Primary Production Export Research Articles

Influence of Mini Warm Pool Extent on Phytoplankton Productivity and Export in the Arabian Sea

The Arabian Sea is a highly productive tropical ecosystem of the Indian Ocean that supports high fluxes of particulate organic carbon to the mesopelagic zone from two distinct periods of elevated biological productivity associated with the semiannual reversals of the monsoonal wind system. There are now strong indications that the Arabian Sea’s monsoonal wind patterns and hydrographic conditions are being impacted by long-term temperature increases, but the consequences of these changes on primary production and carbon export to the mesopelagic zone are unknown. This is especially true for the summer monsoon period when cloud cover obscures much of the Arabian Sea basin and therefore precludes remotely sensed ocean color measurements for estimating phytoplankton biomass and productivity. Here we overcome this limitation by using a database of bio-optical profiles from Biogeochemical Argo floats collected over the last decade to evaluate the impact of interannual temperature increases on Arabian Sea primary production and carbon export. We classify individual years of float observations based on the spatial extent of the Arabian Sea Mini Warm Pool that appears in the southeast Arabian Sea before the onset of the summer monsoon. This mini warm pool, which begins to build in winter and collapses with the onset of the summer monsoon in late spring, has gained considerable interest on account of its influence on the timing of the onset of the summer monsoon. We observed a 35 percent decrease in primary production during the summer monsoon phytoplankton bloom in strong warm pool years, and a 13 percent decrease in particle stocks in the upper mesopelagic zone following the peak of the bloom. Decreases in production and export were additionally accompanied by a decrease in average particle size, indicating a shift from larger cells like diatoms that appear from fertilization of the oligotrophic waters to smaller phytoplankton size classes in response to a deepening of the thermocline and increased stratification of the water column. These results suggest changes in phytoplankton community structure and further decreases in primary production and carbon export in the Arabian Sea in response to future warming.

A Lagrangian Model‐Based Analysis of Protist Plankton Variability and Its Impact on Organic Matter Dynamics Along Transit Pathways Through the Fram Strait

AbstractThe Arctic Ocean is characterized by substantial seasonal and inter‐annual variability, of which the sources and impacts are not yet fully understood. Here, we analyze how much of the variability found in in situ observations of biogeochemical and ecological variables collected at the Long‐Term Ecological Research Observatory HAUSGARTEN can be explained by differences in the physical conditions in the water masses passing through the Fram Strait (FS). Employing a size‐based plankton ecosystem model with nine distinct size classes of protist phyto‐ and zooplankton, we simulate standing stocks and fluxes within the nutrient, phytoplankton, zooplankton, and detritus pools in water parcels that follow trajectories tracing the opposing East‐Greenland and West‐Spitsbergen currents through the FS. Our model results agree with in situ observations of biogeochemical tracers, plankton size measurements, climatological data, and remote sensing observations. They show distinct temporal developments in plankton size composition, growth, and export in trajectory ensembles, highlighting how variable physical conditions affect the communities' specific growth histories. Our study indicates that 10%–72% of the variability in upper water column tracer concentrations observed in the FS can be attributed to differences in water parcel trajectories. The maxima of net primary production and vertical export along the trajectories occurred in some (spatial and temporal) distance upstream of the sites of in situ sampling. This study shows that Lagrangian modeling helps clarify complex biogeochemical‐ecological relationships in highly dynamic systems such as the FS, which is urgently needed to understand the role of climate change in the Arctic carbon cycle.

Performance of two semi-analytical algorithms in deriving water inherent optical properties in the Southern Ocean

