scholarly journals Revisiting the disappearance of terrestrial dissolved organic matter in the ocean: a <i>δ</i><sup>13</sup>C study

2013 ◽  
Vol 10 (11) ◽  
pp. 17117-17144
Author(s):  
K. Lalonde ◽  
A. V. Vähätalo ◽  
Y. Gélinas
Keyword(s):  
Organic Carbon ◽  
Solar Radiation ◽  
World Ocean ◽  
Photochemical Reactions ◽  
Aquatic Systems ◽  
Global Ocean ◽  
Coastal Oceans ◽  
The World ◽  
Radiation Induced ◽  
Simulated Solar Radiation

Abstract. Organic carbon (OC) depleted in 13C is a widely used tracer for terrestrial OM in aquatic systems. Photochemical reactions can however change δ13C of dissolved organic carbon (DOC) when chromophoric, aromatic-rich terrestrial OC is selectively mineralized. We assessed the robustness of the δ13C signature of DOC (δ13CDOC) as a tracer for terrestrial OM by estimating its change during the photobleaching of chromophoric DOM (CDOM) from ten large rivers. These rivers cumulatively account for approximately 1/3 of the world's freshwater discharge to the global ocean. Photobleaching of CDOM by simulated solar radiation was associated with the photochemical mineralization of 16 to 43% of the DOC and, by preferentially removing compounds depleted in 13C, caused a 1 to 2.9‰ enrichment in δ13C in the residual DOC. Such solar radiation-induced photochemical isotopic shift biases the calculations of terrestrial OM discharge in coastal oceans towards the marine end-member. Shifts in terrestrial δ13CDOC should be taken into account when constraining the terrestrial end-member in global calculation of terrestrially derived DOM in the world ocean.

scholarly journals Revisiting the disappearance of terrestrial dissolved organic matter in the ocean: a <i>δ</i><sup>13</sup>C study

2014 ◽  
Vol 11 (13) ◽  
pp. 3707-3719 ◽  
Author(s):  
K. Lalonde ◽  
A. V. Vähätalo ◽  
Y. Gélinas
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Solar Radiation ◽  
World Ocean ◽  
Photochemical Reactions ◽  
Global Ocean ◽  
Terrestrial Organic Matter ◽  
The World ◽  
Radiation Induced ◽  
Simulated Solar Radiation

Abstract. Organic carbon (OC) depleted in 13C is a widely used tracer for terrestrial organic matter (OM) in aquatic systems. Photochemical reactions can, however, change δ13C of dissolved organic carbon (DOC) when chromophoric, aromatic-rich terrestrial OC is selectively mineralized. We assessed the robustness of the δ13C signature of DOC (δ13CDOC) as a tracer for terrestrial OM by estimating its change during the photobleaching of chromophoric DOM (CDOM) from 10 large rivers. These rivers cumulatively account for approximately one-third of the world's freshwater discharge to the global ocean. Photobleaching of CDOM by simulated solar radiation was associated with the photochemical mineralization of 16 to 43% of the DOC and, by preferentially removing compounds depleted in 13C, caused a 1 to 2.9‰ enrichment in δ13C in the residual DOC. Such solar-radiation-induced photochemical isotopic shift could bias the calculations of terrestrial OM discharge in coastal oceans towards the marine end-member. Shifts in terrestrial δ13CDOC should be taken into account when constraining the terrestrial end-member in global calculation of terrestrially derived DOM in the world ocean.

Trends in phytoplankton communities within large marine ecosystems diverge from the global ocean

2021 ◽  
pp. 1-12
Author(s):  
Kevin D. Friedland ◽  
John R. Moisan ◽  
Aurore A. Maureaud ◽  
Damian C. Brady ◽  
Andrew J. Davies ◽  
...  
Keyword(s):  
Chlorophyll Concentration ◽  
World Ocean ◽  
Marine Ecosystems ◽  
Fishing Effort ◽  
Global Ocean ◽  
Human Populations ◽  
Anthropogenic Pressures ◽  
Large Marine Ecosystems ◽  
Phytoplankton Communities ◽  
The World

Large marine ecosystems (LMEs) are highly productive regions of the world ocean under anthropogenic pressures; we analyzed trends in sea surface temperature (SST), cloud fraction (CF), and chlorophyll concentration (CHL) over the period 1998–2019. Trends in these parameters within LMEs diverged from the world ocean. SST and CF inside LMEs increased at greater rates inside LMEs, whereas CHL decreased at a greater rates. CHL declined in 86% of all LMEs and of those trends, 70% were statistically significant. Complementary analyses suggest phytoplankton functional types within LMEs have also diverged from those characteristic of the world ocean, most notably, the contribution of diatoms and dinoflagellates, which have declined within LMEs. LMEs appear to be warming rapidly and receiving less solar radiation than the world ocean, which may be contributing to changes at the base of the food chain. Despite increased fishing effort, fishery yields in LMEs have not increased, pointing to limitations related to productivity. These changes raise concerns over the stability of these ecosystems and their continued ability to support services to human populations.

