Advanced

Geochemistry of stream plants and its statistical relations to soil- and bedrock geology, slope directions and till geochemistry : a GIS-analysis of small catchments in northern Sweden

Eriksson, Harry LU (2017) In Master Thesis in Geographical Information Science GISM01 20171
Dept of Physical Geography and Ecosystem Science
Abstract
Subaquatic mosses and stream plants have been recognized as suitable sample media for detection of geochemical variations in their surrounding environments. These plants were originally used in search for mineral deposits but later on also for detection of environmental pollution. In this study it is investigated if statistically significant correlations could be detected between element content in subaquatic stream plant roots and some spatial parameters related to their catchments, which not necessarily contain mineral deposits or are polluted. Many small accurately outlined catchments and geological data therein from SGU were compared for a 2500 km2 large area in the inland of Västerbotten, northern Sweden.

Research questions:
(1)... (More)
Subaquatic mosses and stream plants have been recognized as suitable sample media for detection of geochemical variations in their surrounding environments. These plants were originally used in search for mineral deposits but later on also for detection of environmental pollution. In this study it is investigated if statistically significant correlations could be detected between element content in subaquatic stream plant roots and some spatial parameters related to their catchments, which not necessarily contain mineral deposits or are polluted. Many small accurately outlined catchments and geological data therein from SGU were compared for a 2500 km2 large area in the inland of Västerbotten, northern Sweden.

Research questions:
(1) Is there a statistical difference in geochemistry between subaquatic stream plant samples from catchments with different types of bedrock?
(2) Is there a statistical difference in geochemistry between subaquatic stream plant samples from catchments with different types of quaternary deposits?
(3) Is there a statistical difference in geochemistry between subaquatic stream plant samples from catchments with different dominating down slope directions, north or south?
(4) Is there a statistical correlation between the geochemistry of sub aquatic stream plants and the geochemistry of the till soils in their catchments?

The main results:
(1) For most elements there were no significant correlations between geochemistry, in plant samples and bedrock types. However, some trace elements (Cu, Ni, Rb and Zn) correlated positively with meta-sediments (negatively with granites) and some other (As, Mo, S, U, V, W, Y and Zr) correlated positively with granitic rocks (negatively with meta-sediments).
(2) For 6 of 27 elements (Al, Cu, Rb, Sr, U and Y) there were significant decreases in plant samples when percentage of peat cover increased in the catchments. Decrease of detrital particles and trapping of elements in the peat could be possible explanations. The areas of the other cover types (bare rocks and sediments) were too small to be interpreted.
(3) No differences in element contents of stream plants were detected related to percentage of down slope directions in the catchments.
(4) For 10 of 23 elements (Mn, Ba, Cu, Ni, Rb, Sr, U, Y, Zn and Zr) there were significant positive correlations between geochemistry, in stream plants and till soils in their catchments.

Generally, strong correlations between geochemistry of subaquatic stream plant samples and investigated landscape parameters are not found in this study. (Less)
Popular Abstract (Swedish)
Prover av bäckvattenväxters rötter har visat sig vara användbara för att detektera geokemiska variatoner i omgivande landskap. Ursprungligen användes de för att hitta malmfyndigheter men senare också för att detektera miljöföroreningar. I detta arbete undersöktes om det fanns statistiskt signifikanta korrelationer mellan metallinnehållet i prover av dessa rötter relaterade till ett antal landskapsparametrar inom provernas avrinningsområden, som inte nödvändigtvis innehåller mineralfyndigheter eller är förorenade. Ett stort antal noggrant beräknade avrinningsområden och geologiska data inom dessa jämfördes över ett 2500 km2 stort område i Västerbottens inland, norra Sverige.

Följande frågor ställdes:
(1) Finns det statistiska skillnader... (More)
Prover av bäckvattenväxters rötter har visat sig vara användbara för att detektera geokemiska variatoner i omgivande landskap. Ursprungligen användes de för att hitta malmfyndigheter men senare också för att detektera miljöföroreningar. I detta arbete undersöktes om det fanns statistiskt signifikanta korrelationer mellan metallinnehållet i prover av dessa rötter relaterade till ett antal landskapsparametrar inom provernas avrinningsområden, som inte nödvändigtvis innehåller mineralfyndigheter eller är förorenade. Ett stort antal noggrant beräknade avrinningsområden och geologiska data inom dessa jämfördes över ett 2500 km2 stort område i Västerbottens inland, norra Sverige.

Följande frågor ställdes:
(1) Finns det statistiska skillnader mellan geokemin i bäckvattenväxtprover från avrinningsområden med olika typer av berggrund?
(2) Finns det statistiska skillnader mellan geokemin i bäckvattenväxter från avrinningsområden med olika typer av kvartära jordavlagringar?
(3) Finns det statistiska skillnader mellan geokemin i bäckvattenväxter från avrinningsområden med olika dominerande sluttningsriktningar, åt norr eller söder?
(4) Finns det statistiska korrelationer mellan geokemin i bäckvattenväxter och geokemin i avrinningsområdenas moränjord.

