Identification by molecular techniques of halophilic bacteria producing important enzymes from pristine area in Campeche, Mexico

Isla Arena is located in the coordinate 20° 70´ N - 90° 45´ W, from Campeche, Mexico. In these estuaries, the ocean mixes with fresh water, and ecosystems are concentrated where petenes and pink flamingos proliferate. Crustaceans and mollusks abound in the sea. Despite its enormous marine wealth, there are no studies carried out on which halophilic microorganisms are present in these waters. In this work, the diversity and structure of the microbial community was investigated through a metagenomics approach and corroborated for sequencing of 16S rRNA genes. It was found that the phylum Fimicutes predominates with more than 50%, in almost the same proportion of the class Bacilli and with almost 41% of relative abundance of the order Bacillales. The sequencing results showed that one of the samples presented a high percentage of similarity (99.75%) using the Nucleotide BLAST program with a peculiar microorganism: Bacillus subtilis. This microorganism is one of the best characterized bacteria among the gram-positive ones. Our results demonstrate that B. subtilis can be an efficient source of proteases, lipases and cellulases, from halophilic microbial communities located in poorly explored areas.

EXTENDING THE LIMITS OF CAMPOS RUPESTRES IN BRAZIL

Campos rupestres are typical ecosystems of rock outcrops with high biodiversity and endemism, located in Brazilian territory, with vegetation analogous in Africa and Australia. The campos rupestres cover deeply dystrophic soils on highlands inserted in Amazon rainforest, Atlantic rainforest and Cerrado biomes. Despite recognition of campos rupestres as a global biodiversity hotspot, little is known its occurrence in dry forests. So, this work aimed to describe vegetable cover and soil properties in highlands associated to rock outcrops on Caatinga biome. A pristine area in Borborema plateau was chosen as study area. Frequency of species and life forms indicate high vegetable density and herbaceous habits predominance. Although the high similarity of species with Caatinga biome, presence of Albizia, Dalbergia, Poecilanthe e Platymiscium indicates a truly distinct floristic composition. Soils are shallower, less fertile and has lower water storage capacity than predominant soils in Caatinga. This work reveals the presence of campos rupestres beyond the areas previously considered favorable to its presence, extending its occurrence to regions of lower precipitation. The occurrence of the campos rupestres is attributed to an additional supply of water from fog in consonance with organic soils. Therefore, areas with similar characteristics should be prioritized to be preserved.

Assessing the Drivers behind the Structure and Diversity of Fish Assemblages Associated with Rocky Shores in the Galapagos Archipelago

Oceanic islands harbor unique yet fragile marine ecosystems that require evidence-based environmental management. Among these islands, the Galapagos archipelago is well known for its fish diversity, but the factors that structure communities within and between its islands remain poorly understood. In this study, water quality, physical habitats and geographical distance were assessed as potential predictors for the diversity and structure of fish assemblages. Differences in the structure of fish assemblages of the two studied islands (Santa Cruz and Floreana) were most likely driven by temperature and nutrient concentrations. In the relatively highly populated island Santa Cruz, the structure of fish assemblages was more affected by water conditions than physical habitats while the contrary was true for the more pristine area of Floreana. A wide variety of species with different geographical origins were distributed over the different islands, which indicates that most fish species are able to reach the islands of the archipelago. However, temperature gradients and elevated nutrient levels cause large differences in the structure of local fish assemblages. In addition, in Santa Cruz nutrient concentrations were negatively correlated with α diversity. Since pollution is a clear pressure on the fish assemblages of oceanic islands, environmental management of the coastal areas is of paramount importance.

