scholarly journals Drivers of Ecosystem Metabolism in Two Managed Shallow Lakes with Different Salinity and Trophic Conditions: The Sauce Grande and La Salada Lakes (Argentina)

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1136 ◽  
Author(s):  
María Alfonso ◽  
Andrea Brendel ◽  
Alejandro Vitale ◽  
Carina Seitz ◽  
María Piccolo ◽  
...  
Keyword(s):  
Water Management ◽  
Shallow Lakes ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Eutrophic Lake ◽  
Ecosystem Metabolism ◽  
Management Policy ◽  
Effective Management ◽  
Trophic Conditions ◽  
Lake Volume

Understanding the drivers and how they affect ecosystem metabolism is essential for developing effective management policy and plans. In this study, net ecosystem production (NEP), ecosystem respiration (R), and gross primary production (GPP) rates were estimated in relation to physicochemical, hydrological, and meteorological variables in La Salada (LS) and Sauce Grande (SG), two shallow lakes located in an important agricultural region with water management. LS is a mesosaline, mesotrophic-eutrophic lake, whereas SG is a hyposaline and eutrophic lake. GPP and R showed daily and seasonal variations, with R exceeding GPP during most of the study period in both lakes. Net heterotrophic conditions prevailed during the study period (NEP LS: −1.1 mmol O2 m−2 day−1 and NEP SG: −1.25 mmol O2 m−2 day−1). From data analysis, the temperature, wind speed, and lake volume are the main drivers of ecosystem metabolism for both lakes. Despite the significant differences between the two lakes, the NEP values were similar. The different hydrological characteristics (endorheic vs. flushing lake) were crucial in explaining why the two different systems presented similar ecosystem metabolic rates, emphasizing the importance of water management.

Data-based machine learning unveils ecosystem metabolic regimes at the scale of entire stream networks

2020 ◽  
Author(s):  
Pier Luigi Segatto ◽  
Tom J. Battin ◽  
Enrico Bertuzzo
Keyword(s):  
Machine Learning ◽  
Carbon Cycle ◽  
Ecosystem Respiration ◽  
Spatial Scales ◽  
Gross Primary Production ◽  
Data Availability ◽  
Ecosystem Metabolism ◽  
Sensor Technology ◽  
Stream Network ◽  
Metabolic Fluxes

<p>Inland waters are major contributors to the global carbon cycle. Nowadays, new sensor technology has changed the way we study ecosystem metabolism in streams. We are able to produce long-term time series of gross primary production (GPP) and ecosystem respiration (ER) to infer drivers of the stream ecosystem metabolic regime and its seasonal timing. Despite big data availability, most studies are limited to individual stream reaches and do not allow the appreciation of metabolic regimes at the scale of entire networks, which, however, would be fundamental to properly assess the relevance of metabolic fluxes within streams and rivers for carbon cycling at the regional and global scale. Machine learning (ML) has great potential in this direction. Firstly, ML could be used to extrapolate both in time and space heterogeneous forcings (e.g., streamwater temperature (T) and photosynthetic active radiation (PAR)) required to run a process-based model for reach-scale metabolism to the scale of an entire stream network. Secondly, the same procedure could be applied to reach-scale estimates of ecosystem metabolism to check whether available data contain enough information to explain the network scale variability. In this study, we used Random Forest to predict patterns of environmental forcings (T and PAR) and stream metabolism (GPP and ER) at the scale of an entire stream network. We used available high-frequency measurements of T and PAR, estimates of ecosystem metabolism and major proximal controls (e.g., incident light, discharge, stream-bed slope, drainage area, water level,  air temperature) from twelve reaches within the Ybbs River network (Austria) and explicitly trained our Random Forests by integrating distal factors, namely:  vegetation type, canopy cover, hydro-geomorphic properties, light,  precipitation, and other climatic variables. We designed two different training setups to assess spatial and temporal predicting model capabilities, respectively. This approach allowed us to reliably infer the target variables (T, PAR, GPP, and ER) on annual basis across a stream network, to filter the most important predictors, to assess the relative contribution of the metabolic fluxes from small to large streams, to estimate annual metabolic budgets at different spatial scales and to provide empirical evidence for long-standing theory predicting shifts of ecosystem metabolism along the stream continuum. Finally, we estimated autochthonous and allochthonous respiration for the entire stream network, which is crucial to integrate the role of ecosystem processes for the carbon cycle.</p>

scholarly journals Hydromorphological restoration stimulates river ecosystem metabolism

