Morgan T. Jones Centre for Earth Evolution and Dynamics (CEED) University of Oslo

Atmospheric & Oceanic Chemistry Land-Ocean Flux Riverine transport Subsurface flow Solid particles

Benthic Processes Dissolution/precipitation Pore waters Hydrothermal Interaction

Biological activity Nutrients (N, P, Fe, Ca) Carbonates

Atmospheric Evaporation/precipitation Aerosols, Dust, Gases

Effects on radiation budget

(Jones et al., 2016)

Stratospheric vs tropospheric injection leads to varying effects

Explosive Eruption Products

Solids consist of minerals, volcanic glass, and country rock Can be transported 1000’s km from source Some volatile phases cool to form salts, condensates & aerosols ‘Ash-leachates’ are very soluble, dissolving quickly in water

After Óskarsson, 1980

Giant Ash Blankets

Largest explosive eruptions can eject >1016 kg material Ash blankets can cover over 106 km2 Ecological response varies with depositional environment

Jones (2015)

Jones (2015)

Terrestrial Ash Deposition Effects

Ash can bury, abrade, or overload vegetation Chemical changes from nutrient and acid release (Ayris & Delmelle, 2012)

Flora varies considerably in resistance to ash loading Lichen >1 cm (Antos & Zobel, 1985)

Mature Pine Trees > 75 cm (Eggler, 1948)

Changes to soils - respiration, decomposition

Post Pinatubo 1991 (volcanoes.usgs.gov)

Jones (2015)

Response depends on volume, chemistry, and buffering effects Systems with low turnover rates (e.g. soils, lakes) particularly vulnerable (Frogner-Kockum et al., 2006)

Acids and metals mostly accumulate in top soils Less groundwater contamination but More incorporation into flora and food chain Can lead to skeletal fluorosis (e.g. Laki 1783)

Ash Leachates

Terrestrial surface changes

Ash can be very reflective (high Si and vesicularity) Reduced evapotranspiration & soil respiration, more runoff

Jones et al. (2007)

Model simulation of an ash blanket from Yellowstone affecting North America High albedo, reduced flora, 50 year duration

Jones et al. (2007)

Terrestrial surface changes

Temperature changes

High albedo + vegetation loss = surface cooling Surface changes affect jet streams, Global response

Jones et al. (2007)

Lower latent heat flux = More stable atmosphere Combined with lower moisture supply = Less precipitation Changes to cloud coverage, surface pressures, global weather patterns

Precipitation changes

Jones et al. (2007)

Ocean circulation changes

North Atlantic overturning from three similar models

Residence Times

Governed by rates of remobilisation and erosion Therefore, geomorphology and climate Fine ash is cohesive, inhibits erosion Slope erosion clogs lakes and river valleys (Adamson et al., 1982)

Ecosystem Recovery

Slower at higher latitudes / larger ash blankets Requires seeding by wind/animals Can be inhibited by insects (Knight & Chase, 2005)

Ecological recovery at Krakatau (after Bush, 2006)

Oceanic Effects

Light shading from ash deposition, resuspension, primary productivity Affects benthic photosynthesis Particles can kill filter-feeding organisms (Wall-Palmer et al., 2011)

Fertilization

Ash & ash-leachates rich in key nutrients (N, P, Si, Fe, Mn, Zn…) Many studies show volcanic ash as a fertilizer May increase ‘carbon pump’ to depth

Reviewed in Duggen et al. (2010); Langmann et al. (2010); Hoffmann et al. (2012)

Fertilization

Olgun et al (2013)

In 2010, a century record of Sock-eye Salmon in Fraser River catchment 35 million salmon Average = 2.1 million

Fertilization

Fertilization Potential of Ocean Waters

Traingles = volcanoes active in Holocene

Nutrients N, P, Fe and others essential for phytoplankton growth Fe is main limiting nutrient in High-Nutrient Low-Chlorophyll (HNLC) water

Poisoning

Toxic metals and acids released (Cu, Zn, Cd, Pb, SO4, HF) Lower pH affects CaCO3 saturation and free metal activities (Cu2+, Al3+) Diatoms > Coccolithophores > Cyanobacteria (Hamme et al., 2010; Hoffmann et al., 2012)

pH change in seawater

Jones & Gislason (2008)

