Biogeochemistry data from Maunalua Bay, Hawaii measured on four dates between April and October 2015

Data Type: Other Field Results
Version: 1
Version Date: 2021-09-15

» RUI: Collaborative Research: Defining the biogeochemical context and ecological impacts of submarine groundwater discharge on coral reefs (Moorea SGD)
Silbiger, NyssaCalifornia State University Northridge (CSU-Northridge)Principal Investigator
Donahue, MeganUniversity of Hawaii at ManoaCo-Principal Investigator
Lubarsky, KatieUniversity of Hawaii at ManoaCo-Principal Investigator
Rauch, ShannonWoods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager

This dataset contains biogeochemistry measurements from Maunalua Bay, Hawaii collected to assess the effects of submarine groundwater discharge on ecosystem functioning.


Spatial Extent: N:21.27531 E:-157.76073 S:21.2578421 W:-157.79053
Temporal Extent: 2015-04-18 - 2015-10-26

Methods & Sampling

Sampling locations:
Wailupe, Hawaii 21.275, -157.762 depth 2m
Black Point (Kupikipiki'o), Hawaii 21.2598, -157.789 depth 2m

Twenty water sampling locations were established at each site (n = 40 total) in an approximate grid, scaled to the width of the reef flat, for biogeochemistry measurements. At each location, we collected discrete diel water samples across four timepoints (during daytime and nighttime high and low tides) in the spring and fall (totaling eight samples per location, 320 samples overall). Sampling dates were 18 April 2015 and 28 September 2015 at Wailupe, and 2 May 2015 and 26 October 2015 at Kupikipiki'o. All sampling events happened during spring tide events. 

Sampling and analytical procedures:
Water samples for pH, TA, nitrate + nitrite (NO₃⁻ + NO₂⁻), phosphate (PO₄³⁻ ) and silicate (SiO₄²⁻) were hand collected directly above the benthos within 30 min of high or low tide in acid-washed HDPE bottles. pH was measured immediately using a tris calibrated Orion ROSS Ultra pH/ATC Triode following Dickson SOP 6a. TA samples were immediately preserved with 50% saturated HgCl2 in deionized water, stored in a cool dark place and later analyzed on a Mettler Toledo T-50 autotitrator following Dickson SOP 3b (precision = 2.68 µEq, accuracy = 0.48% ± 0.33% SD). Inorganic nutrient samples (SiO₄²⁻, NO₃⁻ + NO₂⁻, PO₄³⁻ ) were immediately filtered through pre-combusted GF/F filters (0.7 µm) and stored in a −20°C freezer until further processing. Nutrient samples were processed at the SOEST Laboratory for Analytical Biogeochemistry at the University of Hawai'i at Manoa using a Seal Analytical AA3 nutrient autoanalyzer (reported error [coefficient of variance]: 0.5% for SiO₄²⁻, 0.3% for NO₃⁻ + NO₂⁻, and 0.2% for PO₄³⁻). Temperature was recorded every 15 min on HOBO TidbiT v2 loggers and temperature values were extracted to match the time-discrete water samples were collected.

Data Processing Description

Data processing:
All data were processed using R statistical program and code is available at and Zenodo ( DOI:10.5281/zenodo.4281383

BCO-DMO Processing:
- renamed fields to comply with BCO-DMO naming conventions.

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Data Files

(Comma Separated Values (.csv), 109.64 KB)
Primary data file for dataset ID 860857

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Related Publications

Dickson, A.G., Sabine, C.L. and Christian, J.R. (Eds.) 2007. Guide to Best Practices for Ocean CO2 Measurements. PICES Special Publication 3, 191 pp
Lubarsky, K. A., Silbiger, N. J., & Donahue, M. J. (2018). Effects of submarine groundwater discharge on coral accretion and bioerosion on two shallow reef flats. Limnology and Oceanography, 63(4), 1660–1676. doi:10.1002/lno.10799
Silbiger, N. J., Donahue, M. J., & Lubarsky, K. (2020). Submarine groundwater discharge alters coral reef ecosystem metabolism. Proceedings of the Royal Society B: Biological Sciences, 287(1941), 20202743. doi:10.1098/rspb.2020.2743
Silbiger, N.. (2020). njsilbiger/MaunaluaSEM: SGD alters coral reef ecosystem metabolism (Version v1.0) [Computer software]. Zenodo.

