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The Indo-Pacific warm pool is the warmest ocean in the world and is known as "the global heat engine," which plays an important role in the climate system.

Quantitatively assessing the porewater dissolved inorganic carbon (DIC) cycling in methane-enriched marine sediments is crucial to understanding the contributions of different carbon sources to the global marine carbon pool. In this study, Makran accretionary wedge was divided into Zone 1 (high methane flux area) and Zone 2 (background area). Porewater geochemical compositions (Cl-, SO42-, NH4+, Mg2+, Ca2+, Ba2+, DIC and δ13C-DIC) and a reaction-transport model were used to determine the DIC source and calculate the DIC flux through carbonate precipitation and releasing into overlying seawater in sediments. Zone 1 is characterized by the shallower depth of sulfate-methane transition (SMT), where most of porewater sulfate was consumed by anaerobic oxidation of methane (AOM). In contrast, a relatively low flux of methane diffusion in Zone 2 results in a deeper SMT depth and shallow sulfate is predominantly consumed by organoclastic sulfate reduction (OSR). Based on the porewater geochemical profiles and δ13C mass balance, the proportions of porewater DIC originating from methane were calculated as 51% in Zone 1 and nearly 0% in Zone 2. An increase of porewater DIC concentration leads to authigenic carbonate precipitation. Solid total inorganic carbon (TIC), X-ray diffractometry (XRD) and scanning electron microscopy (SEM) analysis display that carbonate content increases with depth and aragonite appears at or below the depths of SMT. Meanwhile, the flux of DIC released from sediments calculated by the reaction-transport model is 51.3 ~ 90.4 mmol/m2·yr in Zone 1, which is significantly higher than that in Zone 2 (22.4 mmol/m2·yr). This study demonstrates that AOM serves as the dominant biogeochemical process regulating the porewater DIC cycle, which has an important impact on the authigenic carbonate burial and the seawater carbonate chemistry.

We investigated dual carbon isotopes within the vertical water column at sites 67-1 and 67-2 of the western equatorial Indian Ocean to determine the source and age of particulate organic carbon (POC) and thus evaluated the contributions of modern and fossil (aged) POC. The concentration of POC ranged from 7 to 47.3 μgC L−1, δ13CPOC values ranged from -31.8 to -24.4‰, and Δ14CPOC values ranged from -548 to -111‰. Higher values of δ13CPOC and Δ14CPOC near the surface indicated an influence of autochthonous POC, whereas decreasing trends toward the bottom suggested a contribution of aged OC sources to the total POC pool. The contribution of fossil POC was lower near the surface, accounting for only 12% and 6% of the total POC at sites 67-1 and 67-2, respectively; however, in the deeper layers below 1,000 m, the contribution of fossil POC increased to 52% and 44% of the total POC at the two sites. Mechanisms for the increased contributions of fossil OC within deeper POC include the inflow of aged OC from sediments resuspended near slopes, the adsorption of old dissolved organic carbon in deep water masses, and the impact of aged OC that may originate from hydrothermal sources. This study highlights the importance of aged OC in the carbon cycle of the equatorial Indian Ocean.

In the summer of 2022, like in many other regions of the world, an unprecedented period of continuous high-temperature weather occurred in eastern China. The degree and duration of this event far exceeded normal standards. Between 2020 and 2022, the tropical Pacific experienced the most significant three-year consecutive La Nina event recorded in recent decades. We investigate linkages between these events: the high-temperature response in eastern China and Asia under the background of such La Nina events. Development of summer La Nina events contributed to a high-temperature heat wave during the summer of 2022. Rapid development of these events in the third year exacerbated negative Indian Ocean Dipole phases because of energy accumulation from abnormal easterly winds. The combined effects of the negative Indian Ocean Dipole phase and La Nina provided background field support that strengthened the West Pacific Subtropical High (WPSH) and the Iranian High, leading to high terrestrial temperature anomalies. An empirical orthogonal function (EOF) analysis of the vertical velocity in the middle and low latitudes of the tropical Indian Ocean and the Asian continent reveals the first two empirical orthogonal function modes to be conducive to the strengthening of Walker circulation in 2022. These two main modes jointly reflect the rising movement of the equatorial East Indian Ocean and South China Sea in 2022, and the sinking movement to the west of the Tibet Plateau and eastern China, which was conducive to generating high temperatures in eastern China. Finally, the South Asian High was affected by the La Nina event that lasted for three years, showing a strong trend towards the north, thus making an important contribution to this high temperature.

