In 2023, a record-setting marine heat wave triggered the ninth mass coral bleaching event on Florida’s Coral Reef (FCR). We examined spatial patterns of heat exposure along the ~560-kilometer length of FCR and the mortality of two ecologically important, critically endangered reef-building corals. Sea surface temperatures were ≥31°C for an average of 40.7 days, leading to heat exposures 2.2- to fourfold higher than all prior years on record. In the Florida Keys and Dry Tortugas, 97.8 to 100% of the Acropora palmata and Acropora cervicornis colonies died. Mortality was lower offshore southeast Florida (37.9%), reflecting cooler temperatures in this region. Since the late 1970s, multiple stressors had already reduced the ecological relevance of Acropora in Florida, but the 2023 heat wave marks their functional extinction from FCR.

Because herbivory is a critical component of resilient reefs, there is a need to investigate the dynamics of herbivorous fish assemblages over various spatiotemporal scales. During the period of 2011–2019, 483 belt transect surveys were conducted across 26 sites around New Providence to assess the status of parrotfish populations across different reefs. Non-metric multidimensional scaling revealed two distinct parrotfish assemblages around New Providence temporally, differing between 2019 and earlier surveys, and spatially between fore and patch reef zones. Temporal analysis showed a significant decrease (59%) in parrotfish densities across reef sites and significant changes in mean density over time for three species Scarus iseri, Sparisoma aurofrenatum and Sp. atomarium. Changes in the size frequency distribution of parrotfish—particularly reductions in individuals ≥31 cm in size and the complete loss of fish >40 cm across all sites were found. Interactions between reef zone and size class were significant with the greater frequencies of larger individuals (≥21 cm) driving patterns (positive associations) on forereefs. These patterns also appear to be partly driven by variability in the abundance and size composition of Sparisoma viride, which is one of the species primarily targeted by Bahamian fishers, as well as one of the most common parrotfish across reef zones.

Premise: Poikilohydric plants respond to hydration by undergoing dry–wet–dry cycles. Carbon balance represents the net gain or loss of carbon from each cycle. Here we present the first standard protocol for measuring carbon balance, including a custom‐modified chamber system for infrared gas analysis, 12‐h continuous monitoring, resolution of plant–substrate relationships, and in‐chamber specimen hydration.Methods and Results: We applied the carbon balance technique to capture responses to water stress in populations of the moss Syntrichia caninervis, comparing 19 associated physiological variables. Carbon balance was negative in desiccation‐acclimated (field‐collected) mosses, which exhibited large respiratory losses. Contrastingly, carbon balance was positive in hydration‐acclimated (lab‐cultivated) mosses, which began exhibiting net carbon uptake <15 min following hydration.Conclusions: Carbon balance is a functional trait indicative of physiological performance, hydration stress, and survival in poikilohydric plants, and the carbon balance method can be applied broadly across taxa to test hypotheses related to environmental stress and global change.

In sessile, long-lived organisms, such as reef-building corals, phenotypic plasticity may play a key role in mitigating the impacts of climate change. Plasticity is often context-dependent and has costs and limits, resulting in adaptive, neutral, or maladaptive effects. However, our understanding of the mechanisms that maintain variation in, and therefore drive the evolution of, plasticity is still limited. We show context-dependent tradeoffs to morphological plasticity in Acropora cervicornis under real-world conditions driven by climate change. We find that morphological plasticity is neutral under ambient temperatures, but trades off with thermal tolerance during a marine heatwave. Additionally, we find that plasticity changes over time, underlining the importance of its temporal dynamics in long-lived organisms. Our results demonstrate a key role for environmental change in the eco-evolutionary dynamics of plasticity by demonstrating context-dependent costs under real-world thermal stress, revealing a possible constraint on the evolution of plasticity in a changing climate.

This is a protocol for generating images for underwater coral colony-level photogrammetry. In this protocol, we utilize Olympus Tough cameras and custom-made, adjustable PVC arrays that incorporate unique Agisoft Metashape markers for automatic scaling during the model building process and bleaching color cards. Instructions for creating your own Scaling and Color Object for Underwater Photogrammetry References (SCOUPRs) are included here, along with our Underwater Image Capture Pipeline that includes tips to collect photographs to improve model building, and Pre-Processing instructions. Updates from V1: V2 SCOUPR builds that allow for autoscaling in Metashape and other minor improvements In-depth workflow and additional imaging guidance Changes to in water methodologies that allow for the removal image pre-processing steps, thus streamlining the overall pipeline Though this protocol is primarily used by the Kenkel lab for 3D model generation of Acropora cervicornis colonies, these methods can be applied to corals of all morphologies (or any object, really). Our photosets are later batched processed and autoscaled using Agisoft Metashape command-line scripts integrated with USC's high-performance computing system. Additional resources: V2 scripts for batch processing and autoscaling models can be found here: https://github.com/mayagomez/metashape_batch_process and DOI: 10.5281/zenodo.17136227 Additional guidance for using Metashape on the command line and V1 scripts can be found here: https://github.com/wyattmillion/Coral3DPhotogram. Our lab's protocol for deriving coral morphological and growth data from 3D models can be found here: Phenotyping in MeshLab.

In many parts of the Caribbean, diving underwater will transport you to a colorful world of fish, sponges, mammals, and more. This dazzling undersea rainforest is created by rock-like animals called corals. But just like humans, corals can get sick—and right now a disease is spreading throughout the Caribbean, infecting and killing some of the world’s oldest and largest animals at an alarming speed. The deadly disease is called stony coral tissue loss disease (SCTLD). This article explains what we know about SCTLD and how to spot it in the ocean, how far the disease has spread, what kinds of corals are getting sick, and how we can work together to stop it. We need everyone’s help to save the corals and in turn save the homes of an incredible amount of sea life.