Remotely sensed inherent optical properties (IOPs) are key proxies for synoptic mapping of primary production and carbon export in the global ocean. However, the IOPs inversion algorithms are scarcely evaluated in the Southern Ocean (SO) because of limited field observations. In this study, the performance of two widely used semi-analytical algorithms (SAAs), i.e., the quasi-analytical algorithm (QAA) and the generalized IOP model (GIOP), were evaluated using a compiled in situ bio-optical dataset in SO, as well as measurements from the Visible Infrared Imaging Radiometer Suite (VIIRS). Evaluations with in situ data show that QAA and GIOP have comparable performance in retrieving the total absorption coefficient (a(λ)), absorption coefficients of phytoplankton (aph(λ)), and that of detritus and colored dissolved organic matter (adg(λ)). Overall, it was found that remotely sensed a(λ) and aph(λ) by both SAAs agreed well with field measurements, with the mean absolute percentage difference (MAPD) of derived a(λ) and aph(λ) in the blue-green bands being ∼20% and ∼40%, respectively. However, derived adg(λ) by both SAAs were higher than the measured values at the lower end (adg(443) < ∼0.01 m-1), but lower at the higher end (adg(443) > ∼0.02 m-1), with MAPD of ∼60%. Results of this effort suggest confident products of a(λ) and aph(λ) from VIIRS in SO, but more dedicated efforts on the measurements and evaluation of adg(λ) in SO would be desired.

Tracing China's virtual water trade in global value chain: Participation, characteristics, and inequality

The disclosure of global value chain (GVC) division and cooperation is essential for the rational allocation of water resources and the achievement of trade equality, particularly as the global division of labor becomes more pronounced. Currently, there are limited studies on the global value chain at the sub-national level, with most focusing on virtual water trade (VWT) characteristics between two trading partners, without integrating VWT into the global value chain and overlooking significant cooperation among participants. Here, we characterize the international division of GVC and VWT patterns covering 194 regions (31 regions in China and 163 countries) around the world in 2020, and then examine the inequality between virtual water (VW) and value-added (VA) transfer from both environmental and economic perspectives, focusing on the sub-national scale of China. Our results show that in terms of water consumption responsibilities, considerable heterogeneity can be seen in different regions across China. Furthermore, relying solely on the export of primary products for economic development will lead to inequality in trade between countries. In this study, we trace the characteristics of VWT, taking into account the participation and contribution of regions in numerous GVC linkages. In addition, to make our policy implications more targeted, we refine the study resolution to the sub-national scale. Our results suggest that countries should prioritize consumer responsibility in GVC, reduce the drawbacks of trade barriers, and dispassionately exploit the economic and environmental advantages of water resources.

Ocean Biogeochemical Fingerprints of Fast‐Sinking Tunicate and Fish Detritus

AbstractPelagic tunicates (salps, pyrosomes) and fishes generate jelly falls and/or fecal pellets that sink roughly 10 times faster than bulk oceanic detritus, but their impacts on biogeochemical cycles in the ocean interior are poorly understood. Using a coupled physical‐biogeochemical model, we find that fast‐sinking detritus decreased global net primary production and surface export, but increased deep sequestration and transfer efficiency in much of the extratropics and upwelling zones. Fast‐sinking detritus generally decreased total suboxic and hypoxic volumes, reducing a “large oxygen minimum zone (OMZ)” bias common in global biogeochemical models. Newly aerobic regions at OMZ edges exhibited reduced transfer efficiencies in contrast with global tendencies. Reductions in water column denitrification resulting from improved OMZs improved simulated nitrate deficits relative to phosphate. The carbon flux to the benthos increased by 11% with fast‐sinking detritus from fishes and pelagic tunicates, yet simulated benthic fluxes remained on the lower end of observation‐based estimates.

Sensitivity of the thermohaline circulation during the Messinian: Toward constraining the dynamics of Mediterranean deoxygenation

