Preprint: Bottom-water hypoxia in the Paracas Bay (Peru, 13.8°S) associated with seasonal and synoptic time scale variability of winds and water ...
Full title: "Bottom-water hypoxia in the Paracas Bay (Peru, 13.8°S) associated with seasonal and synoptic time scale variability of winds and water stratification"
"Coastal hypoxia can occur naturally in inshore areas of the Eastern Boundary Upwelling Systems, influenced by the nutrient-rich and low-oxygen upwelling waters. This study aims to explore the influence of water stratification and winds on bottom-water hypoxia of the Paracas Bay, an area subjected to the most intense alongshore winds and active coastal upwelling in the Peruvian coast. [...]".
Source: Science Direct
Authors: Lander Merma-Mora et al.
Preprint: Linking northeastern North Pacific oxygen changes to upstream surface outcrop variations
"Understanding the response of the ocean to global warming, including the renewal of ocean waters from the surface (ventilation), is important for future climate predictions. Oxygen (O2) distributions in the ocean thermocline have proven an effective way to infer changes in ventilation because physical processes (ventilation and circulation) that supply oxygen are thought to be primarily responsible for changes in interior oxygen concentrations. Here, the focus is on the North Pacific thermocline, where some of the world ocean's largest oxygen variations have been observed. [...]".
Authors: Sabine Mecking & Kyla Drushka
Extensive Accumulation of Nitrous Oxide in the Oxygen Minimum Zone in the Bay of Bengal
"The production by microorganisms of nitrous oxide (N2O), a trace gas contributing to global warming and stratospheric ozone depletion, is enhanced around the oceanic oxygen minimum zones (OMZs). The production constitutes an important source of atmospheric N2O. Although an OMZ is found in the northern part of the eastern Indian Ocean, the Bay of Bengal (BoB), two earlier studies conducted during the later phase of winter monsoon (February) and spring intermonsoon (March–April) found quite different magnitudes of N2O accumulation. [...]".
Source: Wiley Online Library
Authors: Sakae Toyoda et al.
Decreasing O2 availability reduces cellular protein contents in a marine diatom
"Anthropogenic activities and climate change are exacerbating marine deoxygenation. Apart from aerobic organisms, reduced O2 also affects photoautotrophic organisms in the ocean. This is because without available O2, these O2 producers cannot maintain their mitochondrial respiration, especially under dim-light or dark conditions, which may disrupt the metabolism of macromolecules including proteins. We used growth rate, particle organic nitrogen and protein analyses, proteomics, and transcriptomics to determine cellular nitrogen metabolism of the diatom Thalassiosira pseudonana grown under three O2 levels in a range of light intensities [...]".
Source: Science Direct
Authors: Bokun Chen et al.
GO2NE Webinar on Ocean Deoxygenation
GO2NE Webinar on Ocean Deoxygenation.
"Do you want to know more about deoxygenation in the ocean?
Join us for the upcoming webinar!
Wednesday, 13th September 2023, 17:00 h – 18:00 CEST
Please join the Global Ocean Oxygen Network (IOC Expert Working Group GO2NE) for a new session of its webinar series on ocean deoxygenation. The 22nd webinar will take place 13 September 2023, 17:00 h CEST. The webinar will feature presentations by a more senior and an early-career scientist, 20 minutes each followed by 10 minutes moderated discussion sessions.
If you are interested to present at one of the upcoming webinars please submit a short abstract here.
Scripps Institution of Oceanography, UC San Diego, USA
University of Bergen and Bjerknes Centre for Climate Research, Norway
"Trophic impacts of ocean deoxygenation: Disruption of bentho-pelagic coupling in oxygen minimum zone regions"
Anne Gro Vea Salvanes
University of Bergen, Norway
"The bearded goby (Sufflogobius bibarbatus): a hypoxia-tolerant little fish member of the Namibian Benguela Ecosystem"
If you want to receive further information about upcoming webinars please register here."
Start Date: 9/13/23
Ideas and perspectives: The fluctuating nature of oxygen shapes the ecology of aquatic habitats and their biogeochemical cycles – the aquatic oxyscape
"Oxygen availability is a pivotal factor for ecosystem functioning and the resistance of organisms to the effect of climate change in aquatic habitats. Although extensive work has been done to assess the effect of oxygen on marine and freshwater biota, many studies have not captured the ecological importance of oxygen variations. Overlooking the fluctuating nature of oxygen may cause potential biases in the design and implementation of management policies for aquatic habitats. Conceptual perspectives on the dynamic nature of oxygen fluctuations have been raised in the scientific community in order to enhance [...]".
Authors: Marco Fusi et al.
The response of nitrogen and sulfur cycles to ocean deoxygenation across the Cenomanian-Turonian boundary
"The Cretaceous Oceanic Anoxic Event 2 (OAE2) is a greenhouse episode of severe marine anoxia at the Cenomanian-Turonian boundary. This time interval is characterized by rising sea surface temperature, enhanced marine biological productivity, and widespread occurrence of organic-rich black shales. With an export of biological production to the deep ocean, organisms consume vast amounts of oxygen and subsequently utilize nitrate and sulfate as electron acceptors in organic matter degradation, thereby affecting biogeochemical cycles of nitrogen and sulfur. [...]".
Source: Science Direct
Authors: Ruixiang Zhai et al.
Benthic foraminifera and gromiids from oxygen-depleted environments – survival strategies, biogeochemistry and trophic interactions
"The oceans are losing oxygen (O2), and oxygen minimum zones are expanding due to climate warming (lower O2 solubility) and eutrophication related to agriculture. This trend is challenging for most marine taxa that are not well adapted to O2 depletion. For other taxa this trend might be advantageous because they can withstand low O2 concentrations or thrive under O2-depleted or even anoxic conditions. Benthic foraminifera are a group of protists that include taxa with adaptations to partly extreme environmental conditions. [...]".
Authors: Nicolaas Glock
Indian Ocean glacial deoxygenation and respired carbon accumulation during mid-late Quaternary ice ages
"Reconstructions of ocean oxygenation are critical for understanding the role of respired carbon storage in regulating atmospheric CO2. Independent sediment redox proxies are essential to assess such reconstructions. Here, we present a long magnetofossil record from the eastern Indian Ocean in which we observe coeval magnetic hardening and enrichment of larger, more elongated, and less oxidized magnetofossils during glacials compared to interglacials over the last ~900 ka. Our multi-proxy records of redox-sensitive magnetofossils, trace element concentrations, and benthic foraminiferal Δδ13C consistently suggest a recurrence of lower O2 [...]".
Authors: Liao Chang et al.
Partitioning of the denitrification pathway and other nitrite metabolisms within global oxygen deficient zones
"Oxygen deficient zones (ODZs) account for about 30% of total oceanic fixed nitrogen loss via processes including denitrification, a microbially mediated pathway proceeding stepwise from NO3– to N2. This process may be performed entirely by complete denitrifiers capable of all four enzymatic steps, but many organisms possess only partial denitrification pathways, either producing or consuming key intermediates such as the greenhouse gas N2O. Metagenomics and marker gene surveys have revealed a diversity of denitrification genes within ODZs, but whether these genes co-occur within [...]".
Authors: Irene H. Zhang et al.
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