The use of zooplankton in a biomonitoring program to detect lake acidification and recovery (original) (raw)
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Lake acidification: effects on crustacean zooplankton populations
Environmental Science & Technology, 1993
The ranked acid sensitivities of six common crustacean zooplankton taxa were determined from a multilake field survey in Ontario and from laboratory bioassays. The two approaches gave the same ranking (from most to least sensitive): Daphnia galeata mendotae, Daphnia retrocurua, and Skistodiaptomus oregonensis > Diaphanosoma birgei > Mesocyclops edax > Bosmina longirostris. This finding suggests that acidification has caused the widespread damage which has been documented for the zooplankton of Ontario and northeastern U.S. lakes.
Crustacean zooplankton communities in lakes recovering from acidification
Canadian Journal of Fisheries and Aquatic Sciences, 2002
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.
Freshwater Biology, 1990
I. During the summer of 1987 we conducted an acidification experiment using large enclosure al Emerald Lake, a dilute, high-clcvation lake in the Sierra Nevada, California., U.S.A. The experiment was designed to examine the effects of acidification on the zooplankton and zoobenthos assemblages of Sierran lakes. 2. Treatments consisted of a control (pH 6.3) and pH levels of 5.8, 5.4, 5.3, 5.0 and 4.7; each treatment was run in triplicate. The experiment lasted 35 days. 3. The zooplankton assemblage was sensitive to acidification. Daphnia rosea Sars emend. Richard and Diaptomus sigtiicauda Lilljclwrg decreased in abundance below pH 5.5-5.8, and virtually disappeared below pH 5.0. Bosmina longirostris (Mliller) and Keratella laurocephala Ahlstrom became more abundant with decreasing pH. although B. longirostris was rare in the pH 4.7 treatment. These species might serve as reliable indicators of early acidification in lakes such as Emerald Lake. 4. The elimination of D. rosea in acidified treatments probably allowed the more acid-tolerant taxa to increase in abundance because interspecific competition was reduced. Even slight acidification can therefore alter the structure of the /ooplankton assemblage. 5. In contrast to the zooplankton, there was no evidence that the zoobenthos in the enclosures was affected by acidification.
Freshwater Biology, 2012
1. Acidification has damaged biota in thousands of lakes and streams throughout eastern North America. Fortunately, reduced emissions of sulphur dioxide and nitrogen oxides beginning in the 1960s have allowed pH levels in many affected systems to increase. Determining the extent of biological and pH recovery in these systems is necessary to assess the success of emissions reductions programmes. 2. Although there have been promising signs of biological recovery in many systems, recovery has occurred more slowly than expected for some taxa. Past studies with crustacean zooplankton indicate that a mixture of local abiotic variables, biotic variables and dispersal processes may influence the structure of recovering communities. However, most studies have been unable to determine the relative importance of these three groups of variables. 3. We assessed chemical and biological recovery of acid-damaged lakes in Killarney Park, Ontario. In addition, we assessed the relative importance of local abiotic variables, biotic variables and dispersal processes for structuring recovering communities. We collected zooplankton community data, abiotic and biotic data from 45 Killarney Park lakes. To assess the recovery of zooplankton communities, we compared zooplankton data collected in 2005 to a survey conducted for the same lakes in 1972-73 using several univariate measures of community structure, as well as multivariate methods based on relative species abundances. To determine the factors influencing the structure of recovering zooplankton communities, we used hierarchical partitioning for univariate measures and spatial modelling and variation partitioning techniques for multivariate analyses. 4. Our survey revealed significant pH increases for the majority of sampled lakes but univariate measures of community structure, such as species richness and diversity, indicated that only minor changes have occurred in many acid-damaged lakes. Hierarchical partitioning identified several variables that may influence our univariate measures of recovery, including pH, dissolved organic carbon (DOC) levels, fish presence ⁄ absence, lake surface area and lake elevation. 5. Multivariate methods revealed a shift in communities through time towards a structure more typical of neutral lakes, providing some evidence for recovery. Variation partitioning suggested that the structure of recovering copepod communities was influenced most by dispersal processes and abiotic variables, while biotic (Chaoborus densities, fish presence ⁄ absence) and abiotic variables were more important for cladoceran zooplankton. 6. Our results indicate that the recovery of zooplankton communities in Killarney Park is not yet complete, despite decades of emission reductions. The importance of variables related to acidification, such as pH and DOC, indicates that further chemical recovery may be necessary. The
Responses of zooplankton to long-term environmental changes in a small boreal lake
Boreal Environment Research, 2014
lehtovaara, a., arvola, l., Keskitalo, J., olin, m., rask, m., salonen, K., sarvala, J., tulonen, t. & vuorenmaa, J. 2014: responses of zooplankton to long-term environmental changes in a small boreal lake. Boreal Env. Res. 19 (suppl. a): 97-111.
