Contrasting Magnitude and Timing of Pulsed Aqueous

Overview

This source page is a mechanical bulk-ingest record for a PDF in the research-pulls corpus. It preserves source-level identity, routeable product/analyte scope, and exact extracted numeric lines for later human or fresh-context audit. It does not derive HMTc thresholds, percentiles, or brand-by-brand comparisons.

Key numbers

The worker extracted the full PDF text with layout preservation twice and compared extraction hashes before commit. The following lines are copied from numeric/table-bearing regions of the PDF and retain the source units and wording where legible:

• 250% during destratification, concurrent with increases in aqueous
• was stratified (R2 = 0.21). Mercury concentrations in adult bluegill and juveniles of both fish species increased 20−70% following
• 1. INTRODUCTION than 2 mg/L, typically result from organic matter accumulation
• natural substrate for diverse microbial organisms capable of (mean = 40 m, maximum = 91 m at full pool) and strong
• = 84%), particularly Daphnia galeata mendotae. Zooplankton THg was 0.002 ± 0.0001 mg/kg dw. Quality assurance for
• analysis. During some sampling events (n = 26) we were not (DORM-4, TORT-3), method blanks, and sample duplicates.
• able to collect zooplankton directly from the reservoir. For Quality assurance results are summarized in Table S1. We also
• lyophilized frozen zooplankton samples at −40 °C, ground the fish (Bluegill: 96.8 ± 1.8%, n = 43; Smallmouth Bass: 88.5 ±
• dried samples to a fine powder using a ceramic mortar and 1.1%, n = 45) to confirm THg concentrations were an effective
• represent distinct trophic ecologies.54 At each sampling event, least-squares or geometric means with standard errors
• Bluegill and bass, respectively.54 All fish were euthanized with we standardized THg concentrations to the median length
• accordance with Idaho Department of Fish and Game and range of each species) and the individual-specific residuals.61
• 6).57,58 Quality assurance for aqueous MeHg (mean ± concentrations among stratification categories were tested
• 0.0126 ng/L; n = 40) and sample replicates (n = 39; mean Tukey Honestly Significant Difference (HSD) post hoc
• relative percent difference (RPD) = 24.4%). Quality assurance multiple comparisons. Differences in aqueous MeHg−
• results are summarized in Table S1. zooplankton MeHg and zooplankton MeHg−fish THg
• 3.1. Seasonal Variation in Hg Concentrations. Between (0.019 ± 0.002 ng/L; n = 9; Tukey HSD p < 0.05).
• whereas in 2019 concentrations were similarly variable before Overall, mean MeHg concentrations in zooplankton were
• classifications of Brownlee Reservoir (F2,12.0 = 25.2, p < 0.001; ng/g dw, respectively; F2,167 = 13.7, p < 0.001; Table 1);
• Table 1), with the highest concentrations observed during however, like aqueous MeHg, the magnitude of this increase
• tion (0.030 ± 0.002 ng/L; n = 12), and the lowest MeHg concentration during destratification (220.1 ± 25.3 ng/
• Table 1. Statistical Results of Models Testing the Effect of Our results across multiple matrices implicate the buildup of
• year 1, 28.2 53.57 <0.001 similar range of increases in zooplankton and planktivorous
• g dw) was 3.5-fold higher than the mean MeHg concentration associated with destratification was negatively correlated with
• than the mixed period mean MeHg concentration (123.2 ± the mass of MeHg accumulated in the hypolimnion prior to
• 20.0 ng/g dw). In 2019, the highest mean MeHg concentration turnover. Similarly, the annual volume of hypoxic water in
• lowest mean MeHg concentration (32.0 ± 5.8 ng/g dw); differences in incoming flows, water temperatures, nutrient
• stratification status (Figure 1D; Table 1). In contrast, THg production in the water column.43,67 Together, these data
• species and size-classes (Table 1), much of the variation reservoir food webs.15,31,32
• mean THg concentrations increased between 3-fold in Bluegill understand the rate at which MeHg mobilized from the
• Figure 4. Relationships between zooplankton methylmercury maturity at a younger age and wider range of sizes than
• stable stratification.34,75 Lakes, reservoirs, and rivers display a fishes) may be more effective indicators of discrete manage-
• Reservoir, leading to a 33% reduction in the volume of is for descriptive purposes only and does not imply an
• Table summarizing of quality assurance results, a study (4) Reid, A. J.; Carlson, A. K.; Creed, I. F.; Eliason, E. J.; Gell, P. A.;
• Rangeland Ecosystem Science Center, Corvallis, Oregon 2022, 72 (11), 1050−1061.

Methods (brief)

• sampled the furthest downstream 6 km of Brownlee Reservoir
• 2.2. Sample Collection, Processing, and Chemical
• cases may be the dominate cause of, elevated MeHg risk in Analyses. We collected water, zooplankton, and two species
• productive fisheries,47 and frequent utilization by recreational integrated samples collected at the thalweg of Brownlee
• and subsistence anglers.48,49 The management and remediation Reservoir’s outflow from a bridge using a DH-95 sampler and
• MeHg uptake in the aquatic food web. Here, we report on the sample of Brownlee Reservoir water drawn from the upper
• incorporation into a reservoir food web, a necessary first step of the water column51,53 and water could be collected
• seasonal stratification and destratification of a reservoir and impossible. Within 24 h of collection, water samples were
• groups, and a piscivorous fish were sampled at approximately hydrochloric acid. We only present results from filtered
• We collected bulk plankton from the upper 10 m of the was 2.8 ± 0.01 ng/g dw. Quality assurance for tissue MeHg
• sample jars and kept on ice while in the field (≤10 h). sample duplicates. Quality assurance results are summarized in
• Immediately following collection events, we rinsed samples Table S1.
• samples were dominated by large Cladocera (50−99%, median Protection Agency, 2000). The average detection limit for
• samples were frozen at −20 °C until processing for Hg tissue THg included analysis of calibration standards, CRMs
• analysis. During some sampling events (n = 26) we were not (DORM-4, TORT-3), method blanks, and sample duplicates.
• these events we used the regression between MeHg analyzed a subset of fish samples spanning species, size-classes,
• concentrations in zooplankton samples concurrently collected
• lyophilized frozen zooplankton samples at −40 °C, ground the fish (Bluegill: 96.8 ± 1.8%, n = 43; Smallmouth Bass: 88.5 ±

Implications

This page makes the source discoverable for category-level evidence routing. Values remain source-native and should be used only with the stated matrix, species, basis, geography, and censoring context from the paper. The page does not convert total mercury to methylmercury or use total arsenic as inorganic arsenic.

Wiki pages this source may touch

• Fish — marine, non-predatory (sardines, anchovies, salmon, cod)
• Mercury
• Mercury

Verification notes

• Identity check: DOI, raw handle, candidate cite-key, and SHA-256 were compared against existing wiki/sources/ pages before creation.
• Full-PDF read: pdftotext -layout was run on the full PDF twice; extracted text hashes matched before the page was written.
• Numeric verification: numeric/table-bearing lines were selected mechanically from the verified extraction and preserved without unit conversion or rounding.
• Brand firewall: the worker skips PDFs when extracted numeric lines appear brand/manufacturer-sensitive; this page contains category-level or species-level evidence only.
• HMTc firewall: no threshold, percentile, pass/fail, clean/dirty, or certification math is stated.

Update history

The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.