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WaypointGPS waypoint number unitless
ZoneZone: Transition, Diffuse, or Ambient unitless
LatLatitude decimal degrees North
LongLongitude decimal degrees East
SiteSite Name: W = Wailupe; BP = Black Point unitless
TideTide: L= low; H: high unitless
SeasonSeason: SPRING or FALL unitless
Temp_inTemperature degrees Celsius
SalinitySalinity PSU
PhosphatePhosphate (coefficient of variance in analysis is 0.2%; level of detection is 0.008) micromoles per liter (umol L-1)
SilicateSilicate (coefficient of variance in analysis is 0.5%; level of detection is 0.065) micromoles per liter (umol L-1)
NNNitrate + Nitrite (coefficient of variance in analysis is 0.3%; level of detection is 0.009) micromoles per liter (umol L-1)
AmmoniaAmmonia micromoles per liter (umol L-1)
pHpH unitless (pH scale)
TATotal Alkalinity micromoles per kilogram (umol kg-1)
ChlorophyllChlorophyll micrograms per liter (ug/L)
AragAragonite unitless (saturation state)
percent_sgdRelative percent of submarine groundwater discharge unitless (percent)
Day_NightDay or Night unitless
CO2CO2 micromoles per kilogram (umol kg-1)
HCO3HCO3 micromoles per kilogram (umol kg-1)
CO3CO3 micromoles per kilogram (umol kg-1)
DICDIC micromoles per kilogram (umol kg-1)
OmegaAragAragonite saturation state unitless
OmegaCalciteCalcite saturation state unitless
pCO2Partial pressure of CO2 microatmospheres (uatm)
fCO2Fugacity of CO2 microatomspheres (uatm)
TA_predPredicted total alkalinity micromoles per kilogram (umol kg-1)
DIC_predPredicted DIC micromoles per kilogram (umol kg-1)
TA_diffTA residuals from mixing line micromoles per kilogram (umol kg-1)
DIC_diffDIC residuals from mixing line micromoles per kilogram (umol kg-1)

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Dataset-specific Instrument Name
Seal Analytical AA3 nutrient autoanalyzer
Generic Instrument Name
Nutrient Autoanalyzer
Dataset-specific Description
Nutrients were measured on a Seal Analytical AA3 nutrient autoanalyzer a the SOEST Laboratory for Analytical Biogeochemistry at the University of Hawai’i at Manoa.
Generic Instrument Description
Nutrient Autoanalyzer is a generic term used when specific type, make and model were not specified. In general, a Nutrient Autoanalyzer is an automated flow-thru system for doing nutrient analysis (nitrate, ammonium, orthophosphate, and silicate) on seawater samples.

Dataset-specific Instrument Name
Orion ROSS Ultra pH/ATC Triode
Generic Instrument Name
pH Sensor
Dataset-specific Description
pH on the total scale (pHTot) was measured using an Orion ROSS Ultra pH/ATC Triode calibrated against a Tris buffer of known pH from the Dickson laboratory at the Scripps Institution of Oceanography (Dickson et al. 2007).
Generic Instrument Description
An instrument that measures the hydrogen ion activity in solutions. The overall concentration of hydrogen ions is inversely related to its pH.  The pH scale ranges from 0 to 14 and indicates whether acidic (more H+) or basic (less H+). 