During the Messinian, the sensitivity of the Mediterranean Basin to ecosystem perturbation was enhanced in response to the progressive restriction of water exchange with the Atlantic Ocean. The widespread deposition of organic-rich layers (i.e. sapropel) during the Messinian testifies the perturbation of the carbon and oxygen cycles; indeed, these sediments were deposited under conditions of oxygen starvation, presumably in response to a periodic deterioration of the thermohaline circulation strength. Disentangling the causes, the effect and magnitude of the thermohaline circulation weakening during the geological past is crucial for better constraining present and near-future deoxygenation dynamics in the Mediterranean region under the current climate warming. For this purpose, we investigate a Messinian sapropel-bearing succession cropping out at Monte dei Corvi (Ancona, central Italy) with mineralogical, petrographic, micropaleontological and stable Carbon and Oxygen isotopic analyses. We show that sapropel layers were deposited in response to an increase of the sea surface buoyancy, which hampered the thermohaline circulation and thus the oxygenation of bottom water, in turn affecting the bioturbating organisms. Within the lithological cycle, the recovery of an efficient thermohaline circulation is recorded by thin packstone layers underlying the marly limestone/marlstone, which record intense bottom currents. The marly limestone/marlstone accumulated during periods of intense primary productivity and organic carbon export to the sea bottom, which promoted bottom hypoxia but not organic matter preservation. We infer that these lithological changes resulted from variations in the Adriatic Deep Water formation system, controlled by precession-driven climatic and oceanographic changes.By integrating previously published Sea Surface Temperature (SST) with new isotopic and mineralogical data, we show that variations in Sea Surface Salinity (SSS) were the leading factor controlling sapropel deposition, minimizing the role of primary productivity. The SSTs characterizing the sapropel deposits are close to the range of those projected in the Eastern Mediterranean at the end of this century under climate warming. In this scenario, future warming will be coupled with SSS increase, which will counteract the density loss provided by temperature, making the bottom deoxygenation in the Eastern Mediterranean abysses unlikely. However, additional forcing, such as winter heat waves and eutrophication, could contribute to negatively affecting the Mediterranean oxygen balance and should be considered in model-based projections.

A Gulf Stream frontal eddy harbors a distinct microbiome compared to adjacent waters.

Mesoscale oceanographic features, including eddies, have the potential to alter productivity and other biogeochemical rates in the ocean. Here, we examine the microbiome of a cyclonic, Gulf Stream frontal eddy, with a distinct origin and environmental parameters compared to surrounding waters, in order to better understand the processes dominating microbial community assembly in the dynamic coastal ocean. Our microbiome-based approach identified the eddy as distinct from the surround Gulf Stream waters. The eddy-associated microbial community occupied a larger area than identified by temperature and salinity alone, increasing the predicted extent of eddy-associated biogeochemical processes. While the eddy formed on the continental shelf, after two weeks both environmental parameters and microbiome composition of the eddy were most similar to the Gulf Stream, suggesting the effect of environmental filtering on community assembly or physical mixing with adjacent Gulf Stream waters. In spite of the potential for eddy-driven upwelling to introduce nutrients and stimulate primary production, eddy surface waters exhibit lower chlorophyll a along with a distinct and less even microbial community, compared to the Gulf Stream. At the population level, the eddy microbiome exhibited differences among the cyanobacteria (e.g. lower Trichodesmium and higher Prochlorococcus) and in the heterotrophic alpha Proteobacteria (e.g. lower relative abundances of specific SAR11 phylotypes) versus the Gulf Stream. However, better delineation of the relative roles of processes driving eddy community assembly will likely require following the eddy and surrounding waters since inception. Additionally, sampling throughout the water column could better clarify the contribution of these mesoscale features to primary production and carbon export in the oceans.

Response of oceanic subsurface chlorophyll maxima to environmental drivers in the Northern Indian Ocean

Subsurface Chlorophyll Maxima (SCM) contributes a significant proportion to depth-integrated ocean primary production, making it important to understand its spatiotemporal variability in changing environmental conditions. Based on field observations and in situ data, we studied SCM characteristics in four distinct environmental settings across Northern Indian Ocean: SEAS-south eastern Arabian Sea (coastal upwelling zone), SAS-Southern Arabian Sea (Arabian Sea mini warm pool-ASMWP), SBOB-Southern Bay of Bengal (presence of mesoscale eddies) and ANS-Andaman Sea (region of active volcanoes). SCM displayed significant spatial variability: ZSCM (SCM depth) ranged between 25 and 88 m (mean = 59.5 m), Chlmax (SCM magnitude) ranged between 0.07 and 0.2 mg m−3 (mean = 0.12 mg m−3) while TSCM (SCM thickness) ranged between 33 and 100 m (mean = 69 m). Major factors affecting the ZSCM were light and nutrients, since ZSCM was closely related to Zeu (euphotic depth) and ZN (nitracline depth). Positive relation between Chlmax and micro phytoplankton suggests micro phytoplankton to be a major contributor in increasing Chlmax. TSCM was associated to ZT (thermocline depth) and nutrient concentration. Increase in stratification and oligotrophy, resulted in deeper, thicker peaks of lower magnitude, and such nature of peaks could increase in continued warming scenarios. Dinoflagellates increased in warmer oligotrophic environments. Nanophytoplankton were higher at deeper ZSCM, possibly due to their adaptability to low light. Upwelling caused shoaling of SCM with higher Chlmax in SEAS. SCM deepened in SAS and SBOB, dominated by picophytoplankton due to the influence of ASMWP (in SAS) and anticyclonic eddy (in SBOB). Ammonia and nutrient inputs from submarine vents in ANS, caused shoaling of ZN and ZSCM. Globally, multiple physical processes operate at short spatiotemporal scale, causing SCM variability, and the same should not be overlooked while estimating primary production or carbon export to deep ocean, through generalisations established at larger scale in the world ocean.

