Contributors | Affiliation | Role |
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Gaylord, Brian | University of California-Davis (UC Davis-BML) | Principal Investigator |
Jellison, Brittany | University of New Hampshire (UNH) | Student, Contact |
Heyl, Taylor | Woods Hole Oceanographic Institution (WHOI BCO-DMO) | BCO-DMO Data Manager |
Rauch, Shannon | Woods Hole Oceanographic Institution (WHOI BCO-DMO) | BCO-DMO Data Manager |
This dataset is part of a larger experiment to investigate how pH influences trophic links between intertidal sea stars (Leptasterias hexactis), snails (Tegula funebralis), and macroalgae (Mazzaella flaccida). Organisms were placed for 7 days in mesocosms containing seawater at either ambient (~7.9) or low pH (~7.0). The pH was modified using equimolar additions of sodium bicarbonate (NaHCO3) and hydrochloric acid (HCl). The water in each container was changed daily. The mesocosm array consisted of 40, 13-liter (L) circular plastic containers with a mesh barrier down the center to separate predator, prey, and/or basal resource but allowing for passage of waterborne cue. Mesocosms were filled halfway with seawater, allowing 10 centimeter (cm) of refuge space for snails above the waterline. Mesocosms were held within a seawater table under constant flow to maintain consistent temperatures.
Temperature, salinity, dissolved oxygen, and pH were measured using a YSI ProPlus Sensor.
Total pH was measured using a Sunburst SAMI spectrophotometric unit modified for benchtop use.
Total alkalinity was measured via Gran titration (Riebesell et al. 2010) standardized using certified reference material (A. Dickson, Scripps Institution of Oceanography) using a Metrohm 855 autotitrator.
Values of total pH for each container were measured using a YSI ProPlus Sensor and calibrated to the total scale using daily samples run on a Sunburst SAMI spectrophotometric unit modified for benchtop use.
pCO2 was calculated from daily alkalinity and pH using the seacarb package in R assuming the default dissociation constants.
BCO-DMO processing description:
- Adjusted field/parameter names to comply with BCO-DMO naming conventions
- Replaced blank values with "nd" (no data)
- Added a conventional header with dataset name, PI names, version date
File |
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mesocosm_study_-_seawater_chemistry.csv (Comma Separated Values (.csv), 86.86 KB) MD5:6514617f46d4d8c9314bf6ac61840470 Primary data file for dataset ID 869110 |
Parameter | Description | Units |
Container | Container number | unitless |
Phase | pH treatment level of the container; Low pH ~ 7.0 total pH, Ambient pH ~7.9 total pH | unitless |
Trophic_Treatment | Trophic treatment condition; “no-predator” = four snails and four circular pieces of macroalgae on one side of the barrier, “cue only" = one sea star was housed on one side of the barrier with four snails and macroalgae on the other side, "complete interaction" = one sea star, four snails, and macroalgae all placed on one side of the barrier together, “no prey/no grazing” = one sea star was placed on one side of the barrier with the macroalgae on the other. | unitless |
pH | pH Exposure = 5 day exposure phase before the mesocosm component in which animals were held separately and exposed to ambient and low pH, mesocosm = 7 day mesocosm component of the experimnet in which sea stars, snails and macroalgae were held together under 4 trophic treatments and exposed to the same pH level as they were during the pH exposure phase of the experiment. | unitless |
Day | Day number within the experiment | day number |
Water_Change | Whether water quality measurements were taken before or after daily complete water changes | unitless |
Conductivity | Conductivity measured by a YSI ProPlus sensor | mS/cm |
Salinity | Salinity measured by a YSI ProPlus sensor | ppt |
Dissolved_Oxygen | Dissolved Oxygen measured by a YSI ProPlus sensor | mg/L |
pH_mV | pH millivolts measured by a YSI ProPlus sensor | mV |
Temperature | Temperature measured by a YSI ProPlus sensor | degrees Celsius |
Total_pH | Total pH values for each container were processed using measurements from a YSI ProPlus Sensor and calibrated to the total scale using daily samples run on a Sunburst SAMI | pH units |
Alkalinity | Total alkalinity was measured via Gran titration (Riebesell et al.2010) standardized using certified reference material (A. Dickson, Scripps Institution of Oceanography) using a Metrohm 855 autotitrator | µmol/kgSW |
pCO2 | pCO2 was calculated from daily alkalinity and pH using the seacarb package in R assuming the default dissociation constants. | ppm |
SAMI_total_pH | Total pH was measured using a Sunburst SAMI spectrophotometric unit modified for benchtop use | pH units |
Dataset-specific Instrument Name | Metrohm 855 autotitrator |
Generic Instrument Name | Automatic titrator |
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 | Sunburst SAMI spectrophotometric unit |
Generic Instrument Name | Benchtop pH Meter |
Generic Instrument Description | An instrument consisting of an electronic voltmeter and pH-responsive electrode that gives a direct conversion of voltage differences to differences of pH at the measurement temperature. (McGraw-Hill Dictionary of Scientific and Technical Terms)
This instrument does not map to the NERC instrument vocabulary term for 'pH Sensor' which measures values in the water column. Benchtop models are typically employed for stationary lab applications. |
Dataset-specific Instrument Name | YSI ProPlus Sensor |
Generic Instrument Name | YSI Professional Plus Multi-Parameter Probe |
Generic Instrument Description | The YSI Professional Plus handheld multiparameter meter provides for the measurement of a variety of combinations for dissolved oxygen, conductivity, specific conductance, salinity, resistivity, total dissolved solids (TDS), pH, ORP, pH/ORP combination, ammonium (ammonia), nitrate, chloride and temperature. More information from the manufacturer. |
NSF Award Abstract:
The absorption of human-produced carbon dioxide into the world's oceans is altering the chemistry of seawater, including decreasing its pH. Such changes, collectively called "ocean acidification", are expected to influence numerous types of sea creatures. This project examines how shifts in ocean pH affect animal behavior and thus interactions among species. It uses a case study system that involves sea star predators, snail grazers that they eat, and seaweeds consumed by the latter. The rocky-shore habitats where these organisms live have a long history of attention, and new findings from this work will further extend an already-large body of marine ecological knowledge. The project provides support for graduate and undergraduate students, including underrepresented students from a nearby community college. The project underpins the development of a new educational module for local K-12 schools. Findings will moreover be communicated to the public through the use of short film documentaries, as well as through established relationships with policy, management, and industry groups, and contacts with the media.
Ocean acidification is a global-scale perturbation. Most research on the topic, however, has examined effects on single species operating in isolation, leaving interactions among species underexplored. This project confronts this knowledge gap by considering how ocean acidification may shift predator-prey relationships through altered behavior. It targets as a model system sea stars, their gastropod grazer prey, and macoalgae consumed by the latter, via four lines of inquiry. 1) The project examines the functional response of the focal taxa to altered seawater chemistry, using experiments that target up to 16 discrete levels of pH. This experimental design is essential for identifying nonlinearities and tipping points. 2) The project addresses both consumptive and non-consumptive components of direct and indirect species interactions. The capacity of ocean acidification to influence such links is poorly known, and better understanding of this issue is a recognized priority. 3) The project combines controlled laboratory experiments with field trials that exploit tide pools and their unique pH signatures as natural mesocosms. Field tests of ocean acidification effects are relatively rare and are sorely needed. 4) A final research phase expands upon the above three components to address effects of ocean acidification on multiple additional taxa that interact in rocky intertidal systems, to provide a broad database that may have utility for future experiments or modeling.
Funding Source | Award |
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NSF Division of Ocean Sciences (NSF OCE) |