Carolyn A. Miller

As important members of the marine ecosystem, baleen whales are frequently managed and protected, but methodology to assess their health remains limited. Recent technological advances, such as the use of drones, support the non-invasive collection of promising health-associated data, including respiratory exhalant microbiota. Here, we considered five health metrics paired with respiratory exhalant samples to examine the utility of characterizing respiratory microorganisms for health diagnostics of North Atlantic right whales (Eubalaena glacialis), one of the most endangered baleen whale species. In 2016–2024, we used drones to collect 103 exhalant samples from 85 individuals to examine the associated microbiome, using amplicon sequencing methods targeting bacteria and archaea. The health status of sampled whales was characterized using an index of body condition derived from full-body vertical drone images, three qualitative assessments obtained from photo-identification imagery, and an existing health and vital rates model. Using an elastic net penalized regression approach, we demonstrate significant relationships between these health metrics and respiratory-associated microorganisms. Bacterial taxa that significantly contributed to the model for the body condition index differed between the thinnest and most robust males in the dataset. The thin whale harbored taxa belonging to the same genus as mammalian pathogens, Clostridium and Peptoniphilus, whereas the robust whale harbored taxa commonly observed in lipid-rich environments, Sediminispirochaeta and Candidatus Gracilibacteria. These differences warrant further investigation into the mechanisms by which bacteria contribute to whale health. Our findings demonstrate the utility of non-invasive multi-metric health models that include respiratory exhalant microbiota for whale health assessment and management.

Globally, coral reef ecosystems are undergoing significant change related to climate change and anthropogenic activities. Yet, the Cuban archipelago of Jardines de la Reina (JR) has experienced fewer stressors due to its geographical remoteness and high level of conservation. This study examines the surface and benthic reef water microbial communities associated with 32 reef sites along the JR archipelago and explores the relationship between the community composition of reef microorganisms examined using bacterial and archaeal small subunit ribosomal RNA gene (16S rRNA gene) sequencing compared to geographic, conservation/protection level, environmental, physicochemical, and reef benthic and pelagic community features. Reef nutrient concentrations were low and microbial communities dominated by picocyanobacteria and SAR11 and SAR86 clade bacteria, characteristic of an oligotrophic system. Reef water microbial community alpha and beta diversity both varied throughout the archipelago and were strongly related to geography. Three sites in the western archipelago showed unique microbial communities, which may be related to the hydrogeography and influences of the channels linking the Ana Maria gulf with the Caribbean Sea. Overall, this work provides the first extensive description of the reef microbial ecology of the Caribbean’s ‘Crown Jewel’ reef system and a framework to evaluate the influence of ongoing stressors on the reef microorganisms.

The sensory mechanisms used by baleen whales (Mysticeti) for locating ephemeral, dense prey patches in vast marine habitats are poorly understood. Baleen whales have a functional olfactory system with paired rather than single blowholes (nares), potentially enabling stereo-olfaction. Dimethyl sulfide (DMS) is an odorous gas emitted by phytoplankton in response to grazing by zooplankton. Some seabirds use DMS to locate prey, but this ability has not been demonstrated in whales. For 14 extant species of baleen whale, nares morphometrics (imagery from unoccupied aerial systems, UAS) was related to published trophic level indices using Bayesian phylogenetic mixed modelling. A significant negative relationship was found between nares width and whale trophic level (β= −0.08, lower 95% CI = −0.13, upper 95% CI = −0.03), corresponding with a 39% increase in nares width from highest to lowest trophic level. Thus, species with nasal morphology best suited to stereo-olfaction are more zooplanktivorous. These findings provide evidence that some baleen whale species may be able to localize odorants e.g. DMS. Our results help direct future behavioural trials of olfaction in baleen whales, by highlighting the most appropriate species to study. This is a research priority, given the potential for DMS-mediated plastic ingestion by whales.

