Project
North East Atlantic hub of the Global Ocean Acidification Observing Network
Project Start: November 2018 | Project End: N/A
Project Funder: DEFRA
Principal Investigator: Dr Helen Findlay
The North East Atlantic Ocean Acidification Hub was established to serve European countries that are conducting monitoring, and other OA activities, within the NE Atlantic region.
The Global Ocean Acidification Observing Network (GOA-ON) encouraged grass-roots formation of regional hubs to foster communities of practice for the efficient collection of comparable and geographically distributed data to assess ocean acidification and its effects and to support adaptation tools like model forecasts.
Countries within the region known to be engaged in OA research and/or with data submitted to the GOA-ON data portal: Belgium, Denmark, Faroe Islands, France, Germany, Iceland, Ireland, Netherlands, Norway, Poland, Portugal, Spain, Sweden, UK.
Access the NEA-OA Data Asset List
News
June Update | Publication
New Paper
Characterizing Reef Net Metabolism Via the Diel Co-Variation of pH and Dissolved Oxygen From High Resolution in Situ Sensors
Abstract
Coral reefs are subject to degradation by multiple environmental stressors which are predicted to intensify. Stress can alter ecosystem composition, with shifts from hard coral to macroalgae dominated reefs often accompanied by an increase in soft corals and sponges. Such changes may alter net ecosystem metabolism and biogeochemistry by shifting the balance between photosynthesis, respiration, calcification and dissolution. We deployed high temporal resolution pH and dissolved oxygen (DO) sensors at four Caribbean reef sites with varying covers of hard and soft corals, sponges and macroalgae. The resultant data indicated that the strength of the “metabolic pulse”, specifically the co-variation in daily pH and DO oscillations, was driven by the net balance of light-dependent and -independent metabolism. pH and DO were positively correlated over the diel cycle at coral dominated sites, suggesting that photosynthesis and respiration were the major controlling processes, and further indicated by agreement with a simple production:respiration model. Whereas, at a site with high macroalgal cover, pH and DO decoupling was observed during daylight hours. This indicates that an unidentified light-driven process altered the expected pH:DO relationship. We hypothesize that this could be mediated by the higher levels of macroalgae, which either stimulated bacterial-mediated carbonate dissolution via the production and release of allelopathic compounds or retained oxygen, evolved during photosynthesis, in the gaseous form in seawater (ebullition). Our work demonstrates that high resolution monitoring of pH and DO provides insight into coral reef biogeochemical functioning and can be key for understanding long-term changes in coral reef metabolism.
May Update | Webinar
The Influence of Organic Alkalinity on the Carbonate System in Coastal Waters
GOA-ON held the marine carbon dioxide removal (mCDR) Working Group webinar on April 16, 2024. At this webinar, we presented an overview of mCDR, its overlaps with ocean acidification (OA), and the results from the GOA-ON mCDR Survey. Those that were able to attend discussed future mCDR Working Group activities and were invited to join the GOA-ON mCDR Working Group to help lead these future activities. For those that missed the webinar, you can view the recording here.
If you are interested in joining the working group and/or participating in a position paper, please fill out this form and we will follow up soon. You can also contribute to brainstorming ideas for the position paper and working group by adding to this Jamboard. Overall, this working group will focus on the intersection between OA and mCDR and is open to all GOA-ON members. If you are not yet a GOA-ON member, we encourage you to join GOA-ON here.
The working group aims to bring together a diverse group of ocean practitioners with representation from all GOA-ON Regional Hubs and the early career ICONEC community, so feel free to encourage others throughout GOA-ON to join.
May Update | Event
Wepal-Quasimeme Workshop on Quality Assurance for inorganic carbon system measurements in context of ocean acidification monitoring
22 -24 October 2024
National Oceanography Centre (NOC), Southampton, United Kingdom
8 years after the first Wepal-Quasimeme Ocean Acidification (OA) workshop in Southampton and after 3 years of the AQ15 Wepal-Quasimeme intercalibration exercise, it’s time to bring the Ocean Acidification community back together.
The first OSPAR QSR on OA was published in 2023 but there is still, more than ever before, a need for high quality data (TA, DIC, pH, pCO2) to strengthen all scientific output on OA. OSPAR, as well as other international initiatives such as ICOS, GOA-ON and AMAP, indicate that strong international collaborative monitoring programmes on OA need to continue, to facilitate meaningful data gathering, collation and assessment.
A consistent approach to sampling, sample pre-treatment, analysis, quality control, validation of methods, calculation of derived variables and an understanding of methodological limitations is required; methods should be fit for purpose. Many monitoring agencies, with varying levels of experience are analysing samples for carbonate chemistry parameter on different types of instruments but also using new techniques, as more sensors are installed on buoys or ships, or more automated analysers are set up.
