scholarly journals Response to Comment on “Legacy nitrogen may prevent achievement of water quality goals in the Gulf of Mexico”

Science ◽  
2019 ◽  
Vol 365 (6455) ◽  
pp. eaav3851 ◽  
Author(s):  
K. J. Van Meter ◽  
P. Van Cappellen ◽  
N. B. Basu
Keyword(s):  
Water Quality ◽  
Gulf Of Mexico ◽  
Regression Model ◽  
Recovery Time ◽  
Time Lags ◽  
Decadal Scale ◽  
Two Component ◽  
Lines Of Evidence ◽  
Watershed Processes

Ballard et al. argue that our prediction of a 30-year or longer recovery time for Gulf of Mexico water quality is highly uncertain, and that much shorter time lags are equally likely. We demonstrate that their argument, based on the use of a two-component regression model, does not sufficiently consider fundamental watershed processes or multiple lines of evidence suggesting the existence of decadal-scale lags.

scholarly journals Development of correlation-regression model between land use change and water quality indices in Ciliwung watershed

2018 ◽  
Vol 192 ◽  
pp. 02047
Author(s):  
Yopy Arfan ◽  
Dwita Sutjiningsih
Keyword(s):  
Water Quality ◽  
Regression Model ◽  
Pearson Correlation ◽  
Water Quality Monitoring ◽  
Test Method ◽  
Quality Indices ◽  
Water Quality Indices ◽  
Correlation Test ◽  
Impervious Cover ◽  
Water Ecosystems

Urbanization and industrialization lead to the change of land cover from pervious into impervious. This can impact environmental problems such as water quality degradation that affects human health and water ecosystems. The study aimed to develop a regression-correlation model between impervious cover in Ciliwung watershed and water quality indices in Ciliwung river. The correlation-regression model can be used to predict changes in the status of Ciliwung river water quality due to impervious cover changes. Methods of assessing the indices of water quality are CCME-WQI, NSF-WQI, and STORET within the period of 2005-2016. Monitoring locations from the most upstream to downstream are Atta’awun, Katulampa, Kedung Halang, Pondok Rajeg, Panus Bridge, Kelapa Dua, Condet, Kalibata, MT Haryono and Manggarai. Impervious cover data for each water quality monitoring location is processed using ArcGIS Software. Test of correlation significance between percentage of impervious cover and water quality indices using Pearson Correlation test method. The result of correlation test is significantly a strong inverse relationship between impervious cover and water quality indices. The result of regression test is trend line between impervious cover change and water quality indices that can be used to predict the change of water quality status in Ciliwung River.

Water Quality Effects on Fish Larvae in a Tropical Coastal Lagoon of the Gulf of Mexico

2014 ◽  
pp. 31-38
Author(s):  
Guadalupe de la Lanza-Espino ◽  
Salvador Hernández-Pulido ◽  
Norma Sánchez-Santillán ◽  
José Luis Carbajal-Pérez
Keyword(s):  
Water Quality ◽  
Gulf Of Mexico ◽  
Coastal Lagoon ◽  
Fish Larvae ◽  
Tropical Coastal Lagoon

A hybrid regression model for water quality prediction

OPSEARCH ◽  
2019 ◽  
Vol 56 (4) ◽  
pp. 1167-1178 ◽  
Author(s):  
Tanujit Chakraborty ◽  
Ashis Kumar Chakraborty ◽  
Zubia Mansoor
Keyword(s):  
Water Quality ◽  
Regression Model ◽  
Quality Prediction ◽  
Water Quality Prediction

scholarly journals Comment on “Legacy nitrogen may prevent achievement of water quality goals in the Gulf of Mexico”

Science ◽  
2019 ◽  
Vol 365 (6455) ◽  
pp. eaau8401 ◽  
Author(s):  
Tristan C. Ballard ◽  
Anna M. Michalak ◽  
Gregory F. McIsaac ◽  
Nancy N. Rabalais ◽  
R. Eugene Turner
Keyword(s):  
Water Quality ◽  
Gulf Of Mexico ◽  
Time Scales ◽  
Legacy Effects ◽  
Nitrogen Reduction ◽  
Modeling Approach

Van Meter et al. (Reports, 27 April 2018, p. 427) warn that achieving nitrogen reduction goals in the Gulf of Mexico will take decades as a result of legacy nitrogen effects. We discuss limitations of the modeling approach and demonstrate that legacy effects ranging from a few years to decades are equally consistent with observations. The presented time scales for system recovery are therefore highly uncertain.

