scholarly journals The Distribution of Giant Manta Rays In The Western North Atlantic Ocean Off The Eastern United States

2021 ◽  
Author(s):  
Nicholas A. Farmer ◽  
Lance P. Garrison ◽  
Calusa Horn ◽  
Margaret Miller ◽  
Timothy Gowan ◽  
...  
Keyword(s):  
United States ◽  
Gulf Of Mexico ◽  
Mississippi River ◽  
Oil And Gas ◽  
North Atlantic Ocean ◽  
Shelf Edge ◽  
Eastern United States ◽  
Multiple Sources ◽  
Cape Hatteras ◽  
Manta Birostris

Abstract In 2018, the giant manta ray (Manta birostris) was listed as threatened under the U.S. Endangered Species Act. We integrated decades of sightings and survey effort data from multiple sources in a comprehensive species distribution modeling (SDM) framework to evaluate the distribution of giant manta rays off the eastern United States, including the Gulf of Mexico. Manta rays were most commonly detected at productive nearshore and shelf-edge upwelling zones at surface thermal frontal boundaries within a temperature range of approximately 15–30 °C. SDMs predicted high nearshore concentrations off Northeast Florida during April, with the distribution extending northward along the shelf-edge as temperatures warm, leading to higher occurrences north of Cape Hatteras, North Carolina from June to October, and then south of Savannah, Georgia from November to March as temperatures cool. In the Gulf of Mexico, the highest nearshore concentrations were predicted near the Mississippi River delta from April to June and again from October to November. SDM predictions will allow resource managers to more effectively protect manta rays from fisheries bycatch, boat strikes, oil and gas activities, contaminants and pollutants, and other threats.

scholarly journals Investigating the Causes of Increased Twentieth-Century Fall Precipitation over the Southeastern United States

2018 ◽  
Vol 32 (2) ◽  
pp. 575-590 ◽  
Author(s):  
Daniel A. Bishop ◽  
A. Park Williams ◽  
Richard Seager ◽  
Arlene M. Fiore ◽  
Benjamin I. Cook ◽  
...  
Keyword(s):  
United States ◽  
Twentieth Century ◽  
Gulf Of Mexico ◽  
Specific Humidity ◽  
Precipitation Trend ◽  
Eastern United States ◽  
Atmospheric Models ◽  
Coupled Models ◽  
Fully Coupled ◽  
Precipitation Trends

Abstract Much of the eastern United States experienced increased precipitation over the twentieth century. Characterizing these trends and their causes is critical for assessing future hydroclimate risks. Here, U.S. precipitation trends are analyzed for 1895–2016, revealing that fall precipitation in the southeastern region north of the Gulf of Mexico (SE-Gulf) increased by nearly 40%, primarily increasing after the mid-1900s. Because fall is the climatological dry season in the SE-Gulf and precipitation in other seasons changed insignificantly, the seasonal precipitation cycle diminished substantially. The increase in SE-Gulf fall precipitation was caused by increased southerly moisture transport from the Gulf of Mexico, which was almost entirely driven by stronger winds associated with enhanced anticyclonic circulation west of the North Atlantic subtropical high (NASH) and not by increases in specific humidity. Atmospheric models forced by observed SSTs and fully coupled models forced by historical anthropogenic forcing do not robustly simulate twentieth-century fall wetting in the SE-Gulf. SST-forced atmospheric models do simulate an intensified anticyclonic low-level circulation around the NASH, but the modeled intensification occurred farther west than observed. CMIP5 analyses suggest an increased likelihood of positive SE-Gulf fall precipitation trends given historical and future GHG forcing. Nevertheless, individual model simulations (both SST forced and fully coupled) only very rarely produce the observed magnitude of the SE-Gulf fall precipitation trend. Further research into model representation of the western ridge of the fall NASH is needed, which will help us to better predict whether twentieth-century increases in SE-Gulf fall precipitation will persist into the future.