2016 ◽  
Author(s):  
Benjamin Kupilas ◽  
Daniel Hering ◽  
Armin W. Lorenz ◽  
Christoph Knuth ◽  
Björn Gücker
Keyword(s):  
Open Channel ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Ecosystem Metabolism ◽  
Ecosystem Structure ◽  
Third Order ◽  
Goods And Services ◽  
Ecosystem Structure And Functioning ◽  
The One ◽  
Substantial Effort

Abstract. Both, ecosystem structure and functioning determine ecosystem status and are important for the provision of goods and services to society. However, there is a paucity of research that couples functional measures with assessments of ecosystem structure. In mid-sized and large rivers, effects of restoration on key ecosystem processes, such as ecosystem metabolism, have rarely been addressed and remain poorly understood. We compared three reaches of the third-order, gravel-bed river Ruhr in Germany: two reaches restored with moderate (R1) and substantial effort (R2) and one upstream degraded reach (D). Hydromorphology, habitat composition and hydrodynamics were assessed. We estimated gross primary production (GPP) and ecosystem respiration (ER) using the one-station open-channel diel dissolved oxygen change method over a 50-day period at the end of each reach. Values for hydromorphological variables increased with restoration intensity (D 

scholarly journals Hydromorphological restoration stimulates river ecosystem metabolism

2017 ◽  
Vol 14 (7) ◽  
pp. 1989-2002 ◽  
Author(s):  
Benjamin Kupilas ◽  
Daniel Hering ◽  
Armin W. Lorenz ◽  
Christoph Knuth ◽  
Björn Gücker
Keyword(s):  
Ecosystem Functioning ◽  
Open Channel ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Ecosystem Metabolism ◽  
Transient Storage ◽  
Ecosystem Structure ◽  
Goods And Services ◽  
Wetted Area ◽  
Particulate Nutrients

Abstract. Both ecosystem structure and functioning determine ecosystem status and are important for the provision of goods and services to society. However, there is a paucity of research that couples functional measures with assessments of ecosystem structure. In mid-sized and large rivers, effects of restoration on key ecosystem processes, such as ecosystem metabolism, have rarely been addressed and remain poorly understood. We compared three reaches of the third-order, gravel-bed river Ruhr in Germany: two reaches restored with moderate (R1) and substantial effort (R2) and one upstream degraded reach (D). Hydromorphology, habitat composition, and hydrodynamics were assessed. We estimated gross primary production (GPP) and ecosystem respiration (ER) using the one-station open-channel diel dissolved oxygen change method over a 50-day period at the end of each reach. Moreover, we estimated metabolic rates of the combined restored reaches (R1 + R2) using the two-station open-channel method. Values for hydromorphological variables increased with restoration intensity (D  <  R1  <  R2). Restored reaches had lower current velocity, higher longitudinal dispersion and larger transient storage zones. However, fractions of median travel time due to transient storage were highest in R1 and lowest in R2, with intermediate values in D. The share of macrophyte cover of total wetted area was highest in R2 and lowest in R1, with intermediate values in D. Station R2 had higher average GPP and ER than R1 and D. The combined restored reaches R1 + R2 also exhibited higher GPP and ER than the degraded upstream river (station D). Restoration increased river autotrophy, as indicated by elevated GPP : ER, and net ecosystem production (NEP) of restored reaches. Temporal patterns of ER closely mirrored those of GPP, pointing to the importance of autochthonous production for ecosystem functioning. In conclusion, high reach-scale restoration effort had considerable effects on river hydrodynamics and ecosystem functioning, which were mainly related to massive stands of macrophytes. High rates of metabolism and the occurrence of dense macrophyte stands may increase the assimilation of dissolved nutrients and the sedimentation of particulate nutrients, thereby positively affecting water quality.

scholarly journals Multi-Year Monitoring of Ecosystem Metabolism in Two Branches of a Cold-Water Stream

Environments ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 19
Author(s):  
Daniel J. Hornbach
Keyword(s):  
Climate Change ◽  
Cold Water ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Ecosystem Metabolism ◽  
Freshwater Biodiversity ◽  
Water Stream ◽  
Stream Discharge ◽  
Biodiversity And Ecosystem Function