Determination of Stomatic Density, Index, and Area as Exposition Biomarkers of Pollution in Deschampsia Antárctica Desv. (Poaceae)

Deschampsia antarctica Desv. (Poaceae) is the only native grass described so far for Antarctica, with a distribution mainly centered on the Antarctic Peninsula. The plants were collected at Argentinian Scientific Station Carlini, 25 de Mayo (King George) Island, to determine and evaluate in their leaves: the stomatic index (SI), density (SD), and area (SA) as pollution biomarkers. Samples were taken within the Station's influence area: (A) Supply Area (loading and unloading of fuel and supplies), (B) the area adjacent to the Electric Power Station, and (C) area of Fuel Tanks. Besides, other samples were taken from a pristine area called Peñon 7 (D). The results of SD showed significant differences only on the leaf abaxial face from the plants of the 4 studied sites: Peñón 7 (57.36 ± 2.03), Supply Area (61.30 ± 2.32), Electric Power Station adjacent area (69.56 ± 2.23) and Fuel Tanks area (80.11 ± 2.42). The SI as well as the SA did not have significant differences (p > 0.05) for all the analyzed sites. However, correlation analyses between SD and SI showed a positive and significant association only for the leaf adaxial face from all sites. From the obtained results, we could suggest that the correlation (SD-SI) on the adaxial side of the leaves was a good biomarker to estimate the degree of anthropogenic impact in each studied area.

Correlation of microplastic type and metal association: Croatian coast case study (Žirje Island)

<p>The aim of the study was to determine the correlation of metals on floating marine litter and weathered microplastic samples from the pristine area. Sampled were collected from the accumulated material on the natural beach in Mala Stupica Cove (Žirje Island, Croatia) in June 2020. In addition to weathered microplastic, the concentrations of dissolved metals in the seawater, at the same location were determined. According to these measurements, the sampling site can be considered pristine, with Cd and Pb concentrations as background values and Zn and Cu as elements that have no toxic effect, based on the classification proposed by Bakke et al., (2010). The metals of interest due to their high toxicity were Zn, Cd, Pb, and Cu.</p><p>After sampling, the collected material was sieved through a metal sieve with a 4 mesh size, resulting in 4 subsamples (>4 mm; 4-2 mm; 2-1 mm; 1-0.250 mm). The type of plastic particles from subsample >4 mm was determined by FTIR spectroscopy performed on Bruker Tensor 27 in the region from 400-4000 cm<sup>-1</sup>. On such defined particles and in the seawater sample, trace metal concentrations were determined by the electrochemical method differential pulse anodic stripping voltammetry (DPASV) with standard addition method by Metrohm Autolab modular potentiostat/galvanostat Autolab PGSTAT204. A static mercury drop electrode (SMDE) was used as the working electrode.</p><p>Plastic particles were isolated from additional two fractions (2-1 mm and 1-0.250 mm) as bulk samples, but without polystyrene, and the metal concentration was also determined using the same method. Due to the particle size, the type of plastic was not determined. Additional analyzes of metal concentrations on a defined and isolated polystyrene particles (PS) from a subsample (4-2 mm) and (2-1 mm) were also performed.</p><p>By analogy with sediment particles, one would expect smaller microplastic particles to have higher metal concentrations due to their larger specific surface area, but this was not observed in this study. The metal concentration varied with the type of plastic, and from the observed results, plastics could be ranked according to their affinity for the analyzed metals, as follows: polystyrene (PS)>Polypropylene (PP)>Low-density polyethylene (LDPE). According to an average concentration of all analyzed samples defined as LDPE, Zn could be single out as an element with around 7-time higher affinity for LDPE than other elements (Cd, Pb, and Cu). For samples defined as PP, the highest affinity is observed for Pb, even 30 times higher than in LDPE, followed by Zn and Cu, while Cd has similar values as in LDPE.  For PS samples affinity of all elements is higher in comparison with the LDPE and PP, as follows: Pb>Cu> Zn>Cd, with a concentration of Pb 2.5 times higher than in PP and even 88 times higher than in LDPE.</p><p> A general conclusion could be drawn, but the observed wide ranges indicate the need for additional research to determine the relationship between the degree and type of weathering with the associated metals.</p><p>This work has been fully supported by Croatian Science Foundation under the project lP-2019-04-5832.</p>

