Paleolimnological evidence of change in a shallow, hypereutrophic lake: Upper Klamath Lake, Oregon, USA

Eilers, J. M.; Kann, Jacob; Cornett, Jack; Moser, Katrina A.; Amand, Ann St.

doi:10.1023/b:hydr.0000027718.95901.ae

Cited by 66 publications

(46 citation statements)

References 37 publications

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“…Below Iron Gate dam the river flows free for 300 km before entering the Pacific Ocean. Over the past decades the KR watershed above Iron Gate dam has experienced a multitude of human-induced modifications and pressures, including diversions and drainage for agriculture and generation of hydroelectric power (Eilers et al 2004). The main sampling sites CR01 and IR01 are located in the main stem of the old river channel with depths of approximately 24 and > 30 m, respectively (Fig.…”

Section: Methodsmentioning

confidence: 99%

Diversity of Microcystis aeruginosa in the Klamath River and San Francisco Bay delta, California, USA

Moisander¹,

Lehman²,

Ochiai³

et al. 2009

Aquat. Microb. Ecol.

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Section: Methodsmentioning

confidence: 99%

Diversity of Microcystis aeruginosa in the Klamath River and San Francisco Bay delta, California, USA

Moisander¹,

Lehman²,

Ochiai³

et al. 2009

Aquat. Microb. Ecol.

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“…(Gu 2009). In this sense, the increasing abundance and dominance of C. raciborskii ) could be also contributing to decreasing δ 15 N in Peri Lake, since N fixation from this heterocystous cyanobacterium could be causing more N 2 to be fixed and there is no fractionation in the N fixation process (Fogel and Cifuentes 1993;Eilers et al 2004;Gu 2009). …”

Section: Carbon and Nitrogen Stable Isotopesmentioning

confidence: 99%

“…Atomic C:N ratio has been widely used to identify the different sources of OM (algal versus land-plant) in lake sediments (Meyers 2003;Das et al 2008;Torres et al 2012). Alterations in the N:P ratio in the sediments may have also important effects on community composition of phytoplankton, especially on the cyanobacteria (Eilers et al 2004).…”

Section: Introductionmentioning

confidence: 99%

Paleolimnological record as an indication of incipient eutrophication in an oligotrophic subtropical coastal lake in Southern Brazil

Hennemann

Simonassi

Petrucio

2015

Environ Monit Assess

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Paleolimnology of lake sediments can be a powerful tool to assess various aspects of lake history and catchment change through elemental, isotopic and molecular analysis of the sedimented organic matter (OM). In this sense, the objective of the present study was to investigate the source, depositional history and preservation of OM in the sediments of two different sites in Peri Lake (southern Brazil) to better understand the nature and direction of environmental changes. Therefore, two sediment cores were sampled and analysed for total organic carbon (TOC), total nitrogen (TN) and total phosphorus (TP) concentrations and elemental ratios, and stable isotope ratios of C and N (δ(13)C and δ(15)N). Both cores showed similar general tendencies, with increasing amounts of OM (range 1-35%), TOC (2.55-258.40 mg g(-1)), TN (0.30-25.97 mg g(-1)) and TP (0.03-4.72 mg g(-1)) from the bottom toward the top more recent layers. TOC:TN ratios (range 8.1-14.7) showed a slight decrease in recent times and indicated a mixture of allochthonous and autochthonous contribution to the OM, with predominance of the last source. TN:TP (range 0.2-51.3) indicated a condition of potential limitation by P in general. Both δ(13)C (range -25.58 to -20.85) and δ(15)N (range 2.6 to 7.1) showed a decreasing pattern toward the top of the cores, in opposition to macronutrient concentration. Differences in the depth variation pattern between the two cores were associated to the marginal location of one of the cores. The results suggest that nutrients and primary production are increasing in the lake.

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“…Below UKL, there are five additional dams and reservoirs that fragment the 97 km of the upper basin (from here, designated "upper river") into a series of reservoirs and river reaches ( Table 1). The upper river reaches of the Klamath River experience seasonal algal blooms (summer and fall) dominated by the nitrogen-fixing cyanobacteria Aphanizomenon flos-aquae and are designated hypereutrophic [Eilers et al, 2004;Jacoby and Kann, 2007]. Multiple water quality impairments are found throughout the upper river, including organic matter and nutrient enrichment, low dissolved oxygen, high pH, and high water temperatures [Oregon Department of Environmental Quality, 2010].…”

Section: Seasonal and Impoundment Effects On Dom 1946mentioning

confidence: 99%

Impact of seasonality and anthropogenic impoundments on dissolved organic matter dynamics in the Klamath River (Oregon/California, USA)

Oliver

Spencer

Deas³

et al. 2016

JGR Biogeosciences

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Rivers play a major role in the transport and processing of dissolved organic matter (DOM). Disturbances that impact DOM dynamics, such as river impoundments and flow regulation, have consequences for biogeochemical cycling and aquatic ecosystems. In this study we examined how river impoundments and hydrologic regulation impact DOM quantity and quality by tracking spatial and seasonal patterns of DOM in a large, regulated river (Klamath River, USA). Dissolved organic carbon (DOC) concentrations decreased downstream and longitudinal patterns in DOC load varied by season. Export of DOM (as DOC) was largely driven by river flow, while DOM composition was strongly influenced by impoundments. Seasonal algal blooms in upstream lentic reaches provided a steady source of algal DOM that was processed in downstream reaches. DOM at upstream sites had an average spectral slope ratio (SR) > 1, indicating algal‐derived material, but decreased downstream to an average SR < 1, more indicative of terrestrial‐derived material. The increasingly terrestrial nature of DOM exported from reservoirs likely reflects degraded algal material that becomes increasingly more recalcitrant with distance from upstream source and additional processing. As a result, DOM delivered to free‐flowing river reaches below impoundments was less variable in composition. Downstream of impoundments, tributary influences resulted in increasing contributions of terrestrial DOM from the surrounding watershed. Removal of the four lower dams on the Klamath River is scheduled to proceed in the next decade. These results suggest that management should consider the role of impoundments on altering DOM dynamics, particularly in the context of dam removal.

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Paleolimnological evidence of change in a shallow, hypereutrophic lake: Upper Klamath Lake, Oregon, USA

Cited by 66 publications

References 37 publications

Diversity of Microcystis aeruginosa in the Klamath River and San Francisco Bay delta, California, USA

Diversity of Microcystis aeruginosa in the Klamath River and San Francisco Bay delta, California, USA

Paleolimnological record as an indication of incipient eutrophication in an oligotrophic subtropical coastal lake in Southern Brazil

Impact of seasonality and anthropogenic impoundments on dissolved organic matter dynamics in the Klamath River (Oregon/California, USA)

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