Tammen, Juliane Katharina; Kittu, Leila; Ludwig, Andrea; Faucher, Giulia; Riebesell, Ulf: KOSMOS 2023 Helgoland mesocosm study on ocean alkalinity enhancement: dissolved inorganic nutrients, chlorophyll a and suspended particulate organic matter [dataset]. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.987501 (dataset in review)
Abstract:
We conducted a mesocosm study to investigate ecosystem responses to ocean alkalinity enhancement (OAE) in the temperate waters of the German North Sea on Helgoland in spring 2023. We simulated non-CO2-equilibrated OAE via calcium hydroxide through the addition of calcium chloride and sodium hydroxide. Twelve 6 m³ mesocosms were used to simulate two scenarios: in six mesocosms we established a gradient of added alkalinity from 0 to 1250 µmol/kg in increments of 250 µmol/kg, simulating immediate (imm) dilution of alkalised waters. For the second set of six mesocosms, alkalinity was added only to the top 1 m of each mesocosm, doubling the target added alkalinity. The top layer was mixed with the untreated bottom layer after 48 hours, simulating delayed dilution of alkalised waters (del) and ultimately leading to the same alkalinity gradient as the immediate dilution treatment. This data contains water column biogeochemical variables, including dissolved inorganic nutrient concentrations (µmol/L), chlorophyll a concentrations (µg/L) and suspended particulate matter (biogenic silica, particulate organic carbon, nitrogen and phosphate; µmol/L). Nutrients, particulate organic phosphate and biogenic silica were measured spectrophotometrically (Unicam UV 300, Thermo Spectronic, USA). High-performance liquid chromatography (Thermo Scientific HPLC Ultimate 3000) was performed for chlorophyll a determination and particulate organic carbon and nitrogen were measured using an elemental analyser (Flash EA, Thermo Fisher).
Keyword(s):
Supplement to:
Tammen, Juliane Katharina; Kittu, Leila; Schartau, Markus; Faucher, Giulia; Schulz, Kai Georg; Riebesell, Ulf (in review): Spring phytoplankton bloom dynamics reveal thresholds of ocean alkalinity enhancement in the North Sea.
Project(s):
Funding:
Federal Ministry of Education and Research (BMBF), grant/award no. 03F0895A: DAM CDRmare - RETAKE, GEOMAR
Coverage:
Latitude: 54.183300 * Longitude: 7.900000
Date/Time Start: 2023-03-14T00:00:00 * Date/Time End: 2023-04-21T00:00:00
Event(s):
KOSMOS_2023_Mesocosm-M1 * Latitude: 54.183300 * Longitude: 7.900000 * Date/Time Start: 2023-03-14T00:00:00 * Date/Time End: 2023-04-21T00:00:00 * Location: Helgoland * Campaign: KOSMOS_2023 (KOSMOS Helgoland) * Method/Device: Mesocosm experiment (MESO)
KOSMOS_2023_Mesocosm-M2 * Latitude: 54.183300 * Longitude: 7.900000 * Date/Time Start: 2023-03-14T00:00:00 * Date/Time End: 2023-04-21T00:00:00 * Location: Helgoland * Campaign: KOSMOS_2023 (KOSMOS Helgoland) * Method/Device: Mesocosm experiment (MESO) * Comment: delayed treatment
KOSMOS_2023_Mesocosm-M3 * Latitude: 54.183300 * Longitude: 7.900000 * Date/Time Start: 2023-03-14T00:00:00 * Date/Time End: 2023-04-21T00:00:00 * Location: Helgoland * Campaign: KOSMOS_2023 (KOSMOS Helgoland) * Method/Device: Mesocosm experiment (MESO)
Comment:
The empty cells in the data table refer to outliers that were removed from the dataset.
