Human activities are causing dramatic declines in ecosystem health, compromising the functioning of the life-support system, economic activity, and animal and human health. In this context, ...monitoring the health of ecosystems and wildlife populations is crucial for determining ecological dynamics and assessing management interventions. A growing body of evidence indicates that microbiome provides a meaningful early indicator of ecosystem and wildlife health. Microbiome is ubiquitous and both environmental and host-associated microbiomes rapidly reflect anthropogenic disturbances. However, we still need to overcome current limitations such as nucleic acid degradation, sequencing depth, and the establishment of baseline data to maximize the potential of microbiome studies.
Display omitted
•Microbiome can be an early warning indicator of ecosystem and wildlife health.•Microbiome responds to anthropogenic disturbances and management interventions.•Microbiome potential remains largely unexplored in terrestrial ecosystems.•Future biotechnological advances will be crucial to maximize microbiome studies.•Baseline data need to be defined in order to correctly interpret microbiome dynamics.
Summary
Pseudomonas aeruginosa is a widely distributed environmental bacterium but is also an opportunistic pathogen that represents an important health hazard due to its high intrinsic antibiotic ...resistance and its production of virulence factors. The genetic structure of P. aeruginosa populations using whole genome sequences shows the existence of three clades, one of which (PA7 clade) has a higher genetic diversity. These three clades include clinical and environmental isolates that are very diverse in terms of geographical origins and isolation date. Here, we report the characterization of two distinct clonal P. aeruginosa groups that form a part of the PA14 clade (clade 2) sampled from the Churince system in Cuatro Ciénegas Basin (CCB). One of the clonal groups that we report here was isolated in 2011 (group 2A) and was displaced by the other clonal group (2B) in 2015. Both Churince groups are unable to produce pyoverdine but can produce other virulence‐associated traits. The existence of these unique P. aeruginosa clonal groups in the Churince system is of ecological and evolutionary significance since the microbiota of this site is generally very distinct from other lineages, and this is the first time that a population of P. aeruginosa has been found in CCB.
There are abundant reports of symbiosis wherein crustaceans live inside or on mollusks; however, there are few published records of gastropods hosting decapods. This study examines the biological ...association between fifteen snails (124.86 ± 19.01) from the species Pacific crown conch Melongena patula and the porcelain crab Euceramus transversilineatus. Morphometric relationships of both invertebrates, as well as some sexual characteristics of the crab were conducted. These invertebrates were sampled in the Navachiste Lagoon, in the south eastern Gulf of California, Sinaloa, Mexico. It was found 86.6% of the snails housed at least a female or a male porcelain crab (17.82 ± 3.27 mm total body length) or a pair of them (heterosexual and same sex) with a sexual proportion of 2M:1F. There were no correlations between any of the crab and snail based on their analyzed morphometric relationships. For the crab males, the measurements of both chelae presented relationships with total body length, carapace length, and abdomen width however, no significant differences were observed between the mean width and chelae length of males, females or between sexes. Of the six females collected, four were gravid. Preliminary observations indicated that the porcelain crab E. transversilineatus is a commensal endosymbiont that coexist in short-term association with M. patula. Their population distribution suggests that E. transversilineatus are polygamous with a promiscuous mating pattern.
Pozas Rojas is a hydrological system comprising nine isolated shallow ponds and a deep lagoon, which were temporally merged in 2010 by increased rainfall due to a tropical cyclone. In this work, we ...assess which components, biotic interactions, or environment filtering effects, drive the assembly of microbial communities after a natural perturbation. Arsenic, pH, and temperature are among the most significant environmental variables between each pond, clustering the samples in two main groups, whereas microbial composition is diverse and unique to each site, with no core at the operational taxonomic unit level and only 150 core genera when studied at the genus level. Los Hundidos lagoon has the most differentiated community, which is highly similar to the epipelagic Mediterranean Sea communities. On the other hand, the shallow ponds at the Pozas Rojas system resemble more to epicontinental hydrological systems, such as some cold rivers of the world and the phreatic mantle from Iowa. Overall, despite being a sole of water body 2 years prior to the sampling, interspecific interactions, rather than environmental selection, seem to play a more important role in Pozas Rojas, bolstered by founder effects on each poza and subsequent isolation of each water body.
Objective
Prolonged exposure to heavy metals, such as Pb, Hg, or Cu, has multiple adverse effects on marine organisms at the cellular, physiological, and population levels. Bivalves' histopathology ...provides a sensitive biomarker of pollutant‐induced stress and environmental health. Gonad tissue deterioration is of particular concern, as it affects the reproductive success of a species. This study aimed to examine the histopathological alterations caused by metal exposure in the gonad of the white clam Dosinia ponderosa.
Methods
Organisms were sampled from three locations in the Gulf of California: Santa Rosalia (SR), a former Cu mining town; San Lucas beach (SL), a nearby site influenced by pollution; and Escondida beach (EB), which served as a control site. Histological and histochemical stains were used, and the prevalence and intensity level of each alteration were calculated.
Result
The prevalence of alterations was higher in the ovaries of SR clams (92% compared to 60% in SL clams and 32.7% in EB clams), during spawning (91.4% compared to 20% in SL clams and 4.7% in EB clams), and in winter (93.5% compared to 30% in SL clams and 17.4% in EB clams).
