Publikasjoner
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Nygård, Elise; Kline, Simon Hasselø; Valestrand, Louise & Edvardsen, Bente
(2024).
Exploration of community dynamics of protists during the autumn season through metabarcoding and intensive sampling.
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Increasing anthropogenic stressors and climate change are contributing to shifts in phytoplankton communities, which has significant consequences for marine ecosystems and biogeochemical cycles. Temperate regions, like Southern Norway, have distinct spring and autumn phytoplankton blooms which often differ in species composition due to variations in temperature, salinity, and light conditions, as well as nutrient availability. However, the autumn bloom is less explored than the spring bloom. Traditionally, phytoplankton monitoring programs collect samples once a month in the production period, this frequency may miss important aspects of population dynamics and species composition, especially during periods with rapid environmental and biological changes.
This master’s project aims to get a better understanding of the phytoplankton autumn bloom in the Oslofjord. We intend to see if there is a difference in the composition and timing of the autumn bloom between the inner and outer Oslofjord, and whether frequent sampling reveals more of the changes over time and locality than traditional monthly sampling. This will be done through water sampling twice a week for about a month (mid-September to mid-October) in 2023 and 2024 from two marine sampling stations. The community diversity and composition will be examined by high throughput Illumina sequencing (using the V4 region of the 18S rRNA gene). Environmental factors, such as chlorophyll-a concentrations, along with nutrient and cDOM will be measured.
Preliminary results from 2023 indicate differences in chlorophyll-levels between the stations, as well as temporal differences. Additionally, there appears to be weekly fluctuations in chlorophyll levels even with frequent sampling.
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Kline, Simon Hasselø; Saubrekka, Karoline; Eikrem, Wenche; Valestrand, Louise; Egge, Elianne Dunthorn & Eiler, Alexander
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(2024).
Seasonal dynamics of the protist community in the Oslofjord and Skagerrak in a changing ocean.
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Protists and prokaryotes compose approximately 90% of the biomass in the oceans, and any changes within this microbial community are likely to have reverberating effects throughout the ecosystem. Due to climate coastal marine systems are experiencing increased freshwater discharge from land and a darkening of the water column along with changes in nutrient concentrations. The phenology is also changing and in the inner Oslofjord the spring blooms starts on average 2 weeks later that 15 years ago. The causes for this delay in unclear. In this study we examine the diversity and seasonal dynamics of the protist community by metabarcoding in the inner and outer Oslofjord, and possible changes during 14 years. Monthly plankton samples were collected at two localities and two depths during 2023 and similar samples were collected in 2009-2011, to be sequenced by current high throughput technology (Illumina). Various environmental parameters have been measured including CDOM (colored dissolved organic matter). We ask whether browning or other physico-chemical conditions can explain the delayed spring bloom and other observed changes in the protist community in the Oslofjord and Skagerrak.
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Myrann, Olav; Kline, Simon Hasselø; Andersen, Tom & Edvardsen, Bente
(2024).
The effects of light and salinity on growth of spring bloom diatoms in the Oslofjord.
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Diatoms dominate during the spring bloom in the Oslofjord, with members of the genera Skeletonema, Thalassiosira and Chaetoceros being among the most abundant. During the last 15 years there has been a recorded reduction in Skeletonema abundance during the spring bloom in the Inner Oslofjord, that may explain an overall reduction of diatom abundance. In comparison the concentration of other diatoms such as Chaetoceros spp. has remained stable in the same period. The concentration of dinoflagellates has remained stable in contrast to the decrease of diatom concentration since 2006.
The main aim of this master’s project is to obtain further knowledge on the abiotic factors affecting the important spring bloom diatom genera Skeletonema, Chaetoceros and Thalassiosira, and how environmental changes may affect their growth. To reach these aims, two different growth experiments using diatom cultures isolated from the spring bloom in the Oslofjord will be employed: 1) growing strains of Skeletonema and Chaetoceros separately under a combination of varying salinity and light intensity, and 2) conducting a common garden growth experiment with cultures of two additional diatom cultures Chaetoceros and Thalassiosira resulting in 4 species in total. The common garden growth experiment will test various conditions of salinity. The project will give insight into the dynamics of the spring blooming diatoms in the Oslo fjord and how they are affected by changes in salinity along with their interactions.
