Erosional furrows on continental shelf edge, Mississippi delta region

1981 ◽  
Vol 1 (1) ◽  
pp. 11-15 ◽  
Author(s):  
James M. Coleman ◽  
David B. Prior ◽  
Charles E. Adams
Diversity ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 57 ◽  
Author(s):  
Sean N. Porter ◽  
Michael H. Schleyer

Coral communities display spatial patterns. These patterns can manifest along a coastline as well as across the continental shelf due to ecological interactions and environmental gradients. Several abiotic surrogates for environmental variables are hypothesised to structure high-latitude coral communities in South Africa along and across its narrow shelf and were investigated using a correlative approach that considered spatial autocorrelation. Surveys of sessile communities were conducted on 17 reefs and related to depth, distance to high tide, distance to the continental shelf edge and to submarine canyons. All four environmental variables were found to correlate significantly with community composition, even after the effects of space were removed. The environmental variables accounted for 13% of the variation in communities; 77% of this variation was spatially structured. Spatially structured environmental variation unrelated to the environmental variables accounted for 39% of the community variation. The Northern Reef Complex appears to be less affected by oceanic factors and may undergo less temperature variability than the Central and Southern Complexes; the first is mentioned because it had the lowest canyon effect and was furthest from the continental shelf, whilst the latter complexes had the highest canyon effects and were closest to the shelf edge. These characteristics may be responsible for the spatial differences in the coral communities.


2016 ◽  
Vol 13 ◽  
Author(s):  
Keith P. Gennuso ◽  
Amanda Jovaag ◽  
Bridget B. Catlin ◽  
Matthew Rodock ◽  
Hyojun Park

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1905
Author(s):  
Sanai Li ◽  
David Fleisher ◽  
Dennis Timlin ◽  
Vangimalla R. Reddy ◽  
Zhuangji Wang ◽  
...  

The United States is one of the top rice exporters in the world, but warming temperatures and other climate trends may affect grain yield and quality. The use of crop models as decision support tools for a climate impact assessment would be beneficial, but suitability of models for representative growing conditions need to be verified. Therefore, the ability of CERES-Rice and ORYZA crop models to predict rice yield and growing season duration in the Mississippi Delta region was assessed for two widely-grown varieties using a 34-year database. CERES-Rice simulated growth duration more accurately than ORYZA as a result of the latter model’s use of lower cardinal temperatures. An increase in base and optimal temperatures improved ORYZA accuracy and reduced systematic error (e.g., correlation coefficient increased by 0.03–0.27 and root mean square error decreased by 0.3–1.9 days). Both models subsequently showed acceptable skill in reproducing the growing season duration and had similar performance for predicting rice yield for most locations and years. CERES-Rice predictions were more sensitive to years with lower solar radiation, but neither model accurately mimicked negative impacts of very warm or cold temperatures. Both models were shown to reproduce 50% percentile yield trends of more than 100 varieties in the region for the 34-year period when calibrated with two representative cultivars. These results suggest that both models are suitable for exploring the general response of multiple rice cultivars in the Mississippi Delta region for decision support studies involving the current climate. The response of rice growth and development to cold injury and high temperature stress, and variation in cultivar sensitivity, should be further developed and tested for improved decision making tools.


2019 ◽  
Vol 124 (3) ◽  
pp. 2829-2843 ◽  
Author(s):  
H. Paul Johnson ◽  
Susan Merle ◽  
Marie Salmi ◽  
Robert Embley ◽  
Erica Sampaga ◽  
...  

2019 ◽  
Vol 30 (6) ◽  
pp. 591-601 ◽  
Author(s):  
Whitney E. Zahnd ◽  
Recinda L. Sherman ◽  
Hillary Klonoff-Cohen ◽  
Sara L. McLafferty ◽  
Susan Farner ◽  
...  

2001 ◽  
Vol 13 (3) ◽  
pp. 312-322 ◽  
Author(s):  
Carol J. Pudsey ◽  
Jeffrey Evans ◽  
Eugene W. Domack ◽  
Peter Morris ◽  
Rodolfo A. Del Valle

We present preliminary results of the first detailied surveys of the former Larsen-A Ice Shelf, Larsen Inlet and southern Prince Gustav Channel, where disintegration of small ice shelves in the past ten years has exposed the seafloor. Glacial troughs in the Larsen-A area, Larsen Inlet and Prince Gustav Channel reach 900–1100 m depth and have hummocky floors. Farther south-east, the continental shelf is shallower (400–500 m) and its surface is fluted to smooth, with the density of iceberg furrowing increasing towards the shelf edge. Acoustic profiles show a drape of transparent sediment 4–8 m thick in Prince Gustav Channel, thinning southwards. In cores, this drape corresponds to diatom-bearing marine and glacial-marine mud. In the Larsen-A area and Larsen Inlet, acoustically opaque sediment includes proximal ice shelf glaciomarine gravelly and sandy muds, and firm to stiff diamicts probably deposited subglacilly. These are overlain by thin (up to 1.3 m) glaciomarine muds, locally with distinctive diatom ooze laminae.


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