Stony coral tissue loss disease (SCTLD) is a widespread and deadly disease that affects nearly half of Caribbean coral species. To understand the microbial community response to this disease, we performed a disease transmission experiment on US Virgin Island (USVI) corals, exposing six species of coral with varying susceptibility to SCTLD. The microbial community of the surface mucus and tissue layers were examined separately using a small subunit ribosomal RNA gene-based sequencing approach, and data were analyzed to identify microbial community shifts following disease acquisition, potential causative pathogens, as well as compare microbiota composition to field-based corals from the USVI and Florida outbreaks. While all species displayed similar microbiome composition with disease acquisition, microbiome similarity patterns differed by both species and mucus or tissue microhabitat. Further, disease exposed but not lesioned corals harbored a mucus microbial community similar to those showing disease signs, suggesting that mucus may serve as an early warning detection for the onset of SCTLD. Like other SCTLD studies in Florida, Rhodobacteraceae, Arcobacteraceae, Desulfovibrionaceae, Peptostreptococcaceae, Fusibacter, Marinifilaceae, and Vibrionaceae dominated diseased corals. This study demonstrates the differential response of the mucus and tissue microorganisms to SCTLD and suggests that mucus microorganisms may be diagnostic for early disease exposure.

Whale digestion plays an integral role in many ocean ecosystems. By digesting enormous quantities of lipid-rich prey, whales support their energy intensive lifestyle, but also excrete nutrients important to ocean biogeochemical cycles. Nevertheless, whale digestion is poorly understood. Gastrointestinal microorganisms play a significant role in vertebrate digestion, but few studies have examined them in whales. To investigate digestion of lipids, and the potential contribution of microbes to lipid digestion in whales, we characterized lipid composition (lipidomes) and bacterial communities (microbiotas) in 126 digesta samples collected throughout the gastrointestinal tracts of 38 bowhead whales (Balaena mysticetus) harvested by Alaskan Eskimos. Lipidomes and microbiotas were strongly correlated throughout the gastrointestinal tract. Lipidomes and microbiotas were most variable in the small intestine and most similar in the large intestine, where microbiota richness was greatest. Our results suggest digestion of wax esters, the primary lipids in B. mysticetus prey representing more than 80% of total dietary lipids, occurred in the mid- to distal small intestine and was correlated with specific microorganisms. Because wax esters are difficult to digest by other marine vertebrates and constitute a large reservoir of carbon in the ocean, our results further elucidate the essential roles that whales and their gastrointestinal microbiotas play in the biogeochemical cycling of carbon and nutrients in high-latitude seas.

Low income, medically underserved communities are at increased risk for tuberculosis. Limited population-based national data are available about tuberculous infection in young people from such backgrounds. To determine the prevalence of a positive tuberculin skin test among economically disadvantaged youth in a federally funded job training program during 1995 and 1996, the authors evaluated data from medical records of 22,565 randomly selected students from over 100 job training centers throughout the United States. An estimated 5.6% of students had a documented positive skin test or history of active tuberculosis. Rates were highest among those who were racial/ethnic minorities, foreign born, and (among foreign-born students) older in age (p < 0.001). Weighted rates (adjusting for sampling) were 1.3% for white, 2.2% for Native American, 4.0% for black, 9.6% for Hispanic, and 40.7% for Asian/Pacific Islander students; rates were 2.4% for US-born and 32.7% for foreign-born students. Differences by geographic region of residence were not significant after adjusting for other demographic factors. Tuberculin screening of socioeconomically disadvantaged youth such as evaluated in this study provides important sentinel surveillance data concerning groups at risk for tuberculous infection and allows recommended public health interventions to be offered. Am J Epidemiol 1999; 149:671–9.

A study is in progress to document changes in selected public health departments over the past decade and to use those observations for proposing an assessment protocol that may be helpful in measuring progress toward achieving one of the Health Objectives for the Nation for the Year 2000. Objective no. 8.14 reads: "Increase to at least 90 percent the proportion of people served by a local health department that is effectively carrying out the core functions of public health." The study re-surveys a group of 14 departments that were the subjects of intensive case studies between 1979 and 1981. Some preliminary observations from follow-up study of these departments in 1992 include: growth in budget and staff and even larger growth in pressure for services, especially for personal health care; reorganization that splits away some programs of comprehensive ambulatory care and responsibility for public hospitals, while increasing the aggregation of human service agencies, including public health, under locally organized umbrella agencies; increase in preventive, screening, and categorical programs under public health sponsorship; drastic change in patterns of financing, featuring nearly total loss of direct federal grants, and increase in fee income; increase in the number of community and migrant health centers in the public health jurisdictions under study; diminished collaborative interaction with private practitioners; and continued close collaboration between health departments and community health centers in several communities. The implications of these changes are discussed. Subsequent reports will be based on efforts to measure the impact of specific events of the 1980s on public health performance, and will describe experience with a community-based surveillance approach for assessing public health performance.