Importance of Pheaophyceae
Brown algae
We all know the multifarious benefits of Kelps (Mostly Brown algae of Laminariales), providing edible materials, algin, potash and iodine. They form huge highly productive aquatic ecosystem supporting or sheltering a wealth of shellfish, fish, marine mammals, seabirds, and seaweeds, resources heavily used historically by coastal peoples. Now a collaborative effort between archaeologists and marine ecologists, proves that these kelp forest ecosystems facilitated the movement of maritime peoples from Asia to the Americas about 15,000 years ago or near the end of the Pleistocene and this is named as “Kelp Highway”.
Primitive Earth
By the Last Glacial Maximum (LGM- around 20,000 years ago), Eastern parts of Russia and Siberia were connected to Alaska of North America by land bridge known as Beringia and the whole area was covered with very thick sheets of Ice. Since most of the water on Earth was in the form of ice stored in polar regions global sea levels were more than 100-180 meters lower than today, exposing large expanses of the now submerged continental shelves around the Pacific Rim, including the broad and low lying plains of Beringia that once connected Northeast Asia and Northwest North America.
Beringia is the land and maritime area between the Lena River in Russia and the Mackenzie River in Canada and marked on the north by 72 degrees north latitude in the Chuckchi Sea and on the south on the tip of the Kamchatka Peninsula. Climate change at the end of the Ice Age caused the glaciers to melt, flooding Beringia about 10,000 to 11,000 years ago and closing the land bridge. By 6,000 years ago, coastlines approximated their current boundaries. Recent reconstructions suggest that rising sea levels early in the postglacial created a highly convoluted and island-rich coast along Beringia’s southern shore, conditions highly favorable to maritime hunter-gatherers. Along with the terrestrial resources available in adjacent landscapes, kelp forests and other nearshore habitats sheltered similar suites of food resources that required minimal adaptive adjustments for migrating coastal peoples. With reduced wave energy, holdfasts for boats, and productive fishing, these linear kelp forest ecosystems may have provided a kind of “kelp highway” for early maritime peoples colonizing the New World.
Today, extensive kelp forests are found around the North Pacific from Japan to Baja California. After a break in the tropics—where near shore mangrove forests and coral reefs are highly productive—kelp forests are also found along the Andean Coast of South America. These Pacific Rim kelp forests By about 16,000 years ago, the North Pacific Coast offered a linear migration route, essentially unobstructed and entirely at sea level, from northeast Asia into the Americas.
Archeological evidences of a coastal migration route
During the last decade a number of geological and archaeological evidence from both coastal and interior regions around the Pacific Rim accumulated. These include shell middens (shell mound is an archaeological feature consisting mainly of mollusk shells) or human skeletal remains found on islands in Alta and Baja California (in State of Mexico), sites that demonstrate that coastal Paleoindians had seaworthy boats and other maritime capabilities between about 13,000 and 11,500 years before present (BP).
Evidence for even earlier maritime voyaging by anatomically modern humans (Homo sapiens sapiens) has emerged from islands of the western Pacific Rim, including the colonization of Australia roughly 50,000 years ago and additional ocean voyaging to the islands of western Melanesia, the Ryukyu Archipelago, and Japan between 40,000and 30,000 years ago. By the Last Glacial Maximum (LGM- around 20,000 years ago) these colonizing voyages placed maritime peoples near the base of the Kurile Islands (near Japan), which could have provided a series of staging points for a maritime migration to the Kamchatka Peninsula Eastern portion of Russia) and the south coast of Beringia suggest that the ice-free corridor between the Laurentide and Cordilleran ice sheets only became passable about 13,000 years ago for instance, and there is increasing interest in the hypothesis that humans colonized the Americas before that time Although the site remains controversial , widespread scholarly acceptance of debate about a 14,500 year old occupation of the Monte Verde site near the coast of Chile has also contributed to a broader interest in the coastal migration theory by American archaeologists.
