Biogeochemical transformation processes along lateral gradients. Christoph Humborg

Size: px

Start display at page:

Download "Biogeochemical transformation processes along lateral gradients. Christoph Humborg"

Leon Greer
6 years ago
Views:

1 Biogeochemical transformation processes along lateral gradients Christoph Humborg

2 Improve understanding on biogenic element inputs from the catchment Disentangle dynamics of terrestrial and marine derived DOM The role of DOC, DON and DOP on PP, pco 2, denitrification etc patterns

3 Land cover of the Baltic Sea Basin Urban areas Bare areas Cultivated land Pastures and natural grassland Open herbaceous vegetation with shrubs Lichens and mosses Cropland-woodland mosaic Wetlands Snow and ice Sparse vegetation Broadleaved deciduous closed forest Broadleaved deciduous open forest Mixed closed forest Mixed open forest Needleleaved closed forest Needleleaved open forest Water Ledwith (2003), GLC2000 project

Land cover of the Baltic Sea Basin Urban areas Bare areas Cultivated land Pastures and natural grassland Open herbaceous vegetation with shrubs Lichens and mosses Cropland-woodland mosaic Wetlands

4 Land cover of the Baltic Sea Basin Urban areas Bare areas Cultivated land Pastures and natural grassland Open herbaceous vegetation with shrubs Lichens and mosses Cropland-woodland mosaic Wetlands Snow and ice Sparse vegetation Broadleaved deciduous closed forest Broadleaved deciduous open forest Mixed closed forest Mixed open forest Needleleaved closed forest Needleleaved open forest Water

5 Land cover of the Baltic Sea Basin Urban areas Bare areas Cultivated land Pastures and natural grassland Open herbaceous vegetation with shrubs Lichens and mosses Cropland-woodland mosaic Wetlands Snow and ice Sparse vegetation Broadleaved deciduous closed forest Broadleaved deciduous open forest Mixed closed forest Mixed open forest Needleleaved closed forest Needleleaved open forest Water

6 Land cover of the Baltic Sea Basin Urban areas Bare areas Cultivated land Pastures and natural grassland Open herbaceous vegetation with shrubs Lichens and mosses Cropland-woodland mosaic Wetlands Snow and ice Sparse vegetation Broadleaved deciduous closed forest Broadleaved deciduous open forest Mixed closed forest Mixed open forest Needleleaved closed forest Needleleaved open forest Water

Improve DOC production: Dissolved organic carbon (DOC) submodel* litter decomposition f(t,θ) solid organic C (M) CO 2 emission vegetation T θ temperature

in water k s K τ constant reducing mineralisation of SSOC partitioning coefficient describing sorption equilibrium desorption kinetic constant DOC production

7 Improve DOC production: Dissolved organic carbon (DOC) submodel* litter decomposition f(t,θ) solid organic C (M) CO 2 emission vegetation T θ temperature volumetric water content P microbial decomposition at 20 C ρ peat bulk density s SSOC concentration Q 10 modifier to account for effect of T c DOC concentration in water k s K τ constant reducing mineralisation of SSOC partitioning coefficient describing sorption equilibrium desorption kinetic constant DOC production PρQ 10 (T 20)/10 dissolved organic C (θc) export DOC runoff desorption τρs water flux mineralisation µθc sorption τρkc sorbed soluble organic C (ρs) mineralisation µk s ρs

Ångermanälven Sollefteå Ljusnan Funäsdalen Indalsälven Bergeforsen Ljungan Skallböleforsen Delångersån Iggesund Gavleån Gävle Dalälven Älvkarleby Forsmarksån Johannisfors Norrström Stockholm

