Search results for "orgaaniset aineet"
showing 3 items of 3 documents
Maankäytön ja maaperäeläinten vaikutus ravinteiden ja torjunta-aineiden valuntaan peltomaasta
2011
Tehomaatalous pyrkii maksimoimaan maan tuottavuutta. Samalla se saattaa kuitenkin vaikuttaa negatiivisesti agroekosysteemien ravinnekiertoon ja maaperän rakenteeseen. Maaperäeläinten toiminnallisen monimuotoisuuden pieneneminen voi osaltaan heikentää maan ravinnekiertoa ja rakennetta. Tässä tutkimuksessa kasvatettiin mikrokosmoksissa vehnää ja verrattiin tehomaatalouskäytössä olleen maan ja laidunmaan kykyä pidättää ravinteita (N) ja torjunta-aineita (metributsiini) sekä tutkittiin, miten änkyrimadot ja lierot vaikuttavat ravinteiden ja torjunta-aineen valuntaan. Laidunmaa pidätti torjunta-ainetta paremmin kuin tehomaatalousmaa, mikä johtui lähinnä laidunmaan suuremmasta orgaanisen aineen p…
A stable isotope study of the hydrological and carbon cycle in meromictic lake, Lovojärvi
2012
Lake Lovojärvi, at its deepest point of 17.5 m, is permanently stratified forming two water layers. The mixolimnion (the upper layer, from 0 to 10 m depth) is affected by seasonal changes while the monimolimnion (bottom layer, from 10 to 17.5 m depth) does not mix and is not affected by seasonal changes. As a result, the lake stores large quantities of dissolved inorganic carbon and methane. I used a multiple stable isotope approach to gain insight into the carbon cycle and water balance of Lovojärvi. The δ18O and δ2H profiles reveal that at the 7 m depth in the mixolimnion, there is a sub-surface stream whose isotopic characteristics are similar to surface streams from a nearby mire, sugge…
Ecosystem responses to increased organic carbon concentration: comparing results based on long-term monitoring and whole-lake experimentation
2019
Recent increases in terrestrial dissolved organic carbon (DOC) concentrations in northern inland waters have many ecological consequences. We examined available data on carbon cycles and food webs of 2 boreal headwater lakes in southern Finland. Basic limnology and catchment characteristics of a pristine lake, Valkea-Kotinen (VK), were monitored over the past 25 years while the lake has undergone browning and DOC increased from similar to 11 to 13 mg L-1. Pronounced changes in the early 2000s represent a regime shift in DOC concentration and color. Lake Alinen Mustajarvi (AM) was manipulated for 2 years by additions of labile DOC (cane sugar), raising the DOC concentration from similar to 1…