Övergripande resultat:
(1) För de flesta undersökta metallelementen (ca 25 st.) fanns det inget signifikant statistiskt samband mellan geokemin i bäckvattenväxterna och den för berggrunden. Emellertid, så uppvisade några spårelement (Cu, Ni, Rb och Zn) viss positiv korrelation med metasediment (negativ med graniter) och ett antal andra (As, Mo, S, U, V, W och Y) korrelerade positivt med granitiska bergarter (negativt med metasediment).
(2) För 6 av 27 undersökta element (Al, Cu, Rb, Sr, U och Y) noterades en statistiskt signifikant minskning i bäckväxterna när halten av torv i avrinningsområdena ökade (i förhållande till morän). En minskande halt av mineralpartiklar och fastläggande av ämnen i torvmarkerna är möjliga förklaringar. Övriga jordarter (t.ex. grus/sand och silt/lera) hade för liten areal täckning för att kunna tolkas.
(3) Ingen skillnad i geokemin noterades för bäckvattenväxterna relaterat till de två olika sluttningsriktningarna i avrinningsområdena.
(4) För 10 av 23 element (Mn, Ba, Cu, Ni, Rb, Sr, U, Y, Zn och Zr) fanns det, om än svaga, statistiskt signifikanta positiva korrelationer mellan halterna i bäckvattenväxter och de i avrinningsområdenas moränjord.

Sammanfattningsvis, så fanns det inget starkare statistiskt samband mellan geokemin i bäckvattenväxterna och de undersökta landskapsparametrarna inom avrinningsområdena. (Less)
Please use this url to cite or link to this publication:
author
Eriksson, Harry LU
supervisor
organization
course
GISM01 20171
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Biogeochemistry, GIS, Physical Geography and Ecosystem analysis, Geographical Information Systems, Geochemistry, Catchments, Drainage areas
publication/series
Master Thesis in Geographical Information Science
report number
73
language
English
id
8908936
date added to LUP
2017-06-01 13:24:03
date last changed
2017-06-01 13:24:03
@misc{8908936,
  abstract     = {Subaquatic mosses and stream plants have been recognized as suitable sample media for detection of geochemical variations in their surrounding environments. These plants were originally used in search for mineral deposits but later on also for detection of environmental pollution. In this study it is investigated if statistically significant correlations could be detected between element content in subaquatic stream plant roots and some spatial parameters related to their catchments, which not necessarily contain mineral deposits or are polluted. Many small accurately outlined catchments and geological data therein from SGU were compared for a 2500 km2 large area in the inland of Västerbotten, northern Sweden.

Research questions:
(1) Is there a statistical difference in geochemistry between subaquatic stream plant samples from catchments with different types of bedrock?
(2) Is there a statistical difference in geochemistry between subaquatic stream plant samples from catchments with different types of quaternary deposits?
(3) Is there a statistical difference in geochemistry between subaquatic stream plant samples from catchments with different dominating down slope directions, north or south?
(4) Is there a statistical correlation between the geochemistry of sub aquatic stream plants and the geochemistry of the till soils in their catchments?

The main results:
(1) For most elements there were no significant correlations between geochemistry, in plant samples and bedrock types. However, some trace elements (Cu, Ni, Rb and Zn) correlated positively with meta-sediments (negatively with granites) and some other (As, Mo, S, U, V, W, Y and Zr) correlated positively with granitic rocks (negatively with meta-sediments).
(2) For 6 of 27 elements (Al, Cu, Rb, Sr, U and Y) there were significant decreases in plant samples when percentage of peat cover increased in the catchments. Decrease of detrital particles and trapping of elements in the peat could be possible explanations. The areas of the other cover types (bare rocks and sediments) were too small to be interpreted.
(3) No differences in element contents of stream plants were detected related to percentage of down slope directions in the catchments.
(4) For 10 of 23 elements (Mn, Ba, Cu, Ni, Rb, Sr, U, Y, Zn and Zr) there were significant positive correlations between geochemistry, in stream plants and till soils in their catchments.

Generally, strong correlations between geochemistry of subaquatic stream plant samples and investigated landscape parameters are not found in this study.},
  author       = {Eriksson, Harry},
  keyword      = {Biogeochemistry,GIS,Physical Geography and Ecosystem analysis,Geographical Information Systems,Geochemistry,Catchments,Drainage areas},
  language     = {eng},
  note         = {Student Paper},
  series       = {Master Thesis in Geographical Information Science},
  title        = {Geochemistry of stream plants and its statistical relations to soil- and bedrock geology, slope directions and till geochemistry : a GIS-analysis of small catchments in northern Sweden},
  year         = {2017},
}