Nutrient dynamics in Mediterranean temporary streams: A case study in Pardiela catchment (Degebe River, Portugal)

Lillebø, Ana I.; Morais, Manuela; Guilherme, Pedro; Fonseca, Rita; Serafim, António; Neves, Ramiro

doi:10.1016/j.limno.2007.05.002

Cited by 34 publications

(23 citation statements)

References 18 publications

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“…Previous studies suggest that vertical hydraulic head gradients tend toward zero or negative values (i.e., downwelling) during the stream drying process (Stanley & Valett, 1992). Once hydrologic transport shuts off in Mediterranean-region intermittent streams, disconnected pools develop hypoxic and acidic conditions (Acuña et al, 2005;Lillebø et al, 2007;Von Schiller et al, 2011), with an accompanying increase in reduced forms of nutrients and a decrease in oxidized forms (Acuña et al, 2005;Bernal et al, 2013). These processes are consistent with the summertime increase in PC2 values observed primarily in pools absent of salmon by the end of the summer.…”

Section: Mechanisms Through Which Groundwater May Promote Coho Salmonmentioning

confidence: 99%

Groundwater Is Key to Salmonid Persistence and Recruitment in Intermittent Mediterranean‐Climate Streams

Larsen

Woelfle‐Erskine

2018

Water Resources Research

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Juvenile coho salmon thrive in intermittent streams of the Pacific Northwest yet are in danger of increased mortality from drought and rising temperatures. With warmer temperatures and more frequent climate extremes projected, the need to understand how intermittent stream hydrology and biogeochemistry impact juvenile salmonid habitat and behavior is imperative. Previous investigations indicated that dissolved oxygen limits the persistence of coho salmon in intermittent streams, leading to the hypothesis that groundwater inflow would ultimately control patterns of salmon recruitment and persistence. Here we tested that hypothesis in paired tributaries of Salmon Creek, Sonoma County, CA during California's extreme drought of 2011–2017. We used the fluorescent fingerprint of dissolved organic carbon, together with a parallel factor analysis, to estimate groundwater influence in individual stream pools, corroborating those estimates with stable isotope and radon analyses. Repeat snorkel surveys provided fish counts in those pools at the beginning and end of the period of surface‐water disconnection. Results suggested that coho salmon fry preferentially selected pools with a groundwater inflow signal and persisted in pools maintaining that signal through the dry season. This groundwater inflow signal was distinct from hyporheic influence, which exhibited little correlation with fish distribution. Groundwater within pools was young, and spot measurements suggested that it was relatively oxygenated. Proportional groundwater contributions to pools increased as drought deepened. Results suggest that maintaining relatively high groundwater levels in coastal aquifers may be imperative to the persistence of vulnerable salmonid populations in a changing climate.

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Section: Mechanisms Through Which Groundwater May Promote Coho Salmonmentioning

confidence: 99%

Groundwater Is Key to Salmonid Persistence and Recruitment in Intermittent Mediterranean‐Climate Streams

Larsen

Woelfle‐Erskine

2018

Water Resources Research

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“…It has been observed that as surface water flow decreases, the heterogeneity of local stream-channel environmental conditions (e.g. water residence time, biological community structure, sedimentwater interactions, and redox conditions) increases (Dahm et al, 2003;Lewis et al, 2007;Lillebo et al, 2007;Von Schiller et al, 2011). In contrast, under the high flood conditions of the hyperrheic state (i.e.…”