Part V Regional Perspectives on Global Ocean Governance, 16 The Role of the World Ocean Council and the Ocean Business Community in Global Ocean Governance

2018 ◽  
Author(s):  
Holthus Paul
Keyword(s):  
Sustainable Development Goals ◽  
World Ocean ◽  
Institutional Development ◽  
Business Community ◽  
Global Ocean ◽  
The Sustainable Development ◽  
Ocean Governance ◽  
The World ◽  
Development Goals

This chapter discusses the role of the World Ocean Council (WOC) and the international ocean business community in global ocean governance (GOG). It first provides an overview of the institutional development and profile of the WOC before considering the work and role and work of the WOC on ocean governance with and for the ocean business community. It then examines the Sustainable Development Goals (SDGs) in relation to ocean business and the WOC, as well as the size, complexity trends in the ocean economy and ocean business community, which are fundamental to understanding their importance to GOG. It also analyses GOG issues relevant to the ocean business community and WOC that the United Nations and its associated bodies must address and concludes with an assessment of the role of the ocean business community and WOC in the future of the GOG agenda.

The influence of DEM resolution on simulated solar radiation-induced glacier melt

2010 ◽  
Vol 24 (6) ◽  
pp. 775-788 ◽  
Author(s):  
Chris Hopkinson ◽  
Laura Chasmer ◽  
Scott Munro ◽  
Michael N. Demuth
Keyword(s):  
Solar Radiation ◽  
Dem Resolution ◽  
Glacier Melt ◽  
Radiation Induced ◽  
Simulated Solar Radiation

scholarly journals An algorithm for estimating Absolute Salinity in the global ocean

2009 ◽  
Vol 6 (1) ◽  
pp. 215-242 ◽  
Author(s):  
T. J. McDougall ◽  
D. R. Jackett ◽  
F. J. Millero
Keyword(s):  
Sea Water ◽  
World Ocean ◽  
Seawater Sample ◽  
Global Ocean ◽  
Data Set ◽  
Correlation Relationship ◽  
Salinity Anomaly ◽  
The World ◽  
Standard Composition ◽  
The Absolute

Abstract. To date, density and other thermodynamic properties of seawater have been calculated from Practical Salinity, S P. It is more accurate however to use Absolute Salinity, S A (the mass fraction of dissolved material in seawater). Absolute Salinity S A can be expressed in terms of Practical Salinity S P as S A=(35.165 04 g kg-1/35)S P+δ S A(φ, λ, p) where δ S A is the Absolute Salinity Anomaly as a function of longitude φ, latitude λ and pressure. When a seawater sample has standard composition (i.e. the ratios of the constituents of sea salt are the same as those of surface water of the North Atlantic), the Absolute Salinity Anomaly is zero. When seawater is not of standard composition, the Absolute Salinity Anomaly needs to be estimated; this anomaly is as large as 0.025 g kg−1 in the northernmost North Pacific. Here we provide an algorithm for estimating Absolute Salinity Anomaly for any location (φ, λ, p) in the world ocean. To develop this algorithm we use the Absolute Salinity Anomaly that is found by comparing the density calculated from Practical Salinity to the density measured in the laboratory. These estimates of Absolute Salinity Anomaly however are limited to the number of available observations (namely 811). To expand our data set we take advantage of approximate relationships between Absolute Salinity Anomaly and silicate concentrations (which are available globally). We approximate the laboratory-determined values of δ S A of the 811 seawater samples as a series of simple functions of the silicate concentration of the seawater sample and latitude; one function for each ocean basin. We use these basin-specific correlations and a digital atlas of silicate in the world ocean to deduce the Absolute Salinity Anomaly globally and this is stored as an atlas, δ S A (φ, λ, p). This atlas can be interpolated to the latitude, longitude and pressure of a seawater sample to estimate its Absolute Salinity Anomaly. For the 811 samples studied, ignoring the Absolute Salinity Anomaly results in a standard error in S A of 0.0107 g kg-1. Using our algorithm for δ S A reduces the error to 0.0048 g kg−1, reducing the mean square error by a factor of five. The number of sea water samples used to develop the correlation relationship is limited, and we hope that the algorithm and error can be improved as further data becomes available.

scholarly journals An Assessment of Orthobaric Density in the Global Ocean

2005 ◽  
Vol 35 (11) ◽  
pp. 2054-2075 ◽  
Author(s):  
Trevor J. McDougall ◽  
David R. Jackett
Keyword(s):  
Southern Hemisphere ◽  
World Ocean ◽  
Ocean Basin ◽  
Ocean Modeling ◽  
Global Ocean ◽  
Potential Density ◽  
Vertical Coordinate ◽  
The World ◽  
Density Surface

