrument Name
AIRICA (Marianda Inc.)
Generic Instrument Name
Inorganic Carbon Analyzer
Dataset-specific Description
The Automated Infra Red Inorganic Carbon Analyzer (AIRICA) utilizes infrared detection of CO2 gas purged from an acidified seawater sample. A high-precision syringe pump extracts the seawater sample, acidifies the sample with phosphoric acid, and analyzes the gas released with an infrared light analyzer (LICOR). The CO2 signal is integrated for each sample to quantify the total inorganic carbon for a given aliquot of seawater analyzed. Three aliquots and peak integrations are performed for each seawater sample and averaged to determine the dissolved inorganic carbon for each sample. Please see for a complete instrument description.
Generic Instrument Description
Instruments measuring carbonate in sediments and inorganic carbon (including DIC) in the water column.

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Project Information

CAREER: Biogeochemical Modification of Seawater CO2 Chemistry in Near-Shore Environments: Effect of Ocean Acidification (Nearshore CO2)

Coverage: San Diego, California; Bermuda; Oahu, Hawaii

NSF Award Abstract:
Because of well-known chemical principles, changes in the CO2 chemistry of seawater in the open ocean as a result of rising atmospheric CO2 can be predicted very accurately. On the other hand, in near-shore environments, these projections are much more difficult because the CO2 chemistry is largely modified by biogeochemical processes operating on timescales of hours to months. To make predictions on how near-shore seawater CO2 chemistry will change in response to ocean acidification (OA), it is critical to consider the relative influence of net ecosystem production (NEP) and net ecosystem calcification (NEC), and how these processes might change in response to this major perturbation. Understanding how future OA will alter near-shore seawater CO2 chemistry and variability was identified as a major critical knowledge gap at the recent IPCC WG II/WG I workshop on impacts of ocean acidification on marine biology and ecosystems in January of 2011, and also at the International Ocean Acidification Network workshop in Seattle in June of 2012.

With funding from this CAREER award, a researcher at the Scripps Institute of Oceanography and his students will study how biogeochemical processes and the relative contributions from NEP and NEC modify seawater CO2 chemistry in near-shore environments influenced by different benthic communities under well-characterized environmental and physical conditions, and how these processes might change in response to OA. The team will investigate a limited number of contrasting habitats in subtropical (reef crest, back/patch reef, lagoon, seagrass bed, algal mat) and temperate (kelp bed, inter- and sub-tidal, marsh) environments during summer and winter, employing a method that evaluates the function and performance of the carbon cycle of a system using a stoichiometric vector approach based on changes in total dissolved inorganic carbon (DIC) and total alkalinity (TA). These field studies will be complemented by controlled mesocosm experiments with contrasting and mixed benthic communities under different OA scenarios.

The project has two educational components: (1) developing a research-driven OA and biogeochemistry course based on inquiry-, experience-, and collaborative-based learning; and (2) working with the Ocean Discovery Institute (ODI) to engage individuals from a local underrepresented minority community in science through educational activities focused on OA, and also providing a moderate number of internships for high school and college students to engage in this research project.

Broader Impacts: This project will directly support one PhD student, one junior research technician, and two high school and college interns from underrepresented minorities (URM) each summer of the project. It will contribute to the education of 80 undergraduate and graduate students participating in the research based ocean acidification/biogeochemistry course offered four times throughout the duration of the project at SIO/UCSD. Education and curricular material on the topics of OA, including hands-on laboratories, classroom and field-based activities will be developed through the collaboration with the ODI and brought to hundreds of URM students and their teachers in the City Heights area, a community with the highest poverty and ethnic diversity in the San Diego region. This collaboration will enable URM students to directly engage in a rapidly evolving field of research that has high relevance at both the local and global scales. To ensure broad dissemination of this project and the topic of OA, the research team will work with the Google Ocean team to incorporate information and educational material in the Google Ocean Explorer.

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Funding SourceAward
NSF Division of Ocean Sciences (NSF OCE)

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