News

Extinction of cold-water corals on the Namibian shelf due to low oxygen contents

"They were also able to link this event with a shift in the Benguela upwelling system, and an associated intensification of the oxygen minimum zone in this region. The team has now published their findings in the journal Geology.

Known as 'ecosystem engineers', cold-water corals play an important role in the species diversity of the deep sea. The coral species Lophelia pertusa is significantly involved in reef formation. [...]"

Source: EurekAlert!

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Ocean Deoxygenation and Copepods: Coping with Oxygen Minimum Zone Variability

Abstract.

"Increasing deoxygenation (loss of oxygen) of the ocean, including expansion of oxygen minimum zones (OMZs), is a potentially important consequence of global warming. We examined present day variability of vertical distributions of copepod species in the Eastern Tropical North Pacific (ETNP) living in locations with different water column oxygen profiles and OMZ intensity (lowest oxygen concentration and its vertical extent in a profile). [...]"

Source: Biogeosciences
Authors: Karen F. Wishner, Brad Seibel, and Dawn Outram
DOI: 10.5194/bg-2019-394

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Coral Mortality Event in the Flower Garden Banks of the Gulf of Mexico in July 2016: Local Hypoxia due to Cross-Shelf Transport of Coastal Flood Water

Abstract.

"Remotely sensed and in situ data, in tandem with numerical modeling, are used to explore the causes of an episode of localized but severe mortality of corals, sponges, and other invertebrates at the Flower Garden Banks (FGB) National Marine Sanctuary in July 2016. [...]"

Source: Continental Shelf Research
Authors: Matthieu Le Hénaff et al.
DOI: 10.1016/j.csr.2019.103988

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Oceanic organic carbon as a possible first-order control on the carbon cycle during the Bathonian–Callovian

Abstract.

"Oceans are the largest, readily exchangeable, superficial carbon reservoir; a current challenge in investigating past and present environments and predict future evolution relates to the role of oceanic carbon in regulating Earths' carbon cycle and climate. At least one paired δ13Ccarb-TOC decoupling event is noted in the Late Bathonian–Early Callovian. [...]"

Source: Global and Planetary Change
Authors: Ricardo L.Silva et al.
DOI: 10.1016/j.gloplacha.2019.103058


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Defining CO2 and O2 syndromes of marine biomes in the Anthropocene

Abstract.

"Research efforts have intensified to foresee the prospects for marine biomes under climate change and anthropogenic drivers over varying temporal and spatial scales. Parallel with these efforts is the utilization of terminology, such as ‘ocean acidification’ and ‘ocean deoxygenation’, that can foster rapid comprehension of complex processes driving carbon dioxide (CO2) and oxygen (O2) concentrations in the global ocean and thus, are now widely used in discussions within and beyond academia. [...]"

Source: Global Change Biology
Authors: Shannon G. Klein et al.
DOI: 10.1111/gcb.14879

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Air–sea fluxes of greenhouse gases and oxygen in the northern Benguela Current region during upwelling events

Abstract.

"Ground-based atmospheric observations of CO2δ(O2∕N2), N2O, and CH4 were used to make estimates of the air–sea fluxes of these species from the Lüderitz and Walvis Bay upwelling cells in the northern Benguela region, during upwelling events. Average flux densities (±1σ) were 0.65±0.4 µmol m−2 s−1 for CO2, −5.1±2.5 µmol m−2 s−1 for O2 (as APO), 0.61±0.5 nmol m−2 s−1 for N2O, and 4.8±6.3 nmol m−2 s−1 for CH4. A comparison of our top-down (i.e., inferred from atmospheric anomalies) flux estimates with shipboard-based measurements showed that the two approaches agreed within ±55 % on average, though the degree of agreement varied by species and was best for CO2. [...]"

Source: Biogeosciences
Authors: Eric J. Morgan et al.
DOI: 10.5194/bg-16-4065-2019

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Present climate trends and variability in thermohaline properties of the northern Adriatic shelf

Abstract.

"The paper documents seasonality, interannual-to-decadal variability, and trends in temperature, salinity, and density over a transect in the shallow northern Adriatic Sea (Mediterranean Sea) between 1979 and 2017. The amplitude of seasonality decreases with depth and is much larger in temperature and density than in salinity. [...]"

Source: Ocean Science
Authors: Ivica Vilibić et al.
DOI: 10.5194/os-15-1351-2019

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Seasonal variability of the southern tip of the Oxygen Minimum Zone in the eastern South Pacific (30°‐38°S): A modeling study

Abstract.

"We investigate the seasonal variability of the southern tip (30°–38°S) of the eastern South Pacific oxygen minimum zone (OMZ) based on a high horizontal resolution (1/12°) regional coupled physical‐biogeochemical model simulation. The simulation is validated by available in situ observations and the OMZ seasonal variability is documented. The model OMZ, bounded by the contour of 45 μM, occupies a large volume (4.5x104 km3) during the beginning of austral winter and a minimum (3.5x104 km3) at the end of spring, just 1 and 2 months after the southward transport of the Peru‐Chile Undercurrent (PCUC) is maximum and minimum, respectively.  [...]"

Source: JGR Oceans
Authors: Matias Pizarro‐Koch et al.
DOI: 10.1029/2019JC015201

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Stable aerobic and anaerobic coexistence in anoxic marine zones

Abstract.

"Mechanistic description of the transition from aerobic to anaerobic metabolism is necessary for diagnostic and predictive modeling of fixed nitrogen loss in anoxic marine zones (AMZs). In a metabolic model where diverse oxygen- and nitrogen-cycling microbial metabolisms are described by underlying redox chemical reactions, we predict a transition from strictly aerobic to predominantly anaerobic regimes as the outcome of ecological interactions along an oxygen gradient, obviating the need for prescribed critical oxygen concentrations. [...]"

Source: The ISME Journal 
Authors: Emily J. Zakem et al.
DOI: 10.1038/s41396-019-0523-8

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Ocean-Atmosphere Observations in Philippine Sea by Moored Buoy

Abstract.

"Offequatorial extension of equatorial buoy arrays such as Tropical Atmosphere and Ocean/Triangle Trans-Ocean Buoy Network (TAO/TRITON) buoy array is required to monitor global and regional climates. On December 3, 2016, Japan Agency for Marine-Earth Science and Technology (JAMSTEC) deployed a moored buoy (Ph buoy) at 13°N, 137° E in the Philippine Sea and are measuring temperature, salinity, and dissolved oxygen concentration from the sea surface to 300 m and atmospheric parameters. [...]"

Source: MTS/IEEE Kobe Techno-Oceans (OTO), 2018 OCEANS
Authors: Akira Nagano  et al.
DOI: 10.1109/OCEANSKOBE.2018.8558886

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