Mercury in zooplankton of Northern Wisconsin Lakes: taxonomic and site-specific trends

Back, Richard C.; Watras, Carl J.

doi:10.1007/bf01189747

Cited by 45 publications

(25 citation statements)

References 8 publications

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“…Despite the lower concentrations of MeHg in suspended particles, the particle-water partitioning of MeHg was about twofold higher than Hg, indicating that MeHg is the more particle-reactive species in these waters. This observation is consistent with the observation that MeHg biomagnifies in food chains, whereas non-MeHg becomes progressively more dilute (Watras and Bloom 1992;Back and Watras 1995). Particulate matter in these waters is primarily biogenic rather than mineralogic (Watras et al 1994).…”

Section: Resultssupporting

confidence: 82%

“…This behavior suggests that DOC competes with seston for Hg, as we have observed with zooplankton and fish (Watras and Bloom 1992;Watras et al 1994;Back and Watras 1995). In these lakes, SPM ranged from 0.5 to 6.0 mg liter-' (mean = 1.8 mg liter-') and was not well correlated with DOC or PH.…”

Section: Resultsmentioning

confidence: 59%

“…Although the biogeochemical mechanisms underlying these correlations remain unclear, factors controlling the supply of MeHg (methylmercury) to lower trophic levels may be critical (Rudd 1995). MeHg is the species that biomagnifies in aquatic food webs and the major bioconcentrating step occurs between water and seston (Watras and Bloom 1992;Back and Watras 1995).…”

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confidence: 99%

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Concentration of mercury species in relationship to other site‐specific factors in the surface waters of northern Wisconsin lakes

Watras¹,

Morrison²,

Host³

et al. 1995

Limnology & Oceanography

208

114

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To investigate relationshi.Qs between mercury speciation and site-specific factors in temperate freshwaters, we measured the concentration of seven Hg species along with 18 environmental variables in the surface waters of 23 northern Wisconsin lakes during spring and fall. The lakes spanned relatively wide gradients in Hg (0.15-4.8 ng liter ') and methylmercury (MeHg: 0.04-2.2 ng liter-I). Over the range ofmeasured variables, Hg and MeHg were most strongly correlated with each other (r2 = 0.83-0.88) and with dissolved organic C (DOC) (r2 = 0.64-0.92). Multiple regression models containing DOC and a (DOC x pH) interaction term accounted for 85-90% of the variability in Hg and MeHg between lakes.Observed differences between lakes reflected internal cycling processes and external transport pathways. Internally, high DOC and low pH favored Hg methylation and retention over Hg evasion across the airwater interface. Externally, watershed mapping suggested that the cotransport of DOC, Hg, and MeHg from riparian wetland was also a potentially important process. Observed seasonal differences indicated a 30% increase in MeHg across lakes during summer due to internal or external processes.The effects of DOC on bioaccumulation may be twofold and antagonistic. Although waterborne Hg and MeHg increased with DOC, seston-water partition coefficients tended to decrease, indicating disproportionately more Hg in the dissolved phase. These observations are consistent with previous data on bioaccumulation factors for zooplankton and fish.

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Section: Resultssupporting

confidence: 82%

Section: Resultsmentioning

confidence: 59%

mentioning

confidence: 99%

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Concentration of mercury species in relationship to other site‐specific factors in the surface waters of northern Wisconsin lakes

Watras¹,

Morrison²,

Host³

et al. 1995

Limnology & Oceanography

208

114

View full text Add to dashboard Cite

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“…In CFWR, the presence of large zooplankton species (i.e., cladocerans) appears to be a primary driver for elevated MeHg concentrations in >75 mm PF in the spring. Indeed, higher concentrations of MeHg in larger zooplankton, particularly cladocerans, have been observed in other studies of natural lakes and reservoirs (Back and Watras 1995;Tremblay et al 1998;Kainz et al 2002) and in experimental exposures (Pickhardt et al 2005). As suggested in Pickhardt et al (2005), higher feeding, reproductive, and metabolic rates of cladocerans relative to the copepods and associated stoichiometric differences in essential macronutrients between these taxa may explain the differences observed; however, specific studies have yet to confirm this.…”

Section: Mehg Content Of >75 MM Pfmentioning

confidence: 65%

Influence of plankton mercury dynamics and trophic pathways on mercury concentrations of top predator fish of a mining-impacted reservoir

Stewart

Saiki

Kuwabara

et al. 2008

Can. J. Fish. Aquat. Sci.

