Upwelling events can change the sea water conditions within few hours during several months on a seasonal regimen. These events are predicted to intensify due to climate change, exposing shallow ...benthic organisms to hypoxia and thermal stress, among other extreme conditions. Some coral reefs in the Eastern Tropical Pacific (ETP) recurrently experience upwelling events. Coral reefs off Gorgona Island, Colombia, are exposed to lower oxygen concentrations (3.0 - 3.7 mg O
2
L
-1
) and lower temperatures (17 - 24°C) from mid-January to mid-April, when upwelling develops, compared to the rest of the year (4.9 ± 0.7 mg O
2
L
-1
, 28.4 ± 0.3°C, mean ± SD). While no visible signs of stress have been reported for corals during upwelling, it can be hypothesized that corals would be negatively affected by these changes. Therefore, the objectives of this study were to (1) identify the effects of temperature and hypoxia on the metabolic rate (MO
2
) of
Pocillopora
corals under lab conditions, and (2) to examine the changes in skeletal growth and Symbiodiniaceae density of
Pocillopora
in the field between upwelling and non-upwelling seasons. Findings revealed that MO
2
was significantly reduced by 20% at 24°C and significantly increased by 10% at 32°C compared to 28°C. During the upwelling season,
Pocillopora
corals exhibited a 52% increase in Symbiodiniaceae density, but the growth rate decreased by 50% compared to the non-upwelling season. Fast changes in water conditions during the upwelling strongly affects the metabolism of
Pocillopora
corals. Although conditions during upwelling were not lethal, they compromised the energy of the coral for their vital functions, indicating that upwelling pushes them toward their physiological limit. Consequently, predicted increases in upwelling events in combination with ocean warming and deoxygenation may be particularly critical for upwelling-exposed corals and the reefs they build in the Eastern Tropical Pacific.
Dissolved oxygen concentration (DO) is one of the main factors limiting benthic species distribution. Due to ocean warming and eutrophication, the ocean is deoxygenating. In the Eastern Tropical ...Pacific (ETP), deep waters with low DO (<1 mg L
) may reach coral reefs, because upwelling will likely intensify due to climate change. To understand oxygen variability and its effects on corals, we characterize the Spatio-temporal changes of DO in coral reefs of Gorgona Island and calculate the critical oxygen tension (
) to identify the DO concentration that could represent a hypoxic condition for
, one of the main reef-building species in the ETP. The mean (±SD) DO concentration in the coral reefs of Gorgona Island was 4.6 ± 0.89 mg L
. Low DO conditions were due to upwelling, but hypoxia (<3.71 mg L
, defined as a DO value 1 SD lower than the Mean) down to 3.0 mg O
L
sporadically occurred at 10 m depth. The
of
was 3.7 mg L
and lies close to the hypoxic condition recorded on coral reefs during the upwelling season at 10 m depth. At Gorgona Island oxygen conditions lower than 2.3 mg L
occur at >20 m depth and coincide with the deepest bathymetric distribution of scattered colonies of
. Because DO concentrations in coral reefs of Gorgona Island were comparably low to other coral reefs in the Eastern Tropical Pacific, and the hypoxic threshold of
was close to the minimum DO record on reefs, hypoxic events could represent a threat if conditions that promote eutrophication (and consequently hypoxia) increase.
Strain BCT-7112T was isolated in 1966 in Japan from a survey designed to obtain naturally occurring microorganisms as pure cultures in the laboratory for use as probiotics in animal nutrition. This ...strain, which was primarily identified as Bacillus cereus var toyoi, has been in use for more than 30 years as the active ingredient of the preparation TOYOCERIN®, an additive for use in animal nutrition (e.g. swine, poultry, cattle, rabbits and aquaculture). Despite the fact that the strain was initially classified as B. cereus, it showed significant genomic differences from the type strains of the B. cereus group that were large enough (ANI values below 92%) to allow it to be considered as a different species within the group. The polyphasic taxonomic study presented here provides sufficient discriminative parameters to classify BCT-7112T as a new species for which the name Bacillus toyonensis sp. nov. is proposed, with BCT-7112T (=CECT 876T; =NCIMB 14858T) being designated as the type strain. In addition, a pairwise comparison between the available genomes of the whole B. cereus group by means of average nucleotide identity (ANI) calculations indicated that besides the eight classified species (including B. toyonensis), additional genomospecies could be detected, and most of them also had ANI values below 94%. ANI values were on the borderline of a species definition only in the cases of representatives of B. cereus versus B. thuringiensis, and B. mycoides and B. weihenstephanensis.
There is increased interest in understanding how stress reduces coral resistance to disturbances and how acclimatization increases the ability of corals to resist future stress. Most extreme low ...tides at Gorgona Island, which expose reef flats to air, do not appear to negatively affect corals because corals usually do not undergo lethal bleaching during such events. However, coral physiology and fitness may be impacted by this phenomenon. The aim of this study was to evaluate whether corals exposed to air have modified biological functions to resist bleaching. To test this, an extreme low-tide event was simulated in the field. Colonies of
Pocillopora damicornis
were exposed to air for 15 or 40 min over the course of one, two, or three consecutive days. This procedure was repeated for one to three months. Colonies of
P. damicornis
exposed to air had reduced fecundity, decreased zooxanthellae density, and changed color from darker to lighter. However, the growth rate of exposed corals was similar to that of non-exposed colonies. We conclude that short periods of subaerial exposure during extreme low tides are not lethal to
P. damicornis
, but negatively affect sexual reproduction, which might have deleterious effects at the population level. The periodic occurrence of extreme low tides in the tropical eastern Pacific may be one factor responsible for the high rate of asexual reproduction (e.g., fragmentation) in pocilloporid corals of this region.