. Recent reconstructions of the postglacial flooding of Beringia, however, suggest that its south coast was geomorphically complex with numerous bays, inlets, and islands that may have provided rich habitat for a variety of seals and cetaceans, walrus (Odobenus rosmarus), the massive (and now extinct) Steller’s sea cow (Hydrodamalis gigas), and other relatively large-bodied marine animals
. During the summer months, such convoluted coastlines—especially when combined with the low gradient of the Beringian platform—may have offered broad expanses of productive intertidal and nearshore habitats for early maritime peoples to hunt, forage, and gather in. As Ames (2002:38) illustrated, along such convoluted coastlines people in seaworthy boats can access much larger areas of nearshore habitat—and transport much larger loads back to residential bases—than those travelling on foot.
Kelps in Pacific Rim
Around the Pacific Rim today, kelp forests dominate shallow rocky coasts in cool and cold-watermarine habitats. The distribution of kelp forests is physiologically constrained by water temperature (generally <20◦C) and the availability of light, firm substrates, and nutrients. Fast-growing and structurally complex, kelps are generally limited to nearshore waters less than about 30 m deep Kelp forests are common from Japan to the Aleutians and down the Pacific Coast of North America into Baja California . After a break in the tropics—where productive coral reefs, mangrove swamps, estuaries, and other coastal habitats support similar suites of marine fish, shellfish, and other aquatic animals—kelp forests continue along the Andean Coast, from Peru to Tierra del Fuego. The North Pacific has an especially diverse array of kelps, with at least 21 species in the northeastern Pacificalone. Large canopy forming kelps dominate many Pacific Rim kelp forests, including the giant kelps (Macrocystis spp.) which grow to heights of 45 m along the west coasts of North and South America (Graham et al. 2007). Smaller canopy kelps (e.g., Nereocystis luetkeana, Alaria fistulosa) reach heights up to 10 m and are common from central California to Alaska and from the Aleutians to northeast Asia, respectively (Druehl 1970). Stipitate kelps are smaller (< 5–10 m long), but Laminaria dominates manyNorth Pacific kelp forests from Japan and northeast Asia to coastal Alaska and the Pacific Northwest. Most Pacific kelps thrive along rockyshorelines in conditions of ample light,high nutrients, and moderate water temperatures, but some varieties have adapted to subarctic conditions with strong seasonal fluctuations in light levels, nutrient availability, and water temperatures—even surviving beneath winter sea ice and blooming during a limited growing season (Dunton and Dayton 1995). In the Sea of Okhotsk, for instance, kelp forests form an almost continuous belt along the coastline, photosynthesizing during ice-free summers kelp forests historically supported or sheltered a similar suite of animal and plant resources heavily exploited by coastal and maritime peoples with relatively high population densities. These include sea mammals (sea otters, pinnipeds, etc.), a variety of marine shellfish (abalones, sea urchins, mussels,
chitons, etc.) and fish, sea birds, and edible seaweeds.
Current evidence suggests, however that anatomically modern humans had colonized or explored several archipelagos in the eastern Pacific by 50,000 to 30,000 years ago, islands that could only be reached with seaworthy boats. During the LGM, maritime peoples living in the islands of Japan would
have been adapting to relatively cool waters, potentially comparable to those in parts of the Gulf of Alaska today. Between about 18,200 and 14,700 years ago, three extended warming episodes in the northwestern Pacific may have reduced seasonal sea ice cover significantly, increased human access to intertidal and nearshore habitats, and facilitated the migration of maritime peoples from northeast Asia to Beringia (Sarnthein et al. 2006). By about 16,000 to 15,000 years ago, a migration route following the outer coast of northwestern North America appears to have been open and productive, providing an opportunity for maritime peoples to migrate down the Pacific Coast into more temperate climates. Some of the earliest archaeological sites are found in island or mainland coast settings adjacent to productive kelp forests. Where faunal remains are preserved, many of these sites
contain evidence for the harvest of shellfish, fish, and sea mammals common in kelp forests. Between about 18,000 and 13,000 years ago, as glaciers and sea ice retreated from North Pacific coastlines, a linear band of productive kelp forests may have extended discontinuously from Japan to Baja California, providing a “kelp highway” that could have facilitated the migration of maritime peoples into the New World.
References
Jon M. Erlandsona et al. (2007) The Kelp Highway Hypothesis: Marine Ecology, the Coastal Migration Theory, and the Peopling of the Americas,The Journal of Island and Coastal Archaeology, 2: 2, 161 — 174
Mammen Daniel