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Physical and biogeochemical characteristics of the aquatic environment that affect growth dynamics of phytoplankton and the zooplankton communities that depend on them may also affect uptake of methylmercury (MeHg) into the pelagic food web of oligotrophic reservoirs. We evaluated changes in the quality and quantity of suspended particulate material, zooplankton taxonomy, and MeHg concentrations coincident with seasonal changes in water storage of a mining-impacted reservoir in northern California, USA. MeHg concentrations in bulk zooplankton increased from 4 ngÁg -1 at low water to 77 ± 6.1 ngÁg -1 at high water and were positively correlated with cladoceran biomass (r = 0.66) and negatively correlated with rotifer biomass (r = -0.65). Stable isotope analysis revealed overall higher MeHg concentrations in the pelagic-based food web relative to the benthic-based food web. Statistically similar patterns of trophic enrichment of MeHg (slopes) for the pelagic and benthic food webs and slightly higher MeHg concentrations in zooplankton than in benthic invertebrates suggest that the difference in MeHg bioaccumulation among trophic pathways is set at the base of the food webs. These results suggest an important role for plankton dynamics in driving the MeHg content of zooplankton and ultimately MeHg bioaccumulation in top predators in pelagic-based food webs.Résumé : Les caractéristiques physiques et biogéochimiques du milieu aquatique qui affectent la dynamique de la croissance du phytoplancton et les communautés zooplanctoniques qui en dépendent peuvent aussi influencer l'introduction de méthylmercure (MeHg) dans le réseau alimentaire pélagique des réservoirs oligotrophes. Nous déterminons les changements dans la qualité et la quantité des matières particulaires en suspension, dans la taxonomie du zooplancton et dans les concentrations de MeHg qui coïncident avec les changements saisonniers d'emmagasinement d'eau dans un réservoir affecté par des activités minières dans le nord de la Californie, É .-U. Les concentrations de MeHg dans le zooplancton global augmentent de 4 ngÁg -1 aux basses eaux à 77 ± 6,1 ngÁg -1 aux hautes eaux et elles sont en corrélation positive avec la biomasse des cladocères (r = 0,66) et en corrélation négative avec la biomasse des rotifères (r = -0,65). Une analyse des isotopes stables indique des concentrations globalement plus élevées de MeHg dans le réseau alimentaire pélagique que dans le réseau alimentaire benthique. Les patrons statistiquement semblables d'enrichissement trophique de MeHg (pentes) dans les réseaux alimentaires pélagiques et benthiques et des concentrations légèrement supérieures de MeHg dans le zooplancton par rapport aux invertébrés benthiques font penser que la différence de bioconcentration de MeHg entre les voies trophiques s'établit dès la base des réseaux alimentaires. Ces résultats indiquent un rôle important joué par la dynamique du plancton dans le contenu en MeHg du zooplanction et, en fin de compte, dans la bioconcentration de MeHg chez les prédate...

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“…Past attempts to find such relationships have been limited by a lack of relevant data (Wren and Stephenson 1991) and the wide variation in [MeHg] among benthic organisms observed even within a lake (Back and Watras 1995). The aim of our study was to generate models describing invertebrate [MeHg] based on environmental data typically collected by water-monitoring agencies.…”

Section: Introductionmentioning

confidence: 99%

Predictive models of benthic invertebrate methylmercury in Ontario and Quebec lakes

Rennie¹,

Collins²,

Purchase³

et al. 2005

Can. J. Fish. Aquat. Sci.

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Multivariate analyses on benthic invertebrate methylmercury concentrations ([MeHg]) and water chemistry from 12 Quebec water bodies were used to guide the construction of simple, predictive models of benthic invertebrate [MeHg] in 23 lakes in Ontario and Quebec. Separate predictive models for collector-shredder and predatory benthic invertebrates were constructed using multiple regression and were assessed for their predictive utility by crossvalidation. Predatory benthic invertebrate [MeHg] was negatively related to pH and positively related to dissolved organic carbon (DOC) concentration (cross-validation r 2 = 0.31). Collector-shredder [MeHg] was positively related to [DOC] only (cross-validation r 2 = 0.13). Predictive utility of our models is similar to or surpasses that observed in previously published zooplankton MeHg models tested against independently collected data. Significant environmental variables and their contribution to the overall explanatory power of benthic invertebrate MeHg models are similar to those found in zooplankton models, suggesting that in both pelagic and benthic food webs, pH and DOC are important indicators of MeHg bioavailability. Although seasonal patterns in invertebrate [MeHg] were examined, none was detected. These models represent an effective means of identifying water bodies of interest for researchers and for reconstructing past benthic invertebrate [MeHg] patterns using archived water chemistry data.

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Mercury in zooplankton of Northern Wisconsin Lakes: taxonomic and site-specific trends

Cited by 45 publications

References 8 publications

Concentration of mercury species in relationship to other site‐specific factors in the surface waters of northern Wisconsin lakes

Concentration of mercury species in relationship to other site‐specific factors in the surface waters of northern Wisconsin lakes

Influence of plankton mercury dynamics and trophic pathways on mercury concentrations of top predator fish of a mining-impacted reservoir

Predictive models of benthic invertebrate methylmercury in Ontario and Quebec lakes

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