Helmut stood on the navigation deck of the cargo freighter in the middle of the Atlantic Ocean and peered out at the horizon and the vast surface of the ocean that was all there was to be seen. His wrinkled skin had darkened from months of salty wind and sun, obfuscating the blue lines of the tattoo on his right shoulder depicting an anchor. Cumulus clouds drifted by in the sky above and sank behind the horizon in the distance. Several illuminated spots on the dark water surface reflected the openings in the cloudy heaven and beams of sun light were clearly visible falling through them. Helmut stared at the endless number of crests that formed on the waves. His attention was caught by a sudden black movement on the surface. The constant change in surface pattern interrupted the trance of Helmut’s thoughts induced by the endless sight of repetitive patterns of waves, crests, that rose and fell, disappearing in the mass of water again. Every now and then, he thought he saw a dolphin jump playfully out of the water, or the vague shower of vapor of a whale’s exhalation sprout into the air, but then again he thought he had mistaken himself. As a sailor in the German navy Helmut had sailed the world for four years, from 1954 to 1958. Ever since he had not been back to the sea and had lived on a farm in Westfalen. He enjoyed listening to songs from his favorite shanty choirs and retold adventures with his comrades from the navy. When he retired last year, his children had offered him a ticket around the world on the Rickmers Singapore. But his memories had betrayed him. Even on board this German ship from the most prestigious German shipping company no body spoke German, and no sailor played the accordion to sing a shanty like they used to. For months, all day Helmut stood here in the sun, on the navigation deck, and stared into the distance.
Chapter 7, Estuaries, in: Introduction to the Biology of Marine Life (9th Edition)
The Chesapeake Bay, San Francisco Bay, Great South Bay, Tampa Bay, Puget Sound, and the Mississippi River Delta, the Hudson River Bay, Columbia River and Willapa Bay in Oregon, are among 100 bodies of water designated as estuaries in the US. Over 1/3 of the US population lives within the drainage basins of these estuaries.
Types of estuaries:
a. Coastal plan estuaries;
b. Bar built estuaries;
c. Coastal lagoons;
e. Tectonic estuaries;
Because of the patterns of freshwater and seawater mixing, there is an inward flow of nutrient rich seawater along the bottom of th estuary and a net outward flow at the surface, creating an estuarine upwelling. The time necessary for the total volume of water in an estuary to be replaced is called the flushing time.
The body fluids of osmotic conformers fluctuate to remain isotonic with the water. Most estuarine animals are stenohaline, tolerating exposure only to limited salinity ranges. A few species are euryhaline