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Details regarding mesocosm set-up:
The floating mesocosms were made of a transparent 1mm thick polyurethane bag with a cylindrical upper section and a conical sediment trap at the bottom, extending to 3.5 m depth. The bags were mounted on floating frames and enclosed a water volume of ~6m³. The mesocosms were filled simultaneously with seawater pumped from 2-3 m depth outside the harbour using a peristaltic pump, larger organisms were excluded via pre-filtration with a 3 mm mesh.
Parameter(s):
| # | Name | Short Name | Unit | Principal Investigator | Method/Device | Comment |
|---|---|---|---|---|---|---|
| 1 | Type of study | Study type | Tammen, Juliane Katharina | |||
| 2 | Event label | Event | Tammen, Juliane Katharina | |||
| 3 | Sampling date/time, experiment | Date/time sampling exp | Tammen, Juliane Katharina | Date | ||
| 4 | Day of experiment | DOE | day | Tammen, Juliane Katharina | ||
| 5 | Mesocosm label | Meso label | Tammen, Juliane Katharina | |||
| 6 | Treatment: alkalinity, total | T:AT | µmol/kg | Tammen, Juliane Katharina | ||
| 7 | Treatment: dilution type | T:dilution | Tammen, Juliane Katharina | |||
| 8 | Treatment | Treat | Tammen, Juliane Katharina | OAE | ||
| 9 | Water depth description | Water depth descr | Tammen, Juliane Katharina | Sampling depth: On all sampling days, integrated water samples from 0-2.5 m were taken, with the exception of the layer phase on day 5 and day 6. On these two days, the top layer (0-1m) and the bottom layer (1-2.5m) were sampled separately in the delayed dilution treatment (marked as integrated_top and integrated_bottom). | ||
| 10 | Depth, water, experiment, top/minimum | Depth water exp top | m | Tammen, Juliane Katharina | ||
| 11 | Depth, water, experiment, bottom/maximum | Depth water exp max | m | Tammen, Juliane Katharina | ||
| 12 | Phosphate | [PO4]3- | µmol/l | Tammen, Juliane Katharina | Spectrophotometer, Thermo Spectronic, Unicam UV 300 | |
| 13 | Silicate | Si(OH)4 | µmol/l | Tammen, Juliane Katharina | Spectrophotometer, Thermo Spectronic, Unicam UV 300 | |
| 14 | Nitrate | [NO3]- | µmol/l | Tammen, Juliane Katharina | Spectrophotometer, Thermo Spectronic, Unicam UV 300 | |
| 15 | Nitrite | [NO2]- | µmol/l | Tammen, Juliane Katharina | Spectrophotometer, Thermo Spectronic, Unicam UV 300 | |
| 16 | Nitrogen oxide | NOx | µmol/l | Tammen, Juliane Katharina | Spectrophotometer, Thermo Spectronic, Unicam UV 300 | |
| 17 | Chlorophyll a | Chl a | µg/l | Tammen, Juliane Katharina | High-performance liquid chromatography (HPLC), Thermo Scientific, UltiMate 3000 | |
| 18 | Biogenic silica | bSiO2 | µmol/l | Tammen, Juliane Katharina | Spectrophotometer, Thermo Spectronic, Unicam UV 300 | |
| 19 | Phosphorus, organic, particulate | POP | µmol/l | Tammen, Juliane Katharina | Spectrophotometer, Thermo Spectronic, Unicam UV 300 | |
| 20 | Carbon, organic, particulate | POC | µmol/l | Tammen, Juliane Katharina | Elemental analyser, Thermo Fisher, Flash EA | |
| 21 | Nitrogen, organic, particulate | PON | µmol/l | Tammen, Juliane Katharina | Elemental analyser, Thermo Fisher, Flash EA |
License:
Creative Commons Attribution 4.0 International (CC-BY-4.0) (License comes into effect after moratorium ends)
Status:
Curation Level: Enhanced curation (CurationLevelC) * Processing Level: PANGAEA data processing level 3 (ProcLevel3)
Size:
5259 data points
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