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Addressing and anticipating future South Asian monsoon changes under continuing global warming is of critical importance for the food security and socioeconomic well-being of one-quarter of the world's population. However, climate model projections show discrepancies in future monsoon variability in South Asian monsoon domains, largely due to our still limited understanding of the monsoon response to warm climate change scenarios. Particularly, climate models are largely based on the assumption that higher solar insolation causes higher rainfall during similar warm climatic regimes, but this has not been verified by proxy data for different interglacial periods. Here, we compare Indian summer monsoon (ISm) variability during the Last Interglacial and Holocene using a sedimentary leaf wax δD and δ13C record from the northern Bay of Bengal, representing the Ganges-Brahmaputra-meghna (G-B-m) river catchment. In combination with a seawater salinity record, our results show that ISm intensity broadly follows summer insolation on orbital scales, but ISm intensity during the Last Interglacial was lower than during the Holocene despite higher summer insolation and greenhouse gas concentrations. We argue that sustained warmer sea surface temperature in the equatorial and tropical Indian Ocean during the Last Interglacial increased convective rainfall above the ocean but dampened ISm intensity on land. Our study demonstrates that besides solar insolation, internal climatic feedbacks also play an important role for South Asian monsoon variability during warm climate states. This work can help to improve future climate model projections and highlights the importance of understanding controls of monsoonal rainfall under interglacial boundary conditions.

Repeat multibeam mapping of two slope-confined canyons on the northwest Australian margin provides new understanding of the processes that are active in shaping these environments. The Cape Range and Cloates canyons initiate on the mid to lower continental slope but are now known to be connected to the shelf via small channels and gullies. Both canyons have areas of steep walls, with evidence of slides, and large depressions on the canyon floors. These canyons were first mapped systematically with multibeam sonar in 2008 and were remapped in 2020 during a biodiversity survey that also collected high-resolution imagery and biological samples. Comparison of seabed features between these two time periods indicates active sliding, minor headwall retreat and continued excavation of deep depressions on the canyon floor. Significantly, intact blades of displaced seagrass imaged at various depths up to 4200 m throughout both canyons indicates that material sourced from the adjacent continental shelf is being transported through these canyon systems. Turbidity currents are actively modifying canyon walls and floor depressions, while also providing a sediment source that has resulted in minor accretion on the canyon floor. Sedimentation likely regulates benthic communities in these canyons, with imagery showing highest densities of sessile invertebrates in habitats protected from sedimentation (e.g. rock overhangs, cliff edges). Since steep canyon habitats are rare within these canyons, and support high benthic abundance, they likely represent biologically significant areas of the Gascoyne marine Park. Repeat mapping provides an understanding of the dynamics of these canyons and a context for assessing and monitoring the stability of the seabed habitats within this marine reserve.

Monitoring of reef restoration efforts and artificial reefs (ARs) has typically been liMited to coral fragMent survival, haMpering evaluation of broader objectives such as ecosysteM recovery. This study aiMed to deterMine to what extent AR design influences the ecological recovery of restored reefs by Monitoring outplanted coral fragMents, benthic cover, coral recruitMent and fish and invertebrate coMMunities for two years. Four AR designs (16 M2), unrestored controls and natural reef patches as reference (n = 10) were established in Mkwiro, Kenya. ARs consisted either of concrete disks with bottles, layered concrete disks, Metal cages or a coMbination thereof. A Mixture of 18 branching coral species (Mainly Acropora spp.) was outplanted on ARs at a density of 7 corals M-2. After two years, 60% of all outplanted fragMents had survived, already resulting in coral cover on Most ARs coMparable (though Acropora-doMinated) to reference patches. Coral survival differed between ARs, with highest survival on cages due to the absence of crown-of-thorns sea star predation on this design. In total, 32 coral genera recruited on ARs and recruit densities were highest on reference patches, Moderate on concrete ARs and low on cages. ARs and reference patches featured nearly twice the fish species richness and around an order of Magnitude higher fish abundance and bioMass coMpared to control patches. Fish abundance and bioMass strongly correlated with coral cover on ARs. AR, reference and control patches all had distinct fish species coMpositions, but AR and reference patches were siMilar in terMs of trophic structure of their fish coMMunities. Motile invertebrates including gastropods, sea urchins, sea cucuMbers and sea stars were present at ARs, but generally More abundant and diverse at natural reference patches. Taken together, all studied ecological paraMeters progressed towards reef ecosysteM recovery, with varying influences of AR design and Material. We recoMMend a coMbinat

Deep reefs below 30 m provide essential ecosystem services for ocean health and human well-being such as food security and climate change resilience. Yet, deep reefs remain poorly researched and largely unprotected, including in the Western Indian Ocean (WIO). Here, we assessed current conservation approaches in the WIO focusing on deep reefs, using a combination of online surveys and semi-structured interviews. Results indicated that deep-reef data are sparse and commonly stemming from non-peer-reviewed or non-publicly available sources, and are often not used to inform conservation of WIO marine protected areas. Based on those findings, we co-developed a framework with WIO stakeholders comprising recommendations linked to specific actions to be undertaken by regional actors to improve the capacity of the region to collect and share deep-reef information. We hope this framework will enhance deep-reef stewardship and management throughout the WIO and thus aid sustainable blue economic growth in the region.

