Modeling the role of riverine organic matter in hypoxia formation within the coastal transition zone off the Pearl River Estuary
"Globally expanding hypoxia in estuaries and coastal oceans has largely been attributed to the elevated river nutrient inputs, whereas the role of river-delivered terrestrial organic matter (OMterr) in hypoxia formation has been less investigated. This study uses a coupled physical-biogeochemical model and observations to investigate how OMterr directly (via remineralization) and indirectly (via the nutrients released from OMterr remineralization) promotes hypoxia development in the coastal transition zone[...]"
Source: Association for the Sciences of Limnology and Oceanography
Authors: Liuqian Yu et al.
Biogeochemistry and hydrography shape microbial community assembly and activity in the eastern tropical North Pacific Ocean oxygen minimum zone
"Oceanic oxygen minimum zones (OMZs) play a pivotal role in biogeochemical cycles due to extensive microbial activity. How OMZ microbial communities assemble and respond to environmental variation is therefore essential to understanding OMZ functioning and ocean biogeochemistry. Sampling along depth profiles at five stations in the eastern tropical North Pacific Ocean (ETNP), we captured systematic variations in dissolved oxygen (DO) and associated variables (nitrite, chlorophyll, and ammonium) with depth and between stations. We quantitatively analysed relationships[...]"
Source: Wiley Online Library
Authors: J. Michael Beman et al.
Response of benthic nitrogen cycling to estuarine hypoxia
"The effects of bottom water oxygen concentration on sediment oxygen uptake, oxygen penetration depth, nitrate and ammonium fluxes, anammox, denitrification, dissimilatory nitrate reduction to ammonium, nitrification, and mineralization were investigated off the Changjiang estuary and its adjacent East China Sea, by combining a seasonal comparison[...]"
Source: ASLO- Association for the Sciences Limnology and Oceanography
Authors: Guodong Song et al.
Variable Oxygen Levels Lead to Variable Stoichiometry of Benthic Nutrient Fluxes in a Hypertrophic Estuary
"Harmful blooms of cyanobacteria may extend over long time spans due to self-sustaining mechanisms. We hypothesized that settled blooms may increase redox-dependent P release and unbalance the stoichiometry of benthic nutrient regeneration (NH4+:SiO2:PO43− ratios). We tested this hypothesis in the hypertrophic Curonian Lagoon, the largest in Europe. During summer, at peak chlorophyll and water temperatures, sediment cores were collected over 19 stations representing all the lagoon sedimentary environments. Sediment organic content, granulometry, aerobic respiration, and oxic[...]"
Source: Estuaries and Coasts
Authors: Marco Bartoli et al.
Trends and variability of ocean waves under RCP8.5 emission scenario in the Mediterranean Sea
"Wind-generated ocean waves are key inputs for several studies and applications, both near the coast (coastal vulnerability assessment, coastal structures design, harbor operativity) and off-shore (a.o. oil and gas production, ship routes, and navigation safety). As such, the evaluation of trends in future wave climate is fundamental for the development of efficient policies in the framework of climate change adaptation and mitigation measures. This study focuses[...]"
Source: Ocean Dynamics
Authors: Francesco De Leo et al.
Global patterns for the spatial distribution of floating microfibers: Arctic Ocean as a potential accumulation zone
"Despite their representativeness, most studies to date have underestimated the amount of microfibers (MFs) in the marine environment. Therefore, further research is still necessary to identify key processes governing MF distribution. Here, the interaction among surface water temperature, salinity, currents and winds explained the patterns of MF accumulation. The estimated density of floating MFs is ∼5900 ± 6800 items m−3 in the global ocean; and three patterns of accumulation were predicted by the proposed[...]"
Source: Science Direct
Authors: André R.A.Lima et al.
Clouds and Radiation Processes in Regional Climate Models Evaluated Using Observations Over the Ice‐free Arctic Ocean
"The presence of clouds in the Arctic regulates the surface energy budget (SEB) over the sea‐ice surface and the ice‐free ocean. Following several previous field campaigns, the cloud‐radiation relationship, including cloud vertical structure and phase, has been elucidated; however, modeling of this relationship has matured slowly. In recognition of the recent decline in the Arctic sea‐ice extent, representation of the cloud system in numerical models should consider the effects of areas covered by sea ice and ice‐free areas. Using an in situ stationary meteorological observation[...]"
Source: AGU- Advancing Earth And Space Science
Authors: Jun Inoue et al.
Changing carbon-to-nitrogen ratios of organic-matter export under ocean acidification
"Ocean acidification (OA) will affect marine biotas from the organism to the ecosystem level. Yet, the consequences for the biological carbon pump and thereby the oceanic sink for atmospheric CO2 are still unclear. Here we show that OA considerably alters the C/N ratio of organic-matter export (C/Nexport), a key factor determining efficiency of the biological pump. By synthesizing sediment-trap data from in situ mesocosm studies in different marine biomes[...]
Source: Nature Climate Change
Authors: Jan Taucher et al.
Opposite response of strong and moderate positive Indian Ocean Dipole to global warming
"A strong positive Indian Ocean Dipole (pIOD) induces weather extremes such as the 2019 Australian bushfires and African floods. The impact is influenced by sea surface temperature (SST), yet models disagree on how pIOD SST may respond to greenhouse warming. Here we find increased SST variability of strong pIOD events, with strong equatorial eastern Indian Ocean cool anomalies, but decreased variability of moderate pIOD events, dominated by western warm anomalies[...]"
Source: Nature Climate Change
Authors: Wenju Cai et al.
Pelagic microplastics in surface water of the Eastern Indian Ocean during monsoon transition period: Abundance, distribution, and characteristics
"Microplastics (MPs) have been documented in almost all marine environments, including coastal regions, the open ocean, and the deep sea. However, relatively little knowledge was available about MP pollution in the open ocean, especially the Indian Ocean. We conducted field observations at 36 stations in the Eastern Indian Ocean (EIO), using a typical manta trawl with a mesh size of 330 μm for surface water sampling. Ours is the first study to obtained comprehensive and comparable baseline data about MPs in the EIO, including abundance, spatial distribution and characteristics[...]"
Source: Science Direct
Authors: Changjun Li et al.