Abstract Tropical basin interactions have strong impacts on the evolution of sea surface temperature (SST) in the tropics, in which air–sea interactions play an important role. In this study, impacts of interbasin and air–sea interactions on interannual climate modes in the tropical Indian Ocean (IO) and Pacific Ocean (PO) are assessed with a linear inverse model (LIM) framework built based on SST and 10-m zonal wind (u10) anomalies in these basins. When stochastically forced cyclostationary LIM simulations with different interbasin coupling strengths are conducted, the amplitude of El Niño–Southern Oscillation (ENSO) increases as interbasin interactions become weaker, indicating a delayed negative feedback of the IO on the ENSO. On the other hand, the IO dipole (IOD) variability is reduced as interbasin interactions are weakened, but the IOD exists even when the two basins are completely decoupled, supporting that the IOD is an inherent climate mode in the IO. In addition, the peak of the IOD shifts 2 months earlier when completely decoupled, suggesting that interbasin interactions even affect the seasonality of the IOD. By adjusting the corresponding parts in the linear operators, the influence of air–sea coupling strength is also examined. It is shown that air–sea interactions promote SST variability in both basins, which is expected from the importance of the positive Bjerknes feedback in the tropics. Significance Statement A linear inverse model framework taking account of seasonality is employed in this study to assess impacts of interbasin and air–sea interactions on interannual climate modes in the tropical Indian Ocean (IO) and Pacific Ocean (PO). The present framework is unique in the sense that the coupling strength is adjusted, which is difficult to implement in coupled models that are often used to study those interactions. It is found that the strengthened interbasin interactions not only modulate the seasonality of the sea surface temperature variability but also result in biennial periodicity of the climate modes in the PO and IO.

Responses of mesozooplankton to extreme positive Indian Ocean Dipole (pIOD) and cold-core eddy in the eastern Equatorial Indian Ocean and southern Bay of Bengal during 2019/2020 winter

Goitein, the Indian Ocean, and a Missed Opportunity to Make Medieval History Global

Bacterial community diversity associated with oil degradation from marine environment.

Wind speed and direction influence beach plastic accumulation patterns on remote Christmas Island.

Impacts of the atmospheric mean state on austral early-winter Indian Ocean teleconnections with Chile in CMIP5/CMIP6 models

Planktic foraminifera response to the early Eocene Climatic Optimum in the southern high-latitude Indian Ocean (ODP Site 738)

Geyser and Zélée seamounts and adjacent basin as witnesses of SW Indian Ocean tectonic and carbonate-siliciclastic-volcanoclastic sediment interplay

Early Pleistocene variation of clay minerals in deep-sea sediments from the eastern Indian Ocean implying regulation of ocean currents on Australian monsoon

Nutrient availability controls phytoplankton populations and their nutritional strategy in the eastern Indian Ocean

Multiple markers reveal distinct life-history strategies in equatorial fish populations.

Seafaring and trade across the Indian Ocean have played a pivotal role for Oman and its scholars. Islamic law compendia are reflective of and an important source on the material culture of their times. They discuss all aspects of human life, questions of personal status and trade and international relations. Despite the exposure of Oman and its scholars to the sea and related legal cases, maritime law in the Ibāḍī fiqh encyclopedias is a neglected field of research. This study aspires to close a gap in the literature. It focuses on the earliest extant Omanī fiqh encyclopedias and other relevant material of the 2nd-3rd/8th-9th centuries, mainly the Kitāb Jāmiʿ Abī l-Ḥawwārī (alive in 272/885), Kitāb Jāmiʿ al-Faḍl ibn al-Ḥawwārī (d. 278/891) and Jāmi’ Ibn Jaʿfar al-Izkawī (alive in 277/892), with references to later sources, primarily the Kitāb Bayān al-sharʿ of Muḥammad ibn Ibrāhīm al-Kindī (d. 508/1115), the Muṣannaf of Abū Bakr al-Kindī (d.557/1162), and others. This research analyses the available material to identify the earliest possible source material and authorities of dicta on Ibāḍī maritime law while referencing later material for clarification. Case studies on different questions, such as hiring ships and vessels for transportation, contract work, shipwreck and jettison, taxation, and persons missing at sea, are analyzed with respect to the sea as spatial factor that may (or may not) impact Islamic legal rule.

