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Aug. 17, 2010 by Judy

Location, location, location.

Hawaiian volcanic islands rise out of the sea, taking a couple of million years to do so. It would seem at first glance that nothing could be more unrelated than dry rock and the rolling ocean. And yet, once you begin to look at how life is woven on these mountains, the many ways in which the land informs the sea, and vice-versa, can change your assumptions about what it means to be living on land. Because there IS no living on land without water. For anyone or anything.  

Now, think of the streams of the mountains as veins connected to the pulse of the sea. Warm air being pushed across the Pacific by trade winds, heavy with moisture, runs into the tall impediments of the Hawaiian mountains and is forced to drop the water it carries as it is pushed upwards into cooler elevations. This is called an orthographic rain pattern, and in Hawaii it means every tall island has a very wet side with an especially wet belt right around the 4000-7000ft. range of elevation. The dry, or leeward side of the island, if often left with 10 or less inches of rain a year.

However, even the dry sides of the islands are utilized by adaptable colonizers. More on that later. On the wet sides, during heavy rains and flash-flooding events, freshwater shrimp, molluscs and fish reproduce and their freshly-hatched young are swept down the heavy flowing streams. These young are then flushed into the salt ocean, where they miraculously adapt, mature a bit, and then, after spending some time milling around nearshore, generally find the stream mouth from which they were launched as tiny young and make their way labouriously back upstream to live their mature lives in the stream bed. Some of the young o’opu, the fishes, have adapted fins on their abdomens to help them ‘suction cup’ their way up waterfalls. In the past, Hawaiians were able to catch these returning fry by the millions in baskets, like tiny little salmon. 

In some protected watershed areas, like on the island of Moloka’i, migrations of returning hihiwai, or small dark molluscs, can still be seen steadily moving upstream along the bottom. Most scientists agree that these freshwater species probably adapted from saltwater species that gradually made their way inland and upland through the streambeds, always expanding the reach of life. The part of their life cycle that requires they spend some time in the salt sea is an indication of this ancient link. 

Because of the constant pulses of freshwater into the sea nearshore, even through the porous volcanic rock of the island itself, the reef environment is wildly variable and that allows for an outstanding variety of life to inhabit an infinitude of niches. All of which is to the good, as life tends to beget life. And Hawaiians understand very well that a healthy land is braided into a healthy ocean. There are animals on land that carry names of animals in the ocean, as if these organisms were twins and their relationship a good reminder that these habitats, these worlds, are not seperable

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