Abstract.

"Energetics studies have illuminated how animals partition energy among essential life processes and survive in extreme environments or with unusual lifestyles. There are few bioenergetics measurements for elasmobranch megafauna; the heaviest elasmobranch for which metabolic rate has been measured is only 47.7 kg, despite many weighing >1000 kg. Bioenergetics models of elasmobranch megafauna would answer fundamental ecological questions surrounding this important and vulnerable group, and enable an understanding of how they may respond to changing environmental conditions, such as ocean warming and deoxygenation. [...]"

Source: Trends in Ecology & Evolution
Authors: Christopher L. Lawson et al.
DOI: 10.1016/j.tree.2019.07.001

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Abstract.

"Trace metal measurements in recent years have revealed a complex distribution of dissolved iron (dFe) in the ocean that models still struggle to reproduce. The GEOTRACES section GA03 across the subtropical North Atlantic was chosen to study the driving processes involved in the Fe cycle in the region. [...]"

Source: Ocean Dynamics
Authors: Anna Pagnone et al.
DOI: 10.1007/s10236-019-01288-w

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Abstract.

"The Dungeness crab is an economically and ecologically important species distributed along the North American Pacific coast. To predict how Dungeness crab may physiologically respond to future global ocean change on a molecular level, we performed untargeted metabolomic approaches on individual Dungeness crab juveniles reared in treatments that mimicked current and projected future pH and dissolved oxygen conditions. [...]"

Source: Scientific Reports
Authors: Shelly A. Trigg et al.
DOI: 10.1038/s41598-019-46947-6

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Abstract.

"Bacteriohopanepolyols (BHPs) are pentacyclic triterpenoid lipids that contribute to the structural integrity and physiology of some bacteria. Because some BHPs originate from specific classes of bacteria, BHPs have potential as taxonomically and environmentally diagnostic biomarkers. For example, a stereoisomer of bacteriohopanetetrol (informally BHT II) has been associated with anaerobic ammonium oxidation (anammox) bacteria and suboxic to anoxic marine environments where anammox is active. [...]"

Source: geobiology
Authors: Emily D. Matys et al.
DOI: 10.1111/gbi.12353

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A New Challenge for Element-Ratio-Based Paleoproxies?

 

Abstract.

"Oceanic oxygen decline due to anthropogenic climate change is a matter of growing concern. A quantitative oxygen proxy is highly desirable in order to identify and monitor recent dynamics as well as to reconstruct pre-Anthropocene changes in amplitude and extension of oxygen depletion. Geochemical proxies like foraminiferal I/Ca ratios seem to be promising redox proxies. [...]"

Source: Frontiers in Earth Science
Authors: Nicolaas Glock et al.
DOI: 10.3389/feart.2019.00175

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Abstract.

"Chromium (Cr) isotope fractionation is sensitive to redox changes and the Cr isotopic composition (δ⁵³Cr) of sedimentary rocks has been used to reconstruct marine redox conditions and atmospheric oxygenation in the past. However, little is known about the behaviour of chromium isotopes across modern marine redox boundaries. We investigated Cr concentrations and δ⁵³Cr variations in seawater and sediment across the Peruvian oxygen minimum zone (OMZ) to provide a better understanding of Cr cycling in the ocean. [...]"

Source: Geochimica et Cosmochimica
Authors: S. Bruggmann et al.
DOI: 10.1016/j.gca.2019.05.001

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Abstract.

"The Baltic Sea is a semi-enclosed, brackish water sea in northern Europe. The deep basins of the central Baltic Sea regularly show hypoxic conditions. In contrast, the northern parts of the Baltic Sea, the Bothnian Sea and Bay, are well oxygenated. Lateral inflows or a ventilation due to convection are possible mechanisms for high oxygen concentrations in the deep water of the northern Baltic Sea. [...]"

Source: Ocean Science
Authors: Thomas Neumann et al.
DOI: 10.5194/os-2019-48

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Insights into the timing, duration and extent of environmental perturbations from the palaeo-South Pacific Ocean

Abstract.

"Oceanic Anoxic Event 2 (OAE 2), which took place around the Cenomanian–Turonian boundary (∼94 Ma), is associated with extreme perturbations to the global carbon cycle, affected ocean basins worldwide and was associated with significant biological turnover. Although this event has been well studied in the northern hemisphere, the evolution and character of OAE 2, particularly in terms of the vertical and lateral extent of anoxia, is poorly constrained in the palaeo-Pacific Ocean. [...]"