Effect of an Open Central American Seaway on Ocean Circulation and the Oxygen Minimum Zone in the Tropical Pacific From Model Simulations

AbstractThe tectonic closure of the Central American Seaway (CAS) during the mid‐Miocene to mid‐Pliocene (∼16–3 Ma BP) is thought of as a key interval for the onset of the present‐day tropical Pacific oxygen minimum zone (OMZ). In this study we investigate the impact of an open CAS on the ocean circulation and the OMZ in the tropical Pacific. We perform a series of sensitivity experiments with the Kiel Climate Model, where we vary the CAS sill depth from shallow to deep. We find that the eastern tropical Pacific OMZ was less developed during the period of an open CAS. This is driven mainly by an enhanced eastward subsurface current that facilitated an increased oxygen supply from the western tropical Pacific. In addition, a small decrease in net marine primary production and subsequent weaker export of particulate organic carbon induced less subsurface oxygen consumption in the Eastern Equatorial Pacific.

Synechococcus nitrogen gene loss in iron-limited ocean regions

Synechococcus are the most abundant cyanobacteria in high latitude regions and are responsible for an estimated 17% of annual marine net primary productivity. Despite their biogeochemical importance, Synechococcus populations have been unevenly sampled across the ocean, with most studies focused on low-latitude strains. In particular, the near absence of Synechococcus genomes from high-latitude, High Nutrient Low Chlorophyll (HNLC) regions leaves a gap in our knowledge of picocyanobacterial adaptations to iron limitation and their influence on carbon, nitrogen, and iron cycles. We examined Synechococcus populations from the subarctic North Pacific, a well-characterized HNLC region, with quantitative metagenomics. Assembly with short and long reads produced two near complete Synechococcus metagenome-assembled genomes (MAGs). Quantitative metagenome-derived abundances of these populations matched well with flow cytometry counts, and the Synechococcus MAGs were estimated to comprise >99% of the Synechococcus at Station P. Whereas the Station P Synechococcus MAGs contained multiple genes for adaptation to iron limitation, both genomes lacked genes for uptake and assimilation of nitrate and nitrite, suggesting a dependence on ammonium, urea, and other forms of recycled nitrogen leading to reduced iron requirements. A global analysis of Synechococcus nitrate reductase abundance in the TARA Oceans dataset found nitrate assimilation genes are also lower in other HNLC regions. We propose that nitrate and nitrite assimilation gene loss in Synechococcus may represent an adaptation to severe iron limitation in high-latitude regions where ammonium availability is higher. Our findings have implications for models that quantify the contribution of cyanobacteria to primary production and subsequent carbon export.

Iron and manganese availability drives primary production and carbon export in the Weddell Sea

Next to iron (Fe), recent phytoplankton-enrichment experiments identified manganese (Mn) to (co-)limit Southern Ocean phytoplankton biomass and species composition. Since taxonomic diversity affects aggregation time and sinking rate, the efficiency of the biological carbon pump is directly affected by community structure. However, the impact of FeMn co-limitation on Antarctic primary production, community composition, and the subsequent export of carbon to depth requires more investigation. In situ samplings of 6 stations in the understudied southern Weddell Sea revealed that surface Fe and Mn concentrations, primary production, and carbon export rates were all low, suggesting a FeMn co-limited phytoplankton community. An Fe and Mn addition experiment examined how changes in the species composition drive the aggregation capability of a natural phytoplankton community. Primary production rates were highest when Fe and Mn were added together, due to an increased abundance of the colonial prymnesiophyte Phaeocystis antarctica. Although the community remained diatom dominated, the increase in Phaeocystis abundance led to highly carbon-enriched aggregates and a 4-fold increase in the carbon export potential compared to the control, whereas it only doubled in the Fe treatment. Based on the outcome of the FeMn-enrichment experiment, this region may suffer from FeMn co-limitation. As the Weddell Sea represents one of the most productive Antarctic marginal ice zones, our findings highlight that in response to greater Fe and Mn supply, changes in plankton community composition and primary production can have a disproportionally larger effect on the carbon export potential.

