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Past and present mesophotic coral ecosystems as a predictor for survival of coral reefs in an era of climate change

Periodic Reporting for period 1 - Mesophotic (Past and present mesophotic coral ecosystems as a predictor for survival of coral reefs in an era of climate change)

Reporting period: 2018-10-01 to 2020-09-30

Mesophotic Coral Ecosystems (MCEs) are characterized by the presence of light-dependent corals, found at depths ranging from 30 m to 150 m in tropical and subtropical regions. These coral communities create massive coral reef structures with diverse but characteristic morphologies and geochemical signatures. In many localities, MCEs are linked physically, and possibly also biologically, to their shallow-water reef counterparts. Therefore, they have the potential to act as refugia for shallow reefs with a source of propagules, contributing to the resilience of shallower reefs. However, in recent years, the new discoveries of MCE communities question the assumption that reef corals equate with shallow water, mainly because MCEs extend depth ranges of many corals.
In this study period, I have been investigating the past and modern MCEs to compare the biodiversity, community composition and geochemical properties of shallow reefs and MCEs. In addition, I developed methods to study these challenging environments. The main goal was to discover community structure dynamics over space and time for improved prediction of the Deep Reef Refugia Hypothesis (DRRH) in an era of global climate change. The uniqueness and advantages of this study are largely achieved due to the combination of technology, geology, ecology and molecular approaches. Furthermore, presenting those results to the public via conferences, social media and press releases encourage acting of the general public in favor of these unexplored and understudied ecosystems.
The combination of the studies conducted in this project provides a major step forward towards recognizing selection forces that are shaping coral population structure and through this understanding the potential of MCEs in serving as “lifeboats” for the world’s coral reefs. Management decisions and conservation efforts could be done only with a sufficient amount of basic knowledge which does not exist in the case of mesophotic ecosystems, hence the overall objective of this project is to gain new knowledge and methodologies for the benefit of exploring and conserving the mesophotic ecosystems.
Over the last two years, I have been working and studying at The University of Queensland, Australia for the outgoing phase of the study. I have participated in several developmental workshops and presented the results in three international conferences and one internal seminar. I have published 13 scientific peer-reviewed papers and two scientific peer-reviewed book chapters as part of my role in the project which in all of the cases the action got the appropriate needed mention. I have developed a website specifically to the project which updated regularly with new publications or events (https://mceisrael.wixsite.com/796025). In addition, the results and findings of this project are shared in the social media (e.g. @mceisrael on Twitter, Israel Mesophotic Reefs on Facebook) and on public events and media press. In the time period until today, I have been conducted two expeditions to the Great Barrier Reef and Moreton Bay reefs to work on a wide range of coral reefs, the results of these expeditions are yet to be published but hopefully will be published until the end of the project. Additionally, I had a successful visit to the Museum of Tropical Queensland at Townsville to get samples of mesophotic corals, which were used for testing our ability to accurately date mesophotic corals using the high-persistent U-series dating developed in The University of Queensland. The trials on those samples were highly successful and encouraging us to hopefully conduct more sampling in the near future.
COVID19 restrictions delayed the planned sampling and the evolvement of the project especially in the current outgoing phase, hens I have requested an extension of the outgoing period to be able to complete necessary expeditions and laboratory analyses. A three-month extension of the outgoing phase was permitted as part of the time of the incoming phase period. I am very hoping that in the current situation I will be able to finalize the obligatory data collections of the outgoing phase.
The future expected results and further implications of the project highly dependent on the ability to finish fieldwork and laboratory work in Australia. The COVID19 pandemic and the lockdown in Australia impacted the timeline of the work heavily. During the lockdown, I was managed to work extensively on the data from this project from my home office, and I am expecting to get several more papers published over the next year of the project, but the lack of ability to conduct fieldwork and laboratory work delay the possibility of completion of all work-packages to sufficient novelty for publications. In addition, scientific meetings, public events and seminars were cancelled or postponed to next year or the years after.
The expected results of this project will provide a tool for identifying regional mesophotic reefs, as well as for understanding regional benthic cover characteristics and potential contributions to past and future geomorphology. Characterizing the spatial distribution of geomorphology features and associated benthic cover, and establishing a baseline for ecological productivity at mesophotic depths, also provides a basis for studies ranging from regional tectonics to future risk assessment of increasing anthropogenic stressors along with the total coral reef ecosystems (e.g. global warming, pollution, power and desalination plants, increased coastal development, etc.…).
The focus and implementation of this project are expected to build a baseline for future mesophotic research and conservation decisions for the benefit of coral reefs around the world and the human society depending on them.
2_Fieldwork at Heron Island, QLD, Australia
Photomosaic from fieldwork at Moreton Bay, QLD, Australia
1_Fieldwork at Heron Island, QLD, Australia
3_Fieldwork at Heron Island, QLD, Australia