Freshwater Biology, 2010
1. Recovery of acidified aquatic systems may be affected by both abiotic and biotic processes. However, the relative roles of these factors in regulating recovery may be difficult to determine. Lakes around the smelting complexes near Sudbury, Ontario, Canada, formerly affected by acidification and metal exploration, provide an excellent opportunity to examine the factors regulating the recovery of aquatic communities. 2. Substantial recovery of zooplankton communities has occurred in these lakes following declines in acidity and metal concentrations, although toxicity by residual metals still appears to limit survival for many species. Metal bioavailability, not simply total metal concentrations, was very important in determining effects on zooplankton and was associated with a decrease in the relative abundance of cyclopoids and Daphnia spp., resulting in communities dominated by Holopedium gibberum. 3. As chemical habitat quality has improved and fish, initially yellow perch and later piscivores (e.g. smallmouth bass, walleye), have invaded, biotic effects on the zooplankton are also becoming apparent. Simple fish assemblages dominated by perch appear to limit the survival of some zooplankton species, particularly Daphnia mendotae. 4. Both abiotic (residual metal contamination) and biotic (predation from planktivorous fish) processes have very important effects on zooplankton recovery. The re-establishment of the zooplankton in lakes recovering from stress will require both improvements in habitat quality and the restoration of aquatic food webs.
Environmental Toxicology and Chemistry, 1988
A laboratory acidification experiment was conducted with a Rocky Mountain zooplankton assemblage from a subalpine lake located downwind of energy development activities and significant sources of acid precursors. The objective of the study was to assess the relative effects of lowered pH (treatment pH 4.2 and 5.2, control pH 6.8) on the survival of different crustacean zooplankton species under controlled conditions for extended periods (19 to 41 d). Analysis of variance (e.g., F = 4.55, p c: 0.05) indicated statistically significant differences between controls and treatments (acid treatments contained fewer individuals than did controls) for all four species, and significant differences among species. Newman-Keuls multiple range tests (e.g., q = 4.02, p < 0.025) demonstrated the following ranking of species sensitivity (high to low) to a lowered pH of 5.2:
Canadian Journal of Fisheries and Aquatic Sciences, 2003
Identifying thresholds of biotic community change along stressor gradients may be useful to both ecologists and lake managers; however, there are several weaknesses in the thresholds that have been identified for zooplankton communities along acidity gradients. The thresholds are often based on a single species even though pH sensitivities vary among species. They often measure changes in species occurrences, though abundances may be a more responsive indicator of damage. Their identification may be confounded by spatial and morphometric factors if they are derived from lake surveys. Finally, the thresholds have usually been subjectively identified. Our goal was to establish a threshold in zooplankton community change along an acidity gradient that did not have these four common weaknesses. We used two crustacean zooplankton community metrics: species richness and scores of a correspondence analysis based on species abundances. Spatial and morphometric patterns were detected in the ...
THE INFLUENCE OF DROUGHT-INDUCED ACIDIFICATION ON THE RECOVERY OF PLANKTON IN SWAN LAKE (CANADA)
Ecological Applications, 2001
In response to North American and Western European reductions in atmospheric emissions of SO 2 , research efforts are now being focused on the recovery of aquatic ecosystems from acidification. Improvements in water quality have been hampered by drought-induced acidification events, but the biological consequences of such events have not been described. We present evidence of biotic recovery in Swan Lake near Sudbury, Canada, in response to water quality improvement, then demonstrate the damaging impacts of a 1988 re-acidification event. Changes in species composition, richness, diversity, and multivariate indices were assessed from 1977 to 1997 for phytoplankton, from 1977 to 1990 for rotifers, and from 1977 to 1998 for crustacean zooplankton. While there was some evidence of recovery in the plankton during the 1980s, recovery was incomplete at the time of the re-acidification event. We suspect that the severity of past acidification, ongoing water quality problems, and biological resistance to colonization restricted recovery. The response of each taxonomic group to re-acidification varied. The recovery of both phytoplankton and rotifer communities was impaired by the re-acidification event; both phytoplankton and rotifers reverted to a damaged state, with the effect on phytoplankton lasting seven years. The recovering crustacean zooplankton community was not obviously influenced by the re-acidification event, probably because most acid-sensitive taxa had not recolonized the lake at the time of re-acidification. There was, however, an unexpected response of the crustacean zooplankton to re-acidification. While phytoplankton and rotifer richness decreased, crustacean richness increased even though lake pH fell from near 6 to 4.5. We hypothesize that the explanation is a complex interaction among chemical and physical changes associated with the lake's re-acidification. Specifically we hypothesize that a massive hatching event of zooplankton resting eggs was triggered by increases in light, temperature, or oxygen concentrations at the sediment-water interface and/or desiccation of littoral sediments during the drought.