What proportion of riverine nutrients reaches the open ocean?

Globally, rivers deliver significant quantities of nitrogen (N) and phosphorus (P) to the coastal ocean each year. Currently, there are no viable estimates of how much of this N and P escapes biogeochemical processing on the shelf to be exported to the open ocean; most models of N and P cycling assume that either all or none of the riverine nutrients reach the open ocean. We address this problem by using a simple mechanistic model of how a low-salinity plume behaves outside an estuary mouth. The model results in a global map of riverine water residence times on the shelf, typically a few weeks at low latitudes and up to a year at higher latitudes, which agrees well with observations. We combine the map of plume residence times on the shelf with empirical relationships that link residence time to the proportions of dissolved inorganic N (DIN) and P (DIP) exported and use a database of riverine nutrient loads to estimate the global distribution of riverine DIN and DIP supplied to the open ocean. We estimate that 75% of DIN and 80% of DIP reaches the open ocean. Ignoring processing within estuaries yields annual totals of 17 Tg DIN and 1.2 Tg DIP reaching the open ocean. For DIN this supply is about 50% of that supplied via atmospheric deposition, with significant east-west contrasts across the main ocean basins. The main sources of uncertainty are exchange rates across the shelf break and the empirical relationships between nutrient processing and plume residence time

Arctic Connectivity: A Frugal Approach to Infrastructural Development

As the Arctic is heating up, so are efforts to strengthen connectivity within the region, enhance the connections from remote settlements to the global networks of trade, and increase sociality. With global interest in the Arctic on the rise, it becomes increasingly relevant to ensure that investments in Arctic infrastructure actually serve the people of the Arctic, while promoting industrial and commercial innovation in the region through widespread access to broadband and Internet of things (IoT) services. This challenge calls for interdisciplinary research strategies that are able to connect and integrate technological and societal approaches, which are commonly applied in isolation from one another. In this article, we propose an interdisciplinary collaborative research agenda for Arctic connectivity. Drawing on examples from Greenland, we stress the need for localized knowledge to design valuable and cost-effective connectivity solutions that cover the needs for everyday life and may also provide a new set of collaborative connectivity tools for innovation at an international level. Such solutions, termed “frugal connectivity,” are vital for the development of connected Arctic communities. L’Arctique se réchauffe et en même temps, les efforts visant à renforcer la connectivité dans la région, à améliorer les connexions des localités éloignées aux réseaux mondiaux du commerce et à accroître la socialité s’intensifient. Puisque l’intérêt que porte la planète à l’Arctique augmente, il est de plus en plus pertinent de faire en sorte que les investissements dans les infrastructures de l’Arctique servent vraiment la population de l’Arctique tout en favorisant l’innovation industrielle et commerciale dans la région grâce à l’accès répandu aux services à large bande et à l’Internet des objets (IdO). Ce défi fait appel à des stratégies de recherche interdisciplinaire capables de connecter et d’intégrer des approches technologiques et sociétales, approches couramment appliquées indépendamment les unes des autres. Dans cet article, nous proposons un programme de recherche collaborative interdisciplinaire en vue de la connectivité de l’Arctique. En nous appuyant sur des exemples en provenance du Groenland, nous mettons l’accent sur la nécessité de recourir à des connaissances localisées pour concevoir des solutions de connectivité utiles et rentables couvrant les besoins du quotidien, qui sont également susceptibles de fournir un nouvel ensemble d’outils de connectivité collaborative donnant lieu à l’innovation à l’échelle internationale. De telles solutions, qualifiées de « connectivité économe », sont indispensables à la création de collectivités connectées dans l’Arctique.

Merging plastics, microbes, and enzymes : highlights from an international workshop

In the Anthropocene, plastic pollution is a worldwide concern that must be tackled from different viewpoints, bringing together different areas of science. Microbial transformation of polymers is a broad-spectrum research topic that has become a keystone in the circular economy of fossil-based and biobased plastics. To have an open discussion about these themes, experts in the synthesis of polymers and biodegradation of lignocellulose and plastics convened within the framework of The Transnational Network for Research and Innovation in Microbial Biodiversity, Enzymes Technology and Polymer Science (MENZYPOL-NET), which was recently created by early-stage scientists from Colombia and Germany. In this context, the international workshop “Microbial Synthesis and Degradation of Polymers: Toward a Sustainable Bioeconomy” was held on 27 September 2021 via Zoom. The workshop was divided into two sections, and questions were raised for discussion with panelists and expert guests. Several key points and relevant perspectives were delivered, mainly related to (i) the microbial evolution driven by plastic pollution; (ii) the relevance of and interplay between polymer structure/composition, enzymatic mechanisms, and assessment methods in plastic biodegradation; (iii) the recycling and valorization of plastic waste; (iv) engineered plastic-degrading enzymes; (v) the impact of (micro)plastics on environmental microbiomes; (vi) the isolation of plastic-degrading (PD) microbes and design of PD microbial consortia; and (vii) the synthesis and applications of biobased plastics. Finally, research priorities from these key points were identified within the microbial, enzyme, and polymer sciences