Proposed acidification indicators for the Baltic Sea Rehder, Carstensen, Gustafsson HELCOM S&C, May 2018 3J-05 – Proposed acidification indicators for the Baltic Sea Bo Gustafsson Gregor Rehder Jacob Carstensen
Proposed acidification indicators for the Baltic Sea Rehder, Carstensen, Gustafsson HELCOM S&C, May 2018 Introductory Thoughts MSFD, Annex III (Indicative lists of characteristics, pressures and impacts), MSFD table I, physical and chemical features: „ Profiles of pH and pCO 2 or similar Proton activity (or concentration) is information to measure marine acidification “ per se the most direct acidification indicator pH = - log a H+ • Basically governed by the pH T = -log ([H + ] + [HSO 4 - ]). inorganic carbon system Eutrophication : “ An increase in the rate of supply of organic matter to an ecosystem “ Carbon as eutrophication key variable • Nixon et al., 1995 - 106CO 2 + 16NO 3 2- + + HPO 4 Carbon is the most direct link 122H 2 O + 18 H + → between productivity and O 2 - (CH 2 O) 106 (NH 3 ) 16 (H 3 PO 4 ) + 138O 2∙ 2 consumption
Proposed acidification indicators for the Baltic Sea Rehder, Carstensen, Gustafsson HELCOM S&C, May 2018 pCO 2 : +1.6 µatm yr -1 CO 2 H + + HCO 3 − H 2 CO 3 pH T : -0.0016 yr -1 − HCO 3 Ω = Ca 2+ ∙ [CO 3 2− ] K L Ca 2+ + CO 3 2− Biogenic Weathering calcification CaCO 3 3 Strict linkage relies on constant alkalinity 2 From Doney et al., 2009
Proposed acidification indicators for the Baltic Sea Rehder, Carstensen, Gustafsson HELCOM S&C, May 2018 Carbon dioxide system – C T • Method readily established, very few measurements in the Baltic Sea • No brackish water limitations – A T • Measured since a century, large improvement of data quality in the last 25 years • Baltic Sea: Non negligible contribution from organic alkalinity, trends on decadal scale – p CO 2 • Mainly surface water applications • Not included in HELCOM monitoring manual, but established SOPs (SOCAT) • No brackish water limitations – pH • Inherent problem in potentiometric measurements • Spectrophotometry so far only state-of-the-art method for open ocean conditions 4 • In HELCOM monitoring as “side parameter”
Proposed acidification indicators for the Baltic Sea Rehder, Carstensen, Gustafsson HELCOM S&C, May 2018 From global to local 5
Proposed acidification indicators for the Baltic Sea Rehder, Carstensen, Gustafsson HELCOM S&C, May 2018 A T - Alkalinity Trends in the Baltic 1995 - 2014 Introduction of reference materials! Rate: +3.4 µmol kg -1 yr -1 Relative Change: +5% Comp. North Atlantic: +0.1% A T -increase - mitigates acidificiation through CO 2 -uptake! - Increases potential CO 2 - uptake 6 From Müller et al., 2016
Proposed acidification indicators for the Baltic Sea Rehder, Carstensen, Gustafsson HELCOM S&C, May 2018 p CO 2 – 15 year time line – 15 years of pCO 2 measurements on VOS Finnmaid (and Finnpartner) – long-term joined effort of Alg@line and – Integrated understanding recently published in a Springer monograph Baltic (2008- BATS (1983-2011) 15) Slope (µatm yr −1 ) 4.6 - 6.1 1.62 P-value <0.01 <0.01 R 2 0.007 - 0.023 0.16 7 From Schneider and Müller 2018
Proposed acidification indicators for the Baltic Sea Rehder, Carstensen, Gustafsson HELCOM S&C, May 2018 p CO 2 – Productivity assessment Calculated net – Independent of C/N/P carbon production in stoichiometry the different basins during the spring bloom for 2009. iNCP ( C z F t ) 0 . 8 T eff AS Schneider and Müller, 2018 F AS – CO 2 exchange with the atmosphere; Z eff – effective penetration depth; Δ t considered time intervall; 8