There’s still a gap in availability of CRMs, standards, buffers for quality control and calibrations when analysing marine samples. Worldwide, Scripps reference materials are used for QC or calibration for total alkalinity (TA), dissolved inorganic carbon (DIC) and pH analysis without having a separate way of ensuring that their measurement system is in control and has a calibration with known linearity. Thus, even when reference materials are used there are likely to be unidentified uncertainties showing up on a well-designed proficiency study like the QUASIMEME AQ15.
April Update | News
Antarctic Project DICHOSO: Research Campaigns in South Shetland Archipelago
The Antarctic project DICHOSO will conduct research campaigns from February to March 2024 in the South Shetland archipelago. The primary objectives include measuring seawater pH, greenhouse gases (CO2, CH4, and N2O), and examining acidification patterns in the area.
Links:
March Update | Publication
The Influence of Organic Alkalinity on the Carbonate System in Coastal Waters
Highlights
- Growing consensus that organic matter contributions to alkalinity is significant.
- Organic alkalinity prevalent in the coastal ocean.
- Methods to quantify and characterise organic alkalinity are detailed.
- Possible to reduce propagated errors in carbonate system descriptors.
Abstract
Total alkalinity (TA) is one of the four main carbonate system variables and is a conventionally measured parameter used to characterise marine water carbonate chemistry. It is an important indicator of a waterbody’s buffering capacity and a measure of its ability to resist acidification, a matter of growing concern in the marine environment. Although TA is primarily associated with the inorganic components of seawater such as bicarbonate, there is a growing consensus that dissolved organic matter (DOM) can significantly contribute to TA in coastal waters. This organic fraction of TA (OrgAlk) is typically deemed negligible and is not accounted for in conventional TA expressions. However, omission of OrgAlk can lead to the propagation of errors in subsequent carbonate system calculations and to misinterpretation of key carbonate chemistry descriptors such as calcium carbonate saturation states. Here we provide an overview of OrgAlk contributions to TA and investigate the implications of its omission in carbonate system studies conducted in coastal waters. We examine the prevalence of OrgAlk across both coastal and pelagic waters using publicly available carbonate system data products, such as GLODAP and GOMECC. Current measures to account for, incorporate and characterise the contribution of OrgAlk to TA are also critically examined.
February Update | Publication
New Paper
Organic alkalinity dynamics in Irish coastal waters: Case study Rogerstown Estuary
Highlights
- OrgAlk can be an important fraction of TA in coastal waters.
- OrgAlk acid-base properties are suggestive of carboxyl and phenolic-like signals.
- Complementary fluorescence analysis of DOM can elucidate origins and transformations of OrgAlk.
- OrgAlk can lead to the propagation of uncertainty on calculated carbonate parameters.
Abstract
Total alkalinity (TA) is a popularly measured carbonate system parameter and is widely used in calculations of key carbonate system descriptors such as the calcium carbonate saturation state, an important indicator of ocean acidification. Organic alkalinity (OrgAlk) is recognised as a contributor to TA in coastal waters, with this having implications on the use of TA to calculate key carbonate chemistry descriptors. As titratable charge groups of OrgAlk can act as unknown acid-base species, the inclusion of the total concentration and apparent dissociation constants of OrgAlk in carbonate calculations involving TA is required to minimise uncertainty in computed speciation. Here we present an investigation of the prevalence and properties of OrgAlk as well as the impact of OrgAlk on carbonate chemistry calculations in a transitional waterbody. Water samples were collected during low and high tide over a 5-week period in Rogerstown Estuary, Dublin Ireland. TA and OrgAlk were measured using modified Global Ocean Acidification Observing Network (GOA-ON) titration apparatus in conjunction with OrgAlkCalc, an open-source Python based computational programme. pH was measured on the total scale using meta-cresol purple (mCP) as the indicator dye. Dissolved inorganic carbon (DIC), the partial pressure of CO2 (pCO2), in situ pH on the total scale (pHT) and the saturation state of aragonite (∆ΩA) were calculated using pH and both OrgAlk adjusted TA and measured TA as the input parameters. Optical analysis of DOM was conducted to compliment OrgAlk characterisations and to further elucidate OrgAlk sources and dynamics. OrgAlk charge groups concentrations ranged from 35,198 μmol·kg−1, with the highest concentrations observed in more marine waters. Two apparent charge groups were associated with OrgAlk, with pK values of 4.38 ± 0.27 and 6.95 ± 0.43. Differences between calculated carbonate system parameters when using OrgAlk adjusted TA and non-OrgAlk adjusted TA ranged from 88 to 254 μmol·kg−1 DIC, −98–67 μatm pCO2, −0.02–0.12 pHT and 0.02–0.64 ∆ΩA. Variability in the differences in calculated carbonate systems was largely a factor of OrgAlk charge group concentration and pK. This work highlights the importance of considering OrgAlk if using TA as an input parameter in carbonate system investigations of coastal waters.
