Prochlorococcus and Synechococcus are the two most abundant and widespread phytoplankton in the global ocean. To better understand the factors controlling their biogeography, a reference database of the high-resolution taxonomic marker petB, encoding cytochrome b6, was used to recruit reads out of 109 metagenomes from the Tara Oceans expedition. An unsuspected novel genetic diversity was unveiled within both genera, even for the most abundant and well-characterized clades, and 136 divergent petB sequences were successfully assembled from metagenomic reads, significantly enriching the reference database. We then defined Ecologically Significant Taxonomic Units (ESTUs)-that is, organisms belonging to the same clade and occupying a common oceanic niche. Three major ESTU assemblages were identified along the cruise transect for Prochlorococcus and eight for Synechococcus Although Prochlorococcus HLIIIA and HLIVA ESTUs codominated in iron-depleted areas of the Pacific Ocean, CRD1 and the yet-to-be cultured EnvB were the prevalent Synechococcus clades in this area, with three different CRD1 and EnvB ESTUs occupying distinct ecological niches with regard to iron availability and temperature. Sharp community shifts were also observed over short geographic distances-for example, around the Marquesas Islands or between southern Indian and Atlantic Oceans-pointing to a tight correlation between ESTU assemblages and specific physico-chemical parameters. Together, this study demonstrates that there is a previously overlooked, ecologically meaningful, fine-scale diversity within some currently defined picocyanobacterial ecotypes, bringing novel insights into the ecology, diversity, and biology of the two most abundant phototrophs on Earth.
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http://dx.doi.org/10.1073/pnas.1524865113 | DOI Listing |
Virus Evol
December 2024
Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect Street, New Haven, CT 06511, United States.
Different theoretical frameworks have been invoked to guide the study of virus evolution. Three of the more prominent ones are (i) the evolution of virulence, (ii) life history theory, and (iii) the generalism-specialism dichotomy. All involve purported tradeoffs between traits that define the evolvability and constraint of virus-associated phenotypes.
View Article and Find Full Text PDFStud Mycol
December 2024
Universidade de Lisboa, Faculdade de Ciências, Biosystems and Integrative Sciences Institute (BioISI), Campo Grande, 1749-016 Lisbon, Portugal.
The application of traditional morphological and ecological species concepts to closely related, asexual fungal taxa is challenging due to the lack of distinctive morphological characters and frequent cosmopolitan and plurivorous behaviour. As a result, multilocus sequence analysis (MLSA) has become a powerful and widely used tool to recognise and delimit independent evolutionary lineages (IEL) in fungi. However, MLSA can mask discordances in individual gene trees and lead to misinterpretation of speciation events.
View Article and Find Full Text PDFUnderstanding how ecological communities assemble in relation to natural and human-induced environmental changes is critical, particularly for communities of pollinators that deliver essential ecosystem services. Despite widespread attention to interactions between functional traits and community responses to environmental changes, the importance of sensory traits has received little attention. To address this, we asked whether visual traits of bumblebee communities varied at large geographical scales along a habitat gradient of increased tree cover.
View Article and Find Full Text PDFBMC Public Health
December 2024
Medical Clinic Department, Federal University of Paraná (UFPR), Curitiba, Brazil.
Background: Disability insurance represents a significant economic burden within Brazil's social security system, yet long-term cost trends across disease groups remain understudied, hindering informed prevention and management strategies. Hospital costs, which account for approximately 40% of direct healthcare expenses, were selected as a comparative reference to contextualize the economic burden of disability insurance.
Objective: This study analyzes long-term cost trends of newly granted disability insurance by disease groups in Brazil, comparing them to public health system hospitalization expenses.
Microb Ecol
December 2024
College of Chemistry and Chemical Engineering, Key Laboratory of Chemical Engineering and Technology of State Ethnic Affairs Commission, North Minzu University, Yinchuan, 750021, China.
Soil salinization poses a substantial threat to global food security, particularly under the influence of climate change, and is recognized as one of the most urgent challenges in land degradation. This study aims to elucidate the challenges associated with managing arid and semi-arid saline-alkali lands in China's Ningxia province and propose feasible solutions. To assess moss crust colonization, we measured changes in organic matter and chlorophyll levels.
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