Rocky reef incursions: challenges faced by reef fishes in a Brazilian Hope Spot region.

Biodiversity conservation has been a critical challenge faced by environmental managers worldwide. From 2020 to 2022, a total of 576 underwater visual censuses focused on reef fishes, marine litter (ML), and non-native species were performed in the newest Brazilian Hope Spot, to understand the distribution, characteristics, and effects of ML and Tubastraea spp., on the reef fish community. Plastic was the main category recorded (34.54 %), followed by Metal and Line (mostly fishing gear within a Marine Protected Area). Tubastraea spp. was widely distributed, especially between 10-20 meters deep. The t-test analysis showed that fish abundance and richness were significantly higher at low Tubastraea cover areas. Our efforts present the baseline of ML (mean 1.92 ± 1.5 items/100 m2) and non-native species occurrence (15) and distribution (including three new records) showing their negative impacts on rocky reef ecosystems and provide managers support in the elaboration of marine conservation strategies.

Microbiome diversity from sponges biogeographically distributed between South America and Antarctica.

Sponges from South America and Antarctica are evolutionarily closely related. Specific symbiont signatures that could differentiate these two geographic regions are unknown. This study aimed to investigate the microbiome diversity of sponges from South America and Antarctica. In total 71 sponge specimens were analyzed (Antarctica: N = 59, 13 different species; South America: N = 12, 6 different species). Illumina 16S rRNA sequences were generated (2.88 million sequences; 40K ± 29K/sample). The most abundant symbionts were heterotrophic (94.8 %) and belonged mainly to Proteobacteria and Bacteroidota. EC94 was the most abundant symbiont and dominated the microbiome of some species (70-87 %), comprising at least 10 phylogroups. Each of the EC94 phylogroups was specific to one genus or species of sponge. Furthermore, South America sponges had higher abundance of photosynthetic microorganisms (2.3 %) and sponges from Antarctica, the highest abundance of chemosynthetic (5.5 %). Sponge symbionts may contribute to the function of their hosts. The unique features from each of these two regions (e.g., light, temperature, and nutrients) possibly stimulate distinct microbiome diversity from sponges biogeographically distributed across continents.

Brumadinho dam collapse induces changes in the microbiome and the antibiotic resistance of the Paraopeba River (Minas Gerais, Brazil).

The rupture of the Córrego do Feijão dam in Brumadinho (January 25, 2019) caused serious damage to the Paraopeba River and compromised the quality of its waters for human consumption. However, the possible effects of the dam collapse on the river microbiome and its antibiotic resistance profiles are unknown. The present study aims to analyse the possible shifts in microbial diversity and enhancement of antibiotic resistance in the Paraopeba River. To this end, two sampling campaigns (February and May 2019) were performed to obtain water across the entire Paraopeba River (eight sampling locations: Moeda, Brumadinho, Igarapé, Juatuba, Varginha, Angueretá, Retiro Baixo and Três Marias; ~464 km). This sampling scheme enabled determining the effects of the disaster on the river microbiome. Total DNA and microbial isolation were performed with these water samples. The 16S rRNA-based microbiome analyses (n = 24; 2.05 million 16S rRNA reads) showed changes in microbial diversity immediately after the disaster with the presence of metal-indicating bacteria (Acinetobacter, Bacillus, Novosphingobium, and Sediminibacterium). Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) identification of bacterial isolates (n = 170) also disclosed possible indicators of faecal contamination across the Paraopeba (Cloacibacterium, Bacteroides, Feaecalibacterium, Bifidobacterium, Citrobacter, Enterobacter, Enterococcus and Escherichia). Antibiotic resistance increased significantly to ampicillin, ampicillin/sulbactam, amoxicillin/clavulanate, ceftriaxone, and cefalotin among isolates obtained in May after the disaster. The effects of toxic mud on microbiomes were felt at all points sampled up to Anguereta. The ore mud may have exacerbated the growth of different antibiotic-resistant, metal-resistant, and faecal-indicating bacteria in the Paraopeba River.

Severe impacts of the Brumadinho dam failure (Minas Gerais, Brazil) on the water quality of the Paraopeba River.

On 25 January 2019, Córrego do Feijão's tailing dam at Brumadinho city (Minas Gerais, Brazil) breached, leaving over 250 people dead. At least 12 million cubic meters of ore tailing were spread into Paraopeba River and the surrounding area. To evaluate the short-term impacts of the Brumadinho dam rupture on the environment, we performed biogeochemical, microbiological and ecotoxicological analyses across 464 km of the Paraopeba River in the week following the disaster (1 February 2019) and four months latter (27-29 May 2019). Immediately after the disaster, the water turbidity was 3000 NTU, 30 times greater than the standard recommended by the Brazilian Resolution for Water Quality (CONAMA 357). Up to a 60-fold increase in iron tolerant microbial colony forming unities was observed up to 115 km downstream of the dam failure in May 2019 (compared with February 2019), suggesting changes in microbial metabolic profiles. In the second sampling (May 2019), the ecotoxicological analyses indicate higher zebrafish embryo mortality (up to ~85% embryo mortality) rates in Retiro Baixo (304 km from dam failure location). However, increased zebrafish mortality in Retiro Baixo and Três Marias reservoirs may not be related exclusively to the dam failure. The causal nexus of mortality may be associated with other factors (e.g. local sewage pollution). Our study suggests that independent monitoring programs are needed to quantify the extent of potential impacts caused by the anthropogenic use of the river and to promote the recovery of the impacted area.

Severe impacts of the Brumadinho dam failure (Minas Gerais, Brazil) on the water quality of the Paraopeba River

On 25 January 2019, Córrego do Feijão's tailing dam at Brumadinho city (Minas Gerais, Brazil) breached, leaving over 250 people dead. At least 12 million cubic meters of ore tailing were spread into Paraopeba River and the surrounding area. To evaluate the short-term impacts of the Brumadinho dam rupture on the environment, we performed biogeochemical, microbiological and ecotoxicological analyses across 464 km of the Paraopeba River in the week following the disaster (1 February 2019) and four months latter (27–29 May 2019). Immediately after the disaster, the water turbidity was 3000 NTU, 30 times greater than the standard recommended by the Brazilian Resolution for Water Quality (CONAMA 357). Up to a 60-fold increase in iron tolerant microbial colony forming unities was observed up to 115 km downstream of the dam failure in May 2019 (compared with February 2019), suggesting changes in microbial metabolic profiles. In the second sampling (May 2019), the ecotoxicological analyses indicate higher zebrafish embryo mortality (up to ~85% embryo mortality) rates in Retiro Baixo (304 km from dam failure location). However, increased zebrafish mortality in Retiro Baixo and Três Marias reservoirs may not be related exclusively to the dam failure. The causal nexus of mortality may be associated with other factors (e.g. local sewage pollution). Our study suggests that independent monitoring programs are needed to quantify the extent of potential impacts caused by the anthropogenic use of the river and to promote the recovery of the impacted area.