Since the establishment of diplomatic relations in 1962, Japan has consistently supported Madagascar through Official Development Assistance (ODA) aimed at promoting equitable and sustainable development. During Prime Minister Shinzo Abe’s administration, Japan significantly expanded its development cooperation, focusing on key sectors such as agriculture, infrastructure, healthcare, and education. This study investigates the reasons behind Japan’s decision to intensify its ODA engagement with Madagascar during the Abe administration. Employing a qualitative research approach that combines literature analysis with the theoretical frameworks of Rational Choice Theory, this study reveals that Japan’s ODA policy toward Madagascar reflects not only humanitarian and developmental objectives but also strategic national interests. These include the creation of new markets for Japanese enterprises, access to natural resources, availability of skilled labor that meets the needs of Japanese companies, and enhancement of regional connectivity between the Indian and Pacific Oceans. Ultimately, this study argues that Japan’s ODA toward Madagascar represents a mutually beneficial form of cooperation that stimulates trade, fosters growth, and reinforces Japan’s geopolitical presence in the Indo-Pacific region.

Compound extremes (CEs) pose escalating threats to Southeast Asia (SEA)’s densely populated and economically dynamic communities. This study analyses spatiotemporal trends in three predominant CE types: compound precipitation-wind extremes (CPWEs), dry spell and heat extremes (DSHEs), and humid heatwave extremes (HHWEs). By utilizing multiple widely used datasets, we establish reliable benchmark event sets that are not biased by a single source. Our analysis reveals distinct subregional patterns of CE impacts. CPWEs predominantly occur along coastal areas, with seasonal hotspots shifting in response to monsoonal wind dynamics. DSHEs and HHWEs are concentrated in continental SEA, often compounding during peak seasons. Statistically significant rises in annual HHWE impacts are detected, with decadal increases of 0.4–6.6% in both duration and spatial extent. This is followed by 0.5–3.8% decadal increases in CPWE impacts. Moreover, large-scale climate drivers, including the El Niño-Southern Oscillation and the Indian Ocean Dipole (IOD), amplify heat-related CE impacts by 7.6–91.7% during El Niño or when combined with a positive IOD phase, while reducing them by 15.9–73.2% during La Niña. This consistent assessment of subregional differences in CE hazards and their response to atmospheric circulation shifts can inform decision-making for mitigation and adaptation strategies across SEA.

Predators influence ecosystem functioning through consumptive and non-consumptive effects. Recent studies suggest that predators can also be an essential source of limiting nutrients in ecosystems such as coral reefs, potentially influencing prey ecology through nutrient input via their excreta. With rising commercial fishery, mesopredatory fishes are being selectively harvested from reefs. Yet, there is incomplete knowledge of the consequences of this extraction on essential ecosystem processes. Using field experiments and observations, we examined how mesopredatory fishes influence herbivory along a fishing-induced mesopredatory fish biomass gradient in the Lakshadweep Archipelago in the northern Indian Ocean. We found that mesopredatory fish excreta have greater proportion of phosphorus than nitrogen. Along the gradient, primary and secondary productivity increased, after accounting for pelagic nutrient subsidies. Further, herbivory rates increased with increasing mesopredator biomass, while prey anti-predator response remained unchanged. Our results suggest that mesopredator-induced alterations of nutrient stoichiometry stimulate primary and secondary productivity and enhance herbivory in phosphorus-limited coral reefs, particularly in systems experiencing mesopredator release following selective fishing of apex predators. Our study shifts focus from the traditional top-down role of predators, highlighting an overlooked bottom-up pathway by which mesopredators can influence ecosystem functioning. Global decline of predators could modify ecosystem processes in ways that are yet unknown, leaving them increasingly vulnerable to future disturbances.

Chimanimani District in the Eastern Highlands of Zimbabwe is one of the most at-risk districts for cyclones due to its proximity to the Indian Ocean. Despite it being situated inland, it is one of the locations where cyclonic risk is increasing. As a result, there is a growing population to whom the phenomenon is new, and whose perception of it is not fully explored. This research explores the main modulators of cyclone risk perception in Chimanimani with the purpose of understanding how the population perceives cyclonic risk and why. This information is critical to ensuring the sustainability of cyclone risk management and mitigation programmes. Further, the paper expands the lens of analysis from Western-based modulators to those rooted in Indigenous Knowledge Systems (IKS). The study adopted a qualitative methodology, grounded in phenomenology, to understand the main modulators of risk perception in the study area. The findings of the research point towards two tiers of modulators – those at a micro-level (past experience, credibility of information sources, proximity to risk event, probability factor) and meso-level (visibility of government leadership, indigenous knowledge system, spirituality and religion). At a micro-level, psychological factors were observed to be dominant influencers of risk perception. At the meso-level, Indigenous Knowledge Systems (IKS) and spirituality emerged as strong influences of cyclone risk perception. The study concludes that risk behaviour is ultimately a result of the intricate interactions between individual and societal influences of cyclone risk perception.

