| Contributors | Affiliation | Role |
|---|---|---|
| Johnson, Zackary I. | Duke University | Principal Investigator, Contact |
| Hunt, Dana | Duke University | Co-Principal Investigator |
| Rauch, Shannon | Woods Hole Oceanographic Institution (WHOI BCO-DMO) | BCO-DMO Data Manager |
Spectrophotometric pH, measured at 25 degrees C using the total hydrogen ion scale, from the Pivers Island Coastal Observatory (PICO) from 2010 to 2012.
Note: pH was not measured at all time points, thus, some dates have no data ('nd') in the 'pH' column.
Water was sampled using a 5 L niskin bottle centered at 1 m with a bottle length of 0.7 m. pH was measured spectrophotometrically (Clayton and Byrne, 1993) in triplicate at standard temperature (25 degrees C) immediately following collection. pH samples were collected following recommended procedures (Dickson et al., 2007).
References:
Clayton, T.D., and Byrne, R.H. 1993. Spectrophotometric seawater pH measurements: total hydrogen ion concentration scale calibration of m-cresol purple and at-sea results. Deep Sea Research Part I: Oceanographic Research Papers 40: 2115-2129. doi: 10.1016/0967-0637(93)90048-8
Dickson, A.G., Sabine, C.L., and Christian, J.R. (eds). 2007. Guide to best practices for ocean CO2 measurements: PICES Special Publication 3.
Quality Scores (qflag) as follows:
1 = excellent (no known issues),
2 = suspect,
3 = poor (known reason to suspect data).
BCO-DMO Processing Notes:
- Created 'replicate' column and re-arranged data so that replicates are in rows, not columns.
- Modified parameter names to conform with BCO-DMO naming conventions.
- Replaced blanks with 'nd' to indicate 'no data'.
- Separated date into month, day, and year columns.
| File |
|---|
pH.csv (Comma Separated Values (.csv), 81.11 KB) MD5:ca20281bebf678c071ebca90d602f809 Primary data file for dataset ID 4028 |
| Parameter | Description | Units |
| deployment | Deployment name/id number. | text |
| lat | Latitude of sampling location. Positive = North. | decimal degrees |
| lon | Longitude of sampling location. Positive = East. | decimal degrees |
| year | Year (local time) of the sampling event. | YYYY |
| month_local | Month (local time) when the sampling event occurred. | mm (01 to 12) |
| PID_num | Unique, sequential "occupation" number for sampling. (The unique time/day when sampling occurred.) | dimensionless |
| day_local | Day of month (local time) when the sampling event occurred. | dd (01 to 31) |
| time_local | Time (local) when the sampling event occurred; 24-hour clock. | HHMM.mm |
| depth | Depth of water sampling. | meters |
| replicate | Replicate identifier. (All of the "A" pH samples are from the same bottle, however "A" replicates for pH are unrelated to "A" replicates in the other PICO datasets.) | text |
| pH | Spectrophotometric pH measured at 25 degrees C using the total hydrogen ion scale. | unitless; pH scale |
| pH_qflag | Quality score for pH: | dimensionless |
| yrday | Consecutive day of year for a specified year, as a decimal. The fraction of the value represents the time within the day (e.g. a value of 1.5 means January 1 at 1200 hours). | dimensionless |
| ISO_DateTime_Local | Date-time (local) formatted to ISO 8601 standard. | YYYY-MM-DDTHH:MM:SS.ss |
| Dataset-specific Instrument Name | Niskin bottle |
| Generic Instrument Name | Niskin bottle |
| Dataset-specific Description | Water was sampled using a 5 Liter niskin bottle. |
| Generic Instrument Description | A Niskin bottle (a next generation water sampler based on the Nansen bottle) is a cylindrical, non-metallic water collection device with stoppers at both ends. The bottles can be attached individually on a hydrowire or deployed in 12, 24, or 36 bottle Rosette systems mounted on a frame and combined with a CTD. Niskin bottles are used to collect discrete water samples for a range of measurements including pigments, nutrients, plankton, etc. |
| Dataset-specific Instrument Name | Spectrophotometer |
| Generic Instrument Name | Spectrophotometer |
| Dataset-specific Description | Either a Cary 4000 or a Beckman DU 640 spectrophotomer was used. |
| Generic Instrument Description | An instrument used to measure the relative absorption of electromagnetic radiation of different wavelengths in the near infra-red, visible and ultraviolet wavebands by samples. |
| Website | |
| Platform | Duke University Marine Lab |
| Start Date | 2010-06-28 |
| End Date | 2012-06-26 |
| Description | The PICO time series is sampled weekly (or more frequently) to capture physical, chemical and biological variability in the coastal ocean. This time series enables the investigator to collaborate with a number of researchers and will serve as a long-term research focus.
Project information: http://oceanography.ml.duke.edu/johnson/research/pico/ |
From the project website:
Carbon dioxide is rising at ~3% per year in the atmosphere and oceans leading to increases in dissolved inorganic carbon and a reduction in pH. This trend is expected to continue for the foreseeable future and ocean pH is predicted to decrease substantially making the ocean more acidic, potentially affecting the marine ecosystem. However, coastal estuaries are highly dynamic systems that often experience dramatic changes in environmental variables over short periods of times. In this study, the investigators are measuring key variables of the marine carbon system along with other potential forcing variables and characteristics of the ecosystem that may be affected by these pH changes. The goal of this project is to determine the time-scales and magnitude of natural variability that will be superimposed on any long term trends in ocean chemistry.
Other PICO-related projects in BCO-DMO:
Ocean Acidification: microbes as sentinels of adaptive responses to multiple stressors: contrasting estuarine and open ocean environments
| Funding Source | Award |
|---|---|
| NSF Division of Ocean Sciences (NSF OCE) | |
| NSF Ocean Sciences Research Initiation Grants (NSF OCE-RIG) |