Western boundary upwelling dynamics off Oman

Vic, Clément; Capet, Xavier; Roullet, Guillaume; Carton, Xavier

doi:10.1007/s10236-017-1044-5

Cited by 19 publications

(19 citation statements)

References 49 publications

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“…We consider the Gulf of Oman and the NWAS to be hydrographically distinct regions. The Gulf of Oman is generally warmer and does not show significant seasonal upwelling, whereas the NWAS is cooler due to the strong and persistent seasonal upwelling linked to the monsoon along the eastern coast of Oman (Böhm et al, ; Vic et al, ). The Ras‐Al‐Hadd jet limits exchanges between the Gulf of Oman and the NWAS, leading to prolonged residence times within the Gulf.…”

Section: Introductionmentioning

confidence: 99%

Physical Controls on Oxygen Distribution and Denitrification Potential in the North West Arabian Sea

Queste

Vic

Heywood

et al. 2018

Geophysical Research Letters

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At suboxic oxygen concentrations, key biogeochemical cycles change and denitrification becomes the dominant remineralization pathway. Earth system models predict oxygen loss across most ocean basins in the next century; oxygen minimum zones near suboxia may become suboxic and therefore denitrifying. Using an ocean glider survey and historical data, we show oxygen loss in the Gulf of Oman (from 6-12 to <2 μmol kg À1 ) not represented in climatologies. Because of the nonlinearity between denitrification and oxygen concentration, resolutions of current Earth system models are too coarse to accurately estimate denitrification. We develop a novel physical proxy for oxygen from the glider data and use a high-resolution physical model to show eddy stirring of oxygen across the Gulf of Oman. We use the model to investigate spatial and seasonal differences in the ratio of oxic and suboxic water across the Gulf of Oman and waters exported to the wider Arabian Sea. Plain Language SummaryOxygen is present in the ocean and is required by all marine plants and animals to breathe. In certain regions around the world, oxygen concentrations reach very low levels. These are known as "oxygen minimum zones". When oxygen is absent, chemical cycling of nitrogen, a key nutrient for plant growth, changes dramatically. Computer simulations of ocean oxygen show a decrease in oxygen over the next century and growing oxygen minimum zones. However, these simulations have a difficult time representing small but very important features such as eddies, which impact how oxygen is transported. It is difficult to predict what will happen in the biggest of the world's oxygen minimum zones, the Arabian Sea, as piracy and geopolitical tensions have limited past opportunities for observing these processes. To remedy this, we deployed two remote-controlled submarines, known as a Seagliders, in the Gulf of Oman. These instruments measured a strong decrease of oxygen in the oxygen minimum zone compared to pre-1990 values. We then combined the Seaglider data with a very high resolution computer simulation to determine how oxygen is spread around the northwestern Arabian Sea throughout different seasons and the monsoons.The Arabian Sea is home to the thickest and most intense OMZ worldwide (Figure 1), with suboxic concentrations between 150 and 1,000 m (Bange et al., 2005; Banse et al., 2014; McCreary et al., 2013; Piontkovski QUESTE ET AL. 4143

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Section: Introductionmentioning

confidence: 99%

Physical Controls on Oxygen Distribution and Denitrification Potential in the North West Arabian Sea

Queste

Vic

Heywood

et al. 2018

Geophysical Research Letters

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“…Fundamental forcing is along-shore monsoonal winds in both regions. The Sumatra/Java upwelling is also affected by remote forcing to the west via the equatorial waveguide (Iskandar et al 2005;Chen et al 2016), while the Oman/Somalia upwelling is influenced by wind stress curl in open oceans to the east through westward propagating Rossby waves (Vic et al 2017). These upwelling systems are also affected by interannual climate modes, such as the Indian Ocean Dipole , which is associated with anomalous primary productivity in the basin Currie et al 2013).…”

