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63 Where People Meet the Sea A Fish Spawning on the Beach Why Animals are Well Adapted Challenges of a Rocky Seashore Beginnings of a Marine Biological Station Life in Sand and Mud: A Secret Existence Life in the Kelp Forest Exploration of the sea starts at the shore, whether for food or for science. Seabirds are in evidence along practically all coasts and invite much observation and marveling about different life histories of these feathered vertebrates. Some breed locally and raise their young in full view (fig. 3.1). Others stop over on long migrations, using marine wetlands to rest and to feed. Yet other, permanent residents, add drama to the scene (fig. 3.2). But beyond the many types of birds that enliven the scenery, an incredible diversity of creatures can be found along almost any rocky, sandy, or muddy shore. Anthozoans, arthropods, mollusks , vertebrates, and polychaete worms tend to be conspicuous, as are echinoderms. Of course, the species differ from one place to another. One would not expect to find the very same organisms on the shores of Alaska and of Hawaii. However, the similarities are in many ways more striking than the differences. Thus, the exploration of shore life in any one region opens the door to the understanding of life in many such regions. The environmental challenges for nearshore organisms depend on the nature of the seasons, with the major contrast between subpolar regions and the tropics, as well as on the nature of the shore itself, that is, whether it is flat and muddy, or rugged and rocky. Geology determines that nature: the flat coastal landscape is typical for general sinking, the rugged one for general uplift. Sinking shores have drowned river mouths and large estuaries. Rising shores have narrow beaches and cliffs and terraces, and small lagoons at the end of cliff-bounded river valleys. As a pattern of exploration, the study of coastal ecology has proceeded from taking stock of what is there, to marveling about adaptations of the different species, to studying interactions between species, and finally to assessing the impact of human activities. Humans are now a THREE Life at the Edge of a Fertile Sea THE BIRTHPLACE OF MARINE SCIENCE dominant factor in determining the nature of life along the shores of the world. Such activities include intense fishing, introduction of nutrients and mud, and disturbance of habitat by the sheer numbers of people finding recreation along the edge of the sea. To preserve some of the rich heritage of the seashore, marine reserves have been set up, where fishing is not allowed or is strictly regulated. Questions about how large and restricted such reserves must be to be effective in regard to conservation goals are at the center of modern ecological studies along the edge of the sea. WHERE PEOPLE MEET THE SEA The edge of the sea—from the nearshore wetlands and shorebird nesting sites, to the surf zone—is the major ecologic boundary on the planet. It has always attracted people, because of opportunities for fishing and collecting in the tidal zone, and because of the rich environment for discovery and adventure that it offers to the bold. The opportunities for fishing are on the decrease, but there is still plenty to discover. The exploration of life along the edge, by walking in the tidal zone or snorkeling armed with a facemask , is as exciting as ever to the young. Experiences will differ greatly depending on geography —a dive into a kelp forest is unlike a dive into coral gardens, though equally inspiring. For the experienced, there is a feeling that “things aren’t as they used to be.” The big predators —the giant groupers of the kelp, the large sharks in the reefs—are missing. There are no lobsters or abalone in the kelp, and in some reefs in the Caribbean much of the coral has been replaced by green algae gently waving to and fro in the surging surf. The stories of timeless drama that intrigued ecologists for the better part of the past century are gone; the tale now being told is one of increasing impact of human activities and of climate change. The emphasis in marine ecology has changed along with the changing scenery of life at the edge of the sea, within the last two decades. Scripps’s reef expert Jeremy Jackson, an experienced diver, puts it this way: “Every marine ecosystem I have studied during my 30-year career is...

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