Photochemical production of CO and CO2 in the Northern Gulf of Mexico: Estimates and challenges for quantifying the impact of photochemistry on carbon cycles

2015 ◽  
Vol 171 ◽  
pp. 21-35 ◽  
Author(s):  
Leanne C. Powers ◽  
William L. Miller
Keyword(s):  
Gulf Of Mexico ◽  
Carbon Cycles ◽  
Northern Gulf Of Mexico ◽  
Photochemical Production ◽  
The Impact

scholarly journals Role of Near-Inertial Internal Waves in Subthermocline Diapycnal Mixing in the Northern Gulf of Mexico

2015 ◽  
Vol 45 (12) ◽  
pp. 3137-3154 ◽  
Author(s):  
Zhao Jing ◽  
Ping Chang ◽  
Steven F. DiMarco ◽  
Lixin Wu
Keyword(s):  
Gulf Of Mexico ◽  
Hurricane Katrina ◽  
Internal Waves ◽  
Dominant Role ◽  
Deep Ocean ◽  
Diapycnal Mixing ◽  
Northern Gulf Of Mexico ◽  
Weather Patterns ◽  
The Impact

AbstractMoored ADCP data collected in the northern Gulf of Mexico are analyzed to examine near-inertial internal waves and their contribution to subthermocline diapycnal mixing based on a finescale parameterization of deep ocean mixing. The focus of the study is on the impact of near-inertial internal waves generated by an extreme weather event—that is, Hurricane Katrina—and by month-to-month variation in weather patterns on the diapycnal mixing. The inferred subthermocline diapycnal mixing exhibits pronounced elevation in the wake of Katrina. Both the increased near-inertial (0.8–1.8f, where f is the Coriolis frequency) and superinertial (>1.8f) shear variances contribute to the elevated diapycnal mixing, but the former plays a more dominant role. The intense wind work on near-inertial motions by the hurricane is largely responsible for the energetic near-inertial shear variance. Energy transfer from near-inertial to superinertial internal waves, however, appears to play an important role in elevating the superinertial shear variance. The inferred subthermocline diapycnal mixing in the region also exhibits significant month-to-month variation with the estimated diffusivity in January 2006 about 3 times the values in November and December 2005. The subseasonal change in the diapycnal mixing mainly results from the subseasonal variation of the near-inertial wind work that causes intensification of the near-inertial shear in January 2006.

AGU 2018 Poster: Long-Term Recovery of Life in the Chicxulub Crater

2018 ◽  
Author(s):  
Christopher Lowery ◽  
Heather Jones ◽  
Timothy J. Bralower ◽  
Michael Whalen ◽  
Ligia Perez Cruz ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Ecological Factors ◽  
Calcareous Nannoplankton ◽  
High Productivity ◽  
Northern Gulf Of Mexico ◽  
Southern Gulf Of Mexico ◽  
Chicxulub Crater ◽  
Ocean Ecosystem ◽  
The Impact

At the end of the Cretaceous Period (66 Ma), the impact of a meteorite on the Yucatán platform in the southern Gulf of Mexico caused the extinction of 75% of species on Earth, including 90% of planktic microorganisms like foraminifera and calcareous nannoplankton. As the ocean ecosystem struggled to get back on its feet after this calamity, the recovery of marine primary productivity was geographically heterogeneous. Some authors had speculated that this heterogeneity was driven by the uneven distribution of toxic metals in the ocean, and was directly related to distance from the Chicxulub crater. However, results from recent International Ocean Discovery Program/International Continental Drilling Program (IODP/ICDP) joint Expedition 364, which drilled the Chicxulub crater itself, found evidence of the rapid establishment of a healthy, high-productivity ecosystem in the crater within 30 kyr of the impact. This result suggests that the recovery of marine productivity is likely driven by ecological factors like incumbency and competitive exclusion. However, it also raises several additional questions: How long does high productivity last in the crater? Is this high productivity driven by the impact-generated hydrothermal system or is it a Gulf-wide phenomenon? If so, what’s driving it?Here, we examine planktic and benthic foraminifera, calcareous nannoplankton, major, minor, and trace elements, and stable isotopes from the Paleocene interval of IODP Site M0077 in the Chicxulub Crater, and compare it to publically available planktic foraminifer and nannoplankton counts from three oil wells in the northern Gulf of Mexico to determine the long term trends in productivity in the Chicxulub Crater and whether or not they are limited to the crater or extend across the Gulf. We show that the first ~million years of the Paleocene are characterized by a eutrophic surface waters that slowly transition to mesotrophic and then oligotrophic by the middle Paleocene. Foraminiferal data from the northern Gulf of Mexico demonstrates that this trend is regional.