Section: Upwelling Coastal-open Interactionsmentioning

confidence: 99%

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2020

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THIS EDITION of Exchanges focuses on the recent decadal review of the Indian Ocean Observing System (IndOOS) and its outcomes. IndOOS was established in 2006 under the visionary leadership of Dr. Gary Meyers (1941-2016), the founding chair of the CLIVAR/IOC-GOOS Indian Ocean Regional Panel (IORP), to address the need for a sustained observing system that consists of a variety of observing platforms to support weather and climate research and prediction. Key founding components of the IndOOS were a tropical basin-wide mooring array-the Research moored Array for African Asian Australian Monsoon Analysis and Prediction (RAMA)-and a network of repeat expendable bathythermograph (XBT) lines. Broad international participation and support, facilitated and coordinated by the regional GOOS alliance (IO-GOOS) and the IndOOS Resources Forum (IRF), have played a crucial role in maximizing the limited resources available to implement the IndOOS. IndOOS has now passed the 10-year milestone. A full decadal review report has recently been released as the outcome of a three-year review effort led by the IORP co-chairs, Lisa Beal, Jérôme Vialard, and Mathew Koll Roxy, with a writing team comprising more than 60 scientific experts. As highlighted in their article in this issue, the decadal review has generated 136 actionable recommendations and led to a roadmap of an enhanced observing system for the next decade (2020-2030). This second phase, IndOOS-2 (Figure 1, cover page), is designed to meet the current and future societal needs for seamless prediction of Indian Ocean climate and ecosystems across a wide range of timescales, from days to seasons to years to decades to centuries and beyond. Achieving goals of IndOOS-2 will depend critically on capacity building, resource management, regional partnerships, and information sharing. It is becoming more important than ever that the scientific community actively engages with stakeholders, policy makers, and civil society in the Indian Ocean rim countries to build and sustain IndOOS-2, and to address the grand challenges identified by the World Climate Research Program and the societal outcomes envisioned under the UN Decade of Ocean Science for Sustainable Development. The main body of this edition is a condensed version of the full IndOOS-2 report, reorganized under five main science themes: natural and anthropogenic warming of the Indian Ocean, monsoon and regional airsea interaction, ocean processes and modelling, physical and biogeochemical processes and interactions, and climate information and prediction across timescales. These themed articles, written by many lead authors of the full report, are meant to provide collective reviews that address the progress made and the gaps that still exist in understanding the complex dynamical and biogeochemical processes in the Indian Ocean, and in improving prediction skills for weather, climate, and ecosystems. The OceanObs'19 (16-21 September 2019, Hawaii) called for new cooperative models for Observing System Governance to better align...

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“…During September and October, strong and F I G U R E 7 Map of the study area showing coral-reef habitats available in the Western Indian Ocean (red squares) steady winds blowing along the shore induce offshore movement of the Ekman layer, with consequent depression of the sea surface height (SSH) in coastal areas. This is followed by vertical advection of cooler waters from deeper layers to the surface, especially in the region off Somalia (Bruce, 1979) and Oman (Elliott & Savidge, 1990;Vic et al, 2017). During this period, ichthyoplankton located within the Ekman layer therefore tend to be transported offshore into areas of unsuitable habitat for settlement (Lett et al, 2007).…”

Section: Oceanographic Barriersmentioning

confidence: 99%

Consequences of marine barriers for genetic diversity of the coral‐specialist yellowbar angelfish from the Northwestern Indian Ocean

Torquato

Range

Ben‐Hamadou

et al. 2019

Ecology and Evolution

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Ocean circulation, geological history, geographic distance, and seascape heterogeneity play an important role in phylogeography of coral‐dependent fishes. Here, we investigate potential genetic population structure within the yellowbar angelfish (Pomacanthus maculosus) across the Northwestern Indian Ocean (NIO). We then discuss our results with respect to the above abiotic features in order to understand the contemporary distribution of genetic diversity of the species. To do so, restriction site‐associated DNA sequencing (RAD‐seq) was utilized to carry out population genetic analyses on P. maculosus sampled throughout the species’ distributional range. First, genetic data were correlated to geographic and environmental distances, and tested for isolation‐by‐distance and isolation‐by‐environment, respectively, by applying the Mantel test. Secondly, we used distance‐based and model‐based methods for clustering genetic data. Our results suggest the presence of two putative barriers to dispersal; one off the southern coast of the Arabian Peninsula and the other off northern Somalia, which together create three genetic subdivisions of P. maculosus within the NIO. Around the Arabian Peninsula, one genetic cluster was associated with the Red Sea and the adjacent Gulf of Aden in the west, and another cluster was associated with the Arabian Gulf and the Sea of Oman in the east. Individuals sampled in Kenya represented a third genetic cluster. The geographic locations of genetic discontinuities observed between genetic subdivisions coincide with the presence of substantial upwelling systems, as well as habitat discontinuity. Our findings shed light on the origin and maintenance of genetic patterns in a common coral reef fish inhabiting the NIO, and reinforce the hypothesis that the evolution of marine fish species in this region has likely been shaped by multiple vicariance events.

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Western boundary upwelling dynamics off Oman

Cited by 19 publications

References 49 publications

Physical Controls on Oxygen Distribution and Denitrification Potential in the North West Arabian Sea

Physical Controls on Oxygen Distribution and Denitrification Potential in the North West Arabian Sea

Untitled

Consequences of marine barriers for genetic diversity of the coral‐specialist yellowbar angelfish from the Northwestern Indian Ocean

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