Scheda di dettaglio – i prodotti della ricerca
| Dato | Valore |
|---|---|
| Title | Lake Level Fluctuations Boost Toxic Cyanobacterial "Oligotrophic Blooms" |
| Abstract | Global warming has been shown to strongly influence inland water systems, producing noticeable increases in water temperatures. Rising temperatures, especially when combined with widespread nutrient pollution, directly favour the growth of toxic cyanobacteria. Climate changes have also altered natural water level fluctuations increasing the probability of extreme events as dry periods followed by heavy rains. The massive appearance of Dolichospermum lemmermannii (= planktonic Anabaena), a toxic species absent from the pelagic zone of the subalpine oligotrophic Lake Maggiore before 2005, could be a consequence of the unusual fluctuations of lake level in recent years. We hypothesized that these fluctuations may favour the cyanobacterium as result of nutrient pulses from the biofilms formed in the littoral zone when the lake level is high. To help verify this, we exposed artificial substrates in the lake, and evaluated their nutrient enrichment and release after desiccation, together with measurements of fluctuations in lake level, precipitation and D.lemmermannii population. The highest percentage of P release and the lowest C:P molar ratio of released nutrients coincided with the summer appearance of the D.lemmermannii bloom. The P pulse indicates that fluctuations in level counteract nutrient limitation in this lake and it is suggested that this may apply more widely to other oligotrophic lakes. In view of the predicted increase in water level fluctuations due to climate change, it is important to try to minimize such fluctuations in order to mitigate the occurrence of cyanobacterial blooms. |
| Source | PloS one 9 (10), pp. e109526 |
| Keywords | BiofilmsCyanobacteriaLakesFresh watersShoresSpringSummerSurface water |
| Journal | PloS one |
| Editor | Public Library of Science, San Francisco, CA, Stati Uniti d'America |
| Year | 2014 |
| Type | Articolo in rivista |
| DOI | 10.1371/journal.pone.0109526 |
| Authors | Cristiana Callieri; Roberto Bertoni; Mario Contesini; Filippo Bertoni |
| Text | 328726 2014 10.1371/journal.pone.0109526 ISI Web of Science WOS 000345204000078 Scopus 2 s2.0 84907778044 Biofilms Cyanobacteria Lakes Fresh waters Shores Spring Summer Surface water Lake Level Fluctuations Boost Toxic Cyanobacterial Oligotrophic Blooms Cristiana Callieri; Roberto Bertoni; Mario Contesini; Filippo Bertoni Inst Ecosyst Study CNR; University of Amsterdam Global warming has been shown to strongly influence inland water systems, producing noticeable increases in water temperatures. Rising temperatures, especially when combined with widespread nutrient pollution, directly favour the growth of toxic cyanobacteria. Climate changes have also altered natural water level fluctuations increasing the probability of extreme events as dry periods followed by heavy rains. The massive appearance of Dolichospermum lemmermannii = planktonic Anabaena , a toxic species absent from the pelagic zone of the subalpine oligotrophic Lake Maggiore before 2005, could be a consequence of the unusual fluctuations of lake level in recent years. We hypothesized that these fluctuations may favour the cyanobacterium as result of nutrient pulses from the biofilms formed in the littoral zone when the lake level is high. To help verify this, we exposed artificial substrates in the lake, and evaluated their nutrient enrichment and release after desiccation, together with measurements of fluctuations in lake level, precipitation and D.lemmermannii population. The highest percentage of P release and the lowest C P molar ratio of released nutrients coincided with the summer appearance of the D.lemmermannii bloom. The P pulse indicates that fluctuations in level counteract nutrient limitation in this lake and it is suggested that this may apply more widely to other oligotrophic lakes. In view of the predicted increase in water level fluctuations due to climate change, it is important to try to minimize such fluctuations in order to mitigate the occurrence of cyanobacterial blooms. 9 Published version Articolo 2014_PLOS_ONE_9_10_109526.pdf Articolo in rivista Public Library of Science 1932 6203 PloS one PloS one PLoS ONE PloS one Public Library of Science one PLoS 1 roberto.bertoni BERTONI ROBERTO cristiana.callieri CALLIERI CRISTIANA TA.P04.016.004 Ecologia teorica e applicata degli ecosistemi acquatici |