Influence of land use and rainfall variability on nutrient concentrations in Florida Lakes

2018 ◽  
Vol 35 (1) ◽  
pp. 25-37 ◽  
Author(s):  
Chao Xiong ◽  
Mark V. Hoyer
Keyword(s):  
Land Use ◽  
Rainfall Variability ◽  
Nutrient Concentrations ◽  
Florida Lakes

scholarly journals Land Use/Cover Response to Rainfall Variability: A Comparing Analysis between NDVI and EVI in the Southwest of Burkina Faso

Climate ◽  
2014 ◽  
Vol 3 (1) ◽  
pp. 63-77 ◽  
Author(s):  
Benewinde Zoungrana ◽  
Christopher Conrad ◽  
Leonard Amekudzi ◽  
Michael Thiel ◽  
Evariste Da
Keyword(s):  
Land Use ◽  
Burkina Faso ◽  
Rainfall Variability

scholarly journals Mapping of Major Land-Use Changes in the Kolleru Lake Freshwater Ecosystem by Using Landsat Satellite Images in Google Earth Engine

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2493 ◽  
Author(s):  
Meena Kumari Kolli ◽  
Christian Opp ◽  
Daniel Karthe ◽  
Michael Groll
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Land Use Changes ◽  
Google Earth ◽  
Nutrient Concentrations ◽  
Freshwater Ecosystem ◽  
Lake Ecosystem ◽  
Lake Basin ◽  
Lake Area ◽  
Google Earth Engine

India’s largest freshwater ecosystem of the Kolleru Lake has experienced severe threats by land-use changes, including the construction of illegal fishponds around the lake area over the past five decades. Despite efforts to protect and restore the lake and its riparian zones, environmental pressures have increased over time. The present study provides a synthesis of human activities through major land-use changes around Kolleru Lake both before and after restoration measures. For this purpose, archives of all Landsat imageries from the last three decades were used to detect land cover changes. Using the Google Earth Engine cloud platform, three different land-use scenarios were classified for the year before restoration (1999), for 2008 immediately after the restoration, and for 2018, i.e., the current situation of the lake one decade afterward. Additionally, the NDVI (Normalized Difference Vegetation Index) and NDWI (Normalized Difference Water Index) indices were used to identify land cover dynamics. The results show that the restoration was successful; consequently, after a decade, the lake was transformed into the previous state of restoration (i.e., 1999 situation). In 1999, 29.7% of the Kolleru Lake ecosystem was occupied by fishponds, and, after a decade of sustainable restoration, 27.7% of the area was fishponds, almost reaching the extent of the 1999 situation. On the one hand, aquaculture is one of the most promising sources of income, but there is also limited awareness of its negative environmental impacts among local residents. On the other hand, political commitment to protect the lake is weak, and integrated approaches considering all stakeholders are lacking. Nevertheless, alterations of land and water use, increasing nutrient concentrations, and sediment inputs from the lake basin have reached a level at which they threaten the biodiversity and functionality of India’s largest wetland ecosystem to the degree that immediate action is necessary to prevent irreversible degradation.

scholarly journals Assessing the Eutrophic Susceptibility of New Zealand Estuaries

2020 ◽  
Vol 43 (8) ◽  
pp. 2015-2033 ◽  
Author(s):  
David R. Plew ◽  
John R. Zeldis ◽  
Bruce D. Dudley ◽  
Amy L. Whitehead ◽  
Leigh M. Stevens ◽  
...  
Keyword(s):  
Land Use ◽  
New Zealand ◽  
Physical Properties ◽  
Nutrient Loading ◽  
Management Strategies ◽  
Nutrient Concentrations ◽  
Intertidal Area ◽  
Land Use Patterns ◽  
Regional Patterns ◽  
Nitrogen Concentrations

Abstract We developed a method to predict the susceptibility of New Zealand estuaries to eutrophication. This method predicts macroalgae and phytoplankton responses to potential nutrient concentrations and flushing times, obtained nationally from simple dilution models, a GIS land-use model and physical estuary properties. Macroalgal response was based on an empirically derived relationship between potential nitrogen concentrations and an established macroalgal index (EQR) and phytoplankton response using an analytical growth model. Intertidal area was used to determine which primary producer was likely to lead to eutrophic conditions within estuaries. We calculated the eutrophication susceptibility of 399 New Zealand estuaries and assigned them to susceptibility bands A (lowest expected impact) to D (highest expected impact). Twenty-seven percent of New Zealand estuaries have high or very high eutrophication susceptibilities (band C or D), mostly (63% of band C and D) due to macroalgae. The physical properties of estuaries strongly influence susceptibility to macroalgae or phytoplankton blooms, and estuaries with similar physical properties cluster spatially around New Zealand’s coasts. As a result, regional patterns in susceptibility are apparent due to a combination of estuary types and land use patterns. The few areas in New Zealand with consistently low estuary eutrophication susceptibilities are either undeveloped or have estuaries with short flushing times, low intertidal area and/or minimal tidal influx. Estuaries with conditions favourable for macroalgae are most at risk. Our approach provides estuary-integrated susceptibility scores likely to be of use as a regional or national screening tool to prioritise more in-depth estuary assessments, to evaluate likely responses to altered nutrient loading regimes and assist in developing management strategies for estuaries.

