Náttúrufræðingurinn - 2019, Síða 69

Tímarit Hins íslenska náttúrufræðifélags
141
staðir hafa sérstöðu á heimsvísu, vegna
virkni foksins og eðlis fokefnanna. Það
er mikilvægt að fylgjast vel með þróun
þessara svæða, meðal annars í tengslum
við hörfun jökla vegna hlýnunar jarðar
og breytinga í kjölfar jökulhlaupa. Miklu
skiptir að efla rannsóknir á uppfoki á
ryki og áhrifum þess á vistkerfi, loftslag
og lýðheilsu, svo dæmi séu tekin.
Þar sem auðnir landsins hafa
stækkað verulega á síðustu þúsöld hefur
endurfok efna sem falla á ógróið land
aukist mjög. Það hefur margvísleg nei-
kvæð áhrif, bæði vegna efna frá megin-
uppsprettum ryks og vegna öskufalls,
meðal annars á lýðheilsu. Það er full
ástæða til að huga betur að vistkerfum
í nágrenni virkra eldstöðva á borð við
Heklu og Kötlu út frá þessu sjónar-
miði.22,75 Öflugir fræberandi birkiskógar
ættu að vera markmið vistheimtar á
þessum svæðum, því slíkt gróðurfar
þolir áföllin vel og birkiskógar dreif-
ast ört út aftur eftir náttúruleg áföll, sé
fræframboð mikið og sauðfjárbeit tak-
mörkuð.76,77 Einnig þarf að draga sem
verða má úr sléttu yfirborði, svo sem
úr steypu og malbiki, í þéttbýli nærri
umferðarmannvirkjum og auka tré- og
runnagróður sem bindur rykefni og
dregur úr loftmengun.
ENGLISH SUMMARY
icelaNdic saNdy deserts aNd
aeOliaN PrOcesses – ii. dust
The paper is one of two in this jour-
nal reviewing the nature of sandy des-
erts and aeolian processes in Iceland
with this one primarily focused on dust.
Iceland rates among the most produc-
tive dust areas on Earth with annual
dust production of the order of >10 mil-
lion tons per year. The frequency is >135
dust storms per annum, and most likely
much higher than that. Dust deposition
is a major factor shaping all ecosystems
as the dust is the primary component of
the soil parent materials together with
volcanic ash deposited during erup-
tions. The sources of dust have changed
over the last millennia from being pri-
marily soil materials due to man-in-
duced ecosystem collapse to being
primarily more confined dust desert
areas of continuous silty sediment accu-
mulation. These areas are floodplains
in front of glaciers, areas along glacial
rivers subjected to major flood events,
glacial lakes with fluctuating water lev-
els, and shorelines close to the outlet of
major glacial rivers. These areas include
Dyngjusandur, Mælifellssandur, Haga-
vatnsaurar, Mýrdalssandur, areas at
both sites of the outlets of the Markar-
fljót and Kúðafljót rivers, and Skeiðarár-
sandur. Dyngjusandur, north of Vatna-
jökull glacier, rates among the most pro-
ductive dust sources on Earth and the
dust is blown 100’s and even 1000’s of
km into the Arctic areas. Dust pollution
often exceeds health limits in Iceland,
even at great distances from the major
dust sources. The dust often has a high
component of very fine particles (PM1)
and dust grains of that size are often
elongated with sharp edges which is
also negative from the health aspect.
The basaltic composition of the dust
leads to rapid soil weathering rates that
enhances the fertility of ecosystems in
Iceland. The high iron content may also
enhance fertility of oceans around Ice-
land. The dust has influence on atmo-
spheric conditions such as formation
of clouds and albedo. Dust increases
rates of snow and glacial melt and may
enhance climate warming.
18. Ólafur Arnalds, Pavla Dagsson-Waldhauserová & Haraldur Ólafsson 2016. The
Icelandic volcanic aeolian environment: Processes and impacts – A review.
Aeolian Research 20. 176–195.
19. Gunnhildur Ingibjörg Georgsdóttir 2012. Sandfok á Íslandi 2002 til 2012: Tíðni,
upptakasvæði og veðuraðstæður. MS-ritgerð við jarðvísindadeild Háskóla
Íslands, Reykjavík.
20. Þröstur Þorsteinsson, Guðrún Gísladóttir, Bullard J. & McTainsh G.H. 2011.
