Ocean memory embraces the idea that the ocean retains, processes, and expresses information across a range of timescales, from moments to millennia. The Ocean Memory Project brings together scientists, artists, and scholars to investigate this notion from a transdisciplinary perspective, integrating empirical research with creative expression. Here, our scientific and artistic efforts center on the Lost City hydrothermal field, an otherworldly site on the deep Atlantic seafloor that offers rare insights into early Earth processes and the potential for life beyond our planet. In 2018, we sailed to Lost City and carried out our joint microbiological, geochemical, and artistic efforts. Our sampling revealed that the ultramafic rocks that underlie the field undergo reactions that support complex ecosystems dependent on interspecies cooperation to overcome extreme chemical limitations. These same rocks serve as a geologic sink for organic carbon carried with circulating seawater, a process likely active for as long as hydrothermal circulation has existed on Earth. These discoveries highlight the complex, evolving nature of subseafloor ecosystems and exemplify the ocean’s capacity for memory. Alongside the science, the expedition supported an artist in residence, Anna Davidson, who created a body of work inspired by her time at sea. Her paintings, videos, photos, and mixed media sculptures, some incorporating physical samples and imagery from the dive footage, are not only aesthetic and conceptual reflections of Lost City but also educational resources. By integrating science and art, we argue in this paper for a broader epistemological framework in environmental research—one that recognizes the ocean not only as a site of data but as a dynamic, living archive of memories. Through interdisciplinary inquiry, we can deepen our understanding of the ocean and build more meaningful cultural narratives around its protection in the face of current mounting threats, including climate change and deep-sea mining.

Sea-ice algae account for a substantial part of annual primary production in ice-covered waters and are an important component of the Arctic marine food web. With climate-induced changes to snow and sea-ice cover and their impact on the surface ocean, such as earlier melt, thinner ice, and increased upper-ocean stratification, a shift toward earlier and more extensive nutrient limitation on ice algal growth can be expected. Therefore, increasing our understanding of the processes governing nutrient supply and uptake by sea-ice algae is essential. Here, we compiled a pan-Arctic dataset of concentrations of sea-ice and sub-ice nutrients and sea-ice chlorophyll a (chl a) to assess their regional and seasonal variability, as well as the relationship of sea-ice algae and nutrient dynamics in the Arctic Ocean. This dataset indicates that bottom sea-ice nutrient and chl a concentrations were highest in the central Canadian Arctic Archipelago (Resolute Passage) due to tidal-driven mixing at the ocean-ice interface, and lowest in the Arctic Ocean basins. At the regional scale, Pacific and Atlantic Water influence variability in sea-ice and sub-ice nutrient concentrations. Significant positive relationships of bottom sea-ice nutrient versus chl a concentrations were ubiquitous across the Arctic during the ice algal bloom, suggesting intracellular nutrient storage as an important mechanism to support ice algal growth. This relationship in turn alters nutrient ratios within the sea ice relative to sub-ice waters, decreasing NOx:PO4 ratios, while increasing NOx:Si(OH)4 ratios. In contrast, bottom sea-ice nutrient-chl a relationships were less common and sometimes negative when nutrient concentrations were low, likely reflecting nutrient limitation. In conclusion, we have demonstrated a pan-Arctic, yet regionally specific, influence of the ice algal community on bottom sea-ice nutrient concentrations.

Manganese nodules in the Clarion-Clipperton Fracture Zone (CCZ) of the eastern Pacific Ocean have been considered a target for the development of useful metal resources for more than half a century, due to the depletion of onshore resources and advances in mining technology, and are currently the closest to development. Because sediment surface disturbances and suspended plumes are expected to occur due to manganese nodule mining, characterizing sediments in exploitable areas as an environmental baseline is important to minimizing impacts on the marine environment. Here, we report on sediment properties in the Japanese exploration areas, DORD West Area and APEI-10, an area of particular environmental interest, in the western CCZ, where data are scarce compared with the eastern CCZ. We analyzed grain-size composition, chemical composition, and metals, including mercury, to a depth of 20 cm in the sediment. Based on the distribution patterns, metals were divided into group 1 (Mn, Ni, Cu, Zn, Cd, and rare earth elements), group 2 (Fe, Cr, As, and Pb), and group 3 (Hg), with each group observed to be affiliated with manganese oxides, silicate minerals, and organic materials, respectively. Mercury concentrations (<10 ng g−1 to 102 ng g−1) were comparable to those of deep basins; nevertheless, their fluxes were very low, reflecting the limited sedimentation of organic matter. The bulk compositions of the sediments from the western CCZ in this study were similar to those in the eastern-to-central CCZ, although the strong manganese concentrations in the topmost 10 cm of the eastern CCZ were not observed here. We suggest that during the last glacial period, when bottom-water dissolved oxygen concentrations were lower, the east–west gradient of surface primary production and organic matter flux was stronger than today, resulting in less extensive manganese reduction in surface sediments in the western CCZ.