scholarly journals Conceptual Mini-Catchment Typologies for Testing Dominant Controls of Nutrient Dynamics in Three Nordic Countries

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1776 ◽  
Author(s):  
Fatemeh Hashemi ◽  
Ina Pohle ◽  
Johannes W.M. Pullens ◽  
Henrik Tornbjerg ◽  
Katarina Kyllmar ◽  
...  
Keyword(s):  
Land Use ◽  
Nutrient Dynamics ◽  
Pollution Monitoring ◽  
Organic N ◽  
Particulate Phosphorus ◽  
Nutrient Concentrations ◽  
Data Series ◽  
Nutrient Export ◽  
Small Streams ◽  
Export Behaviour

Optimal nutrient pollution monitoring and management in catchments requires an in-depth understanding of spatial and temporal factors controlling nutrient dynamics. Such an understanding can potentially be obtained by analysing stream concentration–discharge (C-Q) relationships for hysteresis behaviours and export regimes. Here, a classification scheme including nine different C-Q types was applied to a total of 87 Nordic streams draining mini-catchments (0.1–65 km2). The classification applied is based on a combination of stream export behaviour (dilution, constant, enrichment) and hysteresis rotational pattern (clock-wise, no rotation, anti-clockwise). The scheme has been applied to an 8-year data series (2010–2017) from small streams in Denmark, Sweden, and Finland on daily discharge and discrete nutrient concentrations, including nitrate (NO3−), total organic N (TON), dissolved reactive phosphorus (DRP), and particulate phosphorus (PP). The dominant nutrient export regimes were enrichment for NO3− and constant for TON, DRP, and PP. Nutrient hysteresis patterns were primarily clockwise or no hysteresis. Similarities in types of C-Q relationships were investigated using Principal Component Analysis (PCA) considering effects of catchment size, land use, climate, and dominant soil type. The PCA analysis revealed that land use and air temperature were the dominant factors controlling nutrient C-Q types. Therefore, the nutrient export behaviour in streams draining Nordic mini-catchments seems to be dominantly controlled by their land use characteristics and, to a lesser extent, their climate.

scholarly journals Effects of watershed and riparian zone characteristics on nutrient concentrations in the River Scheldt Basin

2006 ◽  
Vol 10 (6) ◽  
pp. 913-922 ◽  
Author(s):  
J. Meynendonckx ◽  
G. Heuvelmans ◽  
B. Muys ◽  
J. Feyen
Keyword(s):  
Land Use ◽  
Agricultural Land ◽  
Wastewater Treatment Plants ◽  
Morphological Characteristics ◽  
Drainage Density ◽  
Point Sources ◽  
Nutrient Concentrations ◽  
Buffer Strip ◽  
Additional Influence ◽  
Scheldt Basin

Abstract. The relative influence of a set of watershed characteristics on surface water nutrient concentrations was examined in 173 watersheds within two subcatchments (Upper-Scheldt and Nete) of the River Scheldt Basin (Flanders, Belgium). Each watershed was described by seasonal rainfall, discharge loading of point sources, morphological characteristics (area, average slope, drainage density, elongation), land use and soil properties (soil texture and drainage). Partial regression analysis revealed that soil drainage variables had the strongest influence on nutrient concentrations. Additional influence was exerted by land use and point source loading variables. Nitrate concentrations were positively correlated with effluent loadings coming from wastewater treatment plants and with the area of agricultural land. Phosphate concentrations were best explained by effluent loadings of industrial point sources and by the area of urban land. Land use close to the river was not a better predictor of nitrate and phosphate concentrations than land use away from the river. This suggests that the mediating impact of riparian zones is rather explained by the hydrologic pathways within the buffer strip.

Phosphorus chemical changes under soils over a period of agricultural intensification

2020 ◽  
Author(s):  
Andrew Tweedie ◽  
Philip M. Haygarth ◽  
Anthony Edwards ◽  
Allan Lilly ◽  
Nikki Baggaley ◽  
...  
Keyword(s):  
Land Use ◽  
Agricultural Intensification ◽  
Agricultural Land ◽  
Ammonium Oxalate ◽  
Water Extraction ◽  
Nutrient Concentrations ◽  
Agricultural Land Use ◽  
Organic P ◽  
P Fertilizer ◽  
Over Time

