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Monte Verde: Seaweed, Food, Medicine, and the Peopling of South America

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Science  09 May 2008:
Vol. 320, Issue 5877, pp. 784-786
DOI: 10.1126/science.1156533

Abstract

The identification of human artifacts at the early archaeological site of Monte Verde in southern Chile has raised questions of when and how people reached the tip of South America without leaving much other evidence in the New World. Remains of nine species of marine algae were recovered from hearths and other features at Monte Verde II, an upper occupational layer, and were directly dated between 14,220 and 13,980 calendar years before the present (∼12,310 and 12,290 carbon-14 years ago). These findings support the archaeological interpretation of the site and indicate that the site's inhabitants used seaweed from distant beaches and estuarine environments for food and medicine. These data are consistent with the ideas that an early settlement of South America was along the Pacific coast and that seaweeds were important to the diet and health of early humans in the Americas.

Most scholars now accept that people entered the Americas through Beringia before 16,000 calendar years ago (13). After entering, it is not known whether people colonized the hemisphere by moving along the Pacific coast, through interior routes, or along both areas. Early coastal migrants probably obtained much of their food from the sea, including sea mammals, shellfish, and seaweed (4, 5). Convincing data have not yet been recovered to support the coastal model, although a few early littoral sites have been reported (611). A coastal route along which resources are similar would more easily explain the rapid movement of people into South America and their presence at Monte Verde II, Chile, the upper layer of the Monte Verde site, dated at ∼14,600 calendar years before the present (cal yr B.P.) (12, 13) [supporting online material (SOM) text, section 2]. Here we report the recovery of three marine, two estuarine, and one terrestrial shoreline algae species new to the site and three additional stone artifacts, one with the remains of seaweed on a worked edge, that suggest a strong reliance on coastal resources for food and medicine.

Monte Verde II is buried in the terraces of a small creek in the Maullín river basin, located midway between the Pacific coast and the Andean mountains. Today, the area is characterized by a cool temperate climate, by wetlands composed of various hydrophytic communities and their successive species, and by remnants of a partly deciduous rainforest (12). During the late Pleistocene, temperatures were cooler, the site was drier, and the coast was situated ∼90 km to the west, where sandy beaches, rocky shores, and delta estuaries offered a wide variety of marine and brackish water resources (Fig. 1). The inland marine bay of Seno de Reloncavi, dominated by a rocky shoreline, was ∼15 km to the south. Monte Verde was 120 m above sea level at the time of human occupation (SOM text, section 1). Today, the sea is ∼55 km west and ∼11 km south of the site and ∼59 m below it.

Fig. 1.

Map of the Monte Verde area showing the location of the sea level and coastline at ∼15,000 to 14,000 cal yr B.P. and at the present day.

At Monte Verde II, organic remains are well preserved under a peat stratum that covers the ∼14,600 cal yr B.P. archaeological layer. Previous research recovered wood tent remains, hut foundations and floors, hearths and braziers, wooden lances, mortars and digging sticks, medicinal and edible plants, animal bones, hide and soft tissue, human footprints, numerous stone tools, and other materials demonstrating human occupation (13). This evidence suggests that the site was occupied year round and that resources were exploited from a wide variety of habitats, including the coast and the mountains. Fifteen species of aquatic plants from freshwater marshes of the distant Maullín flood-plain and from coastal dunes and brackish water estuaries of the delta, along with gomphothere (Cuvieronicus sensu Casamiquela) and paleocamelid (Paleolama sp.) meat, wild potatoes (Solanum maglia), and 45 other plant species from inland forests and wetlands provided the bulk of the Monte Verdeans' diet (12, 13). Included in the plant inventory were four previously reported varieties of seaweed, Durvillaea Antarctica (cochayuyo), Porphyra sp. (luche), Gracilaria sp. (pelillo), and Sargassum sp., from sandy and rocky shorelines (1416). All of these species are edible and have important medicinal properties. Also recovered were the remains of 19 other probable medicinal species, 5 of which came from coastal environments (1416). Other coastal resources collected from beaches and transported to the site were discoidal pebbles made into stone tools, bitumen used as adhesive to attach tools to wooden shafts, and marine fossils (12, 13).

Our new analyses are from 27.2 liters of previously excavated but unstudied sediment fill from 24 hearths and braziers in the floors of two structures thought to be the remains of a medicinal hut and a residential tent. We recovered the remains of seaweed and other economically important plants (SOM text, section 2, and table S1) and three stones, one of which is a flake tool. Identified were Porphyra sp. and Durvillaea Antarctica (Fig. 2) and five new species of seaweed: Gigartina sp. (luga roja); Mazzaella sp. (luga cuchara); Porphyra columbina; probably Sarcothalia crispata (luga negra, Fig. 3); and Macrocystis pyrifera (huiro) (13). We also recovered Trentepohlia sp., an algae that is available exclusively on trees (Aextoxicon punctatum and Griselinia jodinifolia) and rocks in the littoral zone. The excellent preservation of the specimens allowed species-level identifications based on cellular structure, plant morphology, and color. Two accelerator mass spectrometry radiocarbon dates derived from fragments of Gigartina sp. on the floor of a wishbone-shaped hut and from Mazzaella sp. in a brazier on a tent floor are respectively between 14,190 and 13,990 cal yr B.P. (∼12,290 ± 60 C14 yr B.P., Beta Analytic radiocarbon dating service sample number 238355) and 14,220 and 13,980 cal yr B.P. (∼12,310 ± 40 C14 B.P., Beta Analytic sample number 239650). These dates agree with those derived from wood artifacts and charcoal in hearths at Monte Verde II, which range between 14,600 and 14,200 cal yr B.P. (13).

