Niche construction by non-diazotrophs for N2 fixers in the eastern tropical North Atlantic Ocean
"Diazotrophic dinitrogen (N2) fixation contributes ~76% to “new” nitrogen inputs to the sunlit open ocean, but environmental factors determining N2 fixation rates are not well constrained. Excess phosphate (phosphate–nitrate/16 > 0) and iron availability control N2 fixation rates in the eastern tropical North Atlantic (ETNA), but it remains an open question how excess phosphate is generated within or supplied to the phosphate-depleted sunlit layer. [...]"
Source: Geophysical Research Letters
Authors: Arvind Singh et al.
Historical records of coastal eutrophication-induced hypoxia
"Under certain conditions, sediment cores from coastal settings subject to hypoxia can yield records of environmental changes over time scales ranging from decades to millennia, sometimes with a resolution of as little as a few years. A variety of biological and geochemical indicators (proxies) derived from such cores have been used to reconstruct the development of eutrophication and hypoxic conditions over time. [...]"
Authors: A. J. Gooday et al.
U.N. Moved to Protect 60% of the Ocean and the World Hardly Noticed
"After years of talks, the U.N. has taken a major step toward an international treaty to preserve the biodiversity of the high seas to combat climate change, overfishing and plastic pollution.
[...] The move, which ended two weeks of sometimes contentious talks to hash out the major elements of the treaty, could result in far-reaching protections for marine life through the creation of reserves and other actions designed to blunt threats to ocean health from climate change, over-fishing and pollution. The high seas constitute the nearly 60 percent of the ocean beyond any nation’s jurisdiction. They play a crucial role in the global climate, food supply and economy, yet are largely beyond the reach of the law. [...]"
Biological nitrogen fixation in the oxygen-minimum region of the eastern tropical North Pacific ocean
"Biological nitrogen fixation (BNF) was investigated above and within the oxygen-depleted waters of the oxygen-minimum zone of the Eastern Tropical North Pacific Ocean. BNF rates were estimated using an isotope tracer method that overcame the uncertainty of the conventional bubble method by directly measuring the tracer enrichment during the incubations. Highest rates of BNF (~4 nM day−1) occurred in coastal surface waters and lowest detectable rates (~0.2 nM day−1) were found in the anoxic region of offshore stations. [...]"
Source: The ISME Journal
Authors: Amal Jayakuma et al.
Oceanic nitrogen cycling and N2O flux perturbations in the Anthropocene
"There is currently no consensus on how humans are affecting the marine nitrogen (N) cycle, which limits marine biological production and CO2 uptake. Anthropogenic changes in ocean warming, deoxygenation, and atmospheric N deposition can all individually affect the marine N cycle and the oceanic production of the greenhouse gas nitrous oxide (N2O). However, the combined effect of these perturbations on marine N cycling, ocean productivity, and marine N2O production is poorly understood. Here we use an Earth system model of intermediate complexity to investigate the combined effects of estimated 21st century CO2 atmospheric forcing and atmospheric N deposition. [...]"
Source: Global Biogeochemical Cycles
Authors: A. Landolfi, C. Somes, W. Koeve, L. M. Zamora, A. Oschlies
Influence of seaway changes during the Pliocene on tropical Pacific climate in the Kiel climate model
Mean state, annual cycle, ENSO, and their interactions
"The El Niño/Southern Oscillation (ENSO) is the leading mode of tropical Pacific interannual variability in the present-day climate. Available proxy evidence suggests that ENSO also existed during past climates, for example during the Pliocene extending from about 5.3 million to about 2.6 million years BP. Here we investigate the influences of the Panama Seaway closing and Indonesian Passages narrowing, and also of atmospheric carbon dioxide (CO2) on the tropical Pacific mean climate and annual cycle, and their combined impact on ENSO during the Pliocene. [...]"
Source: Climate Dynamics
Authors: Zhaoyang Song, Mojib Latif, Wonsun Park, Uta Krebs-Kanzow, Birgit Schneider
Deep-ocean dissolved organic matter reactivity along the Mediterranean Sea: does size matter?
"Despite of the major role ascribed to marine dissolved organic matter (DOM) in the global carbon cycle, the reactivity of this pool in the dark ocean is still poorly understood. Present hypotheses, posed within the size-reactivity continuum (SRC) and the microbial carbon pump (MCP) conceptual frameworks, need further empirical support. Here, we provide field evidence of the soundness of the SRC model. We sampled the high salinity core-of-flow of the Levantine Intermediate Water along its westward route through the entire Mediterranean Sea. At selected sites, DOM was size-fractionated in apparent high (aHMW) and low (aLMW) molecular weight fractions using an efficient ultrafiltration cell. [...]"
Source: Scientific Reports
Authors: Alba María Martínez-Pérez, Xosé Antón Álvarez-Salgado, Javier Arístegui & Mar Nieto-Cid
2018 Ocean Sciences Meeting
The 2018 Ocean Sciences Meeting will be held 11-16 February 2018 at the Oregon Convention Center, located at 777 NE Martin Luther King Jr Blvd, Portland, OR 97232. Cosponsored by AGU, ASLO, and TOS, the Ocean Sciences Meeting program will span a broad array of marine science topics.
Portland, Oregon’s largest city, sits on the Columbia and Willamette rivers, in the shadow of snow-capped Mount Hood. Portland is known for their eccentric locals, sophisticated yet cosmopolitan atmosphere and eco-friendly culture. It is the perfect venue for the 2018 Ocean Sciences Meeting.
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Start Date: 2/10/18
The PIRATA acronym, originally defined as “Pilot Research Moored Array in the Tropical Atlantic” in 1997, has been changed in 2008 to “Prediction and Research Moored Array in the Tropical Atlantic”. PIRATA is a multinational observation network, established to improve our knowledge and understanding of ocean-atmosphere variability in the tropical Atlantic. It is a joint project of Brazil, France and the United States of America. For more information, visit the main PIRATA web site, including data display and delivery.
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Start Date: 11/4/17
5th International Conference on Oceanography and Marine Biology
Theme: Contemporary challenges and innovative solutions for sustainable oceans
ConferenceSeries Ltd invites all the scholars from all over the world to attend and present their respective scientific research at ' 5th International Conference on Oceanography and Marine Biology October 18-20, 2017 Seoul, South Korea’ during October 18-20, 2017 Seoul, South Korea which includes prompt Keynote presentations, Oral talks, Poster presentations, Delegate views and Exhibitions.
Oceanography Congress is providing a global platform to discuss and learn about Marine Sciences, Marine Biology, Marine Geology, and Marine Oceanography, Marine ecology to exchange their knowledge, experience and research innovations. The aim of Marine Science Conferences is to create a platform for strong exchange of the recent advancement and technologies towards Marine Oceanography and Marine Biology.
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Start Date: 10/17/17