8 Råne älv Niemisel Torne älv Mattila Töre älv Infl.Bölträsket Kalix älv Karlsborg Lule älv Luleå Skellefte älv Slagnäs Alterälven Norrfjärden Pite älv Bölebyn Rickleån Utl Ume älv Stornorrfors Öre älv Torrböle Lögde älv Lögdeå Gide älv Gideåbacka Ångermanälven Sollefteå Ljusnan Funäsdalen Indalsälven Bergeforsen Ljungan Skallböleforsen Delångersån Iggesund Gavleån Gävle Dalälven Älvkarleby Forsmarksån Johannisfors Norrström Stockholm Nyköpingsån Spånga Motala Ström Norrköping Göta Älv Trollhättan Botorpström Brunnsö Viskan Åsbro Emån Emsfors Ätran Falkenberg Nissan Halmstad Ljungbyån Ljungbyholm Lagan Laholm Lyckebyån Lyckeby Mörrumsån Mörrum Rönneån Klippan Helgeån Hammarsjön precipitation ( ) ( ) mm yr 1 Simulated versus observed DOC concentration trends* TOC concentration trend (mgc l 1 yr 1 ) DOC production ( ) ( ) LPJ-GUESS gc m 2 yr 1 TOC (mgc l 1 ) Ljungbyån runoff DOC concentration ( ) ( ) LPJ-GUESS mgc l 1 *Measurements: T. Wällstedt Modelling: Guy Schurgers (wetlands only)

9 Total catchment N retention for 117 catchments draining to the Baltic Sea calculated by combining the results from the MESAW and DAISY models.

mol yr 1 1975 2000 2025 2050 2075 2100 mean scenario

10 Future climate scenarios DOC Alkalinity DIC ~ +25% ~ +15% ~ +25% Runoff to Bothnian Sea emissions scenario ECHAM5 mol yr mean scenario (A1B) business-as-usual (A2) best case (B1) RCA3 LPJ-GUESS CSIM

11 Annual fluxes (Tg) of TC, DIC and DOC compared to BB BS BP GF GR DS KT TC TC DIC DIC DOC DOC

12 2) Challenge: Separate the terrestrial DOM from marine produced DOM Terrestrial source (end member) δ 13 C = -28 Marine source (end member) δ 13 C = -21 δ 13 C = % terrestrial DOC 43 % marine δ 13 C: ( )

13 Share of terrestrial DOC % Bothnian Bay: 70-83% Bothnian Sea: 52-55% Baltic Proper: 43-50% Oder Bight: 60-72% Lat % 52% 50% 66% 70% 58 43% % Long

14 Hypotheses based on studies on DOC ter inferred from isotope signatures At salinities >2 the DOC ter distribution along the Baltic seems to be determined mainly by mixing. Most of the DOC ter removal (~50%) seems to occur in the estuaries.

15 WEGAS on board the German research vessel METEOR 87 (May/June 2012)

18 Conceptual model Expected isotope patterns for δ13c in CO2 and δ18o-o2 dissolved in water as a result of the different processes that drive the fractionation of the isotopes in the different pools.

$Respiration -27 CO 2-12.5 Production, isotope fractionation -13 Salinity=1.5 PSU Alk=0.$

19 River input DOC/DIC Salinity=0 PSU Alk=0.21 mmol/l DIC=0.25 mmol/l DOC=0.5 mmol/l PCO2=800 ppm Needed respiration to maintain isotope value is 32 mmol m -2 per day Respiration -27 CO Production, isotope fractionation -13 Salinity=1.5 PSU Alk=0.62 mmol/l DIC=0.65 mmol/l DOC=0.4 mmol/l PCO 2 =630 ppm CO2sys gives air sea flux of 20 mmol m -2 degassing per day.

$DOC ter (moles/m 3 ) 0,9 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0,1 0 100% refractory Filllipa Franser, MISU REM Deutsch et al.$

20 DOC ter (moles/m 3 ) 0,9 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0, % refractory Filllipa Franser, MISU REM Deutsch et al Station 0,35 DOC ter (moles/m 3 ) 0,3 0,25 0,2 0,15 0,1 0,05 100% labile 9.1 Deutsch et al DOC ter (moles/m 3 ) 0,35 0,3 0,25 0,2 0,15 0,1 0,05 Station 20% refractory, 80% labile 2.1 Deutsch et al Station

$100% labile 20% refractory, 80% labile$

21 100% labile 20% refractory, 80% labile Mean (water column) removal rate in tons/year

