Emerging Solutions to Return Nature to the Urban Ocean
"Urban and periurban ocean developments impact 1.5% of the global exclusive economic zones, and the demand for ocean space and resources is increasing. As we strive for a more sustainable future, it is imperative that we better design, manage, and conserve urban ocean spaces for both humans and nature. We identify three key objectives for more sustainable urban oceans: reduction of urban pressures, protection and restoration of ocean ecosystems, and support of critical ecosystem services. We describe an array of emerging evidence-based approaches, including greening grayinfrastructure, restoring habitats, and developing biotechnologies.
Source: ANNUAL REVIEWS
Authors: Laura Airoldi et al.
11 - Impacts of strong warm ocean currents on development of extratropical cyclones through the warm and cold conveyor belts: A review
"Recent high-resolution observations and numerical simulations have revealed active roles of the ocean in the mid-latitude climate system. In this chapter, we review recent studies on the topic especially focusing on roles of strong oceanic warm currents and associated sea surface temperature (SST) frontal structures in the development of extratropical cyclones, which can cause extreme rainfall/snowfall. Speed of the warm strong ocean currents such as the Kuroshio/Kuroshio Extension and activities of associated mesoscale eddies have strong influence on SST and its meridional[...]"
Source: Science Direct
Authors: Hidetaka Hirata et al.
A benthic oxygen oasis in the early Neoproterozoic ocean
"Benthic oxygen oases linked to photosynthetic mats have been reported in modern anoxic aquatic systems. Benthic macroalgal blooms were common in stratified, anoxic Neoproterozoic oceans, leading us to hypothesize the existence of benthic oxygen oases at that time. This hypothesis has significant implications regarding the bioavailability of transition metals (e.g., Cu, Zn, Ni, Mo, V) and the distribution of aerobic eukaryotes in these oceans. However, little research has been directed toward testing the benthic oxygen[...]"
Source: Science Direct
Authors:Haiyang Wang et al.
Calibration of temperature-dependent ocean microbial processes in the cGENIE.muffin (v0.9.13) Earth system model
"Temperature is a master parameter in the marine carbon cycle, exerting a critical control on the rate of biological transformation of a variety of solid and dissolved reactants and substrates. Although in the construction of numerical models of marine carbon cycling, temperature has been long recognised as a key parameter in the production and export of organic matter at the ocean surface, its role in the ocean interior is much less frequently accounted for. There, bacteria (primarily) transform sinking particulate organic matter (POM) into its dissolved constituents and consume dissolved oxygen (and/or other electron acceptors such as sulfate). The nutrients and carbon[...]"
Source: EGU- European Geosciences Union
Authors: Katherine A. Crichton
Regional patterns and temporal evolution of ocean iron fertilization and CO2 drawdown during the last glacial termination
"The last time Earth's climate experienced geologically rapid global warming was associated with the last glacial termination, when atmospheric CO2 concentrations rose from 180 ppmv during the Last Glacial Maximum (LGM, 26-19 kaBP) to ∼260 ppmv by the early Holocene (12-8 kaBP). About one quarter of that difference is thought to be due to a stronger biological pump during glacial times, driven by increased aeolian dust deposition and hence greater iron availability in[...]"
Source: Science Direct
Authors: Fabrice Lambert et al.
Fossil evidence for vampire squid inhabiting oxygen-depleted ocean zones since at least the Oligocene
"A marked 120 My gap in the fossil record of vampire squids separates the only extant species (Vampyroteuthis infernalis) from its Early Cretaceous, morphologically-similar ancestors. While the extant species possesses unique physiological adaptations to bathyal environments with low oxygen concentrations, Mesozoic vampyromorphs inhabited epicontinental shelves. However, the timing of their retreat towards bathyal and oxygen-depleted habitats is poorly documented. Here, we document a first record of a post-Mesozoic vampire squid from the Oligocene of the Central Paratethys[...]"
Source: Nature - Communications Biology
Authors: Martin Košťák et al.
Quantifying Nitrous Oxide Cycling Regimes in the Eastern Tropical North Pacific Ocean With Isotopomer Analysis
"Nitrous oxide (N2O), a potent greenhouse gas, is produced disproportionately in marine oxygen deficient zones (ODZs). To quantify spatiotemporal variation in N2O cycling in an ODZ, we analyzed N2O concentration and isotopologues along a transect through the eastern tropical North Pacific (ETNP). At several stations along this transect, N2O concentrations reached a near surface maximum that exceeded prior measurements in this region, of up to 226.1 ± 20.5 nM at the coast. Above the σθ = 25.0 kg/m3 isopycnal, Keeling plot analysis revealed two sources[...]"
Source: AGU- Advanced Earth and Space Science
Author: Colette L. Kelly et al.
Read the full article here.
Mixing by Oceanic Lee Waves
"Oceanic lee waves are generated in the deep stratified ocean by the flow of ocean currents over sea floor topography, and when they break, they can lead to mixing in the stably stratified ocean interior. While the theory of linear lee waves is well established, the nonlinear mechanisms leading to mixing are still under investigation. Tidally driven lee waves have long been observed in the ocean, along with associated mixing, but observations of lee waves forced by geostrophic eddies are relatively sparse and largely indirect[...]"
Source: Annual Reviews
Authors: Sonya Legg
Ocean acidification may slow the pace of tropicalization of temperate fish communities
"Poleward range extensions by warm-adapted sea urchins are switching temperate marine ecosystems from kelp-dominated to barren-dominated systems that favour the establishment of range-extending tropical fishes. Yet, such tropicalization may be buffered by ocean acidification, which reduces urchin grazing performance and the urchin barrens that tropical range-extending fishes prefer. Using ecosystems experiencing natural warming and acidification, we show that ocean acidification could buffer warming-facilitated tropicalization by reducing urchin populations (by 87%) and inhibiting the formation of barrens. This buffering effect of CO2[...]"
Source: Nature Climate Change
Authors: Ericka O. C. Coni 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.