Long‐term water color and flow trends in the Mississippi River Headwaters, 1944–2010

2021 ◽  
Author(s):  
Noah P. Germolus ◽  
Patrick L. Brezonik ◽  
Raymond M. Hozalski ◽  
Jacques C. Finlay
Keyword(s):  
Mississippi River ◽  
Water Color

scholarly journals Hurricanes as a Major Driver of Coastal Erosion in the Mississippi River Delta: A Multi-Decadal Analysis of Shoreline Retreat Rates at Bay Champagne, Louisiana (USA)

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1480 ◽  
Author(s):  
Marianne Dietz ◽  
Kam-biu Liu ◽  
Thomas Bianchette
Keyword(s):  
Mississippi River ◽  
Average Rate ◽  
Landsat Imagery ◽  
Mississippi River Delta ◽  
Coastal Lake ◽  
Shoreline Retreat ◽  
The Past ◽  
Coastal Features ◽  
Mexico Coast

The Louisiana shoreline is rapidly retreating as a result of factors such as sea-level rise and land subsidence. The northern Gulf of Mexico coast is also a hotspot for hurricane landfalls, and several major storms have impacted this region in the past few decades. A section of the Louisiana (USA) coast that has one of the highest rates of shoreline retreat in North America is the Caminada-Moreau headland, located south of New Orleans. Bay Champagne is a coastal lake within the headland that provides a unique opportunity to investigate shoreline retreat and the coastal effects of hurricanes. In order to examine the influence of hurricanes on the rate of shoreline retreat, 35 years (1983–2018) of Landsat imagery was analyzed. During that period of time, the shoreline has retreated 292 m. The overall rate of shoreline retreat, prior to a beach re-nourishment project completed in 2014, was over 12 m per year. A period of high hurricane frequency (1998–2013) corresponds to an increased average shoreline retreat rate of >21 m per year. Coastal features created by multiple hurricanes that have impacted this site have persisted for several years. Bay Champagne has lost 48% of its surface area over the last 35 years as a result of long-term shoreline retreat. If shoreline retreat continues at the average rate, it is expected that Bay Champagne will disappear completely within the next 40 years.

scholarly journals Declines in an abundant aquatic insect, the burrowing mayfly, across major North American waterways

2020 ◽  
Vol 117 (6) ◽  
pp. 2987-2992 ◽  
Author(s):  
Phillip M. Stepanian ◽  
Sally A. Entrekin ◽  
Charlotte E. Wainwright ◽  
Djordje Mirkovic ◽  
Jennifer L. Tank ◽  
...  
Keyword(s):  
Mississippi River ◽  
Animal Movement ◽  
Aquatic Insect ◽  
Terrestrial Ecosystems ◽  
Trophic Levels ◽  
Western Lake ◽  
Annual Biomass ◽  
Emergence Event ◽  
Western Lake Erie

Seasonal animal movement among disparate habitats is a fundamental mechanism by which energy, nutrients, and biomass are transported across ecotones. A dramatic example of such exchange is the annual emergence of mayfly swarms from freshwater benthic habitats, but their characterization at macroscales has remained impossible. We analyzed radar observations of mayfly emergence flights to quantify long-term changes in annual biomass transport along the Upper Mississippi River and Western Lake Erie Basin. A single emergence event can produce 87.9 billion mayflies, releasing 3,078.6 tons of biomass into the airspace over several hours, but in recent years, production across both waterways has declined by over 50%. As a primary prey source in aquatic and terrestrial ecosystems, these declines will impact higher trophic levels and environmental nutrient cycling.

scholarly journals Long-Term Discharge Estimation for the Lower Mississippi River Using Satellite Altimetry and Remote Sensing Images

2020 ◽  
Vol 12 (17) ◽  
pp. 2693
Author(s):  
Daniel Scherer ◽  
Christian Schwatke ◽  
Denise Dettmering ◽  
Florian Seitz
Keyword(s):  
Remote Sensing ◽  
Water Level ◽  
Cross Sections ◽  
Mississippi River ◽  
Satellite Altimetry ◽  
Altimetry Data ◽  
Virtual Station ◽  
Lower Mississippi River ◽  
Satellite Altimetry Data

