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National Geographic : 1936 Aug
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SEA CREATURES OF OUR ATLANTIC SHORES Photograph by Koy Waldo Jiner A COLLECTOR SETS TO WORK IN THE TIDAL ZONE AT BLISS ISLAND, PASSAMAQUODDY BAY Precipitous shores here have a tidal rise and fall of 22 feet. Sleeves uprolled, the naturalist wades along a submerged ledge at about three-quarters tide. The zonelike arrangement of animal life is clearly shown here. A band of barnacles edges the high-water mark, and thickly matted rockweed covers the cliff below. Underneath the weed many sea animals cling in crevices, kept moist by the over-draping growth. are hunted by the fishes. Thus a mighty struggle for existence has taken place in these shallow waters over the ages. Many forms, such as the mollusks, have evolved hard protective shells. Still others hide themselves in submarine burrows, as do the marine worms. Many species, such as the jellyfishes, have become adapted for floating in the open seas and are borne away by ocean currents to less closely contested parts of the waters. Some bottom creatures have crept down the oceanic slope, apparently crowded from its well-lighted summit by the teeming armies struggling for a place in the sun. Such forms have gradually accustomed themselves to life in dimmer waters, and among them a still lesser number of species have ventured down into the great abysses to live their lives in the Stygian darkness, the perpetual cold, and the enormous pres sures of the deeps, miles below the surface. As the open seas were peopled from the oceanic shelf, so the fresh-water streams and swamps received parts of the overflow. Countless species found food and a measure of safety from enemies by creeping into the area between the tides, where they 211
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