Evolution pattern of African countries' oil trade under the changing in the global oil market

Africa's oil trade plays a vital role in the global oil market, but it is more vulnerable compared to other regions due to its resource dependency. This study examines the evolution of African countries' oil trade in the context of the changing global oil market, aiming to shed light on the characteristics of resource-dependent oil trade in these areas. By utilizing global oil trade data, an oil trade network of African countries is constructed for the period from 2000 to 2020. The findings reveal that the comparative advantages of most African countries are primarily determined by their abundant resources, with the Gulf of Guinea and North Africa exhibiting greater revealed comparative advantages. However, the over-reliance on primary product exports leaves African countries susceptible to unpredictable changes in the global oil market. Furthermore, due to their single industrial structure, the control over resource flows within the trade network is significantly low for African oil-producing nations. The oil trade of African countries has formed distinct trade communities, including the Gulf of Guinea and North America, North Africa and European countries, and Angola, Sudan, and East Asian countries. These communities exhibit relative independence and self-reinforcement, influenced by factors such as the timing of market entry, international economic trends, energy demand and transformations in consumer countries, and geopolitical risks.

Noxious deindustrialisation and extractivism: Quintero-Puchuncaví in the international division of labour and noxiousness

ABSTRACT This article examines the paradox of ‘noxious deindustrialisation’ – employment deindustrialisation in areas where significantly noxious industries are still operating – in the context of an extractivist economy in the Global South. Analysing the copper-centred industrial area of Quintero-Puchuncaví (Chile), we argue that a key element shaping patterns of local noxious deindustrialisation is the mode of insertion of the affected area in the international division of labour and noxiousness. The latter refers to the global socioecological hierarchy constituted by interconnected differentials in technological capabilities, wage levels, and environmental degradation. In countries marked by extractivism, the simple closure of polluting industries deepens the dependence of their economies on rent-bearing primary product exports, while the permanence of such industries often results in the perpetuation of ‘sacrifice zones’, where communities are exposed to severe noxiousness while receiving only meagre benefits in return. In our view, tackling the ecological crisis requires a more balanced international division of labour, as a step towards decommodifying production and nature. Without transformations in this direction, the current attempts at an energy transition risk provoking an unsustainable deepening of extractivism and inequality.

Biodiversity and Stoichiometric Plasticity Increase Pico‐Phytoplankton Contributions to Marine Net Primary Productivity and the Biological Pump

AbstractEarth System Models generally predict increasing upper ocean stratification from 21st century warming, which will cause a decrease in the vertical nutrient flux forcing declines in marine net primary productivity (NPP) and carbon export. Recent advances in quantifying marine ecosystem carbon to nutrient stoichiometry have identified large latitudinal and biome variability, with low‐latitude oligotrophic systems harboring pico‐sized phytoplankton exhibiting large phosphorus to carbon cellular plasticity. The climate forced changes in nutrient flux stoichiometry and phytoplankton community composition are thus likely to alter the ocean's biogeochemical response and feedback with the carbon‐climate system. We have added three pico‐phytoplankton functional types within the Biogeochemical Elemental Cycling component of the Community Earth System Model while incorporating variable cellular phosphorus to carbon stoichiometry for all represented phytoplankton types. The model simulates Prochlorococcus and Synechococcus populations that dominate the productivity and sinking carbon export of the tropical and subtropical ocean, and pico‐eukaryote populations that contribute significantly to productivity and export within the subtropical to mid‐latitude transition zone, with the western subtropical regions of each basin supporting the most P‐poor stoichiometries. Subtropical gyre recirculation regions along the poleward flanks of surface western boundary currents are identified as regional hotspots of enhanced carbon export exhibiting C‐rich/P‐poor stoichiometry, preferentially inhabited by pico‐eukaryotes and diatoms. Collectively, pico‐phytoplankton contribute ∼58% of global NPP and ∼46% of global particulate organic carbon export below 100 m through direct and ecosystem processing pathways. Biodiversity and cellular nutrient plasticity in marine pico‐phytoplankton combine to increase their contributions to ocean productivity and the biological carbon pump.