January Update | Publication
New Paper
OrgAlkCalc: Estimation of organic alkalinity quantities and acid-base properties with proof of concept in Dublin Bay
Abstract
The presence and influence of organic species is generally omitted in total alkalinity (TA) analysis. This has direct implications to calculated carbonate system parameters and to key descriptors of ocean acidification, especially in coastal waters where organic alkalinity (OrgAlk) can contribute significantly to TA. As titratable charge groups of OrgAlk can act as unknown seawater acid-base systems, the inclusion of the total concentration and apparent dissociation constants of OrgAlk in carbonate calculations involving TA is required to minimise uncertainty in computed speciation. Here we present OrgAlkCalc, an open-source Python based programme that can be used in conjunction with simply modified Global Ocean Acidification Observing Network (GOA-ON) TA titration apparatus to measure TA and OrgAlk, as well as return estimations of associated acid-base properties. The modified titration apparatus and OrgAlkCalc were tested using samples collected from the transitional waters of Dublin Bay, Ireland over a 8 month period (n = 100). TA values ranged from 2257 to 4692 μmol·kg−1 and indicated that freshwater inputs pose a significant source of carbonate alkalinity to Dublin Bay. OrgAlk values ranged from 46 to 234 μmol·kg−1 and were generally observed to be higher in more saline waters, with elevated levels in the Autumn/Winter period. The dissociation constants of two distinct OrgAlk charge groups were identified, with pK values in agreement with previously reported values for humic substances. The majority of OrgAlk charge group concentrations were associated with carboxyl-like charge groups.
December Update | Publication
New Paper
The time series at the Strait of Gibraltar as a baseline for long-term assessment of vulnerability of calcifiers to ocean acidification.
Abstract
The assessment of the saturation state (Ω) for calcium carbonate minerals (aragonite and calcite) in the ocean is important to determine if calcifying organisms have favourable or unfavourable conditions to synthesize their carbonated structures. This parameter is largely affected by ocean acidification, as the decline in seawater pH causes a decrease in carbonate ion concentration, which in turn, lowers Ω. This work examines temporal trends of seawater pH, ΩAragonite and ΩCalcite in major Atlantic and Mediterranean water masses that exchange in the Strait of Gibraltar: North Atlantic Central Water (NACW), Levantine Intermediate Water (LIW) and Western Mediterranean Deep Water (WMDW) using accurate measurements of carbonate system parameters collected in the area from 2005-2021. Our analysis evidences a gradual reduction in pH in the three water mases during the monitoring period, which is accompanied by a decline in Ω for both minerals. The highest and lowest decreasing trends were found in the NACW and LIW, respectively. Projected long-term changes of Ω for future increases in atmospheric CO2 under the IPCC AR6 Shared Socio-economic Pathway "fossil-fuel-rich development" (SSP5-8.5) indicate that critical conditions for calcifiers with respect to aragonite availability will be reached in the entire water column of the region before the end of the current century, with a corrosive environment (undersaturation of carbonate) expected after 2100.
October Update | Presentation
Presentations from the NEA Hub at OA week 2023.
The Zoom sessions will be uploaded to the GOA-ON YouTube channel (GOA-ON – YouTube) very soon.
POGO-funded working group: Action for Sustainable Ocean Acidification Research (ASOAR)
The ASOAR working group aims to build on the draft implementation plans produced by the UN Ocean Decade programme “Ocean Acidification Research for Sustainability (OARS)” outcome working groups by identifying the activities and engagements that can be delivered for the Atlantic region and more broadly across the globe. ASOAR held a workshop at Plymouth Marine Laboratory in March 2023, to bring together participants from across the globe to enable the discussion on the OARS implementation plans. There were 28 participants in our hybrid workshop, representing Argentina, Egypt, France, Germany, India, Lebanon, Spain, Sweden, the UK and USA. We spent two productive days going through all seven OARS outcome documents, assessing known ocean acidification activities. Potential actions needed to fulfil the outcomes were suggested and finally we associated specific tasks and assigned “names” to these tasks. Over the past few months we have been working on aligning those actions and tasks, and these will form the basis of a white paper which provides examples of actions as well as recommendations for the wider ocean acidification community.
Member Assets
Data Asset List
Access the NEA-OA Data Asset List
Fixed-Assets map
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Global Ocean-based Carbon Dioxide Removal (oCDR) Survey
The Ocean-based Carbon Dioxide Removal (oCDR; also often referred to as marine CDR or mCDR) GOA-ON Working Group is conducting a survey to understand the GOA-ON community’s interest and involvement in oCDR.
Project funded by
