Miriam Fernandez

Protecting embryos provides multiple benefits but also entails costs and constraints. In aquatic environments, aggregating metabolically active tissues limits oxygen acquisition, as evidenced by studies reporting oxygen depletion at the center of embryo aggregations across taxa and aggregation types among marine invertebrates. However, the effects of concurrent ocean warming and deoxygenation on species that protect and aggregate their embryos remain poorly understood. We investigated the effects of temperature and hypoxia on oxygen-provisioning behaviors, oxygen conditions within embryo aggregations, and the metabolic costs of oxygen supply in the brachyuran crab Romaleon setosum . We conducted a laboratory experiment manipulating temperature (16 and 20°C) and oxygen conditions (normoxia, > 80% air saturation; and 5-day hypoxia, 17–18% air saturation). Behaviors were video recorded, while oxygen levels (percentage air saturation) within embryo masses were continuously monitored using microsensors. Metabolic costs were estimated from oxygen consumption in respiration chambers for brooding and non-brooding females, as well as embryos (to estimate oxygen consumption of the embryo mass). Oxygen levels within embryo aggregations remained low under environmental normoxia despite increased oxygen-provisioning behaviors as temperature increased, resulting in elevated metabolic costs for brooding females. Notably, no compensatory behavioral responses were observed under ambient hypoxia and increasing temperature, suggesting metabolic constraints on oxygen provision to embryo aggregations. These findings indicate potential consequences for embryo development and clutch size under ongoing ocean warming and deoxygenation. More broadly, our results highlight the need to improve our understanding of how interacting environmental stressors affect reproduction in marine invertebrates across diverse life-history patterns.

Marine animal forests (MAFs) play a crucial role in enhancing biodiversity and ecosystem functionality in marine environments. However, MAFs are poorly known in some ecosystems. This study focuses on one of the least known ecosystems, temperate mesophotic ecosystems (TMEs), by characterizing and quantifying branching invertebrates, particularly corals and sponges, that form MAFs in Central Chile. Utilizing towed underwater video surveys, we identified and quantified three key taxa, the octocorals Leptogorgia chilensis and Plexauridae, and the sponges Axinella spp., across various depths and locations along the central Chilean coast. In addition, we report the presence of black corals (Antipatharia) in the study area. Our findings expand the known geographical and bathymetric ranges of these taxa, thereby contributing to the limited understanding of habitat-forming species in TMEs within this region. Considering the ecological value of MAFs, this study emphasizes the critical need to advance in understanding their role in hosting biodiversity and fostering ecological interactions, particularly in less-studied ecosystems, and provides a foundation for effective management and conservation initiatives.

Temperate mesophotic reef ecosystems (TMREs) are among the least known marine habitats. Information on their diversity and ecology is geographically and temporally scarce, especially in highly productive large upwelling ecosystems. Lack of information remains an obstacle to understanding the importance of TMREs as habitats, biodiversity reservoirs and their connections with better‐studied shallow reefs. Here, we use environmental DNA (eDNA) from water samples to characterize the community composition of TMREs on the central Chilean coast, generating the first baseline for monitoring the biodiversity of these habitats. We analyzed samples from two depths (30 and 60 m) over four seasons (spring, summer, autumn, and winter) and at two locations approximately 16 km apart. We used a panel of three metabarcodes, two that target all eukaryotes (18S rRNA and mitochondrial COI) and one specifically targeting fishes (16S rRNA). All panels combined encompassed eDNA assigned to 42 phyla, 90 classes, 237 orders, and 402 families. The highest family richness was found for the phyla Arthropoda, Bacillariophyta, and Chordata. Overall, family richness was similar between depths but decreased during summer, a pattern consistent at both locations. Our results indicate that the structure (composition) of the mesophotic communities varied predominantly with seasons. We analyzed further the better‐resolved fish assemblage and compared eDNA with other visual methods at the same locations and depths. We recovered eDNA from 19 genera of fish, six of these have also been observed on towed underwater videos, while 13 were unique to eDNA. We discuss the potential drivers of seasonal differences in community composition and richness. Our results suggest that eDNA can provide valuable insights for monitoring TMRE communities but highlight the necessity of completing reference DNA databases available for this region.

The largely unexplored diversity in temperate mesophotic ecosystems (TME, ~30–150 m depth) has attracted much attention over the past years. However, the number of studies and knowledge of TME diversity and ecology remains limited and geographically restricted. The absence of information on how assemblages vary across environmental gradients and with depth for most regions also limits our capacity to delimit conservation areas and devise management plans effectively. This study focuses on TME from central Chile and describes the depth distribution of reef fishes and benthic invertebrates and algae for the first time. Through the analysis of towed underwater video surveys between 4.7–95.5 m in multiple sites, we show that total reef fish density and richness decrease with depth but increase with local topographic complexity. The depth-related density varies among fish species and trophic groups, and it reverses in the case of Sebastes oculatus, which increases in density with depth. Sponges and gorgonians dominate benthic assemblages below 20 m depth, and brachiopods and anemones increase below 40 and 60 m, respectively. Some of these species form animal forests which, to some extent, replace the shallow-water kelp forests as structural habitat providers. Nevertheless, the reef fish and benthic community do not show a clear structure with depth or across studied sites. We highlight the urgency to intensify and expand the quantitative characterization of these communities, through this and other methodologies, to better define ecological patterns and advance towards conservation plans for TME, including the Souteastern Pacific region.

