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| NKS Programme Area: | NKS-B | | Research Area: | Radioecological assessments | | Report Number: | NKS-423 | | Report Title: | NKS-B NORCO - Nordic freshwater ecosystem microcosms study | | Activity Acronym: | NORCO | | Authors: | Tanya H Hevrøy, Anna-Lea Golz, Clare Bradshaw, | | Abstract: | Ecosystem response due to radiation exposure depends on the different species sensitivities and the multitude of direct and indirect pathways by which individual organisms can be affected, including the potential for complex interactions across mulitiple trophic levels. Multi-species model ecosystems (microcosms) were used to investigate effects of ionizing radiation on a model aquatic ecosystem including indirect effects caused by ecological interactions. Microcosms were exposed for 22 days to a gradient of gamma radiation with 4 decreasing doserates (20, 8, 2, 0.8 mGy/h). A range of endpoints were measured at different time points in order to capture effects on individual components of the ecosystems as well as whole-ecosystem processes. Individual and population growth was measured for all species; species interactions were measured in the form of grazing rates, whole ecosystem respiration and production were quantified; and mesurements ecosystem elements, nutrients status and cycling were collected. Plant growth rateswere generally lower in the irradiated treatments. Several photosynthetic parameters were negatively affected by radiation in a dose-dependent manner and ROS production increased with radiation dose in L. minor. Primary production decreased in all treatments during the first week and remained low for the duration of the experiment. Primary consumers were not effected by dose rates, however their impact on primary producers was significants. Abiotic measurements revealed simiair conditions between all microcosms. By taking an ecosystem approach, this study shows that the net effect of radiation in a simple aquatic ecosystem is a combination of the direct effects of radiation to the individual species with different relative radiosensitivity, and the direct effects mediated by ecological and abiotic processes. | | Keywords: | radioecology, radiation, microcosm, freshwater, ecosystem | | Publication date: | 18 Mar 2019 | | ISBN: | ISBN 978-87-7893-512-0 | | Number of downloads: | 1689 | | Download: |  NKS-423.pdf |
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