Unveiling microbiome changes in Mediterranean octocorals during the 2022 marine heatwaves: quantifying key bacterial symbionts and potential pathogens.

BACKGROUND: Climate change has accelerated the occurrence and severity of heatwaves in the Mediterranean Sea and poses a significant threat to the octocoral species that form the foundation of marine animal forests (MAFs). As coral health intricately relies on the symbiotic relationships established between corals and microbial communities, our goal was to gain a deeper understanding of the role of bacteria in the observed tissue loss of key octocoral species following the unprecedented heatwaves in 2022. RESULTS: Using amplicon sequencing and taxon-specific qPCR analyses, we unexpectedly found that the absolute abundance of the major bacterial symbionts, Spirochaetaceae (C. rubrum) and Endozoicomonas (P. clavata), remained, in most cases, unchanged between colonies with 0% and 90% tissue loss. These results suggest that the impairment of coral health was not due to the loss of the main bacterial symbionts. However, we observed a significant increase in the total abundance of bacterial opportunists, including putative pathogens such as Vibrio, which was not evident when only their relative abundance was considered. In addition, there was no clear relation between bacterial symbiont loss and the intensity of thermal stress, suggesting that factors other than temperature may have influenced the differential response of octocoral microbiomes at different sampling sites. CONCLUSIONS: Our results indicate that tissue loss in octocorals is not directly caused by the decline of the main bacterial symbionts but by the proliferation of opportunistic and pathogenic bacteria. Our findings thus underscore the significance of considering both relative and absolute quantification approaches when evaluating the impact of stressors on coral microbiome as the relative quantification does not accurately depict the actual changes in the microbiome. Consequently, this research enhances our comprehension of the intricate interplay between host organisms, their microbiomes, and environmental stressors, while offering valuable insights into the ecological implications of heatwaves on marine animal forests. Video Abstract.

Promoting children's science, technology, engineering, and mathematics learning at home through tinkering and storytelling.

This study examined whether connecting storytelling and tinkering can advance early STEM (science, technology, engineering, and mathematics) learning opportunities for children. A total of 62 families with 4- to 10-year-old (M = 8.03) children were observed via Zoom. They watched a video invitation to tinker at home prepared by museum educators prior to tinkering. Then, half of the families were prompted to think up a story before tinkering (story-based tinkering group), whereas the other half were simply asked to begin tinkering (no-story group). Once they had finished tinkering, researchers elicited children's reflections about their tinkering experience. A subset of the families (n = 45) also reminisced about their tinkering experience several weeks later. The story instructions provided before tinkering engendered children's storytelling during tinkering and when reflecting on the experience. Children in the story-based tinkering group also talked the most about STEM both during tinkering, and subsequently when reminiscing with their parents about their tinkering experience.

Nutrient starvation and nitrate pollution impairs the assimilation of dissolved organic phosphorus in coral-Symbiodiniaceae symbiosis.

Phosphorus (P) is an essential but limiting nutrient for coral growth due to low concentrations of dissolved inorganic concentrations (DIP) in reef waters. P limitation is often exacerbated when concentrations of dissolved inorganic nitrogen (DIN) increase in the reef. To increase their access to phosphorus, corals can use organic P dissolved in seawater (DOP). They possess phosphatase enzymes that transform DOP into DIP, which can then be taken up by coral symbionts. Although the concentration of DOP in reef waters is much higher than DIP, the dependence of corals on this P source is still poorly understood, especially with different concentrations of DIN in seawater. As efforts to predict the future of corals increase, improved knowledge of the P requirements of corals living under different DIN concentrations may be key to predicting coral health. In this study, we investigated P content and phosphatase activities (PAs) in Stylophora pistillata maintained under nutrient starvation, long-term nitrogen enrichment (nitrate or ammonium at 2 µM) and short-term (few hours) nitrogen pulses. Results show that under nutrient depletion and ammonium-enriched conditions, a significant increase in PAs was observed compared to control conditions, with no change in the N:P ratio of the coral tissue. On the contrary, under nitrate enrichment, there was no increase in PAs compared to control conditions, but an increase in the N:P ratio of the coral tissue. These results suggest that under nitrate enrichment, corals were unable to increase their ability to rely on DOP and replenish their cellular P content. An increase in cellular N:P ratio is detrimental to coral health as it increases the susceptibility of coral bleaching under thermal stress. These results provide an overall view of the P requirements of corals exposed to different nutrient conditions and improve our understanding of the effects of nitrogen enrichment on corals.

