| Title | Unexpected increases in rotifer resting egg abundances during the period of contamination of Lake Orta |
| Abstract | Despite their ecological importance and rapid response to environmental changes, rotifers are rarely included in palaeolimnological studies. Here, we describe changes in abundance (ABD) and morphotype (MTs) diversity of rotifer resting eggs in the sediments of deep subalpine Lake Orta, Italy, covering a period prior to (pre-) 1926, during long-term ammonia and metal pollution from a rayon factory, and subsequent recovery of water quality. Following the pollution and bacterial oxidation of the ammonia, Lake Orta became the largest and deepest acid lake in Europe. Recovery of water quality followed both a ban on the discharge of industrial wastes, and a liming intervention in 1989 and 1990. We sectioned a sediment core collected from the deepest part of the lake (ORTA 07/2A) to provide a high time resolution, given the ca. 3-4 y cm-1 of sediment accumulation. Rotifer resting egg (RRE) abundance and morphotypes were examined from the sediments and compared to limnological variables indicating the pollution. Rotifer resting egg abundance significantly increased with lake contamination (r=0.609 and -0.624 for copper and pH, respectively; P<0.001; n=27). A lake-water copper concentration threshold of ca. 40 µg L-1discriminated among pre-, during-, and post- pollution compositions of the rotifer morphotype assemblages. Diversity and morphotype richness increased during the recovery from copper pollution and with complete restoration from acidity, while abundance increased during pollution. The persistence of presumably viable Brachionus resting eggs and of hatched egg cases during the heavy pollution phase suggests that, unlike most other organisms, which were extirpated by the pollution of the lake, rotifers survived producing resting eggs, which secured future generations. |
| Source | Journal of limnology (Testo stamp.) 75 (2S), pp. 76–85 |
| Keywords | Copper and ammonia pollutionDiapauseLake OrtaPaleo-ecotoxicologyRotifera |
| Journal | Journal of limnology (Testo stamp.) |
| Editor | Istituto per lo Studio degli Ecosistemi., Verbania Pallanza, Italia |
| Year | 2016 |
| Type | Articolo in rivista |
| DOI | 10.4081/jlimnol.2016.1300 |
| Authors | Piscia R.; Tabozzi S.; Bettinetti R.; Nevalainen L.; Manca M.M. |
| Text | 386296 2016 10.4081/jlimnol.2016.1300 Scopus 2 s2.0 84964878811 Copper and ammonia pollution Diapause Lake Orta Paleo ecotoxicology Rotifera Unexpected increases in rotifer resting egg abundances during the period of contamination of Lake Orta Piscia R.; Tabozzi S.; Bettinetti R.; Nevalainen L.; Manca M.M. National Research Council, Institute of Ecosystem Study, Largo Tonolli 50, Verbania Pallanza, 28922, , Italy; Department of Theoretical and Applied Sciences, University of Insubria, Via Valleggio 11, Como, 22100, , Italy; Department of Biological and Environmental Science, University of Jyvaskyla, P.O. Box 35, Jyvaskyla, 40014, , Finland Despite their ecological importance and rapid response to environmental changes, rotifers are rarely included in palaeolimnological studies. Here, we describe changes in abundance ABD and morphotype MTs diversity of rotifer resting eggs in the sediments of deep subalpine Lake Orta, Italy, covering a period prior to pre 1926, during long term ammonia and metal pollution from a rayon factory, and subsequent recovery of water quality. Following the pollution and bacterial oxidation of the ammonia, Lake Orta became the largest and deepest acid lake in Europe. Recovery of water quality followed both a ban on the discharge of industrial wastes, and a liming intervention in 1989 and 1990. We sectioned a sediment core collected from the deepest part of the lake ORTA 07/2A to provide a high time resolution, given the ca. 3 4 y cm 1 of sediment accumulation. Rotifer resting egg RRE abundance and morphotypes were examined from the sediments and compared to limnological variables indicating the pollution. Rotifer resting egg abundance significantly increased with lake contamination r=0.609 and 0.624 for copper and pH, respectively; P<0.001; n=27 . A lake water copper concentration threshold of ca. 40 µg L 1discriminated among pre , during , and post pollution compositions of the rotifer morphotype assemblages. Diversity and morphotype richness increased during the recovery from copper pollution and with complete restoration from acidity, while abundance increased during pollution. The persistence of presumably viable Brachionus resting eggs and of hatched egg cases during the heavy pollution phase suggests that, unlike most other organisms, which were extirpated by the pollution of the lake, rotifers survived producing resting eggs, which secured future generations. 75 Published version http //www.scopus.com/inward/record.url eid=2 s2.0 84964878811 partnerID=q2rCbXpz Articolo 2016_Journal_of_Limnlogy_75_2s_76_85.pdf Articolo in rivista Istituto per lo Studio degli Ecosistemi. 1129 5767 Journal of limnology Testo stamp. Journal of limnology Testo stamp. J. limnol. Testo stamp. Journal of limnology. Testo stamp. roberta.piscia PISCIA ROBERTA marinamarcella.manca MANCA MARINA MARCELLA |