<p>The use of phosphorus (P) fertilizer has been one of the defining contributors to productive agriculture since the green revolution during the middle of the last century. However, these increased yields have come at the cost of dependency upon the declining resources of P rock reserves and eutrophication of water bodies downstream. In this context, it is important to understand the long-term effects of these P fertilizer additions on soil chemistry over ~50 years in order explain past and current patterns in fertilizer usage and so to better inform future soil management.</p><p>We tested the hypothesis that phosphorus forms and availability in mixed use (arable and grazed) agricultural soil have changed over a period of 50 to 80 years of agricultural intensification. Spatially matched samples of soil from 34 agricultural sites in North East (NE) Scotland were collected at two timepoints. The first samples were taken between 1951 and 1981 and in all cases the resampling took place in the autumn of 2017. The soils sampled were representative of agricultural soils in NE Scotland.</p><p>The hypothesis was tested by employing a range of soil tests on the ‘old’ and ‘new’ time points.  These included water extraction for inorganic and organic P, nitrate and ammonium and dissolved organic carbon, acid ammonium oxalate extraction to investigate the soil P exchange complex and NaOH-EDTA extraction as a strong alkaline extractant which preserves organic P forms. Analysis by <sup>31</sup>P NMR was conducted on the NaOH-EDTA extracts from 5 pairs of samples, to investigate the organic P chemistry of in greater detail.</p><p>Phosphorus concentrations for stronger extractants (NaOH-EDTA, acid ammonium oxalate) did not increase significantly (P<0.05) over time. However, water extraction results showed increases in total P (P<0.01) and inorganic P but decreases in organic P. Additionally, analysis by <sup>31</sup>P NMR detected changes between timepoints in α-glycero-phosphate and pyrophosphate.</p><p>These results indicate that differences in the various chemical forms of P present in soil between the timepoints can be detected many decades apart. This indicates changes in the functioning of the P cycle in these soils under intensive agricultural land use over time. Knowledge of the P-cycling response of soils under agricultural land-use over decades provides an opportunity to understand changes in soil nutrient concentrations, balances and availability and inform studies seeking to improve the sustainable management of soil fertility.</p>

Effects of intermittency and land use on the in-stream phosphorus and organic carbon uptake

2020 ◽  
Author(s):  
Gabriele Weigelhofer ◽  
Matthias Pucher
Keyword(s):  
Land Use ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Hyporheic Zone ◽  
Agricultural Land ◽  
Headwater Streams ◽  
Phosphorus Release ◽  
Nutrient Concentrations ◽  
Agricultural Land Use ◽  
First Results

<p>Understanding the consequences of the interplay between land use and climate change is among the most pressing challenges of the 21<sup>st</sup> century for river managers. Over the past decades, agricultural land use has altered nutrient concentrations and stoichiometric ratios in stream ecosystems, thereby affecting aquatic biogeochemical cycles and the coupling among carbon, phosphorus, and nitrogen. In addition, the frequency and duration of droughts has increased dramatically across Europe, causing perennial streams to shift to intermittency and changing the capacity of sediments for the uptake and storage of macronutrients.</p><p>Our study aims to understand the effects of drying and re-wetting on the uptake, storage, and release of phosphorus and organic carbon from the benthic and the hyporheic zone of headwater streams under the additional stressor of agricultural land use. In specific, we are interested in the potential coupling and decoupling of phosphorus and dissolved organic carbon cycling in autotrophic and heterotrophic benthic biofilms. We sampled headwater streams before, during, and after the dry period in 2018 and 2019 and performed laboratory experiments with artificial drying and re-wetting and additions of dissolved organic carbon. We measured nutrient uptake and release, microbial biomass, respiration, and the activity of extra-cellular enzymes. The first results show an increased phosphorus release from the sediments immediately after re-wetting, foolowed by a reduced uptake capacity. The uptake of DOC was correlated with phosphorus in autotrophic biofilms, but not in heterotrophic ones.</p>

scholarly journals Predicting the occurrence of stoneflies (Plecoptera) on the basis of water characteristics, river morphology and land use

2013 ◽  
Vol 16 (4) ◽  
pp. 812-821 ◽  
Author(s):  
Koen Lock ◽  
Peter L. M. Goethals
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Sampling Site ◽  
Environmental Parameters ◽  
Nutrient Concentrations ◽  
Support Vector ◽  
River Morphology ◽  
The European Union ◽  
Water Characteristics ◽  
Modelling Techniques

Stoneflies are macro-invertebrates that are sensitive water quality indicators. Here, their occurrence was modelled based on physical–chemical water characteristics, river morphology and land use with five different modelling techniques. In a case-study in Flanders, stoneflies were found in 219 samples and two sets of absence data were gathered: 219 random samples from sites without stoneflies and 219 samples from sites downstream of each sampling site where stoneflies were observed. With both random and downstream absences, logistic regressions, artificial neural networks, support vector machines, random forests and classification trees could all successfully predict stonefly occurrence. For most environmental parameters, significant differences were found between sites with and without stoneflies. As stoneflies were only detected in a few percent of the samples, the ecological water quality is obviously still too low in most watercourses. Based on planned water quality improvement measures, an ensemble forecast using the five mentioned modelling techniques predicted that stonefly prevalence will only increase marginally by 2015 and 2027. To meet the European Union Water Framework Directive requirements, which states that all surface waters should obtain a good ecological quality, a more ambitious management plan is needed to decrease nutrient concentrations and improve habitat quality.

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