Volcanic activity from 1995 to present

Dome growth and dome collapse events

Major collapses in 2003 and 2006

Case Study: Soufrière Hills, Montserrat

Wall-Palmer et al. (2011)

Toxicity Effects: Caribbean Case Study

Toxicity Effects

Wall-Palmer et al. (2011)

From surface of Core 21M (1270m) unaffected by ash fall

From Core 25M (878m) under May 2006 ash layer (3-4cm)

Test surface

Test surface Wall structure

Wall structure Wall structure

Wall structure

SEM images of pteropod tests

Wall-Palmer et al. (2011)

Long-term Climate Change

Remains contentious… Several possible avenues

CO2 fixation mainly occurs in oceans

Animals live, die, and sink Carbon export (organic & inorganic) Affects atmospheric CO2 concentrations

A) Primary Productivity

Hypothesis: Large scale volcanism fertilises HNLC waters (Bay et al., 2004, Cather et al., 2009)

Unknowns: Organic Recycling Volume, duration, and depositional area of eruption Contemporaneous volcanic effects

106 CO2 + 16 NO3- + HPO4

2- + 122 H2O +

18 H +

Photosynthesis Respiration

C106H263O110N16P + 138 O2

~ CO2 + H2O —> CH2O + O2

B) Silicate Weathering

Hypothesis: Chemical weathering of volcanic ash consumes atmospheric CO2 (Gislason et al., 2009)

1 mole Ca2+/Mg2+ =1 mole CO2 consumed

CaAl2Si2O8 + 2 CO2 + 3H2O —>

Al2Si2O5(OH)4 + Ca++ + 2HCO3– ...>

... CaCO3 + CO2 + H2O

Timeframe: 104 - 107 years Sequestration: 0.15Gt(C)/yr Limitation: Speed Effects: The regulation of pCO2

Most important areas are wet, young, and mountainous

Global fluxes of suspended sediment

Milliman & Farnsworth (2011)

Enhanced weathering of igneous material

Basalt: 6.85 x 106 km2 4.6% cont. surface area 30-35% of the terrestrial silicate weathering flux (Dessert et al., 2003)

Weathering vs substrate age (Porder et al., 2007; Vance et al., 2009)

C) Carbon Burial

Hypothesis: Enhanced C burial in sediments

Vertical density currents (Manville & Wilson, 2004)

Transport adhered to ash

Poor recycling efficiency Rapid oxygen depletion from Fe2+ oxidation (Hembury et al., 2012)

Strong preservation of organic C

C) Carbon Burial

On land, burial of soil and flora Taupo ignimbrite covered 20,000 km2 and buried 1km3 of podocarp forest (Hudspith et al., 2010)

Slower decomposition in buried soils (Ayris & Delmelle 2012)

Mt Hood, Oregon - USGS

Summary

• Ash deposition effects subject to many variables

• e.g. Location, volume, chemistry, climate, season, depositional environment

• On land: Vegetation loss and albedo change

• At sea: Fertilization and toxic possibilities

• Long-term climate change - Several potential avenues to lower atmospheric CO2

References • Achterberg, E.P. et al. (2013) Natural iron fertil ization by the Eyjafjallajökull volcanic eruption. Geophys. Res. Lett., 40, 1-6. • Adamson, D.A. et al. (1982) Palaeogeography of the Gezira and of the lower blue and white Nile rivers, 165–219. In: A land between two Niles: Quaternary Geology

and biology of the central Sudan. Balkema, Rotterdam. • Antos, J.A., Zobel, D.B. (1985) Recovery of forest under-stories buried by tephra from Mount St. Helens. Vegetatio., 642(2-3), 103-111. • Ayris, P.M., Delmelle, P. (2012) The immediate environmental effects of tephra emission. Bull. Volc., 74, 1905-1936. • Bay, R.C. et al. (2004) Bipolar correlation of volcanism with millennial climate change. Proc. Natl. Acad. Sci. USA, 101, 6341 -6345. • Browning, T.J. et al. (2014) Strong responses of Southern Ocean phytoplankton communities to volcanic ash. Geophys. Res. Lett., 41(8), 2851–2857. • Bush, M.B. (2006) Ecology of a changing planet. 3rd Ed. Prentice Hall. • Cather, S.M. et al. (2009) Climate forcing by iron fertil ization from repeated ignimbrite eruptions: The icehouse-sil icic large igneous province (SLIP) hypothesis.

