News

Geoengineered Ocean Vertical Water Exchange Can Accelerate Global Deoxygenation

Abstract.

"Ocean deoxygenation is a threat to marine ecosystems. We evaluated the potential of two ocean intervention technologies, that is, “artificial downwelling (AD)” and “artificial upwelling (AU),” for remedying the expansion of Oxygen Deficient Zones (ODZs). The model‐based assessment simulated AD and AU implementations for 80 years along the eastern Pacific ODZ.[...]"

Source: Advancing Earth And Space Science 
Authors: Ellias Yuming Feng et al.
DOI: https://doi.org/10.1029/2020GL088263

Read the full article here.

 


Meiofauna improve oxygenation and accelerate sulfide removal in the seasonally hypoxic seabed

Abstract.

"Oxygen depleted areas are widespread in the marine realm. Unlike macrofauna, meiofauna are abundant in hypoxic sediments. We studied to what extent meiofauna affect oxygen availability, sulfide removal and microbial communities. Meiofauna were extracted alive and added to intact sediments simulating abundance gradients previously reported in the area. [...]"

Source: Marine Environmental Research
Authors: Stefano Bonaglia et al.
DOI: 10.1016/j.marenvres.2020.104968

Read the full article here.


Regulation of nitrous oxide production in low-oxygen waters off the coast of Peru

Abstract.

"Oxygen-deficient zones (ODZs) are major sites of net natural nitrous oxide (N2O) production and emissions. In order to understand changes in the magnitude of N2O production in response to global change, knowledge on the individual contributions of the major microbial pathways (nitrification and denitrification) to N2O production and their regulation is needed. In the ODZ in the coastal area off Peru, the sensitivity of N2O production to oxygen and organic matter was investigated using 15N tracer experiments in combination with quantitative PCR (qPCR) and microarray analysis of total and active functional genes targeting archaeal amoA and nirS as marker genes for nitrification and denitrification, respectively. [...]"

Source: Biogeosciences
Authors: Claudia Frey et al.
DOI: 10.5194/bg-17-2263-2020

Read the full article here.


The role of water masses in shaping the distribution of redox active compounds in the Eastern Tropical North Pacific oxygen deficient zone

and influencing low oxygen concentrations in the eastern Pacific Ocean

Abstract.

"Oceanic oxygen deficient zones (ODZs) influence global biogeochemical cycles in a variety of ways, most notably by acting as a sink for fixed nitrogen (Codispoti et al. 2001). Optimum multiparameter analysis of data from two cruises in the Eastern Tropical North Pacific (ETNP) was implemented to develop a water mass analysis for the large ODZ in this region. This analysis reveals that the most pronounced oxygen deficient conditions are within the 13°C water (13CW) mass, which is distributed via subsurface mesoscale features such as eddies branching from the California Undercurrent. [...]"

Source: Limnology and Oceanography
Authors: Zachary C. Evans et al.
DOI: 10.1002/lno.11412

Read the full article here.


Dinitrogen fixation across physico‐chemical gradients of the Eastern Tropical North Pacific oxygen deficient zone

Abstract.

"The Eastern Tropical North Pacific (ETNP) Ocean hosts one of the world's largest oceanic oxygen deficient zones (ODZs). Hotspots for reactive nitrogen (Nr) removal processes, ODZs generate conditions proposed to promote Nr inputs via dinitrogen (N2) fixation. In this study, we quantified N2 fixation rates by 15N‐tracer bioassay across oxygen, nutrient and light gradients within and adjacent to the ODZ. [...]"

Source: Global Biogeochemical Cycles
Authors: C.R. Selden et al.
DOI: 10.1029/2019GB006242

Read the full article here.


Complete arsenic-based respiratory cycle in the marine microbial communities of pelagic oxygen-deficient zones

Abstract.

"Marine oxygen-deficient zones (ODZs) are naturally occurring midlayer oxygen-poor regions of the ocean, sandwiched between oxygenated surface and deep layers. In the absence of oxygen, microorganisms in ODZs use other compounds, such as oxidized forms of nitrogen and sulfur, as terminal electron acceptors. [...]"

Source: PNAS
Authors: Jaclyn K. Saunders et al.
DOI: 10.1073/pnas.1818349116

Read the full article here.