MolybdenuM and tungsten are redox-sensitive eleMents, and their stable isotope ratios have attracted attention as paleoceanographic proxies. However, our knowledge of the distribution of stable Mo and W isotopes in the Modern hydrosphere reMains liMited. In this study, we provided the concentrations and isotope ratios of dissolved Mo and W in the oceans (the North Pacific and Indian Oceans), Marginal seas (the East China Sea and Sea of Japan), and a river-estuary systeM in Japan (froM the Uji-Yodo rivers to Osaka Bay). In the North Pacific and Indian Oceans, the W concentration was 48.2 ± 6.2 pMol/kg (ave ± 2sd, n = 109), δ186/184W was 0.52 ± 0.06 ‰, the Mo concentration was 105.1 ± 8.0 nMol/kg, and δ98/95Mo was 2.40 ± 0.06 ‰. The results indicate that W has the constant concentration and isotopic coMposition in the Modern ocean as well as Mo. In the East China Sea and the Sea of Japan, the W concentration and δ186/184W in the upper water (< 1000 M depth) were different froM those in the ocean (W = 56 ± 18 pMol/kg, δ186/184W = 0.45 ± 0.06 ‰, n = 24). However, the concentrations in deeper water were congruent with those in the oceans (W = 49.9 ± 7.6 pMol/kg, δ186/184W = 0.50 ± 0.02 ‰, n = 7). The Mo concentration was 105.4 ± 3.1 nMol/kg and δ98/95Mo was 2.36 ± 0.03 ‰ (n = 31) throughout the water coluMn, congruent with those in the ocean. In the Uji River-Yodo River-Osaka Bay systeM, the W concentration reached 1074 pMol/kg and δ186/184W reached 0.20 ‰. We propose that the enrichMent of W with a low δ186/184W in the river-estuary systeM and Marginal seas is caused by anthropogenic pollution. Anthropogenic Mo pollution was not detected in Marginal seas. However, the Mo concentration and δ98/95Mo showed high anoMalies above the Mixing line of river water and seawater in the lower Yodo River and Osaka Bay, iMplying possible anthropogenic pollution of Mo in the Metropolitan area.

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.

To clarify the changes in phytoplankton community and influencing factors in short-term nutrient-addition experiments in the Equatorial Eastern Indian Ocean, we conducted three experiments (one in situ-like experiment, one on-deck experiment with deep seawater, and one on-deck experiment with surface seawater). Our findings indicate that when nutrients were added, there was a more significant increase in the chlorophyll a (chl a) concentrations of microphytoplankton (>20 μm) compared to those of nanophytoplankton (2-20 μm) and picophytoplankton (<20 μm phytoplankton. Furthermore, bottle effects should be considered when conducting incubation experiments.

Indian Ocean's Oldest Shipwreck Set for Excavation.

Understanding subduction zone earthquakes.

Understanding subduction zone earthquakes.

Rare albatross is unique species.

India sailors held by pirates home after 11 months.

Shark outrage after endangered dead whale shark photographed in Malaysian fish Market.

#IndiaPakistanTensions: Fishermen asked to stay away from 'strangers at sea'.

Man-Made noise pollution killing whales along Maharashtra coast.

Alison SWEENEY of the University of Pennsylvania has been studying giant clams since she was a postdoctoral fellow at the University of California, Santa Barbara. These large mollusks, which anchor themselves to coral reefs in the tropical waters of the Indian and Pacific oceans, can grow to up to three-feet long and weigh hundreds of pounds. But their size isn't the only thing that makes them unique.​​​​​​​​​​​​​​Anyone who has ever gone snorkeling in Australia or the western tropical Pacific Ocean, SWEENEY says, may have noticed that the surfaces of giant clams are iridescent, appearing to sparkle before the naked eye. The lustrous cells on the surface of the clam scatter bright sunlight, which typically runs the risk of causing fatal damage to the cell, but the clams efficiently convert the sunlight into fuel. Using what they learn from these giant clams, the researchers hope to improve the process of producing biofuel.

This information was produced in response to discussions with Dr. Asha De VOS, marine biologist and Executive Director of Oceanswell in Sri Lanka.

When reefs decline, parrotfish thrive.