Ecological studies of many pelagic, deep-sea animals are often limited due to their remote habitats and sampling constraints. In the eastern tropical Pacific, numerous studies have been published about the distribution of demersal fishes across the region, yet studies for midwater taxa are lacking. Here, we utilized visual survey transects from an area targeted for polymetallic nodule mining to examine the drivers behind the distribution of two mesopelagic predators, snipe eels (family Nemichthyidae) and sawtooth eels (family Serrivomeridae). Additionally, we compared the vertical distributions of their prey and examined whether the two eels displayed different behaviors in situ. Time of day was not a statistically significant driver of eel distribution, although the shallowest observations were during the night, indicating that some in the populations of Nemichthyidae and Serrivomeridae had migrated weakly to the upper 200 m. Eel distributions were found to be affected by both depth and dissolved oxygen, with Nemichthyidae observed in shallower and lower oxygenated waters and Serrivomeridae in deeper and more oxygenated ones. Two prey taxa (families Euphausiidae and Sergestidae) were abundant at shallower transect depths, which likely drives the distribution of Nemichthyidae, as pelagic crustaceans constitute their primary prey. In terms of behavior, Serrivomeridae were more active and were oriented primarily vertically, suggesting that Nemichthyidae may be less active or under lower predation pressure due to the hypoxic environment in which they occur. This work highlights the importance of visual surveys in obtaining in situ data as a complement to traditional sampling methods, particularly for collecting data on poorly understood animals.

Globally, food systems are at the center of an ecological, social, and health crisis. In the Global South, particularly in sub-Saharan Africa (SSA), the reorganization of food systems is crucial to achieving economic development while addressing the various crises. Raising agricultural productivity is important, within a broader development strategy, if it does not imply the destitution of millions of peasants. Agroecology, with its focus on labor-driven intensification, represents an opportunity to transform food systems and achieve sustainability. National policies play a significant role in promoting or hindering agroecological transitions (AETs). In this article we analyze the contents of agricultural policies in Senegal, to determine to what extent the official texts promote AETs. Senegal, a Western African country in the Sahel region, faces important challenges in terms of providing sufficient food for its inhabitants, within a context of worsening climate and persistent demographic growth. Agroecology could provide an opportunity to promote nation-focused agricultural development while preserving peasants. We draw on the categories of critical political economy to clarify the meaning of AETs, in terms of changes in the prevailing mode of production. Subsequently, we deploy social multi-criteria evaluation to analyze the most important agricultural policies since 2014 and assess to what extent the official policy documents are in line with AETs. The results indicate that the policies are still anchored to a narrative of agricultural modernization and are not particularly transformative. Nevertheless, we also note some improvements, particularly with respect to the gender issue, and to a lesser extent with respect to the management of soil fertility and pest control. We note how the emergence of social movements supporting AETs in Senegal may help to promote public policies that are more transformative. The results contribute to the wider debate on the role of public policies in supporting AETs.

Reducing the environmental and health impacts arising from marine transportation is a central mandate for the International Maritime Organization (IMO), but policy implementation is challenged by overlapping jurisdictions and compartmentalized policy design. Here, we investigate decision-making strategies after the IMO 2020 policy, aimed at reducing sulfur emissions by more stringently regulating fuel sulfur content, came into force. Our analysis highlights the consequences of an exception in IMO 2020 allowing vessels to use exhaust gas cleaning systems as an alternative to fuel-based compliance. Focusing on an example in the Port of Vancouver, Canada, we present a formal model capturing the key decision-makers as they respond to protect their own interests upon the implementation of IMO 2020. We trace how responses to this policy have evolved since 2020, leading to a critical decision point from which a set of alternative technology pathways for marine shipping futures arise. These pathways diverge meaningfully in terms of how they can contribute to policy goals beyond sulfur emissions (e.g., water quality and decarbonization). We then provide recommendations for supporting industry decision-making around those alternatives. While we focus on how this policy manifested in Vancouver, Canada, IMO 2020 has a global impact, and our model provides a framework for systematically investigating its consequences in other jurisdictions. We also provide transferable insights to other multi-scale governance contexts, contributing to policy design that includes co-benefits and trade-offs relevant to interrelated goals.

