The moon's pull on our planet's tides is just one of Earth's many constants.
The timing of animal migrations and mass spawning of corals may be influenced by lunar cycles, according to researchers.
Mangroves as natural carbon sinks could improve our understanding of how much carbon mangrove ecosystems are likely to draw down and sequester in the future.
Understanding the connection between lunar cycles, tides, and mangrove growth could give them advance warning of their vulnerability to severe droughts.
The mangrove canopy cover was measured using a new set of satellite images taken between 1987 and 2020.
Researchers found a sudden change in mangrove canopy cover.
The study found that the growth patterns of the trees that occupy gently sloping intertidal mudflats are affected by long-term fluctuations in the moon's position in the solar system.
This cycle swings around every 18.61 years, pulling low tides lower and pushing high tides higher in two separate phases.
The analysis shows that this wobble is controlling the expansion and contraction of mangrove canopy cover.
We haven't had the length of annual records at an appropriate scale to see these patterns.
When we plotted the trend in annual canopy cover over time, we noticed a really interesting oscillation on an 18 year cycle.
NASA scientists showed in 2021 how the next phase of the moon would cause a surge in coastal flooding. The team discovered a strong connection between lunar cycles and mangrove canopies after putting two and two together.
He says that the timing of the peaks and troughs of the lunar cycle matched perfectly with changes in mangrove canopy cover.
Mangroves would be sucked dry when the lunar wobble is in its minimum phase because they would experience fewer days where their roots were saturated.
The moon's wobble could push tides higher and boost mangrove growth.
The synchronicity between the lunar wobble and mangrove canopy cover stood out against a backdrop of steady climate change, where higher air temperatures, sea levels, and CO 2 levels are associated with mangrove expansion and canopy thickness.
There is more to that. The team found that the factors of lunar cycles and daily tides interact with other weather events such as the El Nio-Southern Oscillation, which influences alternating periods of heavy rain and long periods of dry weather in eastern Australia and the western coast of North and South America.
When the largest mangrove dieback in recorded history took place in the Gulf of Carpentaria in northern Australia in 2015, there was an El Nio.
The researchers theorize that this explains why the Gulf suffered greater mangrove loss.
The trough in the lunar cycle pulled tides even lower, meaning vast areas of mangroves were thirsting for water, because of the dry weather from the El Nio event.
Mangrove dieback was most pronounced in mudflats fringing coastlines and areas subject to the full range of tidal extremes according to the analysis.
According to observations from the 2015 dieback event, the gray mangroveAvicennia marina is particularly susceptible to canopy decline.
The nodal cycle influence on mangrove canopy cover may be explained by the fact that A marina is the most widely distributed mangrove species in Australia.
Studies like this are important for teasing out the Earth's natural rhythms, and this one, in particular, could seed future research looking at whether mangroves' ability to soak up and store carbon in their sodden soils also changes with lunar cycles.
As the world wrestles with how to pull carbon dioxide out of the atmosphere, it's important to understand in detail.
One strategy at our disposal is protecting mighty mangroves. As sea levels rise, there is a limit to what plants can tolerate. We need to move quickly.
The research was published in a peer-reviewed journal.
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