Geosphere, 5, 315-324. • Dessert, C. et al. (2003) Basalt weathering laws and the impact of basalt weathering on the global carbon cycle. Chemical Geology, 202, 257 -273. • Duggen, S. et al. (2010) The role of airborne volcanic ash for the surface ocean biogeochemical cycle: a review. Biogeosci . Disc., 6, 6441-6489. • Eggler, W.A. (1948) Plant communities in the vicinity of the volcano El Paricutin, Mexico, after two and a half years of eruption. Ecology, 29(4) , 415-436. • Frogner-Kockum, P.C. et al. (2006) A diverse ecosystem response to volcanic aerosols. Chem. Geol., 231, 57 -66. • Gislason, S.R. et al. (2009) Direct evidence of the feedback between climate and weathering. Earth Planet. Sci. Lett., 277(1 -2), 213-222. • Hamme, R.C. et al. (2010) Volcanic ash fuels anomalous plankton bloom in subarctic northeast Pacific. Geophys. Res. Lett., 37, L19604. • Hembury, D.J. et al. (2012) Uptake of dissolved oxygen during marine diagenesis of fresh volcanic material. Geochim. Cosmochim. Acta, 84, 353-368. • Hoffmann, L.J. et al. (2012) Influence of trace metal release from volcanic ash on growth of Thalassiosira pseudonana and Emiliania huxleyi. Mar. Chem., 132-133, 28-

33. • Hudspith, V.A. (2010) Charring of woods by volcanic processes: An example from the Taupo ignimbrite, New Zealand. Palaeogeogr. Palaeoclimatol. Palaeoecol., 291,

40-51. • Jones, M.T. (2015) The environmental and climatic impacts of volcanic ash deposition. In: Volcanism and Global Environmental Change, Cambridge Uni. Press, 260-274 • Jones, M.T. et al. (2007) The climatic impact of supervolcanic ash blankets. Clim. Dyn., 29, 553-564. • Jones, M.T., Gislason, S.R. (2008) Rapid releases of metal salts and nutrients following the deposition of volcanic ash into aqueous environments. Geochim.

Cosmochim. Acta, 72, 3661-3680. • Jones, M.T., et al. (2016) The effects of large igneous provinces on the global carbon and sulphur cycles, Palaeogeography, Palaeoclimatology, Palaeoecology, 441, 4-

21. • Knight, T., Chase, J. (2005) Ecological Succession: Out of the Ash. Curr. Biol., 15, R926-R927. • Langmann, B. et al. (2010) Volcanic ash as fertil iser for the surface ocean, Atmos. Chem. Phys., 10, 3891–3899. • Manville, V., Wilson, C.J.N. (2004) Vertical density currents: a review of their potential role in the deposition and interpretation of deep -sea ash layers. J. Geol . Soc.,

161, 947-958. • Milliman, J., Farnsworth, K.L. (2011) River Discharge to the Coastal Ocean: A Global Synthesis. Cambridge University Press. • Olgun, N. et al. (2013) Geochemical evidence of oceanic iron fertil ization by the Kasatochi (2008) volcanic eruption and evaluation of the potential impacts on sockeye

salmon population. Mar. Ecol.-Prog. Ser., 488, 81-88. • Oskarsson, N. (1980) The interaction between volcanic gases and tephra: fluorine adhering to tephra of the 1970 Hekla eruption. J. Volcanol. Geoth. Res., 8, 251-266. • Porder, S. et al. (2007) Chemical weathering, mass loss, and dust inputs across a climate by time matrix in the Hawaiian Islands. Earth Planet. Sci. Lett. 258, 414–427. • Robock A. (2000) Volcanic eruptions and climate. Reviews of Geophysics, 38(2), 191–219 • Vance, D. et al. (2009) Variable Quaternary chemical weathering fluxes and imbalances in marine geochemical budgets. Nature, 458, 493 -496. • Wall-Palmer, D. et al. (2011) Explosive volcanism as a cause for mass mortality of pteropods. Mar. Geol., 282, 3-4, 231-239.

Jones, MT (2015), Volcanism and Global Environmental Change, p.260-274