Extending classical geochemical weathering studies through the mountain block: The effect of increasing scale on geochemical evolution in the Sierra Nevada (CA)

Meyers, Zachary P.; Rademacher, Laura K.; Frisbee, Marty D.; Warix, Sara R.

doi:10.1016/j.chemgeo.2022.120831

Cited by 4 publications

(4 citation statements)

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“…However, only one spring group contained an “excess of excess calcium,” with significantly higher Ca 2+ /Na + ratios (Ca 2+ /Na + > 1.5). This “excess of excess calcium” signature has been interpreted to reflect roof pendant weathering, which is consistent with the location of the five roof pendant springs and their elevated 87 Sr/ 86 Sr ratios (Meyers et al, 2022). Two emerge downgradient from the Pine Creek Pendant units near Mt.…”

Section: Resultssupporting

confidence: 71%

“…Spring geochemistry in both groups reflected recharge through granitoid rock, which predominates the high-elevation recharge zones in the Sierra Nevada. All spring waters also contained an excess of calcium (Ca 2+ /Na + > 0.6) over that expected for plagioclase weathering alone (Ca 2+ /Na + of 0.4-0.6; Figure 1C), consistent with dissolution of disseminated calcite during recharge (Meyers et al, 2022). However, only one spring group contained an "excess of excess calcium," with significantly higher Ca 2+ /Na + ratios (Ca 2+ /Na + > 1.5).…”

Section: Paleozoic Roof Pendants Impart Subtle Geochemical Difference...mentioning

confidence: 75%

“…We documented distinct communities of benthic microorganisms and macroinvertebrates in springs that recharge through Paleozoic roof pendants thousands of meters upslope from the spring sources. Weathering of these roof pendants imparts an “excess of excess calcium” and an increased proportion of dissolved calcium compared with other ions (Meyers et al, 2022) that may promote initial microbial attachment to the negatively charged granitic substrate and enhance biofilm maturation within the spring benthos. Biofilms are multispecies surface‐attached microbial communities embedded in a three‐dimensional matrix of endogenously produced EPS composed of polysaccharides, proteins, extracellular DNA, and lipids (Berne et al, 2018; Flemming & Wingender, 2010).…”

Section: Discussionmentioning

confidence: 99%

“…Additionally, a two-sample Student's t test was conducted using Microsoft Excel version 2204 on the physicochemical data (units as shown in data table 1 archived at https://doi.org/10.5281/zenodo.7603891) to determine which parameters were significantly different between the hydrogeochemical groups. An expanded discussion of the hydrogeochemical framework and analysis is available in another study (Meyers et al, 2022).…”

Section: Analysis Of Spring Hydrogeochemistry Datamentioning

confidence: 99%

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Synecological response of spring benthic prokaryotes and macroinvertebrates to Paleozoic roof pendant‐derived calcium

et al. 2023

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Despite the ecological significance of desert springs, little is known about relationships between spring hydrogeochemistry and ecology, particularly over multiple trophic levels. Here, we surveyed microbial communities (bacteria and archaea) and benthic macroinvertebrate (BMI) communities in springs that recharge through granitoid bedrock in Owens Valley, CA, to determine whether subtle geochemical differences imparted by metamorphosed roof pendant weathering in the source area affect spring ecosystems. Relative to other springs, roof‐pendant‐recharged springs were characterized by elevated (1) Ca2+/Na+, Ca2+/Mg2+, and divalent/monovalent cation ratios, (2) relative abundance of taxa inferred to be benthic aerobes and prosthecate/stalked bacteria, and (3) abundance and diversity of shredder and collector gatherer BMIs. These BMI feeding groups graze on biofilm communities and stimulate bacterial degradation of particulate organic matter, consistent with extensive bacteria–BMI connections in co‐occurrence networks in these springs. Springs not impacted by roof pendants were instead enriched with taxa inferred to be anaerobes, chemolithotrophs, and low‐diversity BMI communities with poor bacteria–BMI network connectivity. We speculate that excess Ca2+ derived from roof pendant weathering plays a key role in biofilm formation on coarse granite substrates, with subsequent trophic interactions between benthic microbial biofilms and diverse BMI shredders/collector gatherers.

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Section: Resultssupporting

confidence: 71%

Section: Paleozoic Roof Pendants Impart Subtle Geochemical Difference...mentioning

confidence: 75%