Dust storm contributions to airborne particulate matter in Reykjavík, Iceland.
Atmospheric Environment 45. 5924–5933.
21. Leadbetter, S.J., Hort, M.C., von Löwis S., Weber, K. & Witham, C.S. 2012.
Modeling the resuspension of ash deposited during the eruption of Eyja-
fjallajökull in spring 2010. Journal of Geophysical Research 117(D20). doi.org
/10.1029/2011JD016802
22. Guðmundur Halldórsson, Anna María Ágústsdóttir, Ása L. Aradóttir, Ólafur
Arnalds, Nilsson, C., Hreinn Óskarsson, Mortensen, L., Pagneux, E., Pilli-
Sihvola, K., Raulund-Rasmussen, K., Kristín Svavarsdóttir & Tolvanen, A. 2017.
Ecosystem restoration for mitigation of natural disasters. TemaNord 2017. 546.
23. Bistrow, C.S. & Moller, T.H. 2018. Dust production by abrasion of aeolian
sands: Analogue for Martian Dust. Journal of Geophysical Research – Planets.
doi:10.1029/2018JE005682
24. Pavla Dagsson-Waldhauserová, Ólafur Arnalds & Haraldur Ólafsson 2014.
Long-term variability of dust events in Iceland. Atmospheric Chemistry and
Physics 14. 13411–13422.
25. Bullard, J.E. 2013. Contemporary glacigenic inputs to the dust cycle. Earth
Surface Processes and Landforms 38. 71–89.
26. Esther Hlíðar Jensen, Davíð Egilsson, Svava Björk Þorláksdóttir, Snorri
Zóphóníasson & Gunnar Sigurðsson 2017. Mælingar á aurburði og rennsli
í Jökulkvísl árin 2015 og 2016. Landsvirkjun og Orkusalan (LV –2017–126,
ORK–1702), Reykjavík.
27. Pavla Dagsson-Waldhauserová, Ólafur Arnalds, Haraldur Ólafsson, Skrabalova,
L., Guðmunda María Sigurðardóttir, Branis, M., Hladil, J., Skala, R., Havratil, T.,
Chadimova, L., von Lowis of Menar, S., Þröstur Þorsteinsson, Carlsen, H.K. &
Ingibjörg Jónsdóttir 2014. Physical properties of suspended dust during moist
and low wind conditions in Iceland. Icelandic Agricultural Sciences 27. 25–39.
28. Pavla Dagsson-Waldhauserová, Ólafur Arnalds & Haraldur Ólafsson 2013.
Long-term frequency and characteristics of dust storm events in Northeast
Iceland (1949–2011). Atmospheric Environment 77. 117–127
29. Pavla Dagsson-Waldhauserová, Ólafur Arnalds & Haraldur Ólafsson 2017. Long
term dust aerosol production from natural sources in Iceland. Journal of the
Air & Waste Management Association 67. 173–181.
30. Moroni B., Ólafur Arnalds, Pavla Dagsson Waldhauserová, Crocchianti, S.,
Vivani R. & Cappelletti, D. 2018. Mineralogical and chemical records of
Icelandic dust sources upon Ny-Ålesund (Svalbard Islands). Frontiers in Earth
Science 2018. 187–219, doi:10.3389/feart.2018.00187
31. Þröstur Þorsteinsson, Þorsteinn Jóhannsson, Stohl A. & Kristiansen, N. 2012.
High levels of particulate matter in Iceland due to direct ash emissions by
the Eyjafjallajökull eruption and resuspension of deposited ash. Journal of
Geophysical Research. 117 (B00C05).
32. Pavla Dagsson-Waldhauserová, Agnes Ösp Magnúsdóttir, Haraldur Ólafs-
son & Ólafur Arnalds 2016. The spatial variation of dust particulate matter
concentrations during two Icelandic dust storms in 2015. Atmosphere 7(6),
3–18. doi:10.3390/atmos7060077 7. 77
33. Lea María Lemarquis 2018. Frequency and origin of dust events in Fljótshlíð,
South Iceland, in 2017. BS-ritgerð við jarðvísindadeild Háskóla Íslands, Reykjavík.
34. Esther Hlíðar Jensen, Davíð Egilson, Emmanuel Pagneux, Bogi B. Björnsson,
Snorri Zóphóníasson, Snorri Páll Snorrason, Ingibjörg Jónsdóttir, Ragnar H.