Tiger sharks support the characterization of the world’s largest seagrass ecosystem

Seagrass conservation is critical formitigating climate change due to the large stocks of carbon they sequester in the seafloor. However, effective conservation and its potential to provide nature-based solutions to climate change is hindered by major uncertainties regarding seagrass extent and distribution. Here, we describe the characterization of the world’s largest seagrass ecosystem, located in The Bahamas. We integrate existing spatial estimates with an updated empirical remote sensing product and perform extensive groundtruthing of seafloor with 2,542 diver surveys across remote sensing tiles. We also leverage seafloor assessments and movement data obtained from instrument-equipped tiger sharks, which have strong fidelity to seagrass ecosystems, to augment and further validate predictions. We report a consensus area of at least 66,000 km2 and up to 92,000km2 of seagrass habitat across The Bahamas Banks. Sediment core analysis of stored organic carbon further confirmed the global relevance of the blue carbon stock in this ecosystem. Data from tiger sharks proved important in supporting mapping and groundtruthing remote sensing estimates. This work provides evidence of major knowledge gaps in the ocean ecosystem, the benefits in partnering with marine animals to address these gaps, and underscores support for rapid protection of oceanic carbon sinks.Beneath The WavesDisney Conservation FundBarry and Mimi Sternlicht FoundationSant FamilyPictet FoundationPacific Treasure FoundationKing FamilyD. and J. Harris, B. Coughlin and FamilyP. Nicholson and WCPD FoundationSouthern TideHillsdaleThayer AcademyDiscovery CommunicationsMary O'Malley and Lupo Dion TrustNational Geographic SocietyJ. Lake and JDL, Inc.Towle Family Ocean FoundationKaro Family TrustScience Foundation Ireland 18/SIRG/5549King Abdullah University of Science & Technology36Pi

Blue carbon ecosystems and shark behaviour: an overview of key relationships, network interactions, climate impacts, and future research needs

Climate change is threatening marine ecosystems and the distribution of species which rely on them. Due to their capacity to sequester vast amounts of carbon, blue carbon ecosystems (BCEs; seagrass, mangroves, salt marshes, kelp forests) are becoming increasingly recognized as key nature-based solutions to climate change. Sharks are mobile species that can exert strong control of food webs and are also key to conservation efforts. BCEs are known to support shark life histories, but the drivers of these relationships remain poorly understood. Here, we highlight two key behavioural pathways directly linking BCEs and sharks (foraging and reproductive activities) and explore the influence of climate on them. Our evaluation of the literature suggested that the physical attributes of the blue carbon plant tissue itself serves as the key link between sharks and BCEs, facilitating high rates of prey biodiversity and a platform for reproductive behaviours. We revealed that shark body size likely has an influence on the nature of these relationships, and that climate may be a modulator of key interactions. We also use basic network theory to explore how ecological information flows throughout BCEs, with sharks as a prominent actor. We identify ways in which future studies can fill knowledge gaps; namely, a focus on smaller endemic species, and empirical assessments between sharks and organic carbon stocks. Maintaining the integrity of these relationships should preserve blue natural capital: BCEs’ capacity to sequester carbon, support local biodiversity, and the role of sharks in preserving resilience

The Impact of Neighborhood Socioeconomic Disadvantage on Operative Outcomes after Single-Level Lumbar Fusion