Skipjack tuna (Katsuwonus pelamis) is important to Indonesian fisheries, which lead to the need of accurate habitat prediction for sustainable management. This study assesses the spatiotemporal coverage and predictive utility of logbook and Vessel Monitoring System (VMS) data for skipjack habitat modeling using MaxEnt, with sea surface temperature (SST), chlorophyll-a, sea surface height (SSH), and salinity as predictors. Findings indicate VMS offers broader positional coverage but suffers from behavioral ambiguity, whereas logbook data, though spatially limited, provides higher accuracy due to direct catch reporting. Model evaluations showed comparable performance: the VMS-derived model achieved an AUC of 0.760 and an F1-score of 0.658, while the logbook-derived model yielded an AUC of 0.742 and an F1-score of 0.624. However, distribution analysis revealed the logbook-derived model performed better, with 87.5% of fishing events occurring in higher Habitat Suitability Index (HSI) areas compared to 73.1% for the VMS-derived model. These results suggest VMS data presents a viable alternative and comparative data source to logbook records for habitat modeling, offering opportunities to enhance fisheries management.

Abstract Oceans are the primary source of atmospheric bromoform (CHBr 3 ) and dibromomethane (CH 2 Br 2 ), with implications for tropospheric chemistry and the ozone layer. Nevertheless, socio‐economic developments are changing the oceans' biological characteristics, which could impact the magnitude and distribution of oceanic emissions in the future. In this work, we couple a machine learning (ML) framework to the Community Earth System Model (CESM) data of the Coupled Model Intercomparison Project (CMIP) and estimate the monthly sea surface concentrations of CHBr 3 and CH 2 Br 2 between 2015 and 2100, under different climate change scenarios. We use these estimates to run CESM version 2 (CESM2), with comprehensive halogen chemistry, and calculate present‐day global emissions of 269–271 Gg Br and 61–65 Gg Br for CHBr 3 and CH 2 Br 2 , respectively, based on different scenarios. Furthermore, we project 14%–40% and 8%–23% increases for global mean emissions of CHBr 3 and CH 2 Br 2 , respectively, by 2100; where more stringent scenarios lead to smaller enhancements. Regionally, there are uncertainties within the magnitudes and signs of the changes that depend on the climate scenarios considered. Nevertheless, the largest enhancements, under all scenarios, were predicted over the western tropical Pacific Ocean, tropical Atlantic Ocean, and Indian Ocean. We attribute these changes primarily to biological parameters rather than physical parameters. These changes project a 0.47–1.13 ppt Br increase from the combined source gases (CHBr 3 and CH 2 Br 2 ) in the upper troposphere by 2100, which could impact the stratospheric ozone budget. Overall, this study highlights the far‐reaching influence of human activities on natural oceanic emissions and atmospheric chemistry.

The Japanese cedar (Cryptomeria japonica), also known as sugi, is one of the most important trees in Japanese forests. It covers 44% of artificial forests, spanning approximately 4.5 million ha. It is cultivated in East Asia, the Azores archipelago, and some islands in the Indian Ocean. It is also grown worldwide as an ornamental tree in parks and gardens. The cultivation and use of sugi in Japan dates back centuries, and clonal forestry through cuttings has been practiced since the early 15th century. Its broad adaptability, genetic diversity, rapid growth, easy propagation, and precocious flowering—enabling early generational crosses—combined with their advanced genomic resources and efficient biotechnological tools, make sugi an outstanding conifer model. This review aims to provide an overview of the biotechnology and genetics of sugi for researchers and stakeholders.

African Small Island Developing States (SIDS) face critical challenges in maritime delimitation, balancing equitable principles with sustainable marine resource governance amid climate change and geopolitical pressures. Regional mechanisms like the Western Indian Ocean Coastal States Association (WIOCSA) employ innovative approaches, including soft-law governance and blockchain technology, to strengthen sovereignty and transparency. Successful cases such as Seychelles' blue bonds and Mauritius' adaptive fisheries management demonstrate effective capacity-building through resilience, adaptation, and systemic transformation. Equitable delimitation requires integrating ecological, economic, and legal dimensions while advancing regional cooperation. Strengthening inclusive governance frameworks remains essential for realizing sustainable development under the Agenda 2063 of the African Union (AU), ensuring African SIDS can navigate complex maritime boundaries while protecting vital marine resources.