Poverty – A Direct Threat to Global Environmental Degradation

The paper highlights that poverty has been a source of a severe threat to global environment. The earth is one but the world is not. For sustainable livelihood of human being, man is destroying the nature, without replacing it any more. Further, high mass of consumption had added fuel to fire. Certainly, majority of the populations in developing economies living within them, depend directly on natural resources. For many of these economies, primary product exports account for the vast majority of their export earnings, and one or two primary commodities make up the bulk of exports. Agricultural value added accounts for an average of 40 per cent GDP, and nearly 80 per cent of the labor force is engaged in agricultural or resources-based activities.For a sample of 76 developing economies from Africa, Asia and Latin America, the incidence of rural poverty rises as developing countries have more of their populations concentrated on fragile lands. Although the average poverty rate across all economies is 45.8 per cent, the rate falls 36.8 per cent for those countries with less than 20 per cent of their population in fragile environments. Much of developing economies are depending on natural resources. The incidence of poverty rises in these economies has been formed with population, whose livelihoods are concentrated on fragile lands. Generally, poor people are forced to overuse environmental resources. In India also all major rivers turned into polluted, one-third forest degraded into one-sixth. Too much logging, turned into loss of flora and fauna. Global countries realised that natural resources are limited, so that we have revive it by reducing population size, rejuvenation of land, reducing pollutions and support for regeneration of natural resources. Protection and promotion of environment is found as a need of the hour. Sustainable development is not as easy as we said. Renewal, recycle, reuse, reduce of resources are to be used regularly for ever green globe. Natural resources accounting, budgeting, management are to be made popular. So that poor can be elevated. Encouragement of political party on environment is badly needed.

Strong particle dynamics counteract the nutrient-pumping effect leading to weak carbon flux in a cyclonic eddy

Sinking particles play a crucial role in transferring carbon from the atmosphere to the deep ocean. However, due to intensive particle transformations such as aggregation, disaggregation, and remineralization, only a small portion of the organic carbon produced in the euphotic zone ends up being sequestered in the deep ocean or sediment. Mesoscale eddies can significantly impact the surface ocean nutrient budget, primary production, and carbon export. Despite this, there is still a lack of research on how particle dynamics in eddy-impacted regions affect the efficiency of carbon export. In this study, we used observations of thorium isotopes (234Th and 228Th) and particulate organic carbon (POC) at two stations in the South China Sea (TS1: a decaying-eddy-impacted station and SEATS: an oligotrophic station) and an inverse model to investigate the impact of particle dynamics on particle export efficiency. Our findings indicate that particle remineralization/fragmentation was enhanced inside the eddy, which counteracted the nutrient pumping effect that promotes surface ocean productivity and eventually led to even lower carbon flux compared to the oligotrophic station.

The Impact of Fine-Scale Currents on Biogeochemical Cycles in a Changing Ocean.

Fine-scale currents, O(1-100 km, days-months), are actively involved in the transport and transformation of biogeochemical tracers in the ocean. However, their overall impact on large-scale biogeochemical cycling on the timescale of years remains poorly understood due to the multiscale nature of the problem. Here, we summarize these impacts and critically review current estimates. We examine how eddy fluxes and upscale connections enter into the large-scale balance of biogeochemical tracers. We show that the overall contribution of eddy fluxes to primary production and carbon export may not be as large as it is for oxygen ventilation. We highlight the importance of fine scales to low-frequency natural variability through upscale connections and show that they may also buffer the negative effects of climate change on the functioning of biogeochemical cycles. Significant interdisciplinary efforts are needed to properly account for the cross-scale effects of fine scales on biogeochemical cycles in climate projections.

Which industrial path contributed to CO2 transfer and emissions slowing-down of China and the United States most in international trade?

