Unexpected increases in rotifer resting egg abundances during the period of contamination of Lake Orta

Piscia, Roberta; Tabozzi, Simone; Bettinetti, Roberta; Nevalainen, Liisa; Manca, Marina

doi:10.4081/jlimnol.2016.1300

Cited by 12 publications

(20 citation statements)

References 44 publications

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“…Finally, from 2001 to 2007 (Phase 4), we detected only a slight additional increase in N rotifer (from 76 to 81) and N crustacea (from 30 to 31), associated with the stabilization of good water quality in the lake, e.g., constant low levels of Cu and Cr, and circumneutral pH (Fig 2). To detect the role of the rotifer egg bank we tested the correlation between the cumulative number of rotifer taxa (N rotifer ) and the cumulative curve of rotifer resting stages extracted from a sediment core (latter data from Piscia et al, 2016), which resulted not statistically significant (Spearman's r=0.31, P<0.05).…”

Section: Resultsmentioning

confidence: 99%

“…Cladocera and rotifers, and also some copepods, produce resting stages which can survive in sediments for decades (Hairston et al, 1995), where they constitute a genetic reserve of potential colonists (Hairston, 1996). Rotifer resting eggs extracted from a Lake Orta sediment cores confirm the presence of an egg bank (Piscia et al, 2012;Piscia et al, 2016). Both the composition (i.e., morphotypes) and the abundance of this internal reserve were related to the different phases of recovery in the lake.…”

Section: Discussionmentioning

confidence: 96%

“…To determine the role of the internal rotifer egg bank we compared the cumulative curve of rotifer resting eggs extracted from a Lake Orta sediment core previous analysed (Piscia et al, 2016) to the cumulative curve of annual new taxa. Between-sample differences in colonist taxa persistence, P, were analyzed by the parametric Scheffé test, while Spearman's rank correlation coefficient, R, was used to test the statistical significance between cumulative data of rotifer resting egg and cumulative data of new taxa in the pelagic column.…”

Section: N O N -C O M M E R C I a L U S E O N L Ymentioning

confidence: 99%

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Mechanisms underlying recovery of zooplankton in Lake Orta after liming

2016

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The goal of this study was to improve the understanding of the large-scale mechanisms underlying the recovery of the zooplankton of Lake Orta from historical contamination, following reduced input of ammonia and metals and the subsequent 1989/90 liming intervention. The industrial pollution had been severe and long-lasting (1929-1990 2001 and 2007 (0.55 and 0.72 for rotifers, 0.85 and 0.86 for crustacean, respectively), much higher than in limed lakes in Sudbury, Canada, and in adjacent Lake Maggiore. We hypothesize this could be related to the lack of Cladoceran predators and zooplanktivorous fish in the pelagic waters of Lake Orta.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 96%

Section: N O N -C O M M E R C I a L U S E O N L Ymentioning

confidence: 99%

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Mechanisms underlying recovery of zooplankton in Lake Orta after liming

2016

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“…High resolution analysis of Lake Orta sediment core also provided evidence for persistence of rotifers during periods of contamination, with increased abundance of resting eggs of different morphotypes. Unlike most other organisms, which were extirpated by the pollution of the lake, rotifers survived, producing resting eggs, attempting to secure future generations (Piscia et al, 2012;Piscia et al, 2016b).…”

Section: The Ecosystem Perspectivementioning

confidence: 99%

What have we learned about ecological recovery from liming interventions of acid lakes in Canada and Italy?

2016

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We adopted an ecosystem perspective, by: i) exploring timing and mechanisms through which the biota responded to changes in hydrochemistry; ii) identifying common versus unique responses in a comparison of similar case studies on a large scale; iii) disentangling specific roles of primary (heavy metals) vs secondary (acidification), direct (chemical) vs indirect (predator/prey), and regional (colonist supply) vs local (colonist survival and growth) regulators of recovery of the biota; and iv) attempting to identify transition points to new, stable communities. If we can circumvent the almost unavoidable issue of lack of replication, and include appropriate hypotheses, controls, and pre-and post-manipulation data, a liming intervention can be comparable to a whole lake experiment. It can provide an opportunity for testing ecosystem-level responses to strictly controlled changes in the physical and chemical environment. Such wholelake experiments have a long tradition in North America, but it is rare that the results of whole-lake restoration experiments in the acidification field have been compared between North America and Europe.Lake Orta and many lakes in Sudbury, Ontario, Canada, suffered from acidification and metal pollution, albeit from different sources. For Lake Orta, the source of acidity was oxidation of ammonia wastes from a textile factory (Bonacina et al., 1986), while for Sudbury lakes, the source was atmospheric deposition of strong, S-based acidity from both the local smelting of metal-rich sulphide ores and long-range transport (Yan et al., 1996). Heavy metals were also greatly elevated in both cases (Calderoni et al., 1992;Keller et al., 2007). In Sudbury, both catchments and several urban lakes were limed, while lime was added directly to Lake Orta.This comparison of Lake Orta with the Sudbury case studies was extremely fruitful. By applying bioassays, Celis-Salgado et al. (2016) found that differences in metal-tolerances, and differences in recovery rates of native Canadian Daphnia species were mediated by calcium and sodium concentrations in Sudbury lakes, and thus their recovery was influenced not just by residual metals, but also by road salt and background geology. From Lake Orta, Di Cesare et al. (2016) learned that because heavy metal pollution may be coupled with antibiotic presence in nature, there may be co-selection for multiple resistances. Lake Orta thus appears to be an excellent location to evaluate the spread and selection of heavy metals and antibiotic resistances in heavily disturbed environments. Macrobenthic assemblages were slow to recover in both countries, but there were success stories. In Sudbury lakes the littoral macrobenthos community remained severely impoverished after catchment liming, indicating that land reclamation would be necessary in severely damaged watershed, before lake ecosystems can recover . In Lake Orta, mussels were extirpated by industrial copper and ammonium sulphate pollution, soon after 1926, when a rayon factory began operations on the lakeshor...

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“…Nonetheless, the vulnerability and the instability of the lake were pointed out by the last survey including chemical and biological information carried out in 2001 (Bonacina, 2001). For example, nowadays the zooplankton community is more structured and diversified than in the past, but it seems that still remains substantially different from the original one (Piscia et al, 2016).…”

Section: Introductionmentioning

confidence: 99%