Detection of methane enhancements over the Eastern United States with improved TROPOMI retrievals

2020 ◽  
Author(s):  
Alba Lorente ◽  
Tobias Borsdorff ◽  
Joost aan de Brugh ◽  
Andre Butz ◽  
Mahesh Kumar Sha ◽  
...  
Keyword(s):  
United States ◽  
Atmospheric Chemistry ◽  
Mississippi River ◽  
Land Surface ◽  
Transport Model ◽  
The United States ◽  
Anthropogenic Sources ◽  
Eastern United States ◽  
Reference Measurements ◽  
Agricultural Areas

<p align="justify"><span>The TROPOspheric Monitoring Instrument (TROPOMI) aboard of the Sentinel 5 Precursor (S5P) has provided methane measurements for more than two years. The high accuracy together with the exceptional spatial resolution (7 x 7 km</span><sup><span>2</span></sup><span>, 7 x 5.2 km</span><sup><span>2 </span></sup><span>since August 2019) and temporal coverage (daily) of TROPOMI provides a unique perspective on local to regional methane enhancements. In this contribution, we discuss observations of enhanced methane concentrations over the United States. We analyse in detail temporal and spatial variability of methane over wetlands and agricultural areas along the Mississippi river and in Florida. To understand the observed CH4 anomalies regarding both natural and anthropogenic sources and transport at regional scales, we support our analysis with simulations from the GEOS-Chem atmospheric chemistry and transport model. We also investigate the possibility to use other datasets as a proxy for CH4 emissions (e.g. NO2 for agricultural areas, land surface temperature for wetlands). These results are based on an improved TROPOMI methane product that features among others a new bias correction that is fully independent of any reference measurements. The verification of the TROPOMI XCH4 data with ground-based measurements by the TCCON network yields a station-to-station variability of the XCH</span><sub><span>4</span></sub><span> error below 10 ppb, in agreement with the comparison with the proxy methane product from the Japanese GOSAT and GOSAT-2 missions. The improved TROPOMI methane product is planned as a future update of the operational TROPOMI processor.</span></p><p align="justify"> </p><p> </p>

Validating the occurrence of Caribbean reef sharks, Carcharhinus perezi (Poey), (Chondrichthyes: Carcharhiniformes) in the northern Gulf of Mexico, with a key for sharks of the family Carcharhinidae inhabiting the region

Zootaxa ◽  
2011 ◽  
Vol 2933 (1) ◽  
pp. 65 ◽  
Author(s):  
WILLIAM B. DRIGGERS III ◽  
ERIC R. HOFFMAYER ◽  
EMMA L. HICKERSON ◽  
TIMOTHY L. MARTIN ◽  
CHRISTOPHER T. GLEDHILL
Keyword(s):  
Gulf Of Mexico ◽  
North Atlantic ◽  
Mississippi River ◽  
North Atlantic Ocean ◽  
Shark Species ◽  
Mississippi River Delta ◽  
The Bahamas ◽  
Northern Gulf Of Mexico ◽  
The Family ◽  
Reef Sharks

Among the sharks inhabiting the continental shelf waters of the western North Atlantic Ocean, those within the genus Carcharhinus are the most speciose (Castro 2011). Authoritative sources agree on the presence of twelve species of carcharhinids in the northern Gulf of Mexico; however, they disagree on the presence of a thirteenth species, C. perezi (Poey), in the region (Compagno 1984, Compagno 2002, McEachran & Fechhelm 1998, Castro 2011). While the range of C. perezi is well-documented to extend from the southeastern coast of Florida and the Bahamas to Brazil (Castro 2011), published records of C. perezi occurring in the northern Gulf of Mexico are limited to two sources. In their description of Eulamia springeri, a junior synonym of C. perezi, Bigelow & Schroeder (1944) place the species in the northern Gulf of Mexico based on “a somewhat shrivelled skin with head” from a specimen collected off the west coast of Florida that was reported by the authors to be “probably of this species.” Later, Springer (1960) reported the capture of a single specimen off the Mississippi River Delta in 1947; however, no detail of the capture was provided other than it being listed within a table summarizing shark species collected during exploratory fishing operations.

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