Crustacean zooplankton communities in lakes recovering from acidification

Abstract

Large reductions in sulphur emissions at the Sudbury, Ont., Canada, smelters in recent decades have resulted in decreased lake acidity, and biological improvements have followed. Lakes in the Sudbury area offer a very unique opportunity to develop our understanding of the processes regulating biological restructuring in aquatic ecosystems recovering from acidification. Here, we examine changes in crustacean zooplankton communities that have accompanied the chemical recovery of Whitepine and Sans Chambre lakes, near Sudbury, over the last two decades. In both these formerly acidic lakes, pH has increased to ~6.0, and some zooplankton community recovery has occurred. However, zooplankton communities have not completely recovered based on multivariate comparisons with the community composition of reference lakes. Although a number of acid-sensitive species have appeared, many did not persist, or did not achieve abundances typical of the reference lakes. This indicates that zooplankton community recovery will most likely depend on biotic and abiotic interactions within these lakes and not on factors affecting species dispersal. Both chemical and biological factors have large influences on biological recovery processes. Assessing biological recovery is very important since the restoration of healthy aquatic communities is a major objective of large-scale sulphur emission control programs.

Spatial, Environmental, and Biotic Determinants of Zooplankton Community Composition in Subarctic Lakes and Ponds in Wapusk National Park, Canada

“…In particular, the observed importance of sampling depth, TP, and color in explaining zooplankton community composition in HBL lakes agrees with the results of various other Ontario surveys that have identified factors related to depth, transparency, and nutrient status as important environmental correlates with zooplankton communities (e.g. Keller and Conlon, 1994;Keller et al, 2002;Yan et al, 2008).…”

Zooplankton recovery after fish removal: Limitations of the egg bank

“…This means that the recovery rates we observed were not affected by gradual changes in environmental conditions, as might occur when fish gradually die out on their own after the elimination of stocking Knapp et al 2001b) or when other types of perturbations, such as acidification and eutrophication, are reversed (Edmondson and Lehman 1981;Keller et al 2002). Discrete experimental reversal of the perturbation, combined with the low zooplankton diversity of high-elevation lakes, maximizes our ability to make inferences about species' intrinsic abilities to recover from perturbation.…”

Freshwater Diatoms as Indicators of Combined Long-Term Mining and Urban Stressors in Junction Creek (Ontario, Canada)

“…Anions (F − , Cl − , SO 4 2− , NO 3 − ) were analysed by ion chromatography (Dionex AutoIon; System DX300), TP was analyzed by persulfate digestion and manual colorimetry (SM 4500-PB), and DOC was analyzed using a total organic carbon analyzer (TOC-500A; Shimadzu). Cations (Na + , Mg 2+ , Al 3+ , K + , Ca 2+ , Mn 2+ , Fe 3+ , Ni 2+ , Cu 2+ , Cd 2+ , Pb 2+ , Zn 2+ ) were analyzed by inductively coupled plasma-atomic emission spectrometry (ICP-AES; Varian Vista AX CCD).…”

“…The health of Junction Creek was impacted by the contamination and degradation in its watershed, and showed highly impaired biological integrity [1]. Still nowadays, despite pollution control and rehabilitation actions having been undertaken, aquatic ecosystems in the region suggest slow recovery [2][3][4][5][6]. Mining activities are still present in the region, although under significantly more restrictive pollution control and regulation, and intensification of urban development represents a supplementary environmental threat.…”