Section: Physicochemical Status (Pchs-tool)mentioning

confidence: 99%

The Mirage Toolbox: An Integrated Assessment Tool for Temporary Streams

Prat

Gallart

Schiller

et al. 2014

River Research & Apps

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The assessment of the ecological status of water bodies, as requires by the European Water Framework Directive, can raise a number of problems when applied to temporary streams. These problems are because of the particular physical, chemical and biological conditions resulting from the recurrent cessation of flow or even the complete drying of the stream beds. In such non‐permanent water bodies, the reference quality standards developed for permanent streams may only be applicable under certain circumstances or may not be applicable at all. Work conducted within the collaborative EU‐funded project Mediterranean Intermittent River ManAGEment (MIRAGE) has addressed most of these difficulties and has used diverse approaches to solve them. These approaches have been brought together in the so‐called MIRAGE Toolbox. This toolbox consists of a series of methodologies that are designed to be used in a sequential manner to allow the establishment of the ecological and chemical status of temporary streams and to relate these findings to the hydrological status of the streams. The toolbox is intended to serve the following purposes: (i) the determination of the hydrological regime of the stream; (ii) the design of adequate schedules for biological and chemical sampling according to the aquatic state of the stream; (iii) the fulfillment of criteria for designing reference condition stations; (iv) the analysis of hydrological modifications of the stream regime (with the definition of the hydrological status); and (v) the development of new methods to measure the ecological status (including structural and functional methods) and chemical status when the stream's hydrological conditions are far from those in permanent streams. Copyright © 2014 John Wiley & Sons, Ltd.

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“…Ecosystem contraction and fragmentation during surface drying disconnected the stream from its catchment as well as from upstream and downstream reaches, causing characteristic low oxygen and acidic conditions in the remaining water (Stanley et al 1997;Acuña et al 2005;Lillebo et al 2007). The concentration and relative dominance of different dissolved N forms responded to these changes.…”

Section: Temporal Variation In Nutrient Concentrationsmentioning

confidence: 99%

“…During contraction and fragmentation, the concentrations of reduced inorganic forms of nutrients, especially ammonium, tend to increase likely due to the effects of the hypoxic environment (Boulton and Lake 1990;VidalAbarca et al 2000;Acuña et al 2005;Lillebo et al 2007). During stream expansion after rewetting, high concentrations of nitrogen (N) and phosphorus (P) originate from groundwater inputs and from leaching of accumulated organic material (Tzoraki et al 2007;Obermann et al 2009;Skoulikidis and Amaxidis 2009).…”

Section: Introductionmentioning

confidence: 99%

Contraction, fragmentation and expansion dynamics determine nutrient availability in a Mediterranean forest stream

Schiller

Acuña

Graeber³

et al. 2011

Aquat Sci

100

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Temporary streams are a dominant surface water type in the Mediterranean region. As a consequence of their hydrologic regime, these ecosystems contract and fragment as they dry, and expand after rewetting. Global change leads to a rapid increase in the extent of temporary streams, and more and more permanent streams are turning temporary. Consequently, there is an urgent need to better understand the effects of flow intermittency on the biogeochemistry and ecology of stream ecosystems. Our aim was to investigate how stream nutrient availability varied in relation to ecosystem contraction, fragmentation and expansion due to hydrologic drying and rewetting. We quantified the temporal and spatial changes in dissolved nitrogen (N) and phosphorus (P) concentrations along a reach of a temporary Mediterranean forest stream during an entire contraction-fragmentation-expansion hydrologic cycle. We observed marked temporal changes in N and P concentrations, in the proportion of organic and inorganic forms as well as in stoichiometric ratios, reflecting shifts in the relative importance of in-stream nutrient processing and external nutrient sources. In addition, the spatial heterogeneity of N and P concentrations and their ratios increased substantially with ecosystem fragmentation, reflecting the high relevance of in-stream processes when advective transport was lost. Overall, changes were more pronounced for N than for P. This study emphasizes the significance of flow intermittency in regulating stream nutrient availability and its implications for temporary stream management. Moreover, our results point to potential biogeochemical responses of these ecosystems in more temperate regions under future water scarcity scenarios.

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Nutrient dynamics in Mediterranean temporary streams: A case study in Pardiela catchment (Degebe River, Portugal)

Cited by 34 publications

References 18 publications

Groundwater Is Key to Salmonid Persistence and Recruitment in Intermittent Mediterranean‐Climate Streams

Groundwater Is Key to Salmonid Persistence and Recruitment in Intermittent Mediterranean‐Climate Streams

The Mirage Toolbox: An Integrated Assessment Tool for Temporary Streams

Contraction, fragmentation and expansion dynamics determine nutrient availability in a Mediterranean forest stream

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