INTRODUCTION: The relationship between socioeconomic status and neurosurgical outcomes has been investigated with respect to insurance status or median household income, but few studies have considered more comprehensive measures of socioeconomic status. This study examines the relationship between Area Deprivation Index (ADI), a comprehensive measure of neighborhood socioeconomic disadvantage, and short-term postoperative outcomes after lumbar fusion surgery. METHODS: 1861 adult patients undergoing single-level, posterior-only lumbar fusion at a single, multihospital academic medical center were retrospectively enrolled. An ADI matching protocol was used to identify each patient\u27s 9-digit zip code and the zip code-associated ADI data. Primary outcomes included 30- and 90-day readmission, emergency department visits, reoperation, and surgical complication. Coarsened exact matching was used to match patients on key demographic and baseline characteristics known to independently affect neurosurgical outcomes. Odds ratios (ORs) were computed to compare patients in the top 10% of ADI versus lowest 40% of ADI.RESULTS: After matching (n = 212), patients in the highest 10% of ADI (compared to the lowest 40% of ADI) had significantly increased odds of 30- and 90-day readmission (OR = 5.00, P \u3c 0.001 and OR = 4.50, P \u3c 0.001), ED visits (OR = 3.00, P = 0.027 and OR = 2.88, P = 0.007), and reoperation (OR = 4.50, P = 0.039 and OR = 5.50, P = 0.013). There was no significant association with surgical complication (OR = 0.50, P = 0.63).CONCLUSIONS: Among otherwise similar patients, neighborhood socioeconomic disadvantage (measured by ADI) was associated with worse short-term outcomes after single-level, posterior-only lumbar fusion. There was no significant association between ADI and surgical complications, suggesting that perioperative complications do not explain the socioeconomic disparities in outcomes

Substantial blue carbon sequestration in the world’s largest seagrass meadow

Seagrass meadows are important sinks for organic carbon and provide co-benefits. However, data on the organic carbon stock in seagrass sediments are scarce for many regions, particularly The Bahamas, which accounts for up to 40.7% of the documented global seagrass area, limiting formulation of blue carbon strategies. Here, we sampled 10 seagrass meadows across an extensive island chain in The Bahamas. We estimate that Bahamas seagrass meadows store 0.42–0.59 Pg organic carbon in the top-meter sediments with an accumulation rate of 2.1–2.9 Tg annually, representing a substantial global blue carbon hotspot. Autochthonous organic carbon in sediments decreased from ~1980 onwards, with concomitant increases in cyanobacterial and mangrove contributions, suggesting disturbance of seagrass ecosystems, likely caused by tourism and maritime traffic activities. This study provides seagrass blue carbon data from a vast, understudied region and contributes to improving climate action for The Bahamas and the Greater Caribbean region

Understanding the individual to implement the ecosystem approach to fisheries management

Ecosystem-based approaches to fisheries management (EAFMs) have emerged as requisite for sustainable use of fisheries resources. At the same time, however, there is a growing recognition of the degree of variation among individuals within a population, as well as the ecological consequences of this variation. Managing resources at an ecosystem level calls on practitioners to consider evolutionary processes, and ample evidence from the realm of fisheries science indicates that anthropogenic disturbance can drive changes in predominant character traits (e.g. size at maturity). Eco-evolutionary theory suggests that human-induced trait change and the modification of selective regimens might contribute to ecosystem dynamics at a similar magnitude to species extirpation, extinction and ecological dysfunction. Given the dynamic interaction between fisheries and target species via harvest and subsequent ecosystem consequences, we argue that individual diversity in genetic, physiological and behavioural traits are important considerations under EAFMs. Here, we examine the role of individual variation in a number of contexts relevant to fisheries management, including the potential ecological effects of rapid trait change. Using select examples, we highlight the extent of phenotypic diversity of individuals, as well as the ecological constraints on such diversity. We conclude that individual phenotypic diversity is a complex phenomenon that needs to be considered in EAFMs, with the ultimate realization that maintaining or increasing individual trait diversity may afford not only species, but also entire ecosystems, with enhanced resilience to environmental perturbations. Put simply, individuals are the foundation from which population- and ecosystem-level traits emerge and are therefore of central importance for the ecosystem-based approaches to fisheries management

