MODELLING (WP3)

WP3 MODELING (NIVA-lead, MSUG, SIORAS, PML, BB)

Objective: Assess the local and regional impacts of Arctic permafrost-derived inputs (organic matter, methane, trace elements) on marine chemistry and the planktonic ecosystem.

Description: We hypothesize that cascade effects of Arctic permafrost-derived inputs (see Figure 1) could have substantial impacts on marine ecosystem functioning and services, including carbon sequestration and absorption of anthropogenic CO2. WP3 will test this hypothesis using a suite of models covering the upper marine sediments, water column, and overlying ice, resolving the interactions of organic matter, methane and trace element inputs with bacterial/planktonic ecosystems (Figure 2). WP3 will use field observations and experimental results from (WP1,WP2) to develop model parameterizations and test/validate the model results, and will deliver impact scenarios at local to global scales to WP4 for socio-ecological analysis.

Figure 2. Coupled model suite for investigating the impacts of permafrost-derived emissions on the marine environment and ecosystem services at local to regional scales

T3.1 Scenarios of land-derived permafrost emissions (NIVA/1.5, MSUG /0.5). T3.1 will use catchment models (Simply, Jackson-Blake et al., 2017; TEOTIL, Thomsland et al., 2010) to derive future Arctic riverine/groundwater inputs of freshwater, sediments, and nutrients, accounting for terrestrial permafrost melt, under different climate change scenarios.

T3.2 Scenarios of subsea permafrost emissions (MSUG /1.5, NIVA/0.5). T3.2 will use a subsea permafrost dynamics model (Nicolsky et al., 2012) driven by new BEST-Siberian scenarios of bottom water warming (T3.4) to derive future permafrost-derived fluxes through the upper marine sediments under different climate change scenarios.

T3.3 Local-scale impacts of permafrost-derived emissions on marine biogeochemistry (NIVA/5, PML/1, BB/2) will use a 1D/2D BROM model (Yakushev et al., 2017) covering ice, water, and upper sediments, coupled to a dynamical bubble evolution model (Leifer et al., 2000; McGinnis et al., 2006) and input permafrost-derived fluxes from T3.2 to assess the impacts of permafrost-derived inputs on local marine biogeochemistry (informing T4.2 and T4.3). Model coupling will be facilitated using the FABM approach (Bruggeman and Bolding, 2014).  This model set will use input fluxes from T3.2, and will be used to develop parameterizations of permafrost-derived fluxes to the water column suitable for incorporation into regional models (T3.4) and ESMs.

T3.4 Basin-scale impacts of permafrost-derived emissions on marine biogeochemistry (NIVA/5, PML/2, BB/1, SIORAS/1). T3.4 will investigate the regional impacts of permafrost-derived emissions on marine biogeochemistry and ecosystem services (informing T4.2, T4.3) using a ROMS ocean model (Shchepetkin and McWilliams, 2005) on a pan-Arctic grid (Roed et al., 2014), coupled to the CICE model for sea ice (Hunke and Lipscomb, 2010). The biological model here will build on the ERSEM model (Butenschon, 2016) with modules from BROM-biogeochemistry (Yakushev et al., 2017), again using the FABM approach for model coupling. T3.4 will use land-derived inputs from T3.1 and subsea emissions from T3.2. Within this model, the parameterizations will be tested and refined for future incorporation into global ESMs.

Deliverables: D3.1 Report on riverine/groundwater inputs accounting for terrestrial permafrost melt, under different climate change scenarios. D3.2 Report on future permafrost-derived fluxes through the upper marine sediments under different climate change scenarios. D3.3 Paper on local-scale PfT-derived fluxes to the water column and impacts on sediments and water column biogeochemistry. D3.4 Paper on basin-scale impacts of PfT-derived emissions on marine biogeochemistry.

Milestones: M3.1 Terresital Inputs evaluated. M3.2 Subsea permafrost emissions evaluated. M3.3 Local scale parameterizations of PfT-derived fluxes elaborated. M3.4 Parameterizations of impacts of PfT- derived emissions on marine biogeochemistry on the the pan-Arctic scale tested and refined for future incorporation into global ESMs.

Modeled seasonal and interannual variability of nutrient (NUT), particulate organic matter (POM) dissolved organic matter (POM), phytoplankton (PHY) and heterotrophs (HET) in mmol N/m3, and dissolved oxygen (OX) in mmol O2/m3

Distributions of DIC, Alk, pCO2, pH, CaCO3, aragonite saturation (Om_Ar), CH4, CH4 in bubbles (Bubble) and dissolved oxygen (Oxy) in the transect after 3 years of seeping for MS scenario.