Despite increasing interest in monitoring the global water cycle, the availability of in situ gauging and discharge time series is decreasing. However, this lack of ground data can partly be compensated for by using remote sensing techniques to observe river stages and discharge. In this paper, a new approach for estimating discharge by combining water levels from multi-mission satellite altimetry and surface area extents from optical imagery with physical flow equations at a single cross-section is presented and tested at the Lower Mississippi River. The datasets are combined by fitting a hypsometric curve, which is then used to derive the water level for each acquisition epoch of the long-term multi-spectral remote sensing missions. In this way, the chance of detecting water level extremes is increased and a bathymetry can be estimated from water surface extent observations. Below the minimum hypsometric water level, the river bed elevation is estimated using an empirical width-to-depth relationship in order to determine the final cross-sectional geometry. The required flow gradient is derived from the differences between virtual station elevations, which are computed in a least square adjustment from the height differences of all multi-mission satellite altimetry data that are close in time. Using the virtual station elevations, satellite altimetry data from multiple virtual stations and missions are combined to one long-term water level time series. All required parameters are estimated purely based on remote sensing data, without using any ground data or calibration. The validation at three gauging stations of the Lower Mississippi River shows large deviations primarily caused by the below average width of the predefined cross-sections. At 13 additional cross-sections situated in wide, uniform, and straight river sections nearby the gauges the Normalized Root Mean Square Error (NRMSE) varies between 10.95% and 28.43%. The Nash-Sutcliffe Efficiency (NSE) for these targets is in a range from 0.658 to 0.946.

scholarly journals Carbon Dioxide Emissions as Affected by Alternative Long-Term Irrigation and Tillage Management Practices in the Lower Mississippi River Valley

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
S. F. Smith ◽  
K. R. Brye
Keyword(s):  
Carbon Dioxide ◽  
Soil Respiration ◽  
Mississippi River ◽  
Management Practices ◽  
River Valley ◽  
Mississippi River Valley ◽  
Growing Seasons ◽  
Lower Mississippi River ◽  
Lower Mississippi River Valley

Ensuring the sustainability of cultivated soils is an ever-increasing priority for producers in the Lower Mississippi River Valley (LMRV). As groundwater sources become depleted and environmental regulations become more strict, producers will look to alternative management practices that will ensure the sustainability and cost-effectiveness of their production systems. This study was conducted to assess the long-term (>7 years) effects of irrigation (i.e., irrigated and dryland production) and tillage (conventional and no-tillage) on estimated carbon dioxide (CO2) emissions from soil respiration during two soybean (Glycine maxL.) growing seasons from a wheat- (Triticum aestivumL.-) soybean, double-cropped production system in the LMRV region of eastern Arkansas. Soil surface CO2fluxes were measured approximately every two weeks during two soybean growing seasons. Estimated season-long CO2emissions were unaffected by irrigation in 2011 (P>0.05); however, during the unusually dry 2012 growing season, season-long CO2emissions were 87.6% greater (P=0.044) under irrigated (21.9 Mg CO2ha−1) than under dryland management (11.7 Mg CO2ha−1). Contrary to what was expected, there was no interactive effect of irrigation and tillage on estimated season-long CO2emissions. Understanding how long-term agricultural management practices affect soil respiration can help improve policies for soil and environmental sustainability.

Meander Loops and the Cahokia Site

1964 ◽  
Vol 30 (1) ◽  
pp. 89-91 ◽  
Author(s):  
Charles J. Bareis
Keyword(s):  
Mississippi River ◽  
River Channel ◽  
River Valley ◽  
Mississippi Valley ◽  
Channel Migration ◽  
Mississippi River Valley ◽  
Lower Mississippi Valley

AbstractThe locations of certain mounds at the Cahokia site indicate that the rate of Mississippi River channel migration in the American Bottoms in the Upper Mississippi Valley has differed from the rate of channel movement in the Lower Mississippi Valley. The American Bottoms was probably the most favorable section of the Mississippi River Valley for long-term prehistoric settlement with regard to location within the present meander belt of the river.