Blue carbon is fast garnering international interest for its disproportionate contribution to global carbon stocks. However, our understanding of the size of these blue carbon stocks, as well as the provenance of carbon that is stored within them, is still poor. This is especially pertinent for many small-island nations that may have substantial blue carbon ecosystems that are poorly studied. Here, we present a preliminary assessment of blue carbon from three islands in the Maldives. The higher purpose of this research was to assess the feasibility of using blue carbon to help offset carbon emissions associated with Maldivian tourism, the largest Maldivian industry with one of the highest destination-based carbon footprints, globally. We used stable isotope mixing models to identify how habitats contributed to carbon found in sediments, and Loss on Ignition (LoI) to determine carbon content. We found that for the three surveyed islands, seagrasses (Thalassia hemprichii, Thalassodendron ciliatum, Halodule pinofilia, Syringodium isoetifolium, and Cymodocea rotundata) were the main contributors to sediment blue carbon (55 - 72%) while mangroves had the lowest contribution (9 - 44%). Surprisingly, screw pine (Pandanus spp.), a relative of palm trees found across many of these islands, contributed over a quarter of the carbon found in sediments. Organic carbon content ('blue carbon') was 6.8 ± 0.3 SE % and 393 ± 29 tonnes ha-1 for mangrove soils, and 2.5 ± 0.2% and 167 ± 20 tonnes ha-1 for seagrasses, which is slightly higher than global averages. While preliminary, our results highlight the importance of seagrasses as carbon sources in Maldivian blue carbon ecosystems, and the possible role that palms such as screw pines may have in supplementing this. Further research on Maldivian blue carbon ecosystems is needed to: 1) map current ecosystem extent and opportunities for additionality through conservation and restoration; 2) determine carbon sequestration ra

As predators of bacteria and viruses and as food sources for microzooplankton, heterotrophic flagellates (HFs) play an important role in the marine micro-food web. Based on the global climate change's impact on marine ecosystems, particularly sea ice melting, we analyzed the community composition and diversity of heterotrophic flagellates, focusing on the Antarctic Cosmonaut Sea. During the 36th China Antarctic research expedition (2019-2020), we collected seawater samples, subsequently analyzing HFs through IlluminaMiSeq2000 sequencing to assess community composition and diversity. Notable variations in HFs abundance were observed between the western and eastern sectors of the Cosmonaut Sea, with a distinct concentration at a 100-meter water depth. Different zones exhibited diverse indicators and dominants taxa influenced by local ocean currents. Both the northern Antarctic Peninsula and the western Cosmonaut Sea, where the Weddell Eddy and Antarctic Land Slope Current intersect, showcased marine stramenopiles as dominant HFs species. Our findings offer insights into dominant taxa, spatial distribution patterns among heterotrophic flagellates, correlations between taxa distribution and environmental factors, and the exploration of potential indicator taxa.

Énergie renouvelable : Maurice veut construire des parcs éoliens en mer.

Somali, African troops recapture key port from Shebab.

East Africa's biggest port inthe Kenyan city of Mombasa said on Saturday it had dismissed 27workers it believed were behind a strike this week thatparalysed operations for two days and cost the

East Africa's biggest port inthe Kenyan city of Mombasa said on Saturday it had dismissed 27workers it believed were behind a strike this week thatparalysed operations for two days and cost the

Fewer ships plying East African waters raises freight rates 45pc.

Japan lends $270m to Kenya to help expand port.

Pêche: l'Afrique bientôt importatrice de poissons?

Luxury resorts in the Maldives are going green.