Substrate regulation leads to differential responses of microbial ammonia-oxidizing communities to ocean warming
"In the context of continuously increasing anthropogenic nitrogen inputs, knowledge of how ammonia oxidation (AO) in the ocean responds to warming is crucial to predicting future changes in marine nitrogen biogeochemistry. Here, we show divergent thermal response patterns for marine AO across a wide onshore/offshore trophic gradient. [...]"
Source: Nature Communications
Authors: Zhen-Zhen Zheng et al.
Twenty-first century ocean warming, acidification, deoxygenation, and upper-ocean nutrient and primary production decline from CMIP6 model projections
"Anthropogenic climate change is projected to lead to ocean warming, acidification, deoxygenation, reductions in near-surface nutrients, and changes to primary production, all of which are expected to affect marine ecosystems. Here we assess projections of these drivers of environmental change over the twenty-first century from Earth system models (ESMs) participating in the Coupled Model Intercomparison Project Phase 6 (CMIP6) that were forced under the CMIP6 Shared Socioeconomic Pathways (SSPs). [...]"
Authors: Lester Kwiatkowski et al.
Is deoxygenation detectable before warming in the thermocline?
"Anthropogenic greenhouse gas emissions cause ocean warming and oxygen depletion, with adverse impacts on marine organisms and ecosystems. Warming is one of the main indicators of anthropogenic climate change, but, in the thermocline, changes in oxygen and other biogeochemical tracers may emerge from the bounds of natural variability prior to warming. Here, we assess the time of emergence (ToE) of anthropogenic change in thermocline temperature and thermocline oxygen within an ensemble of Earth system model simulations from the fifth phase of the Coupled Model Intercomparison Project. [...]"
Authors: Angélique Hameau et al.
Warming stimulates sediment denitrification at the expense of anaerobic ammonium oxidation
"Temperature is one of the fundamental environmental variables governing microbially mediated denitrification and anaerobic ammonium oxidation (anammox) in sediments. The GHG nitrous oxide (N2O) is produced during denitrification, but not by anammox, and knowledge of how these pathways respond to global warming remains limited. [...]"
Source: Nature Climate Change
Authors: Ehui Tan et al.
HKU study shows that control of anthropogenic atmospheric emissions can improve water quality in China’s coastal Seas
"A new research led by MPhil student Miss Yu Yan Yau and supervised by Dr Benoit Thibodeau from the Department of Earth Sciences and the Swire Institute of Marine Science, the University of Hong Kong (HKU), highlighted the importance of reducing fossil fuel combustion not only to curb the trend of global warming, but also to improve the quality of China’s coastal waters. The findings were recently published in the prestigious journal Environmental Science & Technology. [...]"
Source: The University of Hong Kong
Our Vanishing World: Oceans
"As the human onslaught against life on Earth accelerates, no part of the biosphere is left pristine. The simple act of consuming more than we actually need drives the world’s governments and corporations to endlessly destroy more and more of the Earth to extract the resources necessary to satisfy our insatiable desires. In fact, an initiative of the World Economic Forum has just reported that ‘For the first time in history, more than 100 billion tonnes of materials are entering the global economy every year’ – see ‘The Circularity Gap Report 2020’– which means that, on average, every person on Earth uses more than 13 tonnes of materials each year extracted from the Earth. [...]"
Multi-agency report highlights increasing signs and impacts of climate change in atmosphere, land and oceans
"New York / Geneva, 10 March 2020 - The tell-tale physical signs of climate change such as increasing land and ocean heat, accelerating sea level rise and melting ice are highlighted in a new report compiled by the World Meteorological Organization and an extensive network of partners. It documents impacts of weather and climate events on socio-economic development, human health, migration and displacement, food security and land and marine ecosystems. [...]"
Source: World Meteorological Organization (WMO)
Uncovering diversity and metabolic spectrum of animals in dead zone sediments
"Ocean deoxygenation driven by global warming and eutrophication is a primary concern for marine life. Resistant animals may be present in dead zone sediments, however there is lack of information on their diversity and metabolism. Here we combined geochemistry, microscopy, and RNA-seq for estimating taxonomy and functionality of micrometazoans along an oxygen gradient in the largest dead zone in the world. [...]"
Source: Communications Biology
Authors: Elias Broman et al.
Ocean Conference has potential to be a ‘global game-changer’
"“Life under water is essential to life on land”, said Tijjani Muhammad-Bande. The ocean produces “half of the oxygen we breathe” and provides food for millions of around the world, playing a “fundamental role in mitigating climate change as a major heat and carbon sink”. The Ocean Conference, which will run in Lisbon from 2 to 6 June, aims to propel science-based innovative solutions in the form of global ocean action. The worldwide ocean economy is valued at around $1.5 trillion dollars annually, as aquaculture is the fastest growing food sector and 350 million jobs world-wide are linked to fisheries. [...]"
Source: UN News
Anaerobic Activity Is a Big Contributor in Marine “Dead Zones”
Climate models that do not account for anaerobic microbial activity may underestimate future expansion of oxygen-depleted waters.
"Certain parts of Earth’s oceans are so oxygen depleted that they can hardly sustain life. Climate models predict that these “dead zones” will expand as global warming progresses, affecting ecosystems, fisheries, and the climate itself. Now Lengger et al. provide new evidence that such predictions do not adequately account for the activity of anaerobic microbes that consume inorganic carbon within dead zones. [...]"