Source: Earth and Planetary Science Letters
Authors: S. K. Gangl et al.
DOI: 10.1016/j.epsl.2019.04.028

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"In 2019, predictions indicate that the Gulf of Mexico will retain the dubious distinction of having the second-largest low-oxygen dead zone on Earth (the Baltic Sea remains firmly in first place). By the end of the summer, the hypoxic region on the seafloor at the mouth of the Mississippi River is expected to occupy over 22,000 square kilometers—an area the size of the state of Massachusetts. [...]

Source: Earth & Space Science News
Author: Mary Caperton Morton
DOI: 10.1029/2019EO128019

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Abstract.

"The emergence of oxygenic photosynthesis created a new niche with dramatic potential to transform energy flow through Earth’s biosphere. However, more primitive forms of photosynthesis that fix CO2 into biomass using electrons from reduced species like Fe(II) and H2 instead of water would have competed with Earth’s early oxygenic biosphere for essential nutrients. [...]"

Source: Nature Communications
Authors: Kazumi Ozaki et al.
DOI: 10.1038/s41467-019-10872-z

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Abstract.

"Nitrous oxide (N₂O) is a climate-relevant atmospheric trace gas. It is produced as an intermediate of the nitrogen cycle. The open and coastal oceans are major sources of atmospheric N₂O. However, its oceanic distribution is still largely unknown. Here we present the first measurements of the water column distribution of N₂O in the Gulf of Aqaba and the Red Sea. [...]"

Source: Deep Sea Research Part II: Topical Studies in Oceanography
Authors: Hermann W.Bange et al.
DOI: 10.1016/j.dsr2.2019.06.015

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Abstract.

"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 (OMZs) in the world ocean, where dissolved oxygen (O₂) concentrations reach less than 1 µmol kg⁻¹. [...]"

Source: Biogeosciences
Authors: Alexandra N. Loginova et al.
DOI: 10.5194/bg-16-2033-2019

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..over the past 600 years

Abstract.

"The stable sedimentary nitrogen isotope compositions of bulk organic matter (δ¹⁵N_bulk) and the silicon isotope composition of diatoms (δ³⁰Si_BSi) both mainly reflect the degree of past nutrient utilization by primary producers. However, in ocean areas where anoxic and suboxic conditions prevail, the δ¹⁵N_bulk signal ultimately recorded within the sediments is also influenced by water column denitrification, causing an increase in the subsurface δ¹⁵N signature of dissolved nitrate (δ¹⁵NO⁻₃) upwelled to the surface. [...]"

Source: Biogeosciences
Authors: Kristin Doering et al.
DOI: 10.5194/bg-16-2163-2019

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Abstract.

"Monitoring and predicting the biogeochemical state of the ocean and marine ecosystems is an important application of operational oceanography that needs to be expanded. The accurate depiction of the ocean’s physical environment enabled by Global Ocean Data Assimilation Experiment (GODAE) systems, in both real-time and reanalysis modes, is already valuable for various applications, such as the fishing industry and fisheries management. However, most of these applications require accurate estimates of both physical and biogeochemical ocean conditions over a wide range of spatial and temporal scales. [...]"

Source: Oceanography
Authors: Pierre Brasseur et al.
DOI: 10.5670/oceanog.2009.80

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Abstract.

"Ocean acidification (OA) describes the progressive decrease in the pH of seawater and other cascading chemical changes resulting from oceanic uptake of atmospheric carbon. These changes can have important implications for marine ecosystems, creating risk for commercial industries, subsistence communities, cultural practices, and recreation. [...]"

Source: Frontiers in Marine Science
Authors: Jessica N. Cross et al.
DOI: 10.3389/fmars.2019.00356

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"A team of natural and social scientists, supported by 25 post-secondary students from the U.S. and Canada, will study vital signs of a rapidly changing Arctic Ocean this summer, and offer the public a chance to share the experience in real time.

The innovative, 18-day Northwest Passage Project research expedition will depart on July 18 from the U.S. Air Base in Thule, Greenland, aboard the Swedish Icebreaker Oden, returning to Thule August 4 after a 2,000 nautical mile voyage through the Northwest Passage [...]"

Source: EurekAlert!

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Abstract.

"Mesoscale eddies, as a considerable contributor to the transport of ocean heat, dissolved oxygen and other biochemical tracers, have an important influence on the distribution of marine resources and global climate change. The purpose of this research is to capture the high variability of an anticyclonic eddy in South China Sea to observe its thermohaline vertical structure in different transections. [...]"

Source: OCEANS 2018 MTS/IEEE Charleston
Authors: Shufeng Li et al.
DOI: 10.1109/OCEANS.2018.8604623

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