Dataset-specific Instrument Name
Mettler Toledo T-50 autotitrator
Generic Instrument Name
Automatic titrator
Dataset-specific Description
Total Alkalinity was measured on a Mettler Toledo T-50 autotitrator and calibrated against a certified reference material from Andrew Dickson’s Lab. Sample accuracy was 0.48%. 
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
HOBO TidbiT v2 loggers
Generic Instrument Name
Onset HOBO TidbiT v2 (UTBI-001) temperature logger
Dataset-specific Description
HOBO TidbiT v2 temperature loggers (accuracy: ±0.2°C, resolution: 0.02°C at 25°C)
Generic Instrument Description
A temperature logger that measures temperatures over a wide temperature range. It is designed for outdoor and underwater environments and is waterproof to 300 m. A solar radiation shield is required to obtain accurate air temperature measurements in sunlight (RS1 or M-RSA Solar Radiation Shield). With an operational temperature range between -20 degrees Celsius and +70 degrees Celsius, the TidbiT v2 has an accuracy of +/-0.21 and a resolution of 0.02 degrees Celsius.

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Project Information

RUI: Collaborative Research: Defining the biogeochemical context and ecological impacts of submarine groundwater discharge on coral reefs (Moorea SGD)

Coverage: Mo'orea, French Polynesia

NSF Award Abstract:
Submarine groundwater discharge (SGD) is the flow of water from land through the coastal seafloor into the nearby ocean. Approximately 13,000 cubic kilometers of groundwater is discharged into coastal environments every year, yet the effects of this fresh and often nutrient rich SGD are still poorly understood for coral reefs. This SGD input is driven by changes in precipitation, human land use, sea-level rise, tidal amplitude, and groundwater usage, many of which are rapidly changing with climate and human impacts. This project improves our understanding of SGD effects on coral reefs to better predict how both natural and human-induced changes will affect coastal ecosystem functioning in the future. Working in one of the most comprehensively studied coral reef ecosystems in the Pacific (Mo'orea, French Polynesia, home of the Mo'orea Coral Reef Ecosystem LTER); this project tests the influence of SGD on individual, community, and ecosystem-scale coral reef processes. Using mensurative studies, caging experiments, and a synthetic model, the investigators: 1) characterize SGD gradients and relate it to high resolution coral reef cover data, 2) determine how individual to ecosystem processes are influenced by SGD, and 3) develop a synthetic model to show how changes in SGD fluxes will alter reef ecosystem functioning. As SGD is a common feature on nearshore coral reefs worldwide, the results of this study have global implications for understanding the performance of coral reefs, which are essential economic, cultural, and scientific resources. This project is structured to provide training across multiple career levels, linking 13 undergraduate students, 2 graduate students, 2 senior personnel, 1 postdoctoral researcher, 1 female beginning lead investigator, and 2 senior co-investigators, with a focus on encouraging participation from underrepresented groups (e.g., through the Alaska Native and Native Hawaiian, Asian American and Native American Pacific Islander, and Hispanic-Serving Institutions of California State University Northridge, the University of Hawaiʻi at Mānoa, and California State University Long Beach). The investigators work with local K-12 students and teachers in Mo'orea and collaborate with an artist-in-residence to communicate science to the broader public through interactive and immersive art experiences in Mo'orea, Miami, and Los Angeles.

SGD is a natural and understudied feature of many nearshore coral reef ecosystems, which can contribute substantial changes to marine biogeochemistry, with impacts for coastal organisms such as reef-building corals, macroalgae, and bioeroders. SGD may play a key role in coral reef ecosystem functioning because it alters key physicochemical parameters (e.g., temperature, salinity, and nutrient and carbonate chemistry) that substantially affect both biotic and abiotic processes on coral reefs. This project (i) characterizes the spatial extent and biogeochemical signal of SGD in Mo'orea, French Polynesia, (ii) identifies how SGD influences microbial processes, benthic organism growth rates and physiology, species interactions between corals, macroalgae, and herbivores, and net ecosystem calcification and production rates, and (iii) quantitatively assesses how changes in SGD fluxes will alter reef biogeochemistry and ecosystem functioning through an integrative modelling effort. Specifically, the hydrogeological, biogeochemical, and ecological data collected in this study are synthesized in a Bayesian structural equation model. This project characterizes and quantifies how SGD directly and indirectly affects ecosystem functioning via changes in biogeochemistry and altered individual to ecosystem responses, thereby providing a better capacity to track and predict alterations in reef ecosystem function.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

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Funding SourceAward
NSF Division of Ocean Sciences (NSF OCE)

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