Mercury content and speciation in the plankton and benthos of Lake Superior

Back, Richard C.; Gorski, Patrick R.; Cleckner, Lisa B.; Hurley, James P.

doi:10.1016/s0048-9697(02)00580-6

Cited by 37 publications

(34 citation statements)

References 12 publications

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“…Phytoplankton and zooplankton biomass have been shown to be negatively correlated with zooplankton MeHg in both experimental (Kidd et al 1999;Pickhardt et al 2002) and natural systems (Back et al 2003). These studies report chlorophyll and aqueous mercury concentrations within the range of those observed in CFWR annually, yet our results indicate biodilution of MeHg was not a factor in CFWR.…”

Section: Mehg Content Of >75 MM Pfcontrasting

confidence: 45%

“…Conversely, the proportion of total mercury that was MeHg was highest in the spring (67% ± 13%) and lowest in the fall and winter (20% ± 18%) ( Table 1). MeHg concentrations in the >75 mm PF were in the range of concentrations observed for zooplankton in other natural lakes with predominantly atmospheric mercury sources (Montgomery et al 2000;Back et al 2003) and a peatland reservoir (Paterson et al 1998), but did not reach concentrations measured in other artificially flooded reservoirs in Canada (>300 ngÁg -1 , Paterson et al (1998); Plourde et al (1997)) or rivers in the San Francisco Bay-Delta (>100 ngÁg -1 ; A. Stewart, unpublished data).…”

Section: Mehg Content Of >75 MM Pfmentioning

confidence: 63%

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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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Section: Mehg Content Of >75 MM Pfcontrasting

confidence: 45%

Section: Mehg Content Of >75 MM Pfmentioning

confidence: 63%

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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“…Mean MeHg concentration in emergent aquatic insects from Lake Myvatn was 4.5 ng/ g, which is lower than MeHg concentrations in aquatic insects reported in other studies. For example, concentrations of MeHg in chironomids from Canadian high arctic lakes ranged from 40 to 100 ng/g (Che´telat et al 2008), from 32 to 106 ng/g in Quebec lakes (Le Jeune et al 2012), 23 ng/g in Alaska lakes (Hammerschmidt and Fitzgerald, 2005), or 7.9 ng/g in Lake Superior (Back et al 2003). Indeed, if MeHg concentrations are high in aquatic insects, whether due to point source Hg contamination or aquatic chemical conditions that favor MeHg methylation, this could override the trophic bypass.…”

Section: Discussionmentioning

confidence: 99%

Taking the trophic bypass: aquatic‐terrestrial linkage reduces methylmercury in a terrestrial food web

Bartrons

Gratton

Spiesman

et al. 2015

Ecological Applications

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Abstract. Ecosystems can be linked by the movement of matter and nutrients across habitat boundaries via aquatic insect emergence. Aquatic organisms tend to have higher concentrations of certain toxic contaminants such as methylmercury (MeHg) compared to their terrestrial counterparts. If aquatic organisms come to land, terrestrial organisms that consume them are expected to have elevated MeHg concentrations. But emergent aquatic insects could have other impacts as well, such as altering consumer trophic position or increasing ecosystem productivity as a result of nutrient inputs from insect carcasses. We measure MeHg in terrestrial arthropods at two lakes in northeastern Iceland and use carbon and nitrogen stable isotopes to quantify aquatic reliance and trophic position. Across all terrestrial focal arthropod taxa (Lycosidae, Linyphiidae, Acari, Opiliones), aquatic reliance had significant direct and indirect (via changes in trophic position) effects on terrestrial consumer MeHg. However, contrary to our expectations, terrestrial consumers that consumed aquatic prey had lower MeHg concentrations than consumers that ate mostly terrestrial prey. We hypothesize that this is due to the lower trophic position of consumers feeding directly on midges relative to those that fed mostly on terrestrial prey and that had, on average, higher trophic positions. Thus, direct consumption of aquatic inputs results in a trophic bypass that creates a shorter terrestrial food web and reduced biomagnification of MeHg across the food web. Our finding that MeHg was lower at terrestrial sites with aquatic inputs runs counter to the conventional wisdom that aquatic systems are a source of MeHg contamination to surrounding terrestrial ecosystems.

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“…Other studies focused on lakes with low suspended particulate matter (SPM) (Watras and Bloom 1992;Kainz and Mazumder 2005). Results from Back et al (2003) are shown as the range from four size fractions of seston (,35, 35-63, 63-112, and .112 concentrations directly in phytoplankton. Although our calculations indicated that algal MeHg concentrations decreased during the bloom, if phytoplankton rapidly assimilated MeHg from another source (e.g., production in sediments or desorption from the particulate phase), the algal MeHg concentration could have remained constant during the bloom.…”

Section: Discussionmentioning

confidence: 99%

Role of phytoplankton in mercury cycling in the San Francisco Bay estuary

Luengen

Flegal

2009

Limnol. Oceanogr.

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To study the role of phytoplankton in mercury cycling, we measured methylmercury (MeHg) and total mercury (Hg T ) in surface waters during the spring 2003 phytoplankton bloom in San Francisco Bay. Conditions that described the peak of the bloom, the amount of sorbent, and decay of the bloom were summarized by principal component analysis (PCA). Multivariate analyses conducted with the PCA factors demonstrated that the bloom accounted for a significant (p 5 0.03) decrease in dissolved (,0.45 mm) MeHg. Dissolved MeHg was depleted to 0.026 pmol L 21 and was unaffected when chlorophyll a concentrations nearly tripled, indicating that bloom dilution could occur as a result of a limited amount of MeHg. The calculated algal MeHg concentration was 3-10 pmol g 21 (dry weight). As the bloom decayed, dissolved MeHg concentrations significantly (p 5 0.04) increased, likely due to MeHg remineralization from decaying phytoplankton and/or production in sediments. By creating suboxic conditions in surface sediments and stimulating microbial activity, decomposing phytoplankton could bolster MeHg production, a potential side effect of large blooms. Unlike dissolved MeHg, dissolved Hg T concentrations were not measurably altered by the bloom or decay factors. That difference corroborated previous culture studies in which phytoplankton actively accumulated MeHg, but not Hg T . As the bloom decayed, Hg T K d values significantly (p 5 0.012) increased, possibly because particles (i.e., phytoplankton) with low Hg T concentrations were lost from the water column. Based on the relationship between Hg T particulate concentrations and percent phytoplankton, the calculated algal Hg T concentration was ,0.5 nmol g 21 (dry weight).

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Mercury content and speciation in the plankton and benthos of Lake Superior

Cited by 37 publications

References 12 publications

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

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

Taking the trophic bypass: aquatic‐terrestrial linkage reduces methylmercury in a terrestrial food web

Role of phytoplankton in mercury cycling in the San Francisco Bay estuary

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