Salinibacter ruber is an extremely halophilic member of the Bacteroidetes that thrives in crystallizer ponds worldwide. Here, we have analyzed two sets of 22 and 35 co-occurring S. ruber strains, ...newly isolated respectively, from 100 microliters water samples from crystalizer ponds in Santa Pola and Mallorca, located in coastal and inland Mediterranean Spain and 350 km apart from each other. A set of old strains isolated from the same setting were included in the analysis. Genomic and taxonomy relatedness of the strains were analyzed by means of PFGE and MALDI-TOF, respectively, while their metabolomic potential was explored with high resolution ion cyclotron resonance Fourier transform mass spectrometry (ICR-FT/MS). Overall our results show a phylogenetically very homogeneous species expressing a very diverse metabolomic pool. The combination of MALDI-TOF and PFGE provides, for the newly isolated strains, the same scenario presented by the previous studies of intra-specific diversity of S. ruber using a more restricted number of strains: the species seems to be very homogeneous at the ribosomal level while the genomic diversity encountered was rather high since no identical genome patterns could be retrieved from each of the samples. The high analytical mass resolution of ICR-FT/MS enabled the description of thousands of putative metabolites from which to date only few can be annotated in databases. Some metabolomic differences, mainly related to lipid metabolism and antibiotic-related compounds, provided enough specificity to delineate different clusters within the co-occurring strains. In addition, metabolomic differences were found between old and new strains isolated from the same ponds that could be related to extended exposure to laboratory conditions.
Next generation sequencing approaches allow the retrieval of several orders of magnitude larger numbers of amplified single sequences in 16S rRNA diversity surveys than classical methods. However, ...the sequences are only partial and thus lack sufficient resolution for a reliable identification. The OPU approach used here, based on a tandem combination of high quality 454 sequences (mean >500nuc) applying strict OTU thresholds, and phylogenetic inference based on parsimony additions to preexisting trees, seemed to improve the identification yields at the species and genus levels. A total of thirteen biopsies of Crohn-diagnosed patients (CD) and seven healthy controls (HC) were studied. In most of the cases (73%), sequences were affiliated to known species or genera and distinct microbial patterns could be distinguished among the CD subjects, with a common depletion of Clostridia and either an increased presence of Bacteroidetes (CD1) or an anomalous overrepresentation of Proteobacteria (CD2). Faecalibacterium prausnitzii presence was undetectable in CD, whereas Bacteroides vulgatus–B. dorei characterized HC and some CD groups. Altogether, the results showed that a microbial composition with predominance of Clostridia followed by Bacteroidetes, with F. prausnitzii and B. vulgatus–B. dorei as major key bacteria, characterized what could be considered a balanced structure in HC. The depletion of Clostridia seemed to be a common trait in CD.
Knowing the gametic development of the coral Pocillopora damicornis and its relationship to environmental variation at La Azufrada reef (2°58′10″N and 78°11′05″W, Gorgona Island, Colombian Pacific ...Ocean) is essential to understanding the capacity for sexual replenishment of this population. Due to the lack of information about its sexual reproductive process, we collected tissue samples of healthy and unhealthy colonies (with bleaching, or algal or cyanobacterial overgrowth), along with salinity and sea-surface temperature data, between October 2010 and October 2011. During histological analysis we observed four oocyte and three spermary developmental stages in healthy colonies. Colonies were hermaphrodites with synchronous gonadal maturation in May 2011. However, polyps within colonies were either gonochoric, with a 7.8 ± 11.8:1 (mean ± SD) female to male polyp sex ratio, or hermaphroditic, with a 2.8 ± 1.5:1 (mean ± SD) oocyte to spermary ratio. The low number of spermaries observed may reduce the chance of effective fertilization and could explain the low sexual recruitment observed in the study area. There was a positive correlation between salinity and the mean number of gametes (oocytes and spermaries) produced per polyp, although both oocytes and spermaries increased during the warm water, high-salinity season (March to July 2011). Colonies with bleaching or overgrowth by cyanobacteria or algae had no gametes, suggesting that population recovery after disturbances might not be effective if it depends solely on sexual reproduction.
This study presents a model for predicting photovoltaic power generation based on meteorological, temporal and geographical variables, without using irradiance values, which have traditionally posed ...challenges and difficulties for accurate predictions. Validation methods and evaluation metrics are used to analyse four different approaches that vary in the distribution of the training and test database, and whether or not location-independent modelling is performed. The coefficient of determination, R2, is used to measure the proportion of variation in photovoltaic power generation that can be explained by the model’s variables, while gCO2eq represents the amount of CO2 emissions equivalent to each unit of power generation. Both are used to compare model performance and environmental impact. The results show significant differences between the locations, with substantial improvements in some cases, while in others improvements are limited. The importance of customising the predictive model for each specific location is emphasised. Furthermore, it is concluded that environmental impact studies in model production are an additional step towards the creation of more sustainable and efficient models. Likewise, this research considers both the accuracy of solar energy predictions and the environmental impact of the computational resources used in the process, thereby promoting the responsible and sustainable progress of data science.
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