Imazapyr herbicideformulation induced multiple abnormalities in gonadal development of Xenopus laevis at environmentally relevant concentrations

Mankind is now in the era of environmental contamination and pollution, where the environment has become a warehouse of its several toxicants. In fact, there are no longer any pristine area without these anthropogenic toxicants, with serious consequences on wildlife’s physiological processes including growth and reproduction. The widespread occurrence of pesticides for example, is being linked to numerous reproductive malformations in wildlife organisms, but the degree of association has not been characterised. Using the extended Xenopus Metamorphosis Assay (XEMA) protocol, the exposure impacts of imazapyr herbicide formulation (Arsenal), approved for aquatic environment was assessed on gonadal development of Xenopus laevis at environmentally relevant concentrations of 0.5, 2.0, and 3.5 mg/L. The formulation significantly reduced the mean body mass at premetamorphosis (NF-stage 55) at 3.5 mg/L concentration compared to the control. In sex ratio, the exposure only showed marginal fluctuations at all the exposure concentrations. For gonadal malformations, an abnormality index of 17.5%, 25%, and 35% was derived at 0.5 mg/L, 2.0, and 3.5 mg/L concentrations respectively, with malformations including tissues separation, segmented aplasia, aplasia, mixed sex, narrow hypoplasia, and angular deformity. This study showed that at relevant environmental concentrations, this formulation induced concentration dependent complex gonadal malformations, suggesting its potential capacities to induced serious reproductive disruptions that can negatively impacts fecundity, fertility, and general reproductive fitness of amphibians. In order to protect the wildlife from reproductive impacts, there is a serious need for cautions in application of this herbicide formulation

Hg Concentrations and Stable Isotopes Variations in Tropical Fish Species of a Gold-mining Impacted Watershed in French Guiana

The aim of the study was to determine if gold mining activities could impact the mercury (Hg) concentrations and isotopic signatures in freshwater fish consumed by riparian people in French Guiana. Total Hg, MeHg concentrations and Hg stable isotopes ratios were analyzed in fish muscles from different species belonging to three feeding patterns (herbivorous, periphytophagous and piscivorous). We compared tributaries impacted by gold-mining activities (Camopi, CR) with a pristine area upstream (Trois-Sauts, TS), along the Oyapock River. We measured δ15N and δ13C to examine whether Hg patterns are due to differences in trophic level. Differences in δ15N and δ13C values between both studied sites were only observed for periphytophageous fish, with enriched values at TS. Total Hg concentrations and Hg stable isotopes fractionations showed that Hg accumulated in fish from both areas have undergone different biogeochemical processes. Δ199Hg variation in fish (-0.5 to 0.2‰) was higher than the ecosystem baseline defined by a Δ199Hg of -0.66‰ in sediments, and suggested limited aqueous photochemical MeHg degradation. Photochemistry-corrected δ202Hg in fish were 0.7‰ higher than the baseline, consistent with biophysical and chemical isotope fractionations in aquatic environment. While THg concentrations in periphytophagous fish were higher in the gold-mining area than in TS, in contrast to the sediments results, the ensemble of Hg isotope shifts did not allow to trace and quantify the gold-mining related liquid Hg(0) sources in the fish muscles.

