Betydelsen av genetisk diversitet hos marina kiselalgen Skeletonema marinoi under och efter antibiotikastress
Heikkinen, Janni (2021)
Heikkinen, Janni
2021
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https://urn.fi/URN:NBN:fi-fe2021060233325
https://urn.fi/URN:NBN:fi-fe2021060233325
Tiivistelmä
Växtplankton har många viktiga funktioner för både marina ekosystem och det globala klimatet. De spelar en viktig roll i globala biogeokemiska cykler, och de är grunden för näringsväven i marina ekosystem. Specifikt kiselalger dominerar den produktiva vårblomningen i Östersjön. Både abrupta störningar och långsiktiga förändringar kan utsätta växtplankton för direkt och indirekt stress, vilket kan ha konsekvenser för hela ekosystemet. Därför är det viktigt att utreda vilka faktorer som påverkar växtplanktons tillväxt under och efter exponering till olika stressfaktorer. Tidigare studier tyder på att genetisk diversitet hos växtplankton buffrar de negativa effekterna orsakade av bland annat nedsatt salinitet, förhöjd temperatur och betning. Betydelsen av den genetiska diversiteten har dock inte undersökts under stress orsakat av att bakteriesamhället associerat med växtplankton rubbas. Forskning tyder på att växtplankton, speciellt kiselalger har unika bakteriesamhällen associerat med dem. Det finns tecken på att det associerade bakteriesamhället hos flera kiselalger är fördelaktiga, eller till och med livsviktiga för kiselalgernas tillväxt. För att undersöka rollen av det associerade bakteriesamhället och den genetiska diversiteten hos växtplankton, utfördes laboratorieexperiment. Som modellorganism användes kiselalgen Skeletonema marinoi som dominerar vårblomningen i Östersjön. För att undersöka betydelsen av det associerade bakteriesamhället hos S. marinoi, användes två stressbehandlingar bestående av en kombination av antibiotika. För att undersöka rollen av den genetiska diversiteten under, efter och utan antibiotikastress, jämfördes responsen av kulturer med och utan genetisk diversitet. Samtidigt undersöktes ifall de olika genotyperna hade fenotypiska skillnader i de mätta tillväxtparametrarna. En tillsättning av antibiotika hade en stark negativ effekt på tillväxten av S. marinoi. Genetiskt diversa kulturer återhämtade sig betydligt bättre från antibiotikastress i jämförelse med kulturer bestående av endast en genotyp. Genotyperna påvisade även fenotypiska skillnader i en del av de mätta tillväxtparametrarna i enlighet med tidigare studier. De erhållna resultaten understryker betydelsen av den genetiska diversiteten hos växtplankton vid olika stressfaktorer. Resultaten visar också att det krävs fler studier som undersöker betydelsen av interaktioner mellan växtplankton och andra mikroorganismer i marina habitat. Forskning kring ämnet är grundläggande för att förutspå responsen av växtplanktonsamhällen i Östersjön till miljöförändringarna som klimatförändringen kommer att orsaka. -----------
Phytoplankton have many important functions for both marine ecosystems and the global climate. Phytoplankton play a big role in global biogeochemical cycles and are the foundation of marine food webs. Moreover, diatoms dominate the productive spring bloom in the Baltic Sea. Both abrupt disturbances and long-term changes can subject phytoplankton to direct and indirect stress, which may lead to consequences for the entire ecosystem. Therefore, it is vital to investigate which factors affect phytoplankton growth during and after different stress factors. Previous studies suggest that genetic diversity in phytoplankton buffers against negative effects from stressors, such as reduced salinity, elevated temperatures, and grazing. However, the importance of genetic diversity has not been investigated during stress caused by a disruption of the bacterial community associated with phytoplankton. Studies suggest that phytoplankton, especially diatoms, harbor unique bacterial communities. There are indications of the bacterial communities associated with several diatoms being beneficial or even crucial for the diatom growth. Laboratory experiments were conducted to investigate the role of the associated bacterial community and genetic diversity in phytoplankton. The diatom Skeletonema marinoi, which dominates the spring bloom in the Baltic Sea, was used as a model organism. To study the importance of the bacterial community associated with S. marinoi, two stress treatments consisting of a combination of antibiotics were used. To investigate the role of genetic diversity during, after and without antibiotic stress, the response of cultures with and without genetic diversity were compared. Whether or not the different genotypes possessed phenotypic differences in the measured growth parameters was also investigated. The addition of antibiotics resulted in a strong negative effect on the growth of S. marinoi. Genetically diverse cultures showed significantly better recovery from antibiotic stress compared to cultures consisting of only one genotype. The different genotypes also showed phenotypic differences in some of the measured growth parameters in accordance with previous studies. The results obtained in this study emphasize the importance of genetic diversity in phytoplankton during different stressors. The results also highlight the need for more studies investigating the importance of interactions between phytoplankton and other microorganisms in marine habitats. Research of this subject is fundamental to predicting the response of phytoplankton communities in the Baltic Sea to the environmental changes that occur in conjunction with climate change.
Phytoplankton have many important functions for both marine ecosystems and the global climate. Phytoplankton play a big role in global biogeochemical cycles and are the foundation of marine food webs. Moreover, diatoms dominate the productive spring bloom in the Baltic Sea. Both abrupt disturbances and long-term changes can subject phytoplankton to direct and indirect stress, which may lead to consequences for the entire ecosystem. Therefore, it is vital to investigate which factors affect phytoplankton growth during and after different stress factors. Previous studies suggest that genetic diversity in phytoplankton buffers against negative effects from stressors, such as reduced salinity, elevated temperatures, and grazing. However, the importance of genetic diversity has not been investigated during stress caused by a disruption of the bacterial community associated with phytoplankton. Studies suggest that phytoplankton, especially diatoms, harbor unique bacterial communities. There are indications of the bacterial communities associated with several diatoms being beneficial or even crucial for the diatom growth. Laboratory experiments were conducted to investigate the role of the associated bacterial community and genetic diversity in phytoplankton. The diatom Skeletonema marinoi, which dominates the spring bloom in the Baltic Sea, was used as a model organism. To study the importance of the bacterial community associated with S. marinoi, two stress treatments consisting of a combination of antibiotics were used. To investigate the role of genetic diversity during, after and without antibiotic stress, the response of cultures with and without genetic diversity were compared. Whether or not the different genotypes possessed phenotypic differences in the measured growth parameters was also investigated. The addition of antibiotics resulted in a strong negative effect on the growth of S. marinoi. Genetically diverse cultures showed significantly better recovery from antibiotic stress compared to cultures consisting of only one genotype. The different genotypes also showed phenotypic differences in some of the measured growth parameters in accordance with previous studies. The results obtained in this study emphasize the importance of genetic diversity in phytoplankton during different stressors. The results also highlight the need for more studies investigating the importance of interactions between phytoplankton and other microorganisms in marine habitats. Research of this subject is fundamental to predicting the response of phytoplankton communities in the Baltic Sea to the environmental changes that occur in conjunction with climate change.