Strategic planning could reduce farm-scale mariculture impacts on marine biodiversity while expanding seafood production
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The current state, opportunities and challenges for upscaling private investment in biodiversity in Europe
European countries have committed to ambitious upscaling of privately funded nature conservation. We review the status and drivers of biodiversity finance in Europe. By implementing semistructured interviews with 25 biodiversity finance key informants and three focus groups across Europe, we explore opportunities and challenges for upscaling private investment in nature. Opportunities arise from macroeconomic and regulatory changes, along with various technological and financial innovations and growing professional experience. However, persistent barriers to upscaling include the ongoing lack of highly profitable investment opportunities and the multitude of risks facing investors, including political, ecological and reputational risks influencing supply and demand of investment opportunities. Public policy plays the foundational role in creating and hindering these mechanisms. Public policy can create nature markets and investment opportunities, meanwhile agricultural subsidies and poor coordination between public funding sources undermine the supply of return-seeking investment opportunities. Investors demand derisking investments from uncertainties; in part caused by political uncertainty. These markets require profound state intervention to enable upscaling whilst achieving positive ecological outcomes; private investment will probably not upscale without major public policy change and public investment.
Cultivation and genomic characterization of novel and ubiquitous marine nitrite-oxidizing bacteria from the Nitrospirales
Nitrospirales, including the genus Nitrospira, are environmentally widespread chemolithoautotrophic nitrite-oxidizing bacteria. These mostly uncultured microorganisms gain energy through nitrite oxidation, fix CO2, and thus play vital roles in nitrogen and carbon cycling. Over the last decade, our understanding of their physiology has advanced through several new discoveries, such as alternative energy metabolisms and complete ammonia oxidizers (comammox Nitrospira). These findings mainly resulted from studies of terrestrial species, whereas less attention has been given to marine Nitrospirales. In this study, we cultured three new marine Nitrospirales enrichments and one isolate. Three of these four NOB represent new Nitrospira species while the fourth represents a novel genus. This fourth organism, tentatively named “Ca. Nitronereus thalassa”, represents the first cultured member of a Nitrospirales lineage that encompasses both free-living and sponge-associated nitrite oxidizers, is highly abundant in the environment, and shows distinct habitat distribution patterns compared to the marine Nitrospira species. Partially explaining this, “Ca. Nitronereus thalassa” harbors a unique combination of genes involved in carbon fixation and respiration, suggesting differential adaptations to fluctuating oxygen concentrations. Furthermore, “Ca. Nitronereus thalassa” appears to have a more narrow substrate range compared to many other marine nitrite oxidizers, as it lacks the genomic potential to utilize formate, cyanate, and urea. Lastly, we show that the presumed marine Nitrospirales lineages are not restricted to oceanic and saline environments, as previously assumed.
Genomic and transcriptomic insights into complex virus–prokaryote interactions in marine biofilms
Marine biofilms are complex communities of microorganisms that play a crucial ecological role in oceans. Although prokaryotes are the dominant members of these biofilms, little is known about their interactions with viruses. By analysing publicly available and newly sequenced metagenomic data, we identified 2446 virus–prokaryote connections in 84 marine biofilms. Most of these connections were between the bacteriophages in the Uroviricota phylum and the bacteria of Proteobacteria, Cyanobacteria and Bacteroidota. The network of virus–host pairs is complex; a single virus can infect multiple prokaryotic populations or a single prokaryote is susceptible to several viral populations. Analysis of genomes of paired prokaryotes and viruses revealed the presence of 425 putative auxiliary metabolic genes (AMGs), 239 viral genes related to restriction–modification (RM) systems and 38,538 prokaryotic anti-viral defence-related genes involved in 15 defence systems. Transcriptomic evidence from newly established biofilms revealed the expression of viral genes, including AMGs and RM, and prokaryotic defence systems, indicating the active interplay between viruses and prokaryotes. A comparison between biofilms and seawater showed that biofilm prokaryotes have more abundant defence genes than seawater prokaryotes, and the defence gene composition differs between biofilms and the surrounding seawater. Overall, our study unveiled active viruses in natural biofilms and their complex interplay with prokaryotes, which may result in the blooming of defence strategists in biofilms. The detachment of bloomed defence strategists may reduce the infectivity of viruses in seawater and result in the emergence of a novel role of marine biofilms.
Urban growth strategy in Greater Sydney leads to unintended social and environmental challenges
Cities have advanced in terms of economic and social status over the past five decades, improving the living conditions of hundreds of millions of people. However, population growth and urban expansion have put pressure on social and environmental conditions. This study examines urban policymakers’ perceptions about causal relationships in the urban system as revealed in urban planning reports. Here we analyzed 500 pages from published urban plans of Greater Sydney between 1968 and 2018 and coded the text into causal maps. The findings show that policymakers adopted a dominant urban development strategy over the past 50 years to pursue economic and public infrastructure growth. Over time, this growth strategy resulted in a number of social and environmental challenges that negatively impacted societal well-being. Although policymakers eventually recognized the seriousness of social and environmental challenges, they never attempted to fundamentally change the dominant growth strategy. Instead, policymakers sought to address the challenges (that is, symptoms) by responding to each issue piecemeal.
Low-carbon ammonia production is essential for resilient and sustainable agriculture
Ammonia-based synthetic nitrogen fertilizers (N fertilizers) are critical for global food security. However, their production, primarily dependent on fossil fuels, is energy- and carbon-intensive and vulnerable to supply chain disruptions, affecting 1.8 billion people reliant on either imported fertilizers or natural gas. Here we examine the global N-fertilizer supply chain and analyse context-specific trade-offs of low-carbon ammonia production pathways. Carbon capture and storage can reduce overall emissions by up to 70%, but still relies on natural gas. Electrolytic and biochemical processes minimize emissions but are 2–3 times more expensive and require 100–300 times more land and water than the business-as-usual production. Decentralized production has the potential to reduce transportation costs, emissions, reliance on imports and price volatility, increasing agricultural productivity in the global south, but requires policy support. Interdisciplinary approaches are essential to understand these trade-offs and find resilient ways to feed a growing population while minimizing climate impacts.
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