Spatio-temporal variations in culturable bacterial community associated with denitrification in the Arabian Sea oxygen minimum zone
"The Arabian Sea (AS) oxygen minimum zone (OMZ) is a site of intense denitrification, contributing to 20% of the global oceanic denitrification, playing a significant role in the nitrogen cycle. In this study, the structure and diversity of culturable bacterial communities inhabiting the water column of the AS OMZ were investigated through phylogenetic analysis and nitrate-utilizing ability was studied through culture-based studies. A total of 248 isolates collected during pre-monsoon and post-monsoon season were analysed for 16S rRNA gene sequences. [...]".
Source: Marine Biology Research
Authors: Ujwala Amberkar et al.
Vertical distribution of planktic foraminifera through an oxygen minimum zone: how assemblages and test morphology reflect oxygen concentrations
"Oxygen-depleted regions of the global ocean are rapidly expanding, with important implications for global biogeochemical cycles. However, our ability to make projections about the future of oxygen in the ocean is limited by a lack of empirical data with which to test and constrain the behavior of global climatic and oceanographic models. We use depth-stratified plankton tows to demonstrate that some species of planktic foraminifera are adapted to life in the heart of the pelagic oxygen minimum zone (OMZ). In particular, we identify two species, Globorotaloides hexagonus and Hastigerina parapelagica, living within the eastern tropical North Pacific OMZ. The tests of the former are preserved in marine sediments and could be used to trace the extent and intensity of low-oxygen pelagic habitats in the fossil record. Additional morphometric analyses of G. hexagonus show that tests found in the lowest oxygen[...]"
Authors: Catherine V. Davis et al.
Assimilating synthetic Biogeochemical-Argo and ocean colour observations into a global ocean model to inform observing system design
"A set of observing system simulation experiments was performed. This assessed the impact on global ocean biogeochemical reanalyses of assimilating chlorophyll from remotely sensed ocean colour and in situ observations of chlorophyll, nitrate, oxygen, and pH from a proposed array of Biogeochemical-Argo (BGC-Argo) floats. Two potential BGC-Argo array distributions were tested: one for which biogeochemical sensors are placed on all current Argo floats and one for which biogeochemical sensors are placed on a quarter of current Argo floats. Assimilating BGC-Argo data greatly improved model results throughout the water column[...]"
Authors: David Ford et al.
Discrepancy in the Identification of the Atlantic/Pacific Front in the Central Arctic Ocean: NO Versus Nutrient Relationships
"Fronts in the NO parameter, a semiconservative tracer combining nitrate and dissolved oxygen, and dynamic height were observed in the central East Siberian Sea that distinguished Atlantic and Pacific contributions to the upper halocline of the Amerasian Basin during the summer of 2015. [...]"
Source: Geophysical Research Letters
Authors: Matthew B. Alkire, Robert Rember and Igor Polyakov