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Eliassen, Sigurd, skaar; Kline, Simon Hasselø; Andersen, Tom & Edvardsen, Bente
(2024).
Investigating the phytoplankton spring bloom dynamics n the Oslofjord by single species and common garden growth experiments.
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During the last 15 years there has been a gradual decrease of diatom concentration during the spring bloom in the inner Oslofjord. A part of this decrease may be explained by decrease of the concentration of the genus Skeletonema, while other important diatom genera such as Chaetoceros and Thalassiosira have maintained a stable concentration since 2006. The reason for this is unclear.
Possible causes for these changes include changes of the physical or chemical conditions. One potential driver of the observed changes can be coastal darkening due to climate change leading to shifting phytoplankton dynamics in the inner Oslofjord. An increase of light absorbing molecules of dissolved coloured organic matter (cDOM) transferred to the fjord from river input could reduce the growth of phytoplankton and potentially also shift the spring bloom to a later date. Under conditions with limited light, the phytoplankton taxa with the ability to grow at the lowest light intensity may be able to outcompete other competitors for the available light.
The aim of this master’s project is to get a better understanding of the dynamics of important spring bloom diatoms in the Oslofjord and possible explanations to the observed changes. By single-species growth experiments I will determine the compensation light intensity of strains of two diatom genera Chaetoceros and Thalassiosira grown at different salinities. In a common garden experiment strains of the two diatom genera will be grown together with a strain of Skeletonema under different light conditions, to determine their competitive ability to limiting irradiance. This may contribute to a better understanding of the changes in the spring bloom dynamic observed in the Oslofjord since 2006.
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Wahl, Andreas; Lie-Jensen, Anette Christensen & Kline, Simon Hasselø
(2024).
Jøss?! #141 - Biespy, avskyelig snømann som bonde og fulle menns interesse for fastbundet dame (Podcast).
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Delsett, Lene Liebe; Skogvoll, Vidar; Kline, Simon Hasselø & Jemterud, Torkild
(2023).
Abels tårn - Er det flest øyne eller føtter i verden?
[Radio].
NRK P2.
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Wahl, Andreas; Lie-Jensen, Anette Christensen & Kline, Simon Hasselø
(2023).
Jøss?! #136 - Zombieplankton, vettug grunn til å drikke tiss og drukningsdød i verdensrommet (Podcast).
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Jones, Elizabeth Marie; Reigstad, Marit; Espinel, Nadjejda; Gjerland, Audun; Goraguer, Lucie Hélène Marie & Hodal, helene
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(2022).
JC2-1 Joint cruise part 1 2021 : Cruise Report.
Septentrio Academic Publishing.
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The Nansen Legacy Joint Cruise 2, part 1 (JC2-1) 12-29 July 2021, continued the investigation of the interannual variability during the late summer season. At the same time will the cruise provide a late summer reference for the seasonal investigation that was separated to late summer and polar night 2019, and winter and spring 2021. The transect represents an environmental gradient going through the northern Barents Sea, and included 7 process stations (P1-P7) lasting 10-39 hrs. Additional CTD stations (NLEG) were taken between the process stations to increase the hydrographic resolution on the transect. The work started at 76°N at the open Atlantic Water dominated station P1, was sea ice covered from station P4 at 79 45.00 °N and included deep water stations at the P7 station at 82°N in the Nansen Basin.
The program included measurements and sampling from the atmosphere, sea ice, ocean and sea floor. Data collected includes several disciplines to map the physical environment, the chemical characterization and biological communities. Key parameters from the Nansen Legacy joint cruises were selected and included in this reduced sampling program, compared to the other joint cruises. An important aim was to characterize the northern Barents Sea to map the interannual variability, but also to see how the proceeding winter and spring conditions has impacted the environment and conditions this year. A third task is to carry out a shelf investigation that can complement the investigations in the deep Arctic Basin starting in late August. Tests and improvements of a modified pelagic trawl (Harstad) were carried out as preparations for the Arctic Basin cruise in late August 2021.
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Kline, Simon Hasselø
(2021).
A tale of six diatoms: an insight into the taxonomy of Arctic diatoms from different sea-ice communities and their physiological response to climate change.
Universitetet i Oslo.
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Publisert
30. sep. 2024 15:55
- Sist endret
18. sep. 2025 16:05
