this is all starting to make sense now!
Carving giant, monolithic statues under the hot Polynesian Sun is thirsty work. So without freshwater rivers and springs to sustain them, how did thousands of the traditional Rapa Nui people of Easter Island survive?
We might finally have an answer to this historic mystery, and it's one that reconciles early European accounts of the Rapa Nui drinking what appeared to be seawater – but almost certainly wasn't.
A new study shows how coastal groundwater discharge around the island could have been collected by the Rapa Nui people and used as freshwater, because its salt content would have been low enough for humans to drink.
So Europeans arriving in the 18th century got it wrong about the locals drinking seawater (kind of). That wasn't seawater, but fresh rainwater running through the porous volcanic soils that make up Easter Island, where it then mixes with seawater.
"Water beneath the ground flows downhill and ultimately exits the ground directly at the point at which the porous subterranean rock meets the ocean," says the lead researcher behind the study, anthropologist Carl Lipo from Binghamton University in New York.
"When tides are low, this results in the flow of freshwater directly into the sea. Humans can thus take advantage of these sources of freshwater by capturing the water at these points."
Lipo and his team measured this brackish water at multiple points around the island, determining that its salinity was low enough to drink safely (9,000 parts-per-million is considered to be the limit).
This water might have been safe, but it would still have been salty. As it happens, this fits with previous research suggesting the Easter Island diet was very low in salt, maybe because islanders were already getting plenty of salt in their drinking water.
The brackish water is suggested to have been captured in rocky basins that have since been largely lost to time, though some evidence of the wells still remains.
In support of the hypothesis, the team also investigated the scant alternative sources of freshwater on the island, including two lakes (which are difficult to access), and one spring, along with small cisterns called taheta that would've been used to collect rainwater.
Add in the low rainfall of the island (just 1,240 mm or 49 inches per year), and together these freshwater sources wouldn't have been enough to support a population as large as the Rapa Nui, the researchers suggest, especially in times of drought.
What's more, this idea could explain the mystery of why the famous Easter Island statues are mostly found clustered around the coasts – those locations may have signified where people could get a drink.
"Now that we know more about the location of freshwater... the location of these monuments and other features makes tremendous sense," says Lipo. "They are positioned where freshwater is immediately available."
The next step is to work out how this water source might have contributed to the construction of the gigantic Moai statues – a remarkable feat of engineering that Lipo already has quite a few ideas about.
The team has previously published research on how the Easter Island inhabitants might have sustained themselves by farming the land and fishing the nearby seas, even in the challenging conditions of the remote, isolated location.
And it could even teach us more about surviving in difficult conditions in the modern day – by borrowing a few techniques from the inventive people of Rapa Nui.
"This information ultimately sheds light on the conditions that drove and enabled these communities to work together to achieve their feats of engineering," says Lipo.
"By gaining knowledge about community scale behaviour, we can gain insights into the general conditions necessary for group-level cooperation – whether in the past or in contemporary society."
The research has been published in the Hydrogeology Journal.
[link.springer.com]
Is that 49" annual rainfall level correct? That's over 4 feet. I live in Central KY(USA) and the annual rainfall here is anout 46 inches and we are certainly not an arid region. The US average is about 38~39". Curious.
Considering that the island is only 63 sq miles that’s not a big surface. Also KY has rivers fed from Northern wetter terrain.
@Lukian The article stated that the island had "only" 49" of rain annually which made it should like that wasn't much rain. It's quite a lot of rain actually. OTOH, Apparently it isn't a lot for an island. The land mass is obviously the difference. Thanks.
In his book In The Heart of the Sea, Nathaniel Phillbrick has a neat description of a freshwater spring on a small island in the south Pacific. If I recall correctly, the shipwrecked sailors, whose ship had been sunk by a sperm whale, could only access the spring at low tide, because the fresh water emanated from the rocks offshore. A similar thing happens with the fresh waters of the Florida Everglades, which flow through underground limestone caverns to join the salty waters of Caribbean Sea.
The other thing about that groundwater discharge is years ago that flow may have been very different than it is today.