Proposed acidification indicators for the Baltic Sea Rehder, Carstensen, Gustafsson HELCOM S&C, May 2018 pH – Obstacles Søren Sørensen 8.4 Gotland Basin, Carlsberg Laboratorien Baltic Sea 8.2 – Methods used so far not Kopenhagen, 1909 pH 8.0 suitable for long-term analysis “ Potentia Hydrogenii ” 7.8 – Difficult to separate any true 7.6 signal from methodological 1950 1960 1970 1980 1990 2000 2010 2020 problems 8.4 Bornholm Basin, Baltic Sea – Re-calibration not possible 8.2 pH 8.0 pH-time series BY 15 (SMHI data) 7.8 1950 1960 1970 1980 1990 2000 2010 2020 • Glas electrode • Monthly cruises • Only at monitoring stations ------------------------------------------------------ 1995-2015 to detectable trend 9
Proposed acidification indicators for the Baltic Sea Rehder, Carstensen, Gustafsson HELCOM S&C, May 2018 pH – recent progress – Large variablility calls for high spatiotemporal resolution – Until now lack of reference materials for S<20 – Strong, instrument- depending salinity dependence of pH-electrodes – No user-friendly instrument for brackish waters – Considerable progress made within BONUS PINBAL 10
Proposed acidification indicators for the Baltic Sea Rehder, Carstensen, Gustafsson HELCOM S&C, May 2018 pH – recent progress – Large variablility calls for high spatiotemporal resolution – Until now lack of reference materials for S<20 – Strong, instrument- depending salinity dependence of pH-electrodes – No user-friendly instrument for brackish waters – Considerable progress made within BONUS PINBAL 11
BONUS INTEGRAL A BONUS Blue Baltic Research Project BONUS INTEGRAL I ntegrated carbo N and T rac E G as monito R ing for the b AL tic sea • Funded 07/2017 – 06/2020 • 8 partners, 5 nations, 2.1 Mio € Key Theme 5.1 Developing and improving the scientific basis for integrated monitoring programmes for continuous assessment of ecological status and human pressures 5.2 Developing and testing innovative in situ, remote sensing and laboratory techniques
BONUS INTEGRAL A BONUS Blue Baltic Research Project Overarching ideas: • Use of the (extended) ICOS network for biogeochemical monitoring of the Baltic Sea, in combination to existing monitoring programs • Improved ASE-parameterizations for the Baltic Sea • Provide best experimentally based seasonal concentration charts for carbon dioxide, methane, and nitrous oxide • Full integration of carbon system into high resolution physical biogeochemical model • Advice for countries with upcoming ICOS infrastructure • Model-ouput based recommendations on effective biogeochemical monitoring
Proposed acidification indicators for the Baltic Sea Rehder, Carstensen, Gustafsson HELCOM S&C, May 2018 Summary and Discussion points – Inorganic carbon system parameters as the primary tool to assess acidification – Also allowing important insights on eutrophication and the link between net productivity and deep water oxygen demand – Methods (almost) readily developed – Methods allow an important bridge in the spatio-temporal coverage between discrete (monitoring cruises) and entire system (remote sensing / modelling) approaches – Major advantage for ecosystem assessment in a world with MULTIPE DRIVERS 14
Proposed acidification indicators for the Baltic Sea Rehder, Carstensen, Gustafsson HELCOM S&C, May 2018 15
Proposed acidification indicators for the Baltic Sea Rehder, Carstensen, Gustafsson HELCOM S&C, May 2018 Vision – Improved Assessment (Monitoring) of the Baltic Sea biogeochemistry through continuous CO 2 and GHG-observations on a basin wide scale • Carbon system parameters as best indicator for – Eutrophicaton – Acidification • Non-CO 2 GHG flux as ecosystem health indicator • High spatiotemporal resolution bears potential to detect trends and gradual changes • A Baltic Sea marine GHG measurement network • Potential for extension and remote sensing based extrapolation 16
Recommend
More recommend