Advancing opportunities for children's informal STEM learning transfer through parent-child narrative reflection.

This study examined whether families' conversational reflections after a STEM (science, technology, engineering, and mathematics)-related experience in a museum promoted learning transfer. 63 children (M = 6.93 years; 30 girls; 57% White, 17.5% Latinx, 8% Asian, 5% African American, 9.5% mixed, 3% missing race/ethnicity) and their parents received an engineering demonstration, engaged in a building activity, and either recorded a photo-narrative reflection about their building experience or not at the museum. Thirty-six of these families completed a building activity with different materials weeks later at home, and the majority (77%) evidenced learning transfer of the building principle demonstrated at the museum. Those who participated in the photo-narrative reflection at the museum also showed learning transfer by talking more about STEM during the home building activity.

Tinkering With Testing: Understanding How Museum Program Design Advances Engineering Learning Opportunities for Children.

Using a design-based research approach, we studied ways to advance opportunities for children and families to engage in engineering design practices in an informal educational setting. 213 families with 5-11-year-old children were observed as they visited a tinkering exhibit at a children's museum during one of three iterations of a program posing an engineering design challenge. Children's narrative reflections about their experience were recorded immediately after tinkering. Across iterations of the program, changes to the exhibit design and facilitation provided by museum staff corresponded to increased families' engagement in key engineering practices. In the latter two cycles of the program, families engaged in the most testing, and in turn, redesigning. Further, in the latter cycles, the more children engaged in testing and retesting during tinkering, the more their narratives contained engineering-related content. The results advance understanding and the evidence base for educational practices that can promote engineering learning opportunities for children.

Overall assessment of surface water quality in the Lower Danube River.

Water is an important receptor of environmental problems generated by anthropogenic activities, the water quality being affected by their magnitude and impact as well as by climate change. Given the international and cross-border nature of the Danube River and being aware that the pollution risk assessment is one of the key elements of the ecology and health of the people in its region, this paper assessed the state of water quality in the Lower Danube River in accordance with Water Framework Directive (Directive 2000/60/EC). The intensive monitoring program applied by the National Institute for Research and Development in Environmental Protection (INCDPM) took place during the period 2011-2017, in which approximately 1500 samples were taken and processed from 10 monitoring sites and the quality indicators stipulated in M.O. 161/2006 were analysed according to the standards in force. In this monitoring area (km 375-km 175), hydrotechnical works have been done in order to improve navigation conditions. Therefore, on the basis of the data obtained from the monitoring campaigns, multivariate statistical methods of water quality assessment were applied on the complex set of data, and at the same time, the multiparametric quality index (ICPM) was applied, an index of global comparative assessment of water quality over historical trends, developed by INCDPM. Following the evaluation of the results, the water quality in the Lower Danube River was characterized as moderately polluted and corresponds to Class III of surface water quality. The ecosystem approach indicates that the values of the monitored indicators did not correspond to the target values according to the Water Framework Directive.

Promoting children's learning and transfer across informal science, technology, engineering, and mathematics learning experiences.

This study investigated ways to support young children's science, technology, engineering, and mathematics (STEM) learning and transfer of knowledge across informal learning experiences in a museum. Participants were 64 4- to 8-year-old children (Mage = 6.55 years, SD = 1.44) and their parents. Families were observed working together to solve one engineering problem, and then immediately afterward children worked on their own to solve a second engineering problem. At the outset of the problem-solving activities, families were randomly assigned to receive engineering instructions, transfer instructions, both engineering and transfer instructions, or no instructions. Families who received engineering instructions-either alone or in combination with the transfer instructions-demonstrated greater understanding and use of the engineering principle of bracing compared with those who received only transfer instructions. Moreover, older children who received both engineering and transfer instructions were more successful when working on their own to solve a perceptually different engineering problem compared with older children who received only one set of instructions or no instructions. Implications of the work for developmental and learning science research and informal education practice are discussed.