22 Meridional gradients of seasonal dynamics (statistics for ) Simulation Observations Bothnian Bay Phosphate, µm Gotland Sea Phosphate, µm Central Kattegat Phosphate, µm

23 Meridional gradients of seasonal dynamics (statistics for ) Simulation Observations Bothnian Bay Nitrate, µm Gotland Sea Nitrate, µm Central Kattegat Nitrate, µm

Simulated vs. observed primary production (the simulated are systematically lower) BB BS BPa Annual integrals (g C m-2 yr-1) simulated over two periods (mean ± s.d.) vs. literature data 1970/82 4.

24 Simulated vs. observed primary production (the simulated are systematically lower) BB BS BPa Annual integrals (g C m-2 yr-1) simulated over two periods (mean ± s.d.) vs. literature data 1970/ ± ± 3 52 ± 10 Data 12-20i 50-70i d 1994/ ± ± 3 98 ± 16 Data 16j 17i 32j 52i 65j 200i Table 2 Primary production in the major Baltic Sea basins, simulated with BALTSEM and compiled from published estimates for different time intervals a aggregation weighted with basin areas; b month of blooming in the model; c Dahlgren et al., 2010; d Renk and Ochocki, 1999; e Lignell, 1990; f Silina, 1967; g Savchuk, 2002 and references therein; h Rydberg et al., 2006; i- Wasmund et al., 2001a and references therein; j median value from Larsson et al., 2010; k Raateoja et al., 2004; l - Carstensen et al., 2003 Generally, both ERGOM and SCOBI give even lower simulated rates of PP!

25 Hypoxia effects on nitrogen pool in the Baltic Proper. Relationships between annual means of simulated and reconstructed from observations hypoxic volume and DIN pool (A) or reconstructed DIN pool with a 2 year delay and simulated bioavailable nitrogen (B) Dalsgaard et al. GCA 2013: When extrapolated to the entire Baltic Proper (BP) denitrification in the water column was in the range of kton N yr1 and was thus at least as important as sediment denitrification which has recently been estimated to 191 kton N yr1.

BONUS call 2012: Viable ecosystem Project: Biological lenses using

development based on the generation of high-resolution functional

Outcome: A publicly available resource with the capacity to deduce

biodiversity and genetic functional profiles of microbes, the

26 BONUS call 2012: Viable ecosystem Project: Biological lenses using gene prints (BLUEPRINT) Modified from: Matthew Vaughn Aim: Indicator development based on the generation of high-resolution functional databases throughout the Baltic Sea based on metagenomics. Outcome: A publicly available resource with the capacity to deduce environmental status and dominant biogeochemical pathways from the biodiversity and genetic functional profiles of microbes, the blueprint, in a seawater sample. Chial, H. (2008) Bioinformatic evaluation Indicative blueprints

27 WP5: Incorporation of BLUEPRINT in biogeochemical modeling

To develop a general model to quantitatively link CO2 and CH4 fluxes from aquatic ecosystems to primary productivity, degradation and outgassing using new isotope techniques >how much of

28 Outlook Develop more realistic catchment (hydrological and land surface) models -> DOM and nutrient retention are the big unknowns! Coastal degradation processes appear significant-> how much reaches the open Baltic? To develop a general model to quantitatively link CO2 and CH4 fluxes from aquatic ecosystems to primary productivity, degradation and outgassing using new isotope techniques >how much of the terrestrial respiration actually occurs in the sea? Shed light on DOM dynamics in the Baltic Sea-> how it contributes to nutrient dynamics and PP? DOM dynamics along the estuarine gradient in the Baltic play a similar important role as dissolved nutrient dymanamics but is poorly parameterized in the models -> new microbiological tools needed?

Baltic Sea Catchment Modelling

Baltic Sea Catchment Modelling BNI Catchment characteristics and threads CSIM model Modelling eutrophication issues and N and P fluxes Isotope studies in AMBER Christoph Humborg, Carl-Magnus Mörth, Erik