UJI EFEKTIVITAS EKSTRAK BAWANG DAYAK (Eleutherine palmifolia Merr) TERHADAP PENYEMBUHAN INFEKSI JAMUR Saprolegnia sp, PADA IKAN NILA (Efectivity Test Bawang Dayak (Eleutherine palmifolia Merr) Extract in Saprolegnia sp Infection of Nile Tilapia)

2016 ◽  
Vol 1 (1) ◽  
pp. 48
Author(s):  
Junius Akbar
Keyword(s):  
Water Quality ◽  
Survival Rate ◽  
Body Length ◽  
Recovery Time ◽  
Nile Tilapia

The purpose of this research was to know the effect Bawang Dayak (Eleutherine palmifolia Merr) in Saprolegnia sp infection of nile tilapia (Oreochromis sp) with smear method. This research used Completely Randomized Desin consisted one factors with three treatments and three replicates (A: 10 ppt/ind), (B: 20 ppt/ind), and (C: control). The research using aquarium and nile tilapia (5-8 cm body length) with density of 2 ind/aquarium. Parameters observe were inhibitory test, recovery time, survival rate, and water quality. The result showed  that optimal consentration Bawang Dayak (Eleutherine palmifolia Merr) is 20 ppt.

scholarly journals LUMINATE: linking agricultural land use, local water quality and Gulf of Mexico hypoxia

2014 ◽  
Vol 41 (3) ◽  
pp. 431-459 ◽  
Author(s):  
C. L. Kling ◽  
Y. Panagopoulos ◽  
S. S. Rabotyagov ◽  
A. M. Valcu ◽  
P. W. Gassman ◽  
...  
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Gulf Of Mexico ◽  
Agricultural Land ◽  
Agricultural Land Use ◽  
Local Water

Wavelet analysis of time-lags in the response of cyanobacteria growth to water quality conditions in Lake Taihu, China

2014 ◽  
Vol 22 ◽  
pp. 52-57 ◽  
Author(s):  
Xiaoqing Zhang ◽  
Qiuwen Chen ◽  
Friedrich Recknagel ◽  
Ruonan Li
Keyword(s):  
Water Quality ◽  
Wavelet Analysis ◽  
Lake Taihu ◽  
Time Lags

scholarly journals A Global Approach to Assess the Potential Impact of Climate Change on Stream Water Temperatures and Related In-Stream First-Order Decay Rates

2012 ◽  
Vol 13 (3) ◽  
pp. 1052-1065 ◽  
Author(s):  
Manuel Punzet ◽  
Frank Voß ◽  
Anja Voß ◽  
Ellen Kynast ◽  
Ilona Bärlund
Keyword(s):  
Climate Change ◽  
Water Quality ◽  
Regression Model ◽  
Stream Water ◽  
Stream Temperature ◽  
Decay Rates ◽  
Regression Equation ◽  
Impact Of Climate Change ◽  
Global Regression ◽  
Warm Temperate

Abstract Stream water temperature is an important factor used in water quality modeling. To estimate monthly stream temperature on a global scale, a simple nonlinear regression model was developed. It was applied to stream temperatures recorded over a 36-yr period (1965–2001) at 1659 globally distributed gauging stations. Representative monthly air temperatures were obtained from the nearest grid cell included in the new global meteorological forcing dataset—the Water and Global Change (WATCH) Forcing Data. The regression model reproduced monthly stream temperatures with an efficiency of fit of 0.87. In addition, the regression model was applied for different climate zones (polar, snow, warm temperate arid, and equatorial climates) based on the Köppen–Geiger climate classification. For snow, warm temperate, and arid climates the efficiency of fit was larger than 0.82 including more than 1504 stations (90% of all records used). Analyses of heat-storage effects (seasonal hysteresis) did not show noticeable differences between the warming/cooling and global regression curves, respectively. The maximum difference between both limbs of the hysteresis curves was 1.6°C and thus neglected in the further analysis of the study. For validation purposes time series of stream temperatures for five individual river basins were computed applying the global regression equation. The accuracy of the global regression equation could be confirmed. About 77% of the predicted values differed by 3°C or less from measured stream temperatures. To examine the impact of climate change on stream water temperatures, gridded global monthly stream temperatures for the climate normal period (1961–90) were calculated as well as stream temperatures for the A2 and B1 climate change emission scenarios for the 2050s (2041–70). On average, there will be an increase of 1°–4°C in monthly stream temperature under the two climate scenarios. It was also found that in the months December, January, and February a noticeable warming predominantly occurs along the equatorial zone, while during the months June, July, and August large-scale or large increases can be observed in the northern and southern temperate zones. Consequently, projections of decay rates show a similar seasonal and spatial pattern as the corresponding stream temperatures. A regional increase up to ~25% could be observed. Thus, to ensure sufficient water quality for human purposes, but also for freshwater ecosystems, sustainable management strategies are required.

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