Atmospheric Mercury Deposition in Macedonia from 2002 to 2015 Determined Using the Moss Biomonitoring Technique

The moss biomonitoring technique was used in 2002, 2005, 2010 and 2015 in a potentially toxic elements study (PTEs) in Macedonia. For that purpose, more than 70 moss samples from two dominant species (Hypnum cupressiforme and Homalothecium lutescens) were collected during the summers of the mentioned years. Total digestion of the samples was done using a microwave digestion system, whilst mercury was analyzed by cold vapour atomic absorption spectrometry (CV–AAS). The content of mercury ranged from 0.018 mg/kg to 0.26 mg/kg in 2002, from 0.010 mg/kg to 0.42 mg/kg in 2005, from 0.010 mg/kg to 0.60 mg/kg in 2010 and from 0.020 mg/kg to 0.25 mg/kg in 2015. Analysis of the median values shows the increase of the content in the period 2002–2010 and a slight reduction of the air pollution with Hg in the period 2010–2015. Mercury distribution maps show that sites with increased concentrations of mercury in moss are likely impacted by anthropogenic pollution. The results were compared to similar studies done during the same years in neighboring countries and in Norway—which is a pristine area and serves as a reference, and it was concluded that mercury air pollution in Macedonia is significant primarily in industrialized regions.

Searching for humpback whales in a historical whaling hotspot of the Coral Sea, South Pacific

Humpback whales Megaptera novaeangliae were severely depleted by commercial whaling. Understanding key factors in their recovery is a crucial step for their conservation worldwide. In Oceania, the Chesterfield-Bellona archipelago was a primary whaling site in the 19th century, yet has been left almost unaffected by anthropogenic activities since. We present the results of the first multidisciplinary dedicated surveys in the archipelago assessing humpback whale populations 2 centuries post-whaling. We encountered 57 groups during 24 survey days (2016-2017), among which 35 whales were identified using photographs of natural markings (photo-ID), 38 using genotyping and 22 using both. Humpback whales were sparsely distributed (0.041 whales km-1): most sightings concentrated in shallow inner-reef waters and neighbouring offshore shallow banks. The recently created marine protected area covers most of the areas of high predicted habitat suitability and high residence time from satellite-tracked whales. Surprisingly for a breeding area, sex ratios skewed towards females (1:2.4), and 45% of females were with calf. Connectivity was established with the New Caledonia breeding area to the east (mtDNA FST = 0.001, p > 0.05, 12 photo-ID and 10 genotype matches) and with the Australian Great Barrier Reef breeding area to the west (mtDNA FST = 0.006, p > 0.05). Movement of satellite-tracked whales and photo-ID matches also suggest connections with the east Australian migratory corridor. This study confirms that humpback whales still inhabit the Chesterfield-Bellona archipelago 2 centuries post whaling, and that this pristine area potentially plays a role in facilitating migratory interchange among breeding grounds of the western South Pacific.

Historial thallium deposition trends as recorded in peat bogs - examples from Czech sites with contrasting pollution histories

<p>The purpose of this study is to investigate the Tl distribution and accumulation rates in Czech peatbogs with contrasting anthropogenic loads. Nine peat cores were sampled in the mountain areas of the Czech Republic (6 cores in the northern part affected by emissions from coal-burning power plants and 3 in the pristine southern part). In addition, 3 cores were collected close to the Pb mining and smelting area of Pribram. Cores were 210-Pb dated and trace metals/metalloids were measured in the digests by ICP-MS. Maximum Tl concentrations in peat were significantly higher in the polluted northern areas (1.16 mg/kg) and close to the Pb smelter (0.83 mg/kg) than in the pristine area (0.45 mg/kg). Thallium distribution well correlated with other metals (Pb, Hg) and metalloids (As, Sb). Thallium enrichment factors (EFs) calculated against Sc reached the maximum value of 17 indicating significant input of anthropogenic Tl. Thallium accumulation rates in peat varied between 20 and 50 µg/m2/y until 1930s, followed by a significant increase related to industrial activities in the northern part of the Czech Republic (up to 290 µg/m2/y in 1980s). In contrast, maximum Tl accumulation rate at the pristine site was 88 µg/m2/y. Data from the vicinity of Pb mines/smelter indicated higher accumulation rates even in the second half of the 19th century (between 50 and 200 µg/m2/y) followed by a significant decrease in late 1970s as a result of more efficient flue gas cleaning technology installed in the smelter during this period. </p>