Thermal, chemical, and optical properties of Crater Lake, Oregon

Larson, Gary L.; Hoffman, Robert; McIntire, David C.; Buktenica, Mark W.; Girdner, Scott F.

doi:10.1007/978-1-4020-5824-0_5

Cited by 3 publications

(2 citation statements)

References 18 publications

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“…Two dots show the five biggest mixing years used in analyses and three dots shows the least winter mixing years. Headings for summer variables show period of record (years) and type of data (in situ or laboratory) taken from the shaded side of a research vessel with calm surface conditions (Larson et al, 2007b).…”

Section: Long-term Datamentioning

confidence: 99%

Impact of nutrients on photoacclimation of phytoplankton in an oligotrophic lake measured with long-term and high-frequency data: implications for chlorophyll as an estimate of phytoplankton biomass

2020

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Chlorophyll measurements are commonly used to estimate phytoplankton biomass. However, phytoplankton readily acclimate to variations in light through a range of phenotypic responses, including major adjustments in chlorophyll pigmentation at the cellular level. The ratio of pigment chlorophyll to carbon concentration (Chl:C) is a commonly used metric in the oceanographic community to explore photoacclimation responses to varied light levels, yet is relatively rare in freshwater studies. Here we explore how nutrient variability impacted summertime Chl:C ratios of a natural phytoplankton community throughout the water column of a stratified oligotrophic lake. We utilized both long-term (18-24 years) and high-frequency (daily) data from Crater Lake, Oregon, a deep mountain lake with little anthropogenic disturbance. As expected, fluctuation in nutrients had a strong impact on phytoplankton particle density, primary productivity, light penetration, and water clarity. However, chlorophyll concentration did not register predictable changes even though the vertical location of the deep chlorophyll maximum was responsive to the overlying algal density. The impact of elevated nutrients on the Chl:C ratio was further complicated by upward shifts in chlorophyll distribution. The muted response of chlorophyll concentration to nutrients may be partially explained by variations in phytoplankton community composition or iron stress.

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Section: Long-term Datamentioning

confidence: 99%

Impact of nutrients on photoacclimation of phytoplankton in an oligotrophic lake measured with long-term and high-frequency data: implications for chlorophyll as an estimate of phytoplankton biomass

2020

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“…Some metaphors may be used as a resource to show the relevance of the long-term studies in comprehending events with high interannual variability or high spatial variation, such as ice cover or drought events. Among these metaphors, the invisible present and the invisible place may indicate the relevance of historical databases in multiple and broad scales, preventing errors concerning data interpretation in the short term (Magnuson 1990, Swanson andSparks 1990) and allowing distinction between natural and human-induced ecological events (Larson et al 2007). The space-for-time substitution approach has been used to infer past or future trajectories of ecological systems (Blois et al 2013).…”

Section: Contributionsmentioning

confidence: 99%

Advances in limnological research in Earth's drylands

et al. 2020

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Drought is an important driver of change in aquatic ecosystems and generally acts as a filter to select biological traits capable of persisting under severe environmental circumstances. Drylands are highly vulnerable to climate change and increases in climate variability. Consequently, an increase in the processes of eutrophication, salinization, and habitat desiccation may be observed in response to the loss of the hydrological connectivity. The International Network on Limnology of Drylands (INLD) was created with the overall goal of understanding the functioning and conservation status of aquatic ecosystems in drylands globally. INLD was made official in 2016 through the International Society of Limnology. Its objectives are to (1) assess the current state of biological diversity in dryland aquatic ecosystems, (2) evaluate the multiple environmental stressors acting in drylands, and (3) develop models to predict effects of global change on drylands. This special issue, Limnology of Drylands, consists of 10 manuscripts focused on the effects of environmental pressures, including global warming, on the biodiversity and distribution of aquatic communities in drylands.

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A quantitative blueness index for oligotrophic waters: Application to Lake Tahoe, California–Nevada

Watanabe

Vincent

Reuter

et al. 2015

Limnology & Ocean Methods

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The perceived blue color of a lake often contributes to its aesthetic appeal, and changes in blueness can be indicative of major shifts in water quality. We developed a quantitative blue water index (Bw) for natural waters, and used it to evaluate spatial and seasonal variations in ultraoligotrophic Lake Tahoe, where clarity and blueness are of ecological and economic value and a focus for lake management strategies. Spectral reflectance was measured using a profiling hyperspectral radiometer, and the values were converted to the axis values of a color space: the International Commission on Illumination L*a*b*, where L* is the lightness of color, a* ranges from green to magenta, and b* ranges from blue to yellow. The blue water index Bw, defined as negative b*, was similarly high at two offshore monitoring sites in Lake Tahoe, but much lower in a semienclosed bay and a small adjacent lake. Seasonal variations of Bw were determined using a hyperspectral radiometer attached to a buoy in the middle of Lake Tahoe. The Bw values were highest in summer, and there was a strong inverse correlation between Bw and phytoplankton concentrations as measured by in vivo chlorophyll a fluorescence. However, there was no significant correlation between Bw and Secchi depth. Blueness and visual clarity are complementary measures of the perceived optical state of natural waters, and for many lakes may provide a powerful combination of indicators for conveying water quality to the public.

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Thermal, chemical, and optical properties of Crater Lake, Oregon

Cited by 3 publications

References 18 publications

Impact of nutrients on photoacclimation of phytoplankton in an oligotrophic lake measured with long-term and high-frequency data: implications for chlorophyll as an estimate of phytoplankton biomass

Impact of nutrients on photoacclimation of phytoplankton in an oligotrophic lake measured with long-term and high-frequency data: implications for chlorophyll as an estimate of phytoplankton biomass

Advances in limnological research in Earth's drylands

A quantitative blueness index for oligotrophic waters: Application to Lake Tahoe, California–Nevada

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