Climate change is likely to have large impacts on freshwater biodiversity and ecosystem function, especially in cold-water streams. Ecosystem metabolism is affected by water temperature and discharge, both of which are expected to be affected by climate change and, thus, require long-term monitoring to assess alterations in stream function. This study examined ecosystem metabolism in two branches of a trout stream in Minnesota, USA over 3 years. One branch was warmer, allowing the examination of elevated temperature on metabolism. Dissolved oxygen levels were assessed every 10 min from spring through fall in 2017–2019. Gross primary production (GPP) was higher in the colder branch in all years. GPP in both branches was highest before leaf-out in the spring. Ecosystem respiration (ER) was greater in the warmer stream in two of three years. Both streams were heterotrophic in all years (net ecosystem production—NEP < 0). There were significant effects of temperature and light on GPP, ER, and NEP. Stream discharge had a significant impact on all GPP, ER, and NEP in the colder stream, but only on ER and NEP in the warmer stream. This study indicated that the impacts of temperature, light, and discharge differ among years, and, at least at the local scale, may not follow expected patterns.

scholarly journals Differentiation in Aquatic Metabolism between Littoral Habitats with Floating-Leaved and Submerged Macrophyte Growth Forms in a Shallow Eutrophic Lake

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 287 ◽  
Author(s):  
Konstantinos Stefanidis ◽  
Elias Dimitriou
Keyword(s):  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Free Water ◽  
Eutrophic Lake ◽  
Growth Forms ◽  
Metabolic Balance ◽  
Lake Metabolism ◽  
Macrophyte Growth ◽  
Shallow Eutrophic Lake ◽  
Littoral Habitats

The metabolic balance between gross primary production (GPP) and ecosystem respiration (R) is known to display large spatial and temporal variations within shallow lakes. Thus, although estimation of aquatic metabolism using free-water measurements of dissolved oxygen concentration has become increasingly common, the explanation of the variance in the metabolic regime remains an extremely difficult task. In this study, rates of GPP, respiration (R) and the metabolic balance (net ecosystem production, NEP) were estimated in four littoral habitats with different macrophyte growth forms (floating-leaved vs submerged) over a 28-month period in lake of Kastoria (Greece), a shallow eutrophic lake. Our results showed that net heterotrophy prevailed over the studied period, suggesting that allochthonous organics fuel respiration processes in the littoral. Temporal variation in the metabolic rates was driven mainly by the seasonal variation in irradiance and water temperature, with the peak of metabolic activity occurring in summer and early autumn. Most importantly, significant spatial variation among the four habitats was observed and associated with the different macrophyte growth forms that occurred in the sites. The results highlight the importance of habitat specific characteristics for the assessment of metabolic balance and underline the potentially high contribution of littoral habitats to the whole lake metabolism.

scholarly journals Hydrologic Setting Dictates the Sensitivity of Ecosystem Metabolism to Climate Variability in Lakes

Ecosystems ◽  
2021 ◽  
Author(s):  
Isabella A. Oleksy ◽  
Stuart E. Jones ◽  
Christopher T. Solomon
Keyword(s):  
Oxygen Sensor ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Climatic Variability ◽  
Ecosystem Metabolism ◽  
Sensor Data ◽  
Lake Area ◽  
Coefficients Of Variation ◽  
Bog Lakes ◽  
Carbon Concentrations

AbstractGlobal change is influencing production and respiration in ecosystems across the globe. Lakes in particular are changing in response to climatic variability and cultural eutrophication, resulting in changes in ecosystem metabolism. Although the primary drivers of production and respiration such as the availability of nutrients, light, and carbon are well known, heterogeneity in hydrologic setting (for example, hydrological connectivity, morphometry, and residence) across and within regions may lead to highly variable responses to the same drivers of change, complicating our efforts to predict these responses. We explored how differences in hydrologic setting among lakes influenced spatial and inter annual variability in ecosystem metabolism, using high-frequency oxygen sensor data from 11 lakes over 8 years. Trends in mean metabolic rates of lakes generally followed gradients of nutrient and carbon concentrations, which were lowest in seepage lakes, followed by drainage lakes, and higher in bog lakes. We found that while ecosystem respiration (ER) was consistently higher in wet years in all hydrologic settings, gross primary production (GPP) only increased in tandem in drainage lakes. However, interannual rates of ER and GPP were relatively stable in drainage lakes, in contrast to seepage and bog lakes which had coefficients of variation in metabolism between 22–32%. We explored how the geospatial context of lakes, including hydrologic residence time, watershed area to lake area, and landscape position influenced the sensitivity of individual lake responses to climatic variation. We propose a conceptual framework to help steer future investigations of how hydrologic setting mediates the response of metabolism to climatic variability.

