1. |
- Menkveld, Albert J., et al.
(author)
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Nonstandard Errors
- 2024
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In: JOURNAL OF FINANCE. - : Wiley-Blackwell. - 0022-1082 .- 1540-6261. ; 79:3, s. 2339-2390
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Journal article (peer-reviewed)abstract
- In statistics, samples are drawn from a population in a data-generating process (DGP). Standard errors measure the uncertainty in estimates of population parameters. In science, evidence is generated to test hypotheses in an evidence-generating process (EGP). We claim that EGP variation across researchers adds uncertainty-nonstandard errors (NSEs). We study NSEs by letting 164 teams test the same hypotheses on the same data. NSEs turn out to be sizable, but smaller for more reproducible or higher rated research. Adding peer-review stages reduces NSEs. We further find that this type of uncertainty is underestimated by participants.
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2. |
- Medina-Silva, Renata, et al.
(author)
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Microbial diversity from chlorophyll maximum, oxygen minimum and bottom zones in the southwestern Atlantic Ocean
- 2018
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In: Journal of Marine Systems. - : Elsevier. - 0924-7963 .- 1879-1573. ; 178, s. 52-61
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Journal article (peer-reviewed)abstract
- Conspicuous physicochemical vertical stratification in the deep sea is one of the main forces driving microbial diversity in the oceans. Oxygen and sunlight availability are key factors promoting microbial diversity throughout the water column. Ocean currents also play a major role in the physicochemical stratification, carrying oxygen down to deeper zones as well as moving deeper water masses up towards shallower depths. Water samples within a 50-km radius in a pockmark location of the southwestern Atlantic Ocean were collected and the prokaryotic communities from different water depths - chlorophyll maximum, oxygen minimum and deep-sea bottom (down to 1355 m) - were described. At phylum level, Proteobacteria were the most frequent in all water depths, Cyanobacteria were statistically more frequent in chlorophyll maximum zone, while Thaumarchaeota were significantly more abundant in both oxygen minimum and bottom waters. The most frequent microorganism in the chlorophyll maximum and oxygen minimum zones was a Pelagibacteraceae operational taxonomic unit (OTU). At the bottom, the most abundant genus was the archaeon Nitrosopurnilus. Beta diversity analysis of the 16S rRNA gene sequencing data uncovered in this study shows high spatial hetero-geneity among water zones communities. Our data brings important contribution for the characterisation of oceanic microbial diversity, as it consists of the first description of prokaryotic communities occurring in different oceanic water zones in the southwestern Atlantic Ocean.
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3. |
- Giongo, Adriana, et al.
(author)
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Discovery of a chemosynthesis-based community in the western South Atlantic Ocean
- 2016
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In: Deep Sea Research Part I. - : Elsevier. - 0967-0637 .- 1879-0119. ; 112, s. 45-56
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Journal article (peer-reviewed)abstract
- Chemosynthetic communities have been described from a variety of deep-sea environments across the world's oceans. They constitute very interesting biological systems in terms of their ecology, evolution and biogeography, and also given their potential as indicators of the presence and abundance of consistent hydrocarbon-based nutritional sources. Up to now such peculiar biotic assemblages have not been reported for the western South Atlantic Ocean, leaving this large region undocumented with respect to the presence, composition and history of such communities. Here we report on the presence of a chemosynthetic community off the coast of southern Brazil, in an area where high-levels of methane and the presence of gas hydrates have been detected. We performed metagenomic analyses of the microbial community present at this site, and also employed molecular approaches to identify components of its benthic fauna. We conducted phylogenetic analyses comparing the components of this assemblage to those found elsewhere in the world, which allowed a historical assessment of the structure and dynamics of these systems. Our results revealed that the microbial community at this site is quite diverse, and contains many components that are very closely related to lineages previously sampled in ecologically similar environments across the globe. Anaerobic methanotrophic (ANME) archaeal groups were found to be very abundant at this site, suggesting that methane is indeed an important source of nutrition for this community. In addition, we document the presence at this site of a vestimentiferan siboglinid polychaete and the bivalve Acharax sp., both of which are typical components of deep-sea chemosynthetic communities. The remarkable similarity in biotic composition between this area and other deep-sea communities across the world supports the interpretation that these assemblages are historically connected across the global oceans, undergoing colonization from distant sites and influenced by local ecological features that select a stereotyped suite of specifically adapted organisms. (C) 2015 Elsevier Ltd. All rights reserved.
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