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Publikasjoner

NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.

2025

Abstract

One of the key challenges we face today is the changing climate and its environmental impacts, affecting all life on Earth. Examining historical human responses to climate crises provides insights into resilience and adaptability. Robust data is essential for studying past climate and environmental changes effectively. European climate records covering the past 2000 years reveal a prolonged cooling period, known as the Dark Ages Cooling Period (c. 300–800 CE), punctuated by a pronounced cooling in the mid-6th century. Studies show that these cold intervals are more complex and regionally varied than previously believed. In the 6th century in Norway, archaeological evidence points to crop failures, famine, farm abandonment and changes in social organization in some regions, while others experienced minimal impact during these cold periods. However, southeastern Norway lacks detailed high-resolution paleoclimate and paleoenvironmental reconstructions, limiting our ability to fully understand these events. This thesis aims to enhance understanding of climate, environmental, and societal dynamics in southeastern Norway over the past 2000 years, focusing on the Dark Ages Cold Period (c. 300–800 CE), through sediment analysis from Lake Sagtjernet and Lake Ljøgottjern in southeastern Norway. We introduce a μCT scan method for varve counting for Lake Sagtjernet, establishing the first varve chronology from a Norwegian lake, covering c. 4023 years. This chronology enables the first paleoclimate and paleoenvironmental reconstruction from Norwegian varved lake sediments. This reconstruction reveals 2000 years of temperature variability, highlighting a major cooling event—the largest in 2000 years—that aligns with the 6th century cooling event. However, sparse settlements in the first millennium complicate climate impact interpretation at Lake Sagtjernet, while the last millennium shows increased human activities during both warm and cold periods. Reconstructed temperatures between 200 and 1300 CE from Lake Ljøgottjern indicate a notably colder period from 300 to 800 CE, compared to the periods before (200–300 CE) and after (800–1300 CE), identified as the Dark Ages Cold Period. Temperature fluctuations within this cold period significantly influenced agricultural strategies at the more populated Lake Ljøgottjern. Warmer intervals favoring crop cultivation and colder intervals prompting a shift towards livestock farming, illustrating the impact of climatic conditions on societal development.

Abstract

Ice encasement (IE) is one of the big challenges in winter stress management on golf course putting greens in Northern Scandinavia. The turfgrass is damaged due to lack of oxygen (hypoxia or anoxia) and accumulation of toxic by‐products of anaerobic respiration. Breeding IE‐tolerant turfgrass species and varieties is the best defense against these challenges. A method to simulate ice encasement was tested to screen selected varieties of winter‐hardy bentgrass species and red fescue subspecies. Note that 32 varieties were chosen from the SCANGREEN trial seeded at NIBIO Landvik, Norway, in 2019. Samples were taken in December 2020, 2021, and 2022, vacuum sealed in plastic, and stored in darkness at 0.5°C for up to 77 days to test them for their tolerance to simulated ice encasement (SIE). Samples were incubated at different intervals; plants were potted, and tiller survival was tested after 4 weeks of regrowth. Lethal duration of ice encasement (LD 50 ) that is, the number of days under anoxia that kills 50% of the plant population for each species and variety was calculated. The results showed that the ranking of cool season turfgrass species for tolerance to SIE was velvet bentgrass > Chewings fescue > slender creeping red fescue = colonial bentgrass > creeping bentgrass. This ranking does not fully reflect the ranking found in field tests where velvet bentgrass was superior together with creeping bentgrass. SIE caused a more rapid development of anoxia than IE in the field, and we hypothesize that creeping bentgrass is less tolerant to these conditions compared to the other species tested. To make the SIE method more representative for IE in field, it should be further adapted with incubation at lower temperatures, and with acclimation conditions to be standardized prior to sampling. Within species, the best tolerance to IE was found in velvet bentgrass Nordlys, creeping bentgrass Penncross, Chewings fescue Lykke, and slender creeping red fescue Cezanne.