Conclusion
These findings suggest a significant deterioration in the gonads of white clams from SR, probably linked to the chronic exposure to high concentrations of Cu and possibly other heavy metals; hence, the reproductive health of the clams is likely compromised.
Impact statement
This research provides evidence of the adverse impact of the mining industry on marine organisms, when mining waste is transported to the sea by natural runoff. These results also have implications for human health, since the clams studied in this research are part of the regional diet.
Anthropogenic perturbations introduce novel selective pressures to natural environments, impacting the genomic variability of organisms and thus altering the evolutionary trajectory of populations. ...Water overexploitation for agricultural purposes and defective policies in Cuatro Cienegas, Coahuila, Mexico, have strongly impacted its water reservoir, pushing entire hydrological systems to the brink of extinction along with their native populations. Here, we studied the effects of continuous water overexploitation on an environmental aquatic lineage of
over a 13-year period which encompasses three desiccation events. By comparing the genomes of a population sample from 2003 (original state) and 2015 (perturbed state), we analyzed the demographic history and evolutionary response to perturbation of this lineage. Through coalescent simulations, we obtained a demographic model of contraction-expansion-contraction which points to the occurrence of an evolutionary rescue event. Loss of genomic and nucleotide variation alongside an increment in mean and variance of Tajima's
, characteristic of sudden population expansions, support this observation. In addition, a significant increase in recombination rate (R/θ) was observed, pointing to horizontal gene transfer playing a role in population recovery. Furthermore, the gain of phosphorylation, DNA recombination, small-molecule metabolism and transport and loss of biosynthetic and regulatory genes suggest a functional shift in response to the environmental perturbation. Despite subsequent sampling events in the studied site, no pseudomonad was found until the lagoon completely dried in 2017. We speculate about the causes of
final decline or possible extinction. Overall our results are evidence of adaptive responses at the genomic level of bacterial populations in a heavily exploited aquifer.
Routine sampling of pregnant women at first antenatal care (ANC) visits could make Plasmodium falciparum genomic surveillance more cost-efficient and convenient in sub-Saharan Africa. We compare the ...genetic structure of parasite populations sampled from 289 first ANC users and 93 children from the community in Mozambique between 2015 and 2019. Samples are amplicon sequenced targeting 165 microhaplotypes and 15 drug resistance genes. Metrics of genetic diversity and relatedness, as well as the prevalence of drug resistance markers, are consistent between the two populations. In an area targeted for elimination, intra-host genetic diversity declines in both populations (p = 0.002-0.007), while for the ANC population, population genetic diversity is also lower (p = 0.0004), and genetic relatedness between infections is higher (p = 0.002) than control areas, indicating a recent reduction in the parasite population size. These results highlight the added value of genomic surveillance at ANC clinics to inform about changes in transmission beyond epidemiological data.
Symbiosis between decapods and mollusks provides a unique opportunity to examine some of the evolutionary strategies employed by marine invertebrates. We describe the sexual and reproductive traits ...of the pearl oyster shrimp,
Pontoniamargarita
Verril, 1869, found symbiotically inhabiting the mantle cavity of the rugose pen shell,
Pinnarugosa
Sowerby, 1835. Solitary males and females (ovigerous and non-ovigerous) and heterosexual pairs (with ovigerous and non-ovigerous females) were found in a total of 47 rugose pen shells collected from a sandy area with seagrass meadows on the southeastern coast of the Gulf of California, Mexico. The body length (BL) of female
P.margarita
was correlated with the shell volume of their rugose pen shell host. The sex ratio was female-biased (0.85M:1F). Female
P.margarita
were larger than their male counterparts in terms of BL, cephalothorax length (CL), and the maximum chelae length of the second pereopod (MCL). The CL and MCL were more strongly correlated for males (r = 0.70, p = 0.01). The number and volume of eggs per ovigerous female varied from 95 to 1,571 and from 5.46 ± 0.48 to 8.85 ± 0.97 mm
3
, respectively. Our results indicate polygamous behavior and social monogamy among
P.margarita
, and a short-term pairing system for their association with
P.rugosa
.
The shell height-body weight relationship of the black clam Chionista fluctifraga cultivated in the intertidal of the southeastern Gulf of California, was evaluated for the first time, to improve the ...knowledge in determining its harvesting time. Clam seeds (n=900,000; 6.1±1.9 mm) were produced in the laboratory. The culture was divided into pre-fattening in racks on the bottom (2 months) and fattening directly in the bottom (16 months) from May 2018 to October 2019. Each month, 60 (n=1080) clams were randomly selected to stablish the morphometric relationship between shell height (SH) and body weight (BW). The growth rate (mm/d and g/d) was recorded. The SH-BW Interaction in both cultivation phases showed positive allometry. SH in prefattening and fattening registered a growth rate of 0.072 and 0.058 mm/d, respectively. In fattening, the interaction BW-SH displayed a high coefficient of determination (R2=0.99). A final survival rate of 90% was obtained. The results yielded the equations that describe the relative growth of C. fluctifraga for the fattening stage. A harvesting time after 10 months of fattening in the intertidal zone is stablished to reach the commercial size (35 mm, SH).
PDF
