Mn∕Ca intra- and inter-test variability in the benthic foraminifer Ammonia tepida
"The adaptation of some benthic foraminiferal species to low-oxygen conditions provides the prospect of using the chemical composition of their tests as proxies for bottom water oxygenation. Manganese may be particularly suitable as such a geochemical proxy because this redox element is soluble in reduced form (Mn2+) and hence can be incorporated into benthic foraminiferal tests under low-oxygen conditions. [...]"
Authors: Jassin Petersen et al.
Read the full article here.
[GERMAN] Sauerstoff im Ozean – Weniger, noch weniger, weg
Meeresworkshop für Jugendliche
9.–13. April 2018, GEOMAR Kiel
Neue Forschungsergebnisse des Sonderforschungsbereichs 754 der Deutschen Forschungsgemeinschaft weisen darauf hin, dass die Sauerstoffgehalte in einigen Regionen des Pazifischen und Atlantischen Ozeans in mittleren Tiefen allmählich abnehmen. Die Forschenden aus den Bereichen der Meeresbiologie, Chemie, Physik und Geologie vermuten hierbei eine Wechselwirkung zwischen der Klimaänderung und der Ausbreitung dieser sauerstoffarmen Zonen im Meer.
Das GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel veranstaltet zu diesem Thema einen
1-wöchigen Osterworkshop für Jugendliche im Alter von 14-17 Jahren.
Der Kurs für 12 Teilnehmer findet am GEOMAR in der zweiten Woche der Schleswig-Holsteinischen Osterferien statt, ganztägig vom 9. bis 13. April 2018.
Weitere Informationen finden Sie hier.
Start Date: 4/9/18
Ocean Deoxygenation – Another Global Challenge
"The ocean is facing unprecedented pressures that are causing massive ecosystem and nutrient cycle disruption the result of industrial-scale depletion of ocean wildlife and destabilization of steady-state ecosystems. This occurs not only on the seafloor by trawling, dredging, drilling, and mining but also in the water column with nets, long lines, fish aggregating devices and other techniques; methods introduced in recent decades to extract with unprecedented speed and scale from ecosystems hundreds of millions of years in the making. [...]"
Source: GIS and Science
Author: Matt Artz
Tropical Atlantic climate and ecosystem regime shifts during the Paleocene–Eocene Thermal Maximum
"The Paleocene–Eocene Thermal Maximum (PETM, 56 Ma) was a phase of rapid global warming associated with massive carbon input into the ocean–atmosphere system from a C-depleted reservoir. Many midlatitude and high-latitude sections have been studied and document changes in salinity, hydrology and sedimentation, deoxygenation, biotic overturning, and migrations, but detailed records from tropical regions are lacking. [...]"
Source: Climate of the Past
Authors: Joost Frieling et al.
Oxygen loss strains marine ecosystems
A new review highlights the impact of declining oxygen levels in the open ocean and coastal waters due to increasing temperatures and nutrient discharge.
"Half of the world’s oxygen originates from the ocean. Yet, worldwide, the amount of open ocean without any oxygen has quadrupled over the past 50 years. Oxygen-minimum zones have expanded by several million square kilometres, increasing by more than 10-fold since 1950. [...]"
Source: nature Middle East
Author: Lakshini Mendis
Intensification and deepening of the Arabian Sea oxygen minimum zone in response to increase in Indian monsoon wind intensity
"The decline in oxygen supply to the ocean associated with global warming is expected to expand oxygen minimum zones (OMZs). This global trend can be attenuated or amplified by regional processes. In the Arabian Sea, the world's thickest OMZ is highly vulnerable to changes in the Indian monsoon wind. Evidence from paleo-records and future climate projections indicates strong variations of the Indian monsoon wind intensity over climatic timescales. [...]"
Authors: Zouhair Lachkar, Marina Lévy, and Shafer Smith
A record of deep-ocean dissolved O2 from the oxidation state of iron in submarine basalts
"The oxygenation of the deep ocean in the geological past has been associated with a rise in the partial pressure of atmospheric molecular oxygen (O2) to near-present levels and the emergence of modern marine biogeochemical cycles. It has also been linked to the origination and diversification of early animals. [...]"
Authors: Daniel A. Stolper
Read the full article here.
Oceans suffocating as huge dead zones quadruple since 1950, scientists warn
Areas starved of oxygen in open ocean and by coasts have soared in recent decades, risking dire consequences for marine life and humanity
"Ocean dead zones with zero oxygen have quadrupled in size since 1950, scientists have warned, while the number of very low oxygen sites near coasts have multiplied tenfold. Most sea creatures cannot survive in these zones and current trends would lead to mass extinction in the long run, risking dire consequences for the hundreds of millions of people who depend on the sea. [...]"
Source: The Guardian
Declining oxygen in the global ocean and coastal waters
"Oxygen is fundamental to life. Not only is it essential for the survival of individual animals, but it regulates global cycles of major nutrients and carbon. The oxygen content of the open ocean and coastal waters has been declining for at least the past half-century, largely because of human activities that have increased global temperatures and nutrients discharged to coastal waters. [...]"
Authors: Denise Breitburg et al.
Distribution of planktonic biogenic carbonate organisms in the Southern Ocean south of Australia: a baseline for ocean acidification impact assessment
"The Southern Ocean provides a vital service by absorbing about one-sixth of humankind's annual emissions of CO2. This comes with a cost – an increase in ocean acidity that is expected to have negative impacts on ocean ecosystems. The reduced ability of phytoplankton and zooplankton to precipitate carbonate shells is a clearly identified risk. The impact depends on the significance of these organisms in Southern Ocean ecosystems, but there is very little information on their abundance or distribution."
Authors: Thomas W. Trull et al.
Read the full article here.