Scientists discover a strange relationship between ‘wobbly’ lunar canopies and mangrove canopies: ScienceAlert

the moon‘s gravity pull The tides on our planet are just one of the many constant pulses of life on Earth.

Researchers have now found that not only do lunar cycles synchronize Timing of animal migrations and mass reproduction of coral reefs But it may also affect fluctuations in mangrove canopy cover.

Due to the growing interest in mangroves as natural carbon sinksHowever, the study results could improve our understanding of how much mangrove ecosystems are likely to decline and decline in the coming decades.

Understanding the seemingly strange relationship between lunar cycles, tides, and the growth of mangroves may also give an advanced warning that they are experiencing severe drought.

Led by wetland ecologist Neil Santillan of Macquarie University, the team of researchers measured mangrove canopy cover across the entire Australian continent using a new set of high-resolution satellite images taken between 1987 and 2020.

Digging through the data, the researchers found a sudden fluctuation in mangrove canopy cover.

The study found that long-term oscillations in the lunar orbit also affect the growth patterns of these salt-tolerant trees that occupy gently sloping mudflats, just as the moon pulls back and forth — tides that caress the roots of coastal mangroves —.

Dubbed the Lunar Oscillation, this cycle oscillates approximately every 18.61 years, causing low tides and pushing high tides higher in two distinct phases, approximately 9.3 years in length.

The analysis reveals that this fluctuation appears to be a dominant factor controlling the expansion and contraction of mangrove forest cover over much of the Australian continent.

“Until now, we haven’t had the length of annual records at an appropriate scale to see these patterns,” Santillan told ScienceAlert, referring to the dataset used.

“When we plotted the trend in annual canopy cover over time, we noticed a really interesting oscillation over a rough 18-year cycle.”

Fortunately, Santillan heard about the moon’s wobble after NASA scientists showed in 2021 how its next phase is set on Cause an increase in coastal flooding. He put two and two together, and the team discovered what appeared to be a strong connection between lunar cycles and mangrove umbrellas.

“When we looked in detail at the timing of the peaks and troughs in the lunar cycle, it matched perfectly with changes in mangrove canopy cover – one of those ‘Eureka! “Moments you get multiple times in your career.”

When the moon’s oscillation is in its lowest phase, researchers have discovered that mangrove ecosystems will absorb dryness, experience fewer days as their roots are saturated and more water stress, resulting in thinner canopy cover.

At its most extreme, the lunar oscillation may push the tides higher, promoting the growth of mangrove forests.

The two phases of the moon’s oscillation and how it affects tidal group, the difference in water height between high and low tides. (Santilan et al., science progress2022)

The synchronicity between the swaying of the moon and the cover of the mangrove canopy stands out against a solid background Climate changeas air temperatures, sea levels and carbon dioxide rise2 Levels correlate with mangrove forest expansion and canopy thickening.

This is not all. The team discovered that these factors from lunar cycles and daily tides also interact with other weather events such as El Niño-Southern Oscillationwhich affects alternating periods of heavy rain and prolonged drought in eastern Australia and the western coasts of North and South America.

For example, when About 40 million mangroves withered and died In the Gulf of Carpentaria in northern Australia in 2015 – the largest death of mangroves in recorded history – an intense El Niño coincided with the moon’s lowest oscillation, researchers found.

Researchers say this explains why the bay has experienced a greater loss of mangroves than neighboring regions begs.

Not only did the extremely dry weather caused by the severe El Niño lower mean sea levels in the Gulf by 40 cm (16 in), the trough of the lunar cycle lowered the tides, meaning that vast areas of The mangroves were thirsty for water.

The analysis showed that mangrove forests were also more visible in the mudflats that threaten coastlines and river channels, areas subject to a full range of extreme tides, adding to the weight of the researchers’ conclusions.

“Observations from the 2015 death-reaction event indicate that gray mangroves Marsa Ibn Sina Particularly susceptible to canopy slope under low flooding,” Santillan et al Type.

on condition a. Marina are the most widespread mangrove species in Australia, “This may explain the consistency of the effect of the decadal cycle on mangrove canopy cover across the continent,” Add.

Studies like this are important for extrapolating the Earth’s natural rhythms, and this, in particular, could seed future research looking at whether the ability of mangroves to absorb and store carbon in their moist soils also changes with lunar cycles in the way the mangrove canopy covers. Do.

It will be important to understand this in detail as the world grapples with how to withdraw carbon dioxide from the atmosphere to reverse global warming.

Protecting strong mangroves is just one strategy within our reach. But there is a file Determine what these flexible and adaptable plants can tolerate, where they are pushed towards land due to rising sea level. So it is better to move quickly.

The search was published in science progress.