Coral reef microbes point to new way to assess ecosystem health

Summary:A new study shows that ocean acidification is changing the mix of microbes in coral reef systems, which can be used to assess ecosystem health.

A recent study published in Microbiome reveals that ocean acidification is altering the microbial composition of coral reef systems, providing valuable insights into ecosystem health.

The research, focused on coral reefs but potentially applicable to various ecosystems, highlights the significance of microbial communities as indicators of ecosystem responses to human activities.

The findings underscore the importance of monitoring microbial diversity as a means of assessing the impacts of environmental stressors, such as ocean acidification, on marine ecosystems. This approach could offer valuable insights into the health and resilience of coral reefs and other habitats in the face of ongoing environmental challenges.

Assessing how ecosystems evolve in response to human activity is essential for predicting their future and implementing effective conservation measures.

While microbes play a vital role in ecosystem function, their contributions are often overlooked in assessments of ecosystem health, despite their critical functions in processes such as nutrition and immune system regulation.

Led by researchers from Imperial College London, a recent study explored whether evaluating changes across entire communities of both macroorganisms and microbes could offer a novel approach to measuring stress on coral reefs. By integrating microbial data into ecosystem health assessments, researchers aim to gain a more comprehensive understanding of the impacts of environmental stressors on coral reef ecosystems, ultimately informing conservation strategies and promoting their resilience in the face of ongoing environmental challenges.

In ecosystems such as coral reefs, microbes play a particularly crucial role, existing not only within the macro-organisms but also in the surrounding sediment and water. This widespread distribution of microbes underscores their significance in driving key ecological processes within these habitats. Microbes interact with macro-organisms, influencing their health and functioning, while also participating in nutrient cycling, decomposition, and other essential ecosystem processes. Understanding the dynamics of microbial communities across different environmental compartments is essential for comprehensively assessing ecosystem health and resilience in coral reefs and similar habitats.

‍Coral and carbon dioxide

Some coral reefs are located near natural carbon dioxide (CO2) vents on the ocean floor, providing researchers with a unique opportunity to study how reefs respond to elevated CO2 levels and subsequent acidification, mirroring conditions expected from human activities.

In a study conducted in Papua New Guinea, researchers utilized Autonomous Reef Monitoring Structures (ARMS) to collect samples of organisms and sediments from areas with varying CO2 concentrations. By employing genetic sequencing and mass spectrometry techniques, they identified the microbes and metabolites present in each sample.

The study revealed that as oceanic CO2 levels increased, the microbial communities and metabolites associated with reef macro-organisms became more similar to those found in sediment. This phenomenon, termed a decline in 'holobiont community distinctness,' suggests a shift in the microbial composition and metabolic activity within reef ecosystems in response to elevated CO2 levels. These findings provide valuable insights into the potential impacts of ocean acidification on coral reef health and highlight the importance of understanding microbial dynamics in shaping ecosystem responses to environmental stressors.

The study's findings indicate that alterations in microbial communities associated with macro-organisms could serve as an early indicator of ecosystem stress. By monitoring changes in microbial composition and metabolic activity, researchers may be able to detect and assess the impacts of environmental stressors, such as ocean acidification, on coral reef ecosystems before visible signs of decline appear.

Furthermore, the study underscores the significance of adopting an 'ecosystem approach' to comprehensively understanding the effects of human stressors on marine ecosystems. By considering the interconnectedness of various components within ecosystems, including macro-organisms, microbes, and environmental factors, researchers can gain a more holistic understanding of ecosystem dynamics and resilience. This approach allows for a more accurate assessment of the complex interactions driving ecosystem responses to environmental stressors, ultimately informing more effective conservation and management strategies.

Ecosystem stress

The recent findings, although derived from a single ecosystem facing acidification stress, have spurred the research team to expand their investigations to over 80 reef sites worldwide, each subjected to varying degrees of human pressures.

Jake Williams, the first author of the study from Imperial's Department of Life Sciences and ZSL's Institute of Zoology, emphasized the urgency of intensifying human activity and the climate crisis, which are imposing increasing stress on ecosystems globally. Williams highlighted the lack of comprehensive and robust methods for monitoring this stress and understanding ecosystem responses.

Williams suggested that the relationships between microbes and chemicals inside and outside organisms could offer a promising avenue for developing general and robust metrics to monitor ecosystem stress. He stressed the importance of these metrics being applicable across diverse ecosystems, from coral reefs to rainforests.

Dr. Emma Ransome, the lead researcher from Imperial's Department of Life Sciences, emphasized the need for a holistic approach to accurately evaluate and predict impacts on coral reefs. Ransome highlighted the critical role of microbes in all ecosystems and emphasized their importance as a tool for understanding environmental outcomes and achieving environmental sustainability.

Source: sciencedaily