Carbon transfer in international trade has triggered disputes on environmental equity between developed and developing countries. Hence, it is urgent to make it clear the carbon transfer process of international trade between China and the United States, explore the adjustment plan of emission reduction responsibility and formulate targeted emission reduction measures. These will play an important leading and demonstration effect in addressing global warming and coordinating international carbon reduction. This study built a CO2 international trade transfer network model of China and the United States. Based on identifying the carbon transfer path flowing from primary product sector to final production sector, and then to final consumption, we analyzed the industrial association relationship and distribution differences between China and the United States with external countries and regions. Lastly, we put forward emission reduction policy implication in industrial scale. The key paths of China and the United States are concentrated in the two export and import transfer types respectively. Among the key paths of China's bilateral primary production export type, paths from domestic Electricity, Gas and Water to foreign Construction accounted for the largest 40% share. As for the United States, transfer type of bilateral final production import is the most prominent, and path number and flow from foreign Transport to domestic Public Administration both accounted for more than 30%. Based on shared responsibility to adjust the emission reduction tasks under the Paris Agreement, China and the US will allow to emit 10% more and reduce 6% more, reaching 54% and 25% respectively. Taking into full consideration the national economic development level and the differences in the production technology level of industrial sectors, as well as the upstream and downstream related sectors' relationship, the refined emission reduction strategy is proposed from different aspects, such as technical assistance, financial support, import control, technology sharing and consumption transformation.

Diplomacy among Nations: The Case Study of Malaysia and Nigeria

Nigeria and Malaysia have a shared historical background. Both countries were free of British authority. They have a federal style of government with a bicameral legislature, and the regions are home to people of many racial and ethnic backgrounds. Both economies had a lot of natural resources. Malaysia and Nigeria were the main exporters of primary products when they gained independence in 1957 and 1960, respectively, due to their tropical climates. Nigeria has the capacity to emerge as the largest economy in Sub-Saharan Africa as well as even the world and play a significant role in the world economy, according to experts (Okezie C. A, 2017) and (Amir Baharuddin, 2017). These potentials have remained untapped, and Nigeria faces the risk of failing to reach the globally agreed millennium development goals (MDGs) by 2015, or the vision 2020, if current trends continue. This study aims to examine the untapped opportunities in the diplomatic relationship between these nations and also to determine what went wrong and take lessons from Malaysia achievement and how it was implemented. Nigeria and Malaysia share a very identical historical background: both had sultans as spiritual and political leaders in their major areas, were colonized by the British, and gained independence in 1960 and 1957, respectively. Malaysia has progressed in terms of human development since 1980 and strives to be among the industrialized nations. Nigeria has seen a rise in poverty from 1980 to the present, and it is likely to be classified as an underdeveloped country.

A regional-scale approach for modeling primary production and biogenic silica export in the Southern Ocean

Persistent uncertainties in the representations of net primary production (NPP) and silicate in the Southern Ocean have been noted in recent assessments ofthe ocean biogeochemical components of Earth system models (ESMs). Consequently, more mechanistic studies at the regional scale are required. To reduce these uncertainties, we applied a one-dimensional (1D) marine ecosystem model to different bioregions in the Southern Ocean: the Polar Frontal Zone in the Pacific sector, the seasonal sea ice zone in the northwestern Ross Sea, and the inner shelf of Terra Nova Bay. To make the existing ecosystem model applicable to the Southern Ocean, we modified the phytoplankton physiology (stoichiometry depending on species) and the silicate cycle (dissolution rate of biogenic silica (BSi) depending on latitude) in the model. We quantified and compared seasonal variations in several limitation factors of NPP, namely, iron, irradiance, silicate and temperature, in the three regions. The simulation results showed that dissolved iron plays the most significant role in determining the magnitude of NPP and the phytoplankton community structure during summer. Additionally, the modified model successfully reproduced the vertical flux of BSi and particulate organic carbon (POC). The POC export efficiency was high in the inner shelf zone, which had high levels of iron concentration, NPP, and Phaeocystis biomass. In contrast, BSi export occurred most efficiently in the Polar Frontal Zone, where diatoms are dominant, the BSi dissolution rate is low, and NPP is extremely low. Our results from the integrated mechanistic framework at the regional scale demonstrate which specific processes should be urgently included in ESMs for better representation of the biogeochemical dynamics in the Southern Ocean.