Consequences of “natural” disasters on aquatic life and habitats

“Natural” disasters (also known as geophysical disasters) involve physical processes that have a direct or indirect impact on humans. These events occur rapidly and may have severe consequences for resident flora and fauna as their habitat undergoes dramatic and sudden change. Although most studies have focused on the impact of natural disasters on humans and terrestrial systems, geophysical disasters can also impact aquatic ecosystems. Here, we provide a synthesis on the effects of the most common and destructive geophysical disasters on aquatic systems (life and habitat). Our approach spanned realms (i.e., freshwater, estuarine, and marine) and taxa (i.e., plants, vertebrates, invertebrates, and microbes) and included floods, droughts, wildfires, hurricanes/cyclones/typhoons, tornadoes, dust storms, ice storms, avalanches (snow), landslides, volcanic eruptions, earthquakes (including limnic eruptions), tsunamis, and cosmic events. Many geophysical disasters have dramatic effects on aquatic systems. The evidence base is somewhat limited for some natural disasters because transient events (e.g., tornadoes and floods) are difficult to study. Most natural disaster studies focus on geology/geomorphology and hazard assessment for humans and infrastructure. However, the destruction of aquatic systems can impact humans indirectly through loss of food security, cultural services, or livelihoods. Many geophysical disasters interact in complex ways (e.g., wildfires often lead to landslides and flooding) and can be magnified or otherwise mediated by human activities. Our synthesis reveals that geophysical events influence aquatic ecosystems, often in negative ways, yet systems can be resilient provided that effects are not compounded by anthropogenic stressors. It is difficult to predict or prevent geophysical disasters but understanding how aquatic ecosystems are influenced by geophysical events is important given the inherent connection between peoples and aquatic ecosystems.acceptedVersio

Energy metabolism in mobile, wild-sampled sharks inferred by plasma lipids

Evaluating how predators metabolize energy is increasingly useful for conservation physiology, as it can provide information on their current nutritional condition. However, obtaining metabolic information from mobile marine predators is inherently challenging owing to their relative rarity, cryptic nature and often wide-ranging underwater movements. Here, we investigate aspects of energy metabolism in four free-ranging shark species (n = 281; blacktip, bull, nurse, and tiger) by measuring three metabolic parameters [plasma triglycerides (TAG), free fatty acids (FFA) and cholesterol (CHOL)] via non-lethal biopsy sampling. Plasma TAG, FFA and total CHOL concentrations (in millimoles per litre) varied inter-specifically and with season, year, and shark length varied within a species. The TAG were highest in the plasma of less active

Neurosurgeons Deliver Similar Quality Care Regardless of First Assistant Type: Resident Physician versus Nonphysician Surgical Assistant

OBJECTIVE: There are limited data evaluating the out-comes of attending neurosurgeons with different types of first assistants. This study considers a common neurosurgical procedure (single-level, posterior-only lumbar fusion surgery) and examines whether attending surgeons deliver equal patient outcomes, regardless of the type of first assistant (resident physician vs. nonphysician surgical assistant [NPSA]), among otherwise exact-matched patients. -METHODS: The authors retrospectively analyzed 3395 adult patients undergoing single-level, posterior-only lumbar fusion at a single academic medical center. Primary outcomes included readmissions, emergency department visits, reoperation, and mortality within 30 and 90 days after surgery. Secondary outcome measures included discharge disposition, length of stay, and length of surgery. Coarsened exact matching was used to match patients on key demographics and baseline characteristics known to independently affect neurosurgical outcomes. -RESULTS: Among exact-matched patients (n [ 1402), there was no significant difference in adverse postsurgical events (readmission, emergency department visits, reoperation, or mortality) within 30 days or 90 days of the index operation between patients who had resident physicians and those who had NPSAs as first assistants. Patients who had resident physicians as first assistants demonstrated a longer length of stay (mean: 100.0 vs. 87.4 hours, P \u3c 0.001) and a shorter duration of surgery (mean: 187.4 vs. 213.8 minutes, P \u3c 0.001). There was no significant difference between the two groups in the percentage of patients discharged home. -CONCLUSIONS: For single-level posterior spinal fusion, in the setting described, there are no differences in short-term patient outcomes delivered by attending surgeons assisted by resident physicians versus NPSAs