The impact of hypoxia on bioturbation rates in the louisiana continental shelf, northern Gulf of Mexico

OCEANS 2009 ◽  
2009 ◽  
Author(s):  
Valerie A. Hartmann ◽  
Kevin Briggs ◽  
Shivakumar Shivarudrappa ◽  
Kevin M. Yeager ◽  
Robert Diaz
Keyword(s):  
Gulf Of Mexico ◽  
Continental Shelf ◽  
Northern Gulf Of Mexico ◽  
Louisiana Continental Shelf ◽  
The Impact

scholarly journals The impact of recently excavated dredge pits on coastal hypoxia in the northern Gulf of Mexico shelf

2021 ◽  
Vol 163 ◽  
pp. 105199
Author(s):  
Laura Thompson ◽  
Kanchan Maiti ◽  
John R. White ◽  
Christopher M. DuFore ◽  
Haoran Liu
Keyword(s):  
Gulf Of Mexico ◽  
Northern Gulf Of Mexico ◽  
The Impact

scholarly journals Submesoscale Dynamics in the Northern Gulf of Mexico. Part III: Lagrangian Implications

2017 ◽  
Vol 47 (9) ◽  
pp. 2361-2376 ◽  
Author(s):  
Jun Choi ◽  
Annalisa Bracco ◽  
Roy Barkan ◽  
Alexander F. Shchepetkin ◽  
James C. McWilliams ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Finite Size ◽  
Spatial And Temporal Variability ◽  
Model Resolution ◽  
Northern Gulf Of Mexico ◽  
Lagrangian Statistics ◽  
Positive Vorticity ◽  
Mixing Rates ◽  
Lateral Mixing ◽  
The Impact

AbstractFour numerical simulations are used to characterize the impact of submesoscale circulations on surface Lagrangian statistics in the northern Gulf of Mexico over 2 months, February and August, representative of winter and summer. The role of resolution and riverine forcing is explored focusing on surface waters in regions where the water column is deeper than 50 m. Whenever submesoscale circulations are present, the probability density functions (PDFs) of dynamical quantities such as vorticity and horizontal velocity divergence for Eulerian and Lagrangian fields differ, with particles preferentially mapping areas of elevated negative divergence and positive vorticity. The stronger the submesoscale circulations are, the more skewed the Lagrangian distributions become, with greater differences between Eulerian and Lagrangian PDFs. In winter, Lagrangian distributions are modestly impacted by the presence of the riverine outflow, while increasing the model resolution from submesoscale permitting to submesoscale resolving has a more profound impact. In summer, the presence of riverine-induced buoyancy gradients is the key to the development of submesoscale circulations and different Eulerian and Lagrangian PDFs. Finite-size Lyapunov exponents (FSLEs) are used to characterize lateral mixing rates. Whenever submesoscale circulations are resolved and riverine outflow is included, FSLEs slopes are broadly consistent with local stirring. Simulated slopes are close to −0.5 and support a velocity field where the ageostrophic and frontogenetic components contribute stirring at scales between about 5 and 7 times the model resolution and 100 km. The robustness of Lagrangian statistics is further discussed in terms of their spatial and temporal variability and of the number of particles available.

scholarly journals A Two Decadal (1993–2012) Numerical Assessment of Sediment Dynamics in the Northern Gulf of Mexico

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 938 ◽  
Author(s):  
Zhengchen Zang ◽  
Z. George Xue ◽  
Kehui Xu ◽  
Samuel J. Bentley ◽  
Qin Chen ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Gulf Of Mexico ◽  
Sedimentation Rate ◽  
River Discharge ◽  
Southern Oscillation ◽  
Sediment Dynamics ◽  
Sediment Flux ◽  
Northern Gulf Of Mexico ◽  
Sensitivity Tests ◽  
The Impact

We adapted the coupled ocean-sediment transport model to the northern Gulf of Mexico to examine sediment dynamics on seasonal-to-decadal time scales as well as its response to decreased fluvial inputs from the Mississippi-Atchafalaya River. Sediment transport on the shelf exhibited contrasting conditions in a year, with strong westward transport in spring, fall, and winter, and relatively weak eastward transport in summer. Sedimentation rate varied from almost zero on the open shelf to more than 10 cm/year near river mouths. A phase shift in river discharge was detected in 1999 and was associated with the El Niño-Southern Oscillation (ENSO) event, after which, water and sediment fluxes decreased by ~20% and ~40%, respectively. Two sensitivity tests were carried out to examine the response of sediment dynamics to high and low river discharge, respectively. With a decreased fluvial supply, sediment flux and sedimentation rate were largely reduced in areas proximal to the deltas, which might accelerate the land loss in down-coast bays and estuaries. The results of two sensitivity tests indicated the decreased river discharge would largely affect sediment balance in waters around the delta. The impact from decreased fluvial input was minimum on the sandy shoals ~100 km west of the Mississippi Delta, where deposition of fluvial sediments was highly affected by winds.

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