Abstract Orthobaric density has recently been advanced as a new density variable for displaying ocean data and as a coordinate for ocean modeling. Here the extent to which orthobaric density surfaces are neutral is quantified and it is found that orthobaric density surfaces are less neutral in the World Ocean than are potential density surfaces referenced to 2000 dbar. Another property that is important for a vertical coordinate of a layered model is the quasi-material nature of the coordinate and it is shown that orthobaric density surfaces are significantly non-quasi-material. These limitations of orthobaric density arise because of its inability to accurately accommodate differences between water masses at fixed values of pressure and in situ density such as occur between the Northern and Southern Hemisphere portions of the World Ocean. It is shown that special forms of orthobaric density can be quite accurate if they are formed for an individual ocean basin and used only in that basin. While orthobaric density can be made to be approximately neutral in a single ocean basin, this is not possible in both the Northern and Southern Hemisphere portions of the Atlantic Ocean. While the helical nature of neutral trajectories (equivalently, the ill-defined nature of neutral surfaces) limits the neutrality of all types of density surface, the inability of orthobaric density surfaces to accurately accommodate more than one ocean basin is a much greater limitation.

scholarly journals Air-to-sea flux of soluble iron: is it driven more by HNO<sub>3</sub> or SO<sub>2</sub>? – an examination in the light of dust aging

2007 ◽  
Vol 7 (4) ◽  
pp. 10043-10063 ◽  
Author(s):  
H. Yang ◽  
Y. Gao
Keyword(s):  
Atmospheric Chemistry ◽  
Transport Model ◽  
World Ocean ◽  
Global Ocean ◽  
Relative Role ◽  
Chemistry Transport Model ◽  
Acidic Gases ◽  
Relative Contribution ◽  
The World

Abstract. Aeolian dust provides the major micronutrient of soluble Fe to organisms in certain regions of the global ocean. In this study, we conduct numerical experiments using the MOZART-2 atmospheric chemistry transport model to simulate the global distribution of soluble Fe flux and Fe solubility. One of the mechanisms behind the hypothesis of acid mobilization of Fe in the atmosphere is that the coating of acidic gases changes dust from hydrophobic to hydrophilic, a prerequisite of Fe mobilization. We therefore include HNO3, SO2 and sulfate (SO42−) as dust transformation agents in the model. General agreement in Fe solubility within a factor of 2 is achieved between model and observations. The total flux of soluble Fe to the world ocean is estimated to be 731–924×109 g yr−1, and the average Fe solubility is 6.4–8.0%. Wet deposition contributes over 80% to total soluble Fe flux to most of the world oceans. Special attention is paid to the relative role of HNO3 versus SO2 and sulfate. We demonstrate that coating by HNO3 produces over 36% of soluble Fe fluxes compared to that by SO2 and sulfate combined in every major oceanic basin. Given present trends in the emissions of NOx and SO2, the relative contribution of HNO3 to Fe mobilization may get even larger in the future.

scholarly journals POTENTIALITY OF MULTI-MODULAR TRANSFORMER WATERCRAFTS FOR OCEAN EXPLORATION

2020 ◽  
Vol 17 (5) ◽  
pp. 114-128
Author(s):  
N. N. Ostroukhov ◽  
E. V. Chumakova
Keyword(s):  
World Ocean ◽  
Characteristic Size ◽  
Water Area ◽  
Continuous Operation ◽  
Global Ocean ◽  
New Class ◽  
Floating Base ◽  
Production Processes ◽  
The World

The multi-modular transformer watercrafts based on modules with vortex engines might represent a new class of watercrafts significantly expanding the range of achievable parameters in production processes carried out in the World Ocean. Composed of modules of the same type and capable of functioning autonomously with vortex propulsion devices, they can, firstly, be assembled to sizes and shapes that are not accessible to modern vessels of traditional design, and secondly, if necessary, they will not have limitations in terms of independent operation, so their properties are similar to artificial islands in any given water area of the Global Ocean, while possessing mobility.The objective of this paper is to assess the prospects for the use of multi-modular transformer watercrafts as carriers of technological systems for scientific and production processes carried out in the World Ocean.Models of application of multi-modular transformer watercrafts with vortex propulsion are suggested for their autonomous year-round continuous operation in given non-freezing waters. To assess the effectiveness of the use of the proposed transformer watercrafts, a simulation of their operation was carried out, as well as a direct comparison of their specifications with traditional vessels that support operation of scientific and production complexes in the World Ocean. For comparison, the currently known marine complexes are selected that require long-term continuous operation (fish canning floating base; a floating complex for extraction and production of liquefied natural gas).The paper shows that, in relation to all the considered processes, the proposed multi-modular transformer watercrafts have at least two advantages. Firstly, they make it possible to realize continuous and long-term (determined by direct wear of the main module) functioning of the complex, and secondly, with autonomous functioning of individual modules, the zone of action of the complex as a whole is an area with a characteristic size of hundreds of miles. 

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