scholarly journals Extensive reproductive disruption, ovarian masculinization and aromatase suppression in Atlantic croaker in the northern Gulf of Mexico hypoxic zone

2011 ◽  
Vol 279 (1726) ◽  
pp. 28-38 ◽  
Author(s):  
Peter Thomas ◽  
Md. Saydur Rahman
Keyword(s):  
Gulf Of Mexico ◽  
Mississippi River ◽  
Aromatase Activity ◽  
Northern Gulf Of Mexico ◽  
Hypoxia Exposure ◽  
Hypoxic Zone ◽  
Seasonal Hypoxia ◽  
Reproductive Disruptions ◽  
Reproductive Disruption

The long-term impacts on marine ecosystems of the recent dramatic worldwide increase in the incidence of coastal hypoxia are unknown. Here, we show widespread reproductive disruption in Atlantic croakers collected from hypoxic sites approximately 120 km apart in the extensive northern Gulf of Mexico continental shelf hypoxic zone. Gonadal growth and gamete production were impaired in croakers from hypoxic sites compared with fish from reference normoxic sites east of the Mississippi River Delta. Male germ cells were detected in approximately 19 per cent of croaker ovaries collected in the hypoxic region, but were absent in ovaries from normoxic sites. In addition, the sex ratio was skewed towards males at the hypoxic sites. The masculinization and other reproductive disruptions were associated with declines in neuroendocrine function, as well as ovarian and brain expression of aromatase (the enzyme that converts androgens to oestrogens). A similar incidence of ovarian masculinization and decline in ovarian aromatase expression were observed in croaker after chronic laboratory hypoxia exposure, indicating that ovarian masculinization is a specific hypoxia response and is due to decreased aromatase activity. The results suggest severe reproductive impairment can occur over large coastal regions in marine fish populations exposed to seasonal hypoxia, with potential long-term impacts on population abundance.

Dendrochronological analysis of baldcypress (Taxodium distichum) responses to climate and contrasting flood regimes

2012 ◽  
Vol 42 (3) ◽  
pp. 423-436 ◽  
Author(s):  
Richard F. Keim ◽  
J. Blake Amos
Keyword(s):  
Mississippi River ◽  
Taxodium Distichum ◽  
Growth Responses ◽  
Ecological Processes ◽  
Ecosystem Responses ◽  
Local Climate ◽  
Dendrochronological Analysis ◽  
Key Species ◽  
Climatic History

Baldcypress (Taxodium distichum (L.) Rich.) has been used extensively for dendrochronological reconstruction of climate and is a key species in globally important wetlands with complex, poorly understood relationships between hydrological and ecological processes. To better understand ecosystem responses to changing climate and hydrology and to test whether hydrological or climatological variables are most reflected in chronologies, we developed tree-ring chronologies for six stagnant or riverine swamps in the Mississippi River deltaic plain and modeled growth responses to historical hydrology (51 years of data) and climate (111 years of data). Decoupled flooding and local climate in this deltaic setting allowed for relatively independent assessments of the roles of hydrology and climate in baldcypress growth. Depth of annual flooding was positively correlated with growth that year but negatively correlated with growth in the ensuing year for both riverine and stagnant swamps. Depth of 10-year mean flooding was positively correlated with growth in riverine swamps but negatively correlated with growth in stagnant swamps. Results corroborate previous findings that long-term, stagnant flooding reduces productivity, but growth at these deltaic sites was less correlated with climatic variables than elsewhere. At least in these frequently flooded sites, baldcypress tree rings appear to be a better long term record of hydrological history than of climatic history.

Long-Term Agroecosystem Research in the Central Mississippi River Basin: Goodwater Creek Experimental Watershed Weather Data

2015 ◽  
Vol 44 (1) ◽  
pp. 13-17 ◽  
Author(s):  
E. John Sadler ◽  
Kenneth A. Sudduth ◽  
Scott T. Drummond ◽  
Earl D. Vories ◽  
Patrick E. Guinan
Keyword(s):  
River Basin ◽  
Mississippi River ◽  
Weather Data ◽  
Mississippi River Basin
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