Metabolic changes and the resistance and resilience of a subtropical heterotrophic lake to typhoon disturbance

2011 ◽  
Vol 68 (5) ◽  
pp. 768-780 ◽  
Author(s):  
Jeng-Wei Tsai ◽  
Timothy K. Kratz ◽  
Paul C. Hanson ◽  
Nobuaki Kimura ◽  
Wen-Cheng Liu ◽  
...  
Keyword(s):  
High Frequency ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Ecosystem Metabolism ◽  
Lake Metabolism ◽  
Typhoon Disturbance ◽  
Ecosystem Production ◽  
Rate Of Recovery ◽  
Induced Changes

We studied how typhoon strength affects the daily dynamics of ecosystem metabolism of a subtropical alpine lake in Taiwan. We identified proximal agents of typhoon disturbance and assessed the resistance (the extent of change induced by a disturbance) and resilience (the rate of recovery after a disturbance) of lake metabolism to them. Gross primary production (GPP), ecosystem respiration (ER), and net ecosystem production were estimated from high-frequency dissolved oxygen data provided by an instrumented buoy. Typhoons resulted in significantly lower GPP (3%–81% decrease), and higher ER (7%–828% increase) compared with immediately before the events, and thus the lake became more heterotrophic (28%–852% increase in heterotrophy). The resistance and resilience of lake metabolism depended on the intensity of the typhoon. Smaller typhoons (with average daily accumulated precipitation (ADAP) < 200 mm·day–1) had greater effects on lake metabolism than medium (ADAP = 200–350 mm·day–1) and large (ADAP > 350 mm·day–1) typhoons. However, metabolism also recovered more quickly after smaller typhoons than after medium or larger typhoons. Typhoon effects on ecosystem metabolism is likely mediated by the magnitude and duration of typhoon-induced changes in lake mixing, the quantity and quality of dissolved organic carbon, and the biomass of primary producers.

Collaboration platforms in water management

2011 ◽  
Vol 6 (3) ◽  
Author(s):  
C. E. Hidaka ◽  
H. R. Kolar ◽  
R. P. Williams ◽  
P. G. Hartswick ◽  
S. B. Foong
Keyword(s):  
Water Management ◽  
Information Technology ◽  
Water Resources ◽  
Data Sources ◽  
Effective Management ◽  
Holistic View ◽  
The World ◽  
Technical Architecture ◽  
Multiple Levels ◽  
Collaboration Platforms

In many parts of the world, management of water resources and infrastructures is fragmented between agencies at multiple levels – state, provincial, and local – and sometimes between functions within individual agencies. Consequently it is often impossible to take a holistic view of the issues at hand to enable effective management of the resource or infrastructure – either because of the overhead of managing the coordination required, and/or because of politics between the different stakeholders. In their work for IBM, the authors created a concept of an information technology (IT)-enabled “collaboration platform” that integrates different water data sources with IT tools to enable multiple entities to maintain and share a “common operating picture.” This greatly assists with coordination and reduces politics to manageable levels. In this paper, the authors describe the collaboration platform and its benefits by reference to examples of such platforms in use, and propose a reference technical architecture for creating collaboration platforms.

Systematic approaches in water management: Aquatic outlook and decision support systems combining monitoring, research, policy analysis and information technology

1996 ◽  
Vol 34 (12) ◽  
pp. 9-16 ◽  
Author(s):  
J. de Jong ◽  
J. T. van Buuren ◽  
J. P. A. Luiten
Keyword(s):  
Water Management ◽  
Policy Analysis ◽  
Research Policy ◽  
Human Life ◽  
Management Policy ◽  
Ecological Aspects ◽  
Management Plans ◽  
Water Management Plans ◽  
Life On Earth

Sustained developments is the target of almost every modern water management policy. Sustainability is focused on human life and on the ecological quality of our environment. Both aspects are essential for life on earth. Within a river catchment area this means that well balanced relations have to be laid between human activities and ecological aspects in the involved areas. Policy analysis is especially looking for the most efficient way to analyse and to overcome bottlenecks. In The Netherlands project “The Aquatic Outlook” all these elements are worked out in a nationwide scale, providing the scientific base and policy analysis from which future water management plans can be derived.

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