Biofouling control on human-made structures and seagoing technologies that minimize environmental impacts is a major focus of research in marine industries. However, the most widely used antifouling (AF) method is still copper-based coatings. Some “eco-friendly” approaches are commercially available but have been scarcely tested in natural conditions, especially high-energy environments. We conducted a replicated long-term field experiment in a highly wave-exposed, high productivity coastal environment to test three untreated materials used in maritime industries, two traditional copper-based AF coatings, and two materials offered as “eco-friendly” AF in the market (i.e., a slow-copper release and a self-adhesive, fiber-covered, skin-like coating). We showed that biofouling cover and biomass increased at similar rates over time among all untreated materials, including the skin-like AF. The two traditional copper-based AF coatings and the slow-release AF paint both showed similarly low biofouling biomass and richness, demonstrating their efficacy after 12 months in the field. Although the “eco-friendly” slow-release technologies are not completely innocuous to the environment, we suggest this approach over the more environmentally aggressive traditional copper paints, which are the most widely used in aquaculture and shipping industries today. However, further research is needed to test whether their environmental impact is significantly lower in the long-term than traditional AF paints, and therefore the search for non-toxic coating must continue. The fortuitous settlement and growth of sea urchins in our experiments also suggest that a combination of “eco-friendly” AF and biological control would be possible and should be further investigated. The skin-like coatings must be tested under different environmental conditions, and they are not recommended in wave-exposed coastal habitats.

Consistency in conservation: Marine protected areas (MPAs) are now well established globally as tools for conservation, for enhancing marine biodiversity, and for promoting sustainable fisheries. That said, which regions are labeled as MPAs varies substantially, from those that full protect marine species and prohibit human extraction to those that permit everything from intensive fishing to mining. This inconsistency can in some cases inhibit both conservation and quantifying the proportion of the marine environment that is truly protected. Grorud-Colvert et al . review the consistency of MPAs and propose a framework by which levels of protection can be evaluated and improved. —SNV

Despite significant progress made in Chile, and globally, in establishing marine protected areas (MPAs), the actual contribution to marine biodiversity conservation needs to be revised, to focus on representativeness and the diversity of tools alongside effective implementation, management, and enforcement. This study makes progress in this direction, describing the most recent advances in marine conservation in Chile and analysing the contribution of the different conservation instruments as well as the distribution of designated areas across ecoregions. Furthermore, it examines the potential contribution of alternative area‐based instruments to balance ocean protection. The advances observed in Chile were compared among four South American countries and five leading countries in ocean conservation, analysing protection levels in coastal areas, continental exclusive economic zones, and overseas territories. Data on MPA boundaries and attributes were sourced from the World Database on Protected Areas and complemented the official information on MPAs and territorial user rights for fisheries and for indigenous people in South America. The current level of protection in Chile is among the highest in the world in area coverage and in the proportion of the continental exclusive economic zone assigned to fully protected areas. However, it exhibits the strongest imbalances in the distribution of designated MPAs between coastal and oceanic waters, in comparison with the leading countries and also within South America (Perú, Chile, Argentina, and Uruguay), and among ecoregions. The patterns observed suggest that Chile has advanced, but concentrated, conservation efforts in low‐threat, remote ecoregions. There is an urgent need to progress towards high‐threat ecoregions, which implies balancing the needs of nature and people. The distribution of ancillary conservation instruments can help double the level of protection in threatened coastal areas, filling gaps in marine conservation and creating an opportunity to progress and diversify conservation strategies.

Maritime enterprises have long sought solutions to reduce the negative consequences of the settlement and growth of marine biofouling (micro- and macro-organisms) on virtually all surfaces and materials deployed at sea. The development of biofouling control strategies requires solutions that are cost-effective and environmentally friendly. Polymer-based coatings, such as the poly (3,4-ethylenedioxythiophene) (PEDOT) and its potential applications, have blossomed over the last decade thanks to their low cost, nontoxicity, and high versatility. Here, using multiple-choice larval settlement experiments, we assessed the efficacy of PEDOT against the balanoid barnacle Notobalanus flosculus one of the most common biofouling species in Southeastern Pacific shores, and compared results against a commercially available antifouling (AF) coating, and biofilms at different stages of succession (1, 2, 4 and 8 weeks). We show that larval settlement on PEDOT-coated surfaces was similar to the settlement on AF-coated surfaces, while larvae settled abundantly on roughened acrylic and on early-to-intermediate stages of biofilm (one to four weeks old). These results are promising and suggest that PEDOT is a good candidate for fouling-resistant coating for specific applications at sea. Further studies to improve our understanding of the mechanisms of barnacle larval deterrence, as well as exposure to field conditions, are encouraged.