The Rapa Nui may have been aware of the changing water source and this could have prompted the what seems to us over zealous need to erect these monuments.
TY for posting.
I have no problem whatsoever funding legitimate research, on Any subject!
But, as several posters on here point out, thius question has been answered, on other islands, such as Hawaii, already. So why ask it again? I damned sure don 't feel we should be paying to reinvent the wheel! You?
several may have pointed out a similar way to collect water but it would be significant if the Rapa Nui people were the ones that invented that. Several yes but you are the only sour one in the group here.
Science is discovery not invention
In Hawaii today the public water system consists of pumping water from a lens of fresh/brackish water that floats on top of the seawater under the islands. The lava rock is porous and groundwater flows down through the land to float on seawater that has migrated in from the shore. Since fresh water is lighter than salt water we have a lens of fresh/brackish water about eleven to twelve feet thick. ancient Hawaiians used land depressions that were slightly below sea level as a sort of well or "Queens Bath".
josh_is_exciting Thank you for the "like". I noticed in your bio that you said: "many who do are antagonistic towards believers;". Just want to clarify that I too have many friends who are believers, even batshit crazy believers. I was also, about sixty years ago. But then I turned ten and knew this was all BS. I have no animosity towards them, just their policies that promote hate, damage to the earth and climate change denial, and unfair tax policies. I will admit that although I have friends that are believers I don't include them as "best friends". We just don't have that much in common. Be well.
interesting info.
I lived on the Big Isalnd for a year & when snorkeling you could see & feel the freshwater springs emptying into the ocean. The visual effect looked kind of like heat waves rising off a hot road & swimming through them, the water felt MUCH colder. There were old villages where they got all their water by diving down with gourds & collecting the somewhat brackish water from the submerged springs. In one ancient village I followed a trail & found their water source, a tiny Queen's bath with 2 steps down & a little stone wall & cover protecting it. I may have been the first person to taste that water in years, & the delicate hint of sea salt, along with no chlorine, made it probably the best tasting & most memorable mouthful of water I've had.
Is this what you meant? [hosessa.com]
This is not how it was done on Easter Island but rather the water was captured at the coast from fresh water springs at low tide. I thought Hawaii was using the same technique as the article. The Rapa Nui people did not dig wells.
Great info though.
@Lukian Yes I think this is basically the same as I was explaining but a little more technical. I know the well in Keahou goes in at an angle that a vehicle can drive down. There I believe they pump freshwater possibly from a floating intake. This last statement is my own conjecture. I live part time in Kona HI. Lived here for 30 years in the past.
@rogueflyer I live in Montreal
@rogueflyer Yes I lived in Kailua & hiked all over the place--got pretty good at identifying old villages & trails I what not. Was sad to leave.
It has been known among fishermen, specifically divers that there are areas in the sea underwater where they can drink freshwater. Maybe that has been lost to the research team, but ancient people had many tricks we don't know about. Oh that thing about diver fishermen story come from Lebanese coast
Those are underwater springs along the coastline, where during most parts of the year, the flow is so strong it creates a freshwater area in the middle of the sea under surface level
To know about stories and actually being able to prove it is what science is all about. Also the positioning of the statues makes this story more fascinating.
Umm, there are herds of wild goats roaming the island, among plenty of other creatures.
They have to have fresh water as well.
Just common sense, not aliens, magic, or any other crapola!
common sense yes but not for thousands of people. Rain water was not enough to sustain humans.
@Lukian umm, cisterns, aqueducts, waterproof baskets, windmills or other lifting devices (perhaps human-powered, thus no traces)?
Example: The Nile only flooded once a year, yet the Delta supported many thousands.....
Plus, I think your estimate of the population of Easter Island is somewhat inflated.
@AnneWimsey I’m just referring to the article.
@Lukian Getting a $$ grant trumps (ooohhh, see what I did there?LOL!) true science (and common sense!) every time.....
@AnneWimsey wow you're referring to science funding to Trump? One cannot make a living on research? This cynicism has no end.
There are always traces in archeology... in this case, no trace nor voyager records said that they had cisterns, aqueducts, waterproof baskets, windmills or other lifting devices.