Differential bleaching susceptibility among coral taxa and colony sizes, relative to bleaching severity across Australia's Great Barrier Reef and Coral Sea Marine Parks

As climate change increases the rate of environmental change and the frequency and intensity of disturbance events, selective forces intensify. However, given the complicated interplay between plasticity and selection for ecological - and thus evolutionary - outcomes, understanding the proximate signals, molecular mechanisms and the role of environmental history becomes increasingly critical for eco-evolutionary forecasting. To enhance the accuracy of our forecasting, we must characterize environmental signals at a level of resolution that is relevant to the organism, such as the microhabitat it inhabits and its intracellular conditions, while also quantifying the biological responses to these signals in the appropriate cells and tissues. In this Commentary, we provide historical context to some of the long-standing challenges in global change biology that constrain our capacity for eco-evolutionary forecasting using reef-building corals as a focal model. We then describe examples of mismatches between the scales of external signals relative to the sensors and signal transduction cascades that initiate and maintain cellular responses. Studying cellular responses at this scale is crucial because these responses are the basis of acclimation to changing environmental conditions and the potential for environmental 'memory' of prior or historical conditions through molecular mechanisms. To challenge the field, we outline some unresolved questions and suggest approaches to align experimental work with an organism's perception of the environment; these aspects are discussed with respect to human interventions. 

Reconciling the variability in the biological response of marine invertebrates to climate change

Coral reefs are facing rapid deterioration, primarily due to a global rise in seawater temperature. In conjunction, the frequency and intensity of extreme high temperature events, known as marine heatwaves (MHWs), are increasing. The Gulf of Aqaba (GoA) in the northern Red Sea is home to corals known for their thermal resilience, yet concerns have been raised regarding the potential for MHWs to put this coral refuge at risk. In summer of 2021, the hottest MHW so far occurred in the GoA, with sea surface temperatures peaking at 31°C and persisting above the local summer maximum for 34 days. To assess the physiological response of the corals Stylophora pistillata and Pocillopora damicornis to this event, we analyzed the monthly content across a year of host and symbiont proteins, carbohydrates, and lipids, pre-, during, and post the MHW, as a proxy for metabolic stress. We found that the MHW was not fatal to either species and did not induce bleaching, based on algal densities and chlorophyll content. Species-specific responses were detected. In S. pistillata , host protein content decreased (33%) at the onset of the MHW (August) compared to pre-MHW levels (July). Algal symbionts of S. pistillata were unaffected by the MHW in their maximal photosynthetic efficiency ( Fv/Fm ) and exhibited higher carbohydrate levels (+34%) at the end of the MHW (September) compared to its onset. In contrast, no significant catabolic response was detected in P. damicornis host or symbionts, and the maximal relative electron transport rate (rETRmax) of symbionts was 37% higher during the MHW than the annual average. These results highlight the remarkable ability of common GoA corals to withstand extreme thermal anomalies, underscoring the global significance of this coral refuge. 

Reef building corals show resilience to the hottest marine heatwave on record in the Gulf of Aqaba

Long distance swimmers in warming waters: Active transport in postlarval American lobsters (Homarus americanus) in the context of climate change in the Gulf of Maine

Marine heatwaves and mass bleaching have devastated coral populations globally, yet bleaching severity often varies among reefs. To what extent a reef’s past exposure to heat stress influences coral bleaching and mortality remains uncertain. Here we identify persistent local-scale hotspots and thermal refugia among the reefs of Palau, Micronesia, based on 36 years of satellite-derived cumulative heat stress (degree heating weeks–DHW, units: °C-weeks). One possibility is that hotspots may harbour more heat tolerant corals due to acclimatisation, directional selection, and/or loss of tolerant genotypes. Historic patterns of assemblage-wide mass bleaching and marine heatwaves align with this hypothesis, with DHW-bleaching responses of hotspots occurring at 1.7°C-weeks greater heat stress than thermal refugia. This trend was consistent yet weaker for Acropora and corymbose Acropora , with severe bleaching risk reduced by 4–10% at hotspots. However, we find a contrasting pattern for Acropora digitifera exposed to a simulated marine heatwave. Fragments of 174 colonies were collected from replicate hotspot and thermal refugium outer reefs with comparable wave exposure and depth. Higher heat tolerance at thermal refugia (+0.7°C-weeks) and a correlation with tissue biomass suggests that factors other than DHW may overwhelm any spatially varying effects of past DHW exposure. Further, we found considerable A . digitifera heat tolerance variability across sites; compared to the least-tolerant 10% of colonies, the most-tolerant 10% could withstand additional heat stresses of 5.2 and 4.1°C-weeks for thermal refugia and hotspots, respectively. Our study demonstrates that hotspot reefs do not necessarily harbour more heat tolerant corals than nearby thermal refugia, and that mass bleaching patterns do not necessarily predict species responses. This nuance has important implications for designing climate-smart initiatives; for instance, in the search for heat tolerant corals, our results suggest that investing effort into identifying the most tolerant colonies within individual reefs may be warranted. 

pdf/high-coral-heat-tolerance-at-local-scale-thermal-refugia-2o4e0s7al1.pdf

High coral heat tolerance at local-scale thermal refugia

: Marine heatwaves (MHWs) are becoming more frequent as a consequence of climate change. These discrete events are causing widespread stress and mortality in marine ecosystems, including coral reefs. The heat tolerance of different coral species is often complex and depends on a combination of environmental and biological factors, making accurate predictions of the impact of MHWs on individual species challenging. Heating rate has been shown to influence coral bleaching in Acropora species, but it remains unknown how heating rate influ-ences bleaching in other corals with contrasting morphology and bleaching sensitivities. In this study, we explored the sensitivity of Pocillopora damicornis and Plesiastrea versipora , representing branching and encrusting growth forms, respectively, to heating rate. We experimentally simulated MHWs with slow (0.5°C d −1 ) and fast (1°C d −1 ) heating rates and measured physiological responses to quantify changes in coral health, including photochemical efficiency, holobiont metabolism, tissue biomass, chl a , and symbiont density. Our results confirm that heating rate is a good predictor of coral bleaching sensitivity for these species, with faster heating rates causing more severe bleaching and declines in coral health. However, bleaching sensitivity differed between P. damicornis and P. versipora , with P. damicornis more affected by the faster heating rate. The use of heating rate, in addition to other metrics such as duration and intensity of heat, will enhance our capacity to predict the local impact of MHW events and their overarching ecological consequences for coral ecosystems.

/pdf/heating-rate-explains-species-specific-coral-bleaching-8f9vjm6e.pdf

Heating rate explains species-specific coral bleaching severity during a simulated marine heatwave

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

DP Thomson

Author Tools

Chat about Author

Papers

Heating rate explains species-specific coral bleaching severity during a simulated marine heatwave