Nepal’s community forestry program is widely regarded as successful. At its peak, the program enlisted a large share of the rural population as managers of the country’s communal forests. However, recent empirical evidence suggests that voluntary participation in the program is in decline. Analyzing the empirical literature, we describe this surprising pattern of decline and discuss potential negative impacts. We also use political-economic reasoning and extant evidence to theorize about the drivers of this decline, arguing that livelihood diversification and profitable out-migration have altered the forest–people relationship in many villages, weakening incentives for participation in community forestry. Finally, we assess the viability of several institutional options for either replacing the program with other management approaches or reforming it to boost incentives for participation in light of the noted socioeconomic changes in rural Nepal. We argue that well-designed payment schemes or reforms that enable local people to commercialize community forests could both support participation by enhancing the associated benefits, and institutional changes related to local meetings and labor requirements could do so by reducing the associated costs. The replacement of community-based approaches with top-down management or privatization, however, appears risky due to a potential lack of government capacity and the possibility that such institutional changes could damage livelihoods or create negative externalities for some households. The consolidation of community forests also presents governance and management challenges. Our analysis suggests the need for greater scholarly attention to how environmental policy tools withstand social and economic change and to environmental policy succession—or how environmental policies are reimagined when they are no longer an appropriate fit for the local context.

Land and agrarian conflicts have intensified Colombia’s internal war, particularly through land grabbing and dispossession, victimizing rural communities. National policies have favored industrial agriculture while marginalizing traditional smallholder practices. In the Colombian Caribbean region, this has hindered campesino livelihoods and biocultural memory. This research examines how agrarian conflicts have influenced agricultural practices and local crop diversity at the scale of a campesino community. It offers insights into the links between agrarian conflicts, transformations in local food systems, and the erosion of biocultural memory. Drawing on concepts from agrobiodiversity, biocultural memory, and political ecology, this study uses social mapping and historical analysis to assess how people experience spatiotemporal changes in land use and crop diversity. The findings show that people connect the decrease in crop diversity to wider changes in the food system, the effects of the violent agrarian conflict, and the expansion of industrial agriculture supported by the State.

Polar environments are increasingly important to study as they are some of the regions most dramatically impacted by climate change. However, large field campaigns in these remote and sensitive regions may have impacts on both the local environment they aim to study and the global climate. Understanding the impact of such activities is necessary to weigh the costs and benefits and minimize negative impacts. This study provides the first example of a methodology to conduct an environmental impact assessment (EIA) for a polar research expedition at sea. We first summarize prior work on quantifying the environmental impact of polar science (including those stipulated by the Antarctic Treaty) and highlight the need for a similar process in the Arctic. The proposed methodology for measuring the impact of Arctic expeditions at sea includes a collection of data that should be gathered pre-, during, and post-expedition. Future seagoing expeditions can follow this framework to quantify their impact. The methodology is applied to quantify the impact of the scientific component of the 2019–2020 MOSAiC expedition to highlight the value of this process and potential blind spots. Our main takeaways include the need for (i) standardization of EIAs to allow comparison, (ii) better preparation of logistic parameters and opportunistic data collection in the lead-up to the expedition, (iii) life cycle assessments for on-ice instrument deployments, water, and waste disposal, (iv) revisiting the EIA upon expedition completion, and publishing lessons learnt. We provide a methodology for scientific EIAs that balances being easily implementable and sufficiently detailed, such that we can build up a database of assessments across a range of expeditions that can, in the future, be used to make recommendations on how to best reduce impacts on the polar environment.

The central Arctic is experiencing warming up to four times faster than the global average. This Arctic amplification is accompanied by large deviations in climate projections, making anticipation of high-impact, near-term regional biodiversity and climate change difficult. Several atmospheric processes contribute simultaneously to Arctic amplification and biodiversity change yet remain largely unstudied, not least because of the difficulty to access the central Arctic Ocean and conduct year-round studies. This article introduces the near- to mid-term objectives of the Tara Polar Station scoping group on “atmosphere-biosphere interactions,” with a focus on identifying and quantifying the origin and genetic composition of local and long-range transported biogenic particles that can impact biodiversity and cloud formation, the role of the stratified boundary layer on vertical fluxes of cloud seeds, bioaerosols and nutrients, and the impact of clouds on atmospheric light transmission. The Tara Polar Station is a fortified research vessel built to drift in the Arctic sea ice throughout the next 20 years in ten Tara Polaris expeditions, each lasting one and a half years. The platform allows for year-round interdisciplinary studies targeted at understanding the central Arctic Ocean ecosystem functioning, biodiversity, and climate change at the ocean-ice-atmosphere nexus. This scoping group will deploy novel and automated instruments for in situ, real-time vertical and remote sensing observations of aerosols, clouds, and radiation. The link between the biosphere and atmosphere will be investigated specifically through bio- and chemo-molecular sampling of air, clouds, ice, and water. We expect the early Tara Polaris expeditions to deliver insights that can be implemented into models for improved scenarios of Arctic change, in particular for the next few decades when we expect a regime shift in summer sea-ice presence.