Early Palaeozoic ocean anoxia and global warming driven by the evolution of shallow burrowing


"The evolution of burrowing animals forms a defining event in the history of the Earth. It has been hypothesised that the expansion of seafloor burrowing during the Palaeozoic altered the biogeochemistry of the oceans and atmosphere. However, whilst potential impacts of bioturbation on the individual phosphorus, oxygen and sulphur cycles have been considered, combined effects have not been investigated, leading to major uncertainty over the timing and magnitude of the Earth system response to the evolution of bioturbation. [...]"

Source: Nature Communications
Authors: Sebastiaan van de Velde et al.
DOI: 10.1038/s41467-018-04973-4

Read the full article here.

Nitrogen – ocean plastics pollution’s forgotten neighbour

"Tremendous – and deserved - attention has been paid for the last few years to the scourge of ocean plastics pollution, which we now know reaches the farthest depths of the ocean and can have impacts on ocean life from the smallest plankton to the largest whales.  We know (Jambeck et al., 2015) that some 4.8 million to 12.7 million metric tonnes of plastic enter the ocean each year. UN Environment has estimated the socio-economic costs of ocean plastics pollution at about US$13 billion per year.  We are only beginning to explore and understand the potential human health impacts of plastics in the oceanic food chain. [...]"

Source: United Nations Development Programme
Author: Andrew Hudson

Read the full article here.

Annual plankton community metabolism in estuarine and coastal waters in Perth (Western Australia)


"The planktonic metabolic balance that is the balance between gross primary production (GPP) and community respiration (CR) was determined in Matilda Bay (estuarine) and Woodman Point (coastal) in Perth, Western Australia. The rates of net community production (NCP = GPP – CR) and the ratio between GPP and CR (P/R) were assessed to evaluate whether the metabolic balance in the two coastal locations tends to be net autotrophic (production exceeding community respiration) or net heterotrophic (respiration exceeding production).  [...]"

Source: PeerJ
Authors: Susana Agusti, Lorena Vigoya, Carlos Manuel Duarte
DOI: 10.7717/peerj.5081

Read the full article here.

Changing storminess and global capture fisheries

"Climate change-driven alterations in storminess pose a significant threat to global capture fisheries. Understanding how storms interact with fishery social-ecological systems can inform adaptive action and help to reduce the vulnerability of those dependent on fisheries for life and livelihood."

Source: Nature Climate Change
Authors: Nigel C. Sainsbury et al.
DOI: 10.1038/s41558-018-0206-x

Read the full article here.

Accurate estimation of net community production from O2/Ar measurements


"Under physically isolated conditions, net community production (NCP) can be accurately estimated from the rate of oxygen evasion to the atmosphere derived from local mixed layer oxygen/argon measurements. We use a simple box model to demonstrate that, when physical inputs are negligible, the sea‐to‐air flux of biological oxygen (bioflux) represents the average NCP exponentially weighted over the past several residence times of oxygen in the mixed layer. This new weighting scheme shows that there is no apparent lag between bioflux and exponentially‐weighted time‐averaged NCP.  [...]"

Source: Global Biogeochemical Cycles
Authors: Lianna Teeter et al.
DOI: 10.1029/2017GB005874

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Extensive marine anoxia during the terminal Ediacaran Period


"The terminal Ediacaran Period witnessed the decline of the Ediacara biota (which may have included many stem-group animals). To test whether oceanic anoxia might have played a role in this evolutionary event, we measured U isotope compositions (δ238U) in sedimentary carbonates from the Dengying Formation of South China to obtain new constraints on the extent of global redox change during the terminal Ediacaran. [...]"

Source: Science Advances
Authors: Feifei Zhang et al.
DOI: 10.1126/sciadv.aan8983

Read the full article here.

Chesapeake Bay: Larger-than-average summer 'dead zone' forecast for 2018 after wet spring

"Ecologists from the University of Michigan and the University of Maryland Center for Environmental Science are forecasting a larger-than-average Chesapeake Bay "dead zone" in 2018, due to increased rainfall in the watershed this spring.

This summer's Chesapeake Bay hypoxic or dead zone, an area of low to no oxygen that can kill fish and other aquatic life, is expected to be about 1.9 cubic miles (7.9 cubic kilometers), according to the forecast released today by the two universities. [...]"


Read the full article here.

The devil's in the disequilibrium: multi-component analysis of dissolved carbon and oxygen changes under a broad range of forcings... a general circulation model


"The complexity of dissolved gas cycling in the ocean presents a challenge for mechanistic understanding and can hinder model intercomparison. One helpful approach is the conceptualization of dissolved gases as the sum of multiple, strictly defined components. Here we decompose dissolved inorganic carbon (DIC) into four components: saturation (DICsat), disequilibrium (DICdis), carbonate (DICcarb), and soft tissue (DICsoft). The cycling of dissolved oxygen is simpler, but can still be aided by considering O2, O2sat, and O2dis. [...]"

Source: Biogeosciences
Authors: Sarah Eggleston and Eric D. Galbraith
DOI: 10.5194/bg-15-3761-2018

Read the full article here.

Diapycnal dissolved organic matter supply into the upper Peruvian oxycline


"The Eastern Tropical South Pacific (ETSP) hosts the Peruvian upwelling system, which represents one of the most productive areas in the world ocean. High primary production followed by rapid heterotrophic utilization of organic matter supports the formation of one of the most intense oxygen minimum zones (OMZ) in the world ocean where dissolved oxygen (O2) concentrations reach well below 1 µmol kg−1. The high productivity leads to an accumulation of dissolved organic matter (DOM) in the surface layers that may serve as a substrate for heterotrophic respiration.  [...]"

Source: Biogeosciences
Authors: lexandra N. Loginova et al.
DOI: 10.5194/bg-2018-284

Read the full article here.

GOOS Webinar: GO2NE by Marilaure Gregoire

Deoxygenation in the global and coastal ocean: challenges of observing and modelling low oxygen zones

Dr Marilaure Grégoire, University of Liège

Tuesday 19 June, 13:00 GMT/UTC

Click this link to join the webinar to register and be reminded to join at the appropriate time.

"The IOC-Unesco Global Ocean Oxygen Network (GO2NE)
Since about 1960, ocean deoxygenation is occurring in the coastal and global ocean and is expected to worsen in a warming world with consequences on living organisms and on regional and global budgets of essential elements. Better understanding of the deoxygenation process can be achieved by access to accurate observations and to furthering the reliability and coupling capabilities of physical, biogeochemical, plankton and benthic foodweb, and upper trophic level models. Rapid advancement is being made in each of the modeling types, as well as in how best to couple them, in order to generate "climate to fish" models (e.g. Rose et al. 2010) that include oxygen effects.  [...]"

More information about the webinar series >>.

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