Zooplankton grazing of microplastic can accelerate global loss of ocean oxygen
"Global warming has driven a loss of dissolved oxygen in the ocean in recent decades. We demonstrate the potential for an additional anthropogenic driver of deoxygenation, in which zooplankton consumption of microplastic reduces the grazing on primary producers. In regions where primary production is not limited by macronutrient availability, the reduction of grazing pressure on primary producers causes export production to increase. Consequently, organic particle remineralisation in these regions[...]"
Source: Nature Communications
Authors: K. Kvale et al.
Oxygen Seasonality, Utilization Rate, and Impacts of Vertical Mixing in the Eighteen Degree Water Region of the Sargasso Sea as Observed by Profiling
"Seasonal oxygen structure and utilization in the Sargasso Sea are characterized using nine profiling floats with oxygen 2021 sensors (years 2005–2008), deployed in an Eighteen Degree Water (EDW) experiment (CLIMODE). During autumn-winter when the mixed layer is deepening, oxygen increases from the surface to the base of the EDW at 400 m. During spring-summer, oxygen decreases except between the seasonal pycnocline and compensation depth, creating the seasonal shallow oxygen maximum layer (SOMax) with oxygen production[...]"
Source: Advancing Earth and Space Science
Authors: Samuel J. Billheimer et al.
Fossil evidence for vampire squid inhabiting oxygen-depleted ocean zones since at least the Oligocene
"A marked 120 My gap in the fossil record of vampire squids separates the only extant species (Vampyroteuthis infernalis) from its Early Cretaceous, morphologically-similar ancestors. While the extant species possesses unique physiological adaptations to bathyal environments with low oxygen concentrations, Mesozoic vampyromorphs inhabited epicontinental shelves. However, the timing of their retreat towards bathyal and oxygen-depleted habitats is poorly documented. Here, we document a first record of a post-Mesozoic vampire squid from the Oligocene of the Central Paratethys represented[...]"
Source: Communications Biology
Authors: Martin Košťák et al.
The Ocean barcode atlas: A web service to explore the biodiversity and biogeography of marine organisms
"The Ocean Barcode Atlas (OBA) is a user friendly web service designed for biologists who wish to explore the biodiversity and biogeography of marine organisms locked in otherwise difficult to mine planetary scale DNA metabarcode data sets. Using just a web browser, a comprehensive picture of the diversity of a taxon or a barcode sequence is visualized graphically on world maps and interactive charts. Interactive results panels allow dynamic threshold adjustments and the display of diversity results[...]"
Source: Wiley Online Library
Authors: Caroline Vernette et al.
Antioxidant responses of the mussel Mytilus coruscus co-exposed to ocean acidification, hypoxia and warming
"In the present study, the combined effects of pH, dissolved oxygen (DO) and temperature levels on the antioxidant responses of the mussel Mytilus coruscus were evaluated. Mussels were exposed to two pH (8.1, 7.7-acidification), two DO (6 mg L−1, 2 mg L−1-hypoxia) and two temperature levels[...]"
Source: Science Direct
Authors: Fahim Ullah Khan et al
Redox control on the tungsten isotope composition of seawater
"Free oxygen represents an essential basis for the evolution of complex life forms on a habitable Earth. The isotope composition of redox-sensitive trace elements such as tungsten (W) can possibly trace the earliest rise of oceanic oxygen in Earth’s history. However, the impact of redox changes on the W isotope composition of seawater is still unknown. Here, we report highly variable W isotope compositions in the water column of a redox-stratified basin (δ186/184W between +0.347 and +0.810 ‰) that contrast with the homogenous W isotope composition of the open ocean[...]"
Source: PNAS- Proceedings of the National Academy of Sciences of the United States of America
Authors: Florian Kurzweil et al.
Response of benthic nitrogen cycling to estuarine hypoxia
"The effects of bottom water oxygen concentration on sediment oxygen uptake, oxygen penetration depth, nitrate and ammonium fluxes, anammox, denitrification, dissimilatory nitrate reduction to ammonium, nitrification, and mineralization were investigated off the Changjiang estuary and its adjacent East China Sea, by combining a seasonal comparison[...]"
Source: ASLO- Association for the Sciences Limnology and Oceanography
Authors: Guodong Song et al.
A benthic oxygen oasis in the early Neoproterozoic ocean
"Benthic oxygen oases linked to photosynthetic mats have been reported in modern anoxic aquatic systems. Benthic macroalgal blooms were common in stratified, anoxic Neoproterozoic oceans, leading us to hypothesize the existence of benthic oxygen oases at that time. This hypothesis has significant implications regarding the bioavailability of transition metals (e.g., Cu, Zn, Ni, Mo, V) and the distribution of aerobic eukaryotes in these oceans[...]"
Source: Science Direct
Authors: Haiyang Wang et al.
Ocean acidification locks algal communities in a species-poor early successional stage
"Long-term exposure to CO2-enriched waters can considerably alter marine biological community development, often resulting in simplified systems dominated by turf algae that possess reduced biodiversity and low ecological complexity. Current understanding of the underlying processes by which ocean acidification alters biological community development and stability remains limited, making the management of such shifts problematic. Here, we deployed recruitment[...]"
Source: Wiley Online Library
Authors: Ben P. Harvey et al.
Environmental Drivers of Mesophotic Echinoderm Assemblages of the Southeastern Pacific Ocean
"Mesophotic ecosystems (50–400 m depth) of the southeastern Pacific have rarely been studied because of the logistical challenges in sampling across this remote zone. This study assessed how oxygen concentrations and other environmental predictors explain variation in echinoderm assemblages at these mesophotic systems, where this group is among the predominant fauna. We compiled data on echinoderm taxa at 91 sampling stations, from historical and recent surveys (between 1950 and 2019), covering a longitudinal gradient of approximately 3,700 km along with the Nazca, Salas y Gómez[...]"
Source: Frontiers in Marine Science
Authors: Ariadna Mecho et al.