LABORATORY ACIDIFICATION OF A CRUSTACEAN ZOOPLANKTON ASSEMBLAGE FROM A ROCKY MOUNTAIN SUBALPINE LAKE (U.S.A) (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.
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.
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.
The use of zooplankton in a biomonitoring program to detect lake acidification and recovery
Water, Air, & Soil Pollution, 1993
A detailed review of the zooplankton literature found strong evidence that lake acidification consistently causes declines in crustacean and rotifer species richness, the relative abundance of cyclopoids and daphnids, and the relative abundance of 16 particular zooplankton species. Five species were found to consistently increase as lake pH declines. Inconsistent effects were observed on crustacean biomass and mean organism size. Biomonitoring response variables recommended to detect incipient community changes include the relative abundance of pH sensitive species, overall crustacean and rotifer community composition plotted in abundance ordination space, crustacean and rotifer species richness, and the relative abundance of acid tolerant species. If acidification effects have been detected using the above response variables, then more detailed monitoring to understand the functional characteristics of affected systems (e.g. crustacean biomass, rotifer biomass and/or overall community size spectra) is appropriate. A lake selection procedure is recommended to maximize the number of systems containing sensitive species, and ensure a set of reference systems whose acidity is unlikely to change significantly. -3, 12, 14
Can J Fisheries Aquat Sci, 1996
By comparing long-term changes in the crustacean zooplankton communities of three experimentally limed lakes near the Sudbury, Ontario, metal smelters with both temporal and spatial reference lakes distant from Sudbury, we (i) demonstrate the value of reference lakes for studies of recovery, (ii) compare univariate versus multivariate indicators of recovery, and (iii) determine if the pace of recovery was regulated by the severity of acid and metal contamination. The reference lakes provide recovery targets and norms of interannual variability. As indicators of damage and recovery, the performance of the univariate metrics was richness = diversity > evenness > abundance. Multivariate metrics were developed by projecting the Sudbury data onto a correspondence analysis of the spatial reference data. Univariate and multivariate approaches were equally sensitive for metrics based on species presence; however, the multivariate metrics incorporating the relative abundances of taxa were the best overall performers. While the two more acidic (pH 4.5) lakes had not recovered 15 years after neutralization, the zooplankton of Nelson Lake, the least acidic (pH 5.7) of the experimental lakes, recovered completely within 10 years of liming. This augurs well for the recovery of zooplankton in thousands of moderately acidic North American lakes, should international reductions in SO 2 emissions reverse their acidification.
Crustacean plankton in northeastern Ontario lakes subjected to acidic deposition
Water, Air, and Soil Pollution, 1984
During the summer of 1981, crustacean plankton was sampled in 249 northeastern Ontario lakes, including a large proportion of acidic lakes. Species cluster analysis showed that a major species group containing B. longirostris, D. minutus, H.gibberum, and M. edax was common to most lakes. Two species subgroups most associated with more productive waters (D. retrocurva, D. oregonensis, T. p. mexicanus, and Diaphanosoma sp.) and less productive waters (D. longiremis, C. scutfer, D. g. mendotae, C.b. thomasi, E. longispina, and E. lacustris) in the study area were identified. Acidic lakes were characterized by reduced numbers of species related to declines in the importance of cyclopoids, Daphnidae, L. kindtii and E. lacustris and high relative abundance of D. minutus. Stepwise multiple linear regression of physico-chemical lake characteristics against percent composition of individual species failed to explain much of the variation in species proportions. However, variables related to lake thermal structure were most frequently the primary correlates with species proportions in near-neutral lakes while in acidic lakes the best statistical predictors of species percent composition were most often variables directly related to lake acidity. Water, Air, and Soil Pollution 23 (1984) 271-291. 0049-6979/84/0233-0271503.15. © 1984 by D. Reidel Publishing Company.
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 ...
Effects of acidification on aquatic biota in Atlantic Canada
Environmental Reviews, 2011
Acidification of surface waters is a high-profile environmental issue in Atlantic Canada. Despite a reduction of emissions of acid-precursors (particularly SO 2) by more than 50% in major regions in North America, there has not yet been a significant recovery of surface waters in the region, likely because of the impoverished acid-neutralizing capacity (ANC) of watersheds. Nevertheless, any detection of a biological recovery in the region requires knowledge of acidification threshold values for indicator species, so that they can be used in an appropriate bio-monitoring program. Our review of information on the effects of acidification on aquatic organisms in Atlantic Canada suggests that the greatest changes in phytoplankton occur over a pH range of 4.7 to 5.6, just beyond the interval (pH 5.5 to 6.5) where bicarbonate (HCO À 3), a key source of both ANC and inorganic carbon for photosynthesis, becomes rapidly depleted and then lost. Similarly, the pH threshold of 5.5 appears to be critical to sensitive macrophytes. The pH tolerance is highly variable among invertebrate taxa, but the median tolerable pH for most sensitive species is between 5.2 and 6.1. Sensitive fish species are affected at pH levels as high as 6.0-6.5, but tolerant ones may do well even at pH <5.0. Amphibian species are relatively tolerant, surviving even to pH 3.5 to 4.0. Aquatic birds breed in the region at pH values greater than 5.5. Résumé : L'acidification des eaux de surface constitue une préoccupation environnementale de premier ordre dans le Canada Atlantique. En dépit d'une réduction des émissions des précurseurs (surtout le SO 2) de plus de 50 % dans la plupart des régions de l'Amérique du Nord, on n'observe toujours pas de récupération significative des eaux de surface dans la région, vraisemblablement dû à un appauvrissement de la capacité à neutraliser les acides (CNA) des bassins versants. Tout de même, toute détection de recouvrement biologique dans la région nécessite une connaissance des valeurs d'acidification critiques chez des espèces indicatrices, de sorte qu'elles puissent être utilisées dans un programme approprié de suivi biologique. Cette revue de l'information sur les effets de l'acidification sur les organismes aquatiques du Canada Atlantique suggère que les plus grands changements du phytoplancton surviennent à un pH allant de 4,7 à 5,6, juste au-delà de l'intervalle de pH (5,5 à 6,5) où le bicarbonate (HCO À 3), une source clé d'ANC aussi bien que de carbone inorganique pour la photosynthèse, devient rapidement épuisé avant d'être perdu. De la même façon, le seuil de pH de 5,5 semble critique pour les macrophytes sensibles. La tolérance au pH varie fortement chez les taxons d'invertébrés, mais la médiane du pH tolérable pour les organismes les plus sensibles va de 5,2 à 6,1. Les espèces de poissons sensibles sont affectées à des pH aussi élevés que 6,0-6,5, mais celles qui sont tolérantes peuvent performer même à des pH < 5,0. Les espèces d'amphibiens sont relativement tolérantes, survivant même à des pH de 3,5 à 4,0. Les oiseaux aquatiques se reproduisent dans les régions où les valeurs de pH sont supérieures à 5,5.
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