Cold water corals are an important component of deep sea ecosystems, where they play the role of habitat formers. The monograph Cold-water coral reefs of the world is a welcome addition to the literature on these important bioconstructions

Seasonal differences in marine size spectra of micronekton at the shelf-ocean interface of the northern (NBUS) and southern Benguela Upwelling System (SBUS) in Feb-Mar 2019 and Sep-Oct 2021 were analysed. It was distinguished between mesopelagic fishes and total micronekton, comprising both the invertebrate and the vertebrate components. The metabolic theory of ecology (MTE) model containing a resource and a temperature term and a term representing a transfer function was applied to test three different types of size spectra slope estimates. The model fitted best with linear slopes calculated of log-binned averaged community biomass (LBNbiom method), while maximum likelihood without binning and quantile regression estimates without averaging proved less effective. The best model for total micronekton contained significant effects both for resource term and transfer function, but not for temperature. Normalized biomass size spectra slopes of the total micronekton were in the range predicted by MTE ranging between -0.80 and -1.37, and NBUS slopes were steeper than SBUS slopes in both seasons. The slopes for the fishes’ subcomponents were less steep ranging from -0.23 to -0.92, where values > -0.75 fall outside the theoretical range, suggesting that selecting taxonomic subsets for size spectrum analysis is problematic. The importance of the productivity regime shaping the biomass spectrum directly through the resource level and indirectly through the transfer function is highlighted.

javascript:void(0) The northern Humboldt Current System (nHCS) is an area with high environmental variability that impacts key demographic and community-scale processes. Understanding the role and ecological implications of these interannual or long-term events is crucial in describing the dynamics of the nHCS community. Using catch data from pelagic assessment surveys from 1983 to 2019 and the community trajectory analysis framework, we tested and characterised the patterns and compositional dynamics of the nHCS pelagic fish community over space and time. Spatially, changes were evaluated for ecological regions with similar community composition identified through hierarchical clustering with spatial constraint. We found that the community is in constant inter-annual variability consistent with the long-term warm and cold periods of the system. A long trajectory segment suggests a community regime shift between 1994 and 1999, years associated with a change in the average oceanographic conditions in the system and an extreme El Niño event (1997-98). After 1999, we identified a period where the community was constantly changing and dominated by coastal species. These long-term community changes were not homogeneous over the ecological areas, finding a lower temporal variability in the coastal area than in the northern and offshore. The main factor controlling the spatial and temporal dynamics of the nHCS pelagic fish community seems to be the long and short-term environmental conditions in the system. This study helps to understand the magnitude and direction of pelagic fish community changes and define the community’s recovery process after an event-driven change.

A document by prudhvi Narayana Bandaru. Click on the document to view its contents.

Mangrove and seaweed ecosystems, as integral components of blue carbon habitats, play pivotal roles in global carbon sequestration and coastal protection, showcasing unique environmental dynamics and biological diversity. This study explores seaweed and mangrove-associated bacterial communities and their functional dynamics in Goa coastal habitats, highlighting their critical ecological roles within blue carbon habitats. Physicochemical analysis revealed contrasting environmental conditions, with the seaweed ecosystem experiencing stable marine influences and the mangrove ecosystem subject to dynamic terrestrial-aquatic interactions. Elevated levels of pathogenic bacteria in both ecosystems indicate significant pollution from anthropogenic activities. Advanced metagenomic techniques, including Illumina’s 16S V3-V4 amplicon sequencing, were employed to assess bacterial diversity. The seaweed ecosystems were predominated by Proteobacteria, Cyanobacteria, and Actinobacteria, crucial for nutrient cycling and organic matter decomposition. In contrast, mangrove ecosystems displayed a more complex microbiota, represented by Firmicutes, adapted to anaerobic conditions. Core microbiome analysis revealed the prevalence of the pathogen Pleurocapsa in seaweeds, suggesting ecosystem health decline, while mangrove microbiomes showed the dominance of genera such as Bacillus and Clostridium, which are key in processing organic material under low-oxygen conditions. Notably, Clostridium levels indicated faecal contamination, underscoring the impact of external pollution. Functional pathway analysis conducted with PICRUSt2 analysis elucidated the metabolic specializations of the microbiomes. Seaweed-associated microbiomes excelled in carbohydrate metabolism, cellular growth and death and environmental information processing, whereas mangrove microbiomes showed advanced capabilities in carbohydrate metabolism, xenobiotics biodegradation and complex organic compound metabolism such as terpenoids and polyketides, reflecting complex microbial dynamics and pollution in mangroves. The findings emphasize the urgent need for effective conservation strategies to protect these vital ecosystems against the rising threats of anthropogenic pressures pollution, and climate change. An enhanced understanding of microbial dynamics and functional capabilities is essential for implementing informed management practices, ensuring the conservation and restoration of these critical blue carbon ecosystems.

Taxonomic monographs, such as those of the Fauna and Flora of the Gulf of Naples, have almost eternal life, in terms of scientific relevance, and keep being cited even after centuries.