Fig. 2.

Microscopic view of an archaeological specimen of Durvillaea antarctica from a hearth matrix located in the remains of a domestic hut. Scale bar, ∼100 μm.

Fig. 3.

Microscopic view of an archaeological specimen of Sarcothalia crispata from a hearth matrix located in the remains of a domestic hut. Scale bar, ∼ 200 μm.

It was difficult to count the soft remains of the 10 species of algae because many were fragmented and mixed with other plants in masticated cuds, thought to be representative of an ancient pharmacopeia (14, 15) (SOM text, section 3, and fig. S1), or were trampled and embedded in hut floors. However, the dry weight total of all excavated seaweed remains was ∼125 g. Several algae fragments were partially burned, suggesting that they had been dried, probably for transport from the coast or for storage, or were cooked. The fragility of soft leafy seaweeds, their unlikely preservation in archaeological sites, and yet their widespread dispersion in hearths and braziers across the site and their combination with other medicinal plants in the form of masticated cuds suggest their value for both food and medicinal purposes.

The seaweeds represent contrasts in environment and seasonal availability. Four genera (Durvillaea, Porphyra, Mazzaella, and Sarcothalia) derive from rocky coastlines and intertidal pools located west and south of Monte Verde (16, 17), whereas three (Gracilaria, Gigartina, and Macrocystis) originate only from sandy coastlines west of the site. The peak availability of three (Mazzaella, Gigartina, and Sarcothalia) occurs from early spring to early summer, one (Gracilaria) is available from late spring to early summer, one (Porphyra) is found in mid-summer, and one (Durvillaea) occurs in late summer to early fall (1821). Sargassum sp. (Fig. 4) is a warm-water species with a wide Pacific natural range. Its growth anywhere in Chile, where the cold Humboldt Current sweeps the coast, is doubtful (1722). Sargassum probably reached Chile through violent storms or major El Niño events, or perhaps the configuration of ocean currents was different at the time of site occupation. Trentepohlia sp. is available year round along the littoral. Seaweed collection by Monte Verdeans was thus conducted at various coastal locales from early spring to early fall. Today, the tidal range of the sea varies from 6.5 m near Puerto Montt in the Reloncavi Bay to 4 m at the mouth of the Maullín River, in both areas producing a wide and abundantly available resource-rich intertidal beach. With the exception of Sargassum sp., moderate quantities of all varieties of seaweeds are deposited along the shoreline during storm surges. All nine seaweed species recovered at Monte Verde II are excellent sources of iodine, iron, zinc, protein, hormones, and a wide range of trace elements, particularly cobalt, copper, boron, and manganese (2329). Secondary beneficial effects of these seaweeds include aiding cholesterol metabolism, increasing the calcium uptake of bones, antibiotic effects, and increasing the body's ability to fight infection. These species have medicinal uses that closely correspond to common contemporary health problems in the study area today (SOM text, section 3). Two species, Gigartina and Sargassum, are non-edible and were evidently used exclusively for medicinal purposes. Collectively, the seaweeds and 10 other plant species at Monte Verde II suggest a medicinal stock derived from the cool temperate environment of the region. These same species are used today as medicinal plants by local indigenous populations.

Fig. 4.

Microscopic view of Sargassum sp. from the floor of the wishbone-shaped hut. Scale bar, ∼100 μm.

We also recovered a total of 268 edible seeds, fruits, and other plant parts (SOM and table S1) from the processed feature fills, which correspond with the genera previously reported from the site (1316). Also recovered were three stone tools, one of which exhibits microparticles of Gigartina sp. on a used edge (SOM text, section 4, and fig. S2), suggesting that it was used for cutting and preparing seaweed. Fragments of Porphyra sp. and Sargassum sp. were reported previously on other stone tools (13). The remaining two stones show indeterminate human modification (SOM and figs. S4 to S6).

Not known is whether people arrived at Monte Verde through an interior or coastal route. However, these new data indicate that the people inhabiting Monte Verde II were accustomed to frequently exploiting coastal resources year round, which, coupled with interior foods, allowed them to remain in the area. Prior evidence suggests that the Monte Verdeans also regularly moved up and down the Maullín basin to exploit resources and/or to exchange them with other people living in the area (13, 16). Assuming that other late Pleistocene people operated under similar subsistence and settlement practices, our data imply that if groups traveled along the Pacific coast, they may have migrated slowly and exploited the interior resources of the hundreds of river basins descending the long mountain chain from Alaska to Tierra del Fuego to the sea. Several recent archaeological findings support the idea of early coastal migration and specialized maritime sites, but this evidence also indicates contacts with interior people or transhumance between coastal and interior areas and thus broad-spectrum economies (7, 8, 10, 11).

Supporting Online Material

www.sciencemag.org/cgi/content/full/320/5877/784/DC1

SOM Text

Figs. S1 to S6

Table S1

References

References and Notes

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