How to Excavate an Underwater Village During a Pandemic

As the Ice Age waned, prehistoric villages along Israel’s coast were swamped and now lie beneath the waves. Excavating them has peculiar challenges in the age of the coronavirus

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A simulation of the digging area at Habonim Beach, which was created by the team of researchers from San Diego.
A simulation of the digging area at Habonim Beach, which was created by the team of researchers from San Diego.

Around 8,000 years ago a group of people lived at the foot of Mount Carmel, supporting themselves with rudimentary agriculture, animal husbandry, fishing, hunting and gathering in the marshes in the area. They carried out farming and hunting with tools from stone, but the technological revolution of the time, pottery, had already reached their village. With pottery, food could be stored and shared in innovative ways.

Today the site lies around 3 meters beneath the waves, not the far from Habonim Beach. Most of the ruins are covered with sand. All that snorkelers can see on the sea floor are boulders once used to build the village’s walls, which are exposed from time to time by the water and waves.

The village was one of a string of prehistoric communities along the Eastern Mediterranean coast, an area that had been inhabited from the earliest days of human settlement out of Africa. It is now being excavated by a group of researchers from the University of Haifa and the University of California, San Diego, funded by the Koret Foundation in San Francisco, whose goal is to strengthen cooperation between Israeli and American academic institutions.

A Zoom conversation between experts on ancient maritime civilizations from the University of Haifa and UC San Diego.Credit: Hector Bracho

The excavations have been hampered by coronavirus restrictions in both the United States and Israel, which prevented the American team from coming to participate. Thus the researchers, led by Prof. Assaf Yasur-Landau of the University Haifa and Prof. Thomas Levy from UC San Diego, had to come up with a new approach to the excavation given that part of the team was left behind halfway around the world.

In the spirit of the times, Zoom is playing a key role – but uniquely, some of the videoconference participants are underwater, at least sometimes. The researchers also harnessed the supercomputer scientific visualization platforms at the Qualcomm Institute at the San Diego campus to create computer models of the site based from high-resolution photographs, and 3D printers to build physical models of the ancient villages and the objects found there.

It’s an ill wind. The methods developed for this excavation will make undersea excavation more precise and efficient, Yasur-Landau, the head of the Leon Recanati Institute for Maritime Studies and a Professor in the Department of Maritime Civilizations at the University of Haifa, adding that he expects these tools to be useful even after the pandemic is over.

Yasur-Landau notes happily that the work on two sides of the globe enables optimal use of the entire day for research. “In the morning we go into the water and dig as usual, with a local team and students,” he says, as divers can be seen entering and exiting the sea.

The excavators, headed by doctoral candidate Roey Nickelsberg, use underwater high-resolution cameras and regular GoPro cameras to document the excavation work. At the end of the workday Nickelsberg transmits these visual materials directly to his American counterpart, doctoral candidate Anthony Tamberino.

Time zone-wise, Israel is nine hours later than California. When the workday begins in California, Tamberino and his colleagues find the new material waiting for them. The researchers hold an end of day/beginning of the day meeting on Zoom. The archaeologists in Haifa go to bed, while the researchers and supercomputer in San Diego get to work.

Prof. Levy, a director at the Scripps Center for Marine Archaeology at UC San Diego and head of the Center for Cyber-Archaeology at the campus’ Qualcomm Institute, is harnessing the capabilities of both research institutes for the current excavations. Algorithms process the data collected in the high-resolution photos and within a few hours Qualcomm’s computer cluster produces a three-dimensional image of the excavation site, updated to include the sections that were excavated during that day’s dig.

Researchers at work in the study.Credit: Hector Bracho

Interesting objects that were found at the underwater site are scanned with the University of Haifa's 3D scanner. The scan file is transmitted to California where the researchers print the objects on 3D printers, in full size and at high quality. Among the findings are stone walls, flint tools, some of very high quality, very coarse pottery shards, basalt grinding stones and bones of various animals.

“There are things that couldn’t be seen in a computer rendering,” says Levy, describing a stone axe head they had printed the previous day. “Sometimes you have to hold an object in your hand to understand how it was made.”

The researchers in San Diego have also printed a 3D model (not life size) of the entire site, to gain better understanding of the village’s characteristics, such as the topography on which the ancient homes rested.

Live from the seafloor

When night descends on California and the researchers meet again for an end/beginning of the day summary, the Haifa excavators arrive at the shore. Assuming the condition of the sea enables them to proceed and based on the work done on the U.S. West Coast, they decide how to set up their workday on the Israeli coast. If there are questions that require consultation at the site itself, the researchers take cameras underwater and the discussion takes place live from the seafloor.

Underwater excavators at Habonim Beach near Haifa in the study.Credit: Amir Yurman

The 24/7 scientific work is a bonus, but the importance of using these sophisticated computerized tools is more basic. Underwater archaeology poses difficulties unknown to land-based archaeologists. In the desert, at the end of the day the site can be covered by a tarpaulin and find it in exactly the same state the next day. At sea, one can spend the whole day painstakingly uncovering a row of stones or a well and come back the next day to find that the currents buried everything in sand again.

“What we used to do was have a student swim with a paper and pencil that can write underwater and record where every stone was found using tape measures,” Levy tells Haaretz in a Zoom conversation from California. The result wasn’t really accurate, he adds with a smile. Now the photos and computerized models permit accurate mapping, marking the location of each stone with satellite-level precision, Yasur-Landau says.

The photos and models also enable estimation of how much sediment, sand and other material is dug up each day, and help deduce sizes – the volume and depth – of the village structures. As Levy points out, “these data can tell us about the function and social organization of this ancient village.”

“Thus, from the lemon of inconvenient constraints, the collaboration has made lemonade by enabling both more precise work and maximizing the time spent actually digging”, Yasur-Landau adds.

The computer models place the interesting objects found at the site, like stone or earthenware vessels, at the exact spots they were found. This precise documentation also enables ancient-DNA researchers, hoping to elucidate what animals and plants were typical of the village based on genetic analysis of remains, to know exactly where the samples they are analyzing came from.

The excavation season ended earlier this month. Now the researchers on both sides of the globe are processing the vast amount of data collected, preparing scientific publications, and working to connect it with information from other joint research projects being conducted in the region by the two universities.

The graces of the weather

Based on the evidence collected to date, the village consisted of small structures. The archaeologists excavated in two places within the village, but can’t establish how far the village had extended because most of it remains buried. It could even extend beneath the current beach, Yasur-Landau says.

The overarching goal of the research is to investigate the links between environmental changes and cultural, social and technological changes in the settlements of the time.

The harbingers of agriculture and permanent settlement in the region began around 11,000 years ago. Changes in nutrition that accompanied the agricultural revolution spurred higher birth rates. But just as the population was expanding, it was becoming more vulnerable to the graces of the weather, especially the communities along the shore, including at the foot of Mount Carmel.

A 3D printer at the University of California, San Diego, at work in a study of prehistoric villages along Israel's coast.Credit: Scott McAvoy

The topography of the Carmel coast confined its first settlers to “micro-regions” delineated by the mountain, the sea and the surrounding swamps. While movement may have been constrained, resources were abundant in the area.

But just as the villages were rising along the coast, the last ice age was starting to wind down fast. Sea levels rose as the northern glaciers retreated and these early villages were drowned.

Yasur-Landau adds that two significant climatic events occurred 9,200 years ago and 8,200 years ago, possibly causing the climate to become drier and colder during the lifetime of the village.

The archaeologists also hope to shed light on the development of pottery in the region and to shed light on the link, if any, between the climatic changes of the period and the rise of a technology to produce robust vessels from clay. With it’s a combination of stone vessels and coarse pottery, this village could indeed represent this transition period.

Another study being pursued jointly by Haifa and San Diego aims to provide an important new viewpoint on climate changes and the influence of human settlement along the Israeli shoreline, which 9,000 years ago was around 1.5 kilometers further west than it is now. For this purpose the researchers have already drilled soil cores along the Carmel coast. Analyzing the sediment levels revealed in the soil cores should help determine the climatic and environmental conditions along the coast over thousands of years, and how they were affected by the gradually rising sea level.

Yasur-Landau says that “the study is part of the joint scientific effort by the University Haifa and UC San Diego to understand the relationship of humans and the environment in the Carmel region during the past 10,000 years, until the Crusader period. The project also includes excavations of an Iron Age-era port at Dor Beach, a Hellenistic port to the south and a Neolithic site beneath it”.

Levy, who excavated in the deserts of Israel and Jordan for 40 years until he became involved in marine excavations a decade ago, says that the collaboration “enables the integration of the marine and technological capabilities of San Diego with the extraordinary expertise that Haifa University has develop in underwater archaeological excavations. Haifa’s underwater excavations are pioneering at a global level,” he says with admiration. And despite the upsides of the division of labor, the next excavation season starts in February and Levy hopes that the pandemic won’t prevent him from coming to Habonim Beach himself.

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