Hurricanes are natural periodic events that disrupt marine ecosystems along their path, altering the distribution and abundance of organisms. In October 2016, Hurricane Matthew struck the Santa Marta region and impacted its coastal zone, yet there have been insufficient studies to measure its effects. The aim of this study was to assess the impact of Hurricane Matthew on the meiofaunal community in the Santa Marta region. To achieve this, sediment samples were collected from the intertidal zone of three beaches five days after the hurricane had passed. The results were compared with previous data on the abundance and diversity of taxonomic groups of intertidal meiofauna, as well as physicochemical variables such as granulometry, organic matter, salinity, and water temperature. Following Hurricane Matthew, the physicochemical variables showed changes due to the effect of the cyclonic surge in the coastal zone. The average organism density on the beaches ranged from 29.3 to 250.8 ind./10cm 2, which were lower values than those recorded before the hurricane. However, the total number of recorded taxa was 13, which is close to the 15 previously registered. The ANOSIM test confirmed differences in the meiofaunal community before and after Hurricane Matthew, with nauplius and copepod being the groups that contributed the most to the dissimilarity between periods. The environmental variables of organic matter and temperature best explained the structure of the meiofaunal community after the natural phenomenon. This study highlights the importance of meiofauna as a monitoring tool for beaches and the effects of environmental disturbances such as hurricanes, which are expected to become more common in coastal areas due to climate change.

Ostreobium comprise endolithic algae commonly seen in conjunction with scleractinian corals. In the past, it was solely recognized as a coral skeleton bioeroder. Yet, their relationship with corals is critical because they give photosynthetic byproducts and help the coral when it loses its primary symbionts due to stress. The variety of these algae among coral species of the genus Porites in the tropical easter Pacific and western Atlantic was investigated here. We extracted Ostreobium samples from seven Porites species including two from the Tropical Easter Pacific-TEP ( P. panamensis, P. lobata) and five from the Caribbean (P . furcata, P. porites, P. colonensis, P. branneri, and P. astreoides). We also compared the new rbcL sequences from algae found within various coral species from other parts of the world. A biogeographic analysis and two methodologies, PTP (Poisson tree process) and GMYC (General Mixed Yule-Coalescent), were used to delineate the different species. The findings revealed a significant degree of genetic diversity within Ostreobium, with more than 15 groups of no more than three individuals and 40 individual lineages. Its origins date back to the Ordovician, 500 Ma, and it does not appear to preserve host-specificity. The sampled locations include a wide variety of Ostreobium still, biogeographically, varied patterns were confirmed, making it impossible to pinpoint the precise origins of most clades. The ancestry analyses revealed convergent events for the emergence of Ostreobium in a few genera of local corals, but the phenomenon also occurred in genera from far-off places.

The adaptation of marine sponges to their environment is often attributed to the specific composition of their bacterial communities. In this study, we assessed the bacterial microbiome of two dominant sponges, Rhabdastrella globostellata and Hyrtios erectus, living in the Bouraké lagoon (New Caledonia), where abiotic conditions reach extreme values of temperature, pH, and oxygen during low tide. Scuba divers collected sponge specimens and sediment and seawater samples at 2-3m depth. The bacterial communities were studied using 16S rRNA metabarcoding, and variations between the two sponges were compared using Principal Component Analyses (PCA) biplots. The phylum Chloroflexi and clade SAR202 appeared dominant in both sponge species reaching an average relative abundance of 41.2% and 53.2% in H. erectus and 53.2% and 78.7% in R. globostellata, respectively, while they were absent in sediments and seawater. Principal Component Analyses (PCA) explained 70.9% (phyla) and 86.6% (clade) showing that the bacterial community’s structure in both sponges is driven by Chloroflexi. This study is the first report of such a noteworthy relative abundance of Chloroflexi and SAR202 has been described in the microbiome of marine sponges. As these bacteria are known to play key roles in sponge nutrition and fitness, their high abundance strongly suggests an adaptive response to the extreme environmental conditions of the Bouraké lagoon.

During a cold La Niña period (August 2007-January 2008) in the central Galápagos archipelago, 70% of Pocillopora finger corals were bleached across three long-term monitoring sites, affording an opportunity to examine the impact of El Niño Southern Oscillation-related temperature anomalies on the persistence of these corals and their associated community of fish and mobile macroinvertebrates. Using a time series empirical approach, we tagged and tracked the fate of 96 coral heads and their associates. When surveyed in July 2008, live (recovered) and dead corals supported similar levels of randomized observed species richness and Chao 1 estimated species richness. Whereas richness on the surviving live corals remained fairly stable, Chao 1 estimated richness on dead corals underwent a nearly 50% increase between July and January 2009, thereafter declining to 50% of originally surveyed richness by February 2010. This nonlinear change in species richness was largely due to influx and decline in opportunistic generalists including pencil urchin bioeroders, gastropod snails, and hermit crabs that colonized dead corals and fed on sessile invertebrates and algae that had initially recruited to dead and undefended coral substrate. Thus, dead corals retained high overall species richness until live corals had recovered; after which richness declined as dead corals eroded and disappeared (July 2011). Live corals attracted a less speciose but stable assemblage of mutualistic xanthid crabs and fishes that increased in abundance over time with the recovery and growth of live coral tissue. Overall, three physical features of the finger coral habitats (coral vital status, total surface area, and maximum branch length) predicted the number of species associated with each colony. The delayed diversity loss of associated species following La Niña disturbance to a foundation species represents a local extinction debt of 32-49-month duration. A better understanding of the scale of extinction debt in foundational marine ecosystems is needed to quantify the breadth of impacts of climate oscillations on biodiversity and ecosystem functioning.