Fixed nitrogen limits primary productivity in most areas of the surface ocean. Nitrite oxidation is main source nitrate, abundant form inorganic fixed nitrogen. Even though known as an aerobic process, nitrite not always stimulated by increased oxygen concentration, and occurs layers minimum zones (OMZs) where detectable. Nitrite-oxidizing bacteria, since their original isolation aerobes, were ...

Abstract The Paleocene Eocene Thermal Maximum (PETM) represents a major carbon cycle and climate perturbation that was associated with ocean de-oxygenation, in qualitatively similar manner to the more extensive Mesozoic Oceanic Anoxic Events. Although indicators of de-oxygenation are common for PETM, linked biotic turnover, global extent temporal progression is poorly constrained. Here we prese...

Palaeo-oceanographical archives in the Mediterranean Sea indicate occurrence of Sapropel depositions, which are characteristic anoxic bottom conditions and a stratified sea. The impact such drastic changes thermohaline circulation on large-scale circulations North Atlantic basin is not fully understood. Here we evaluate direct perturbation through different idealized simulations with freshwater...

A three dimensional ocean circulation model (Princeton Ocean Model) is utilised to study the thermohaline variability of the eastern Arabian Sea associated with changes in the three input bathymetry data sets, viz. ETOPO5 (E5), Modified ETOPO5 (ME5) and ME5 further modified based on actual fine resolution data collected using Multibeam echo-sounder (MEN5). The temperature and salinity measureme...

Wind, wave and current interactions control the boundary fluxes, momentum and energy exchange between the atmosphere and the ocean, and within the water column. The wind wave effect on surface stress is investigated using a three-dimensional time-dependant ocean circulation model. The POM (Princeton Ocean Model) based model is implemented with realistic coastlines in South China Sea and emphasi...

Heat shock and anoxia are environmental stresses that are known to trigger similar cellular responses. In this study, we used the locust to examine stress cross-tolerance by investigating the consequences of a prior anoxic stress on the effects of a subsequent high-temperature stress. Anoxic stress and heat shock induced thermotolerance by increasing the ability of intact locusts to survive nor...

Lactate dehydrogenase (LDH; E.C. 1.1.1.27) is a crucial enzyme involved in energy metabolism in muscle, facilitating the production of ATP via glycolysis during oxygen deprivation by recycling NAD(+). The present study investigated purified LDH from the muscle of 20 h anoxic and normoxic T. s. elegans, and LDH from anoxic muscle showed a significantly lower (47%) K m for L-lactate and a higher ...

Iron redox cycling in metal-rich, hypersaline, anoxic brines plays a central role in the biogeochemical evolution of life on Earth, and similar brines with the potential to harbor life are thought to exist elsewhere in the solar system. To investigate iron biogeochemical cycling in a terrestrial analog we determined the iron redox chemistry and isotopic signatures in the cryoencapsulated liquid...

The crucian carp (Carassius carassius) seems unique among vertebrates in its ability to maintain cardiac performance during prolonged anoxia. We investigated whether this phenomenon arises in part from a myocardium tolerant to severe acidosis or because the anoxic crucian carp heart may not experience a severe extracellular acidosis due to the fish's ability to convert lactate to ethanol. Spont...

We have recently found that in the mouse cortex, activation of delta-opioid receptor (DOR) attenuates the disruption of K(+) homeostasis induced by hypoxia or oxygen-glucose deprivation. This novel observation suggests that DOR may protect neurons from hypoxic/ischemic insults via the regulation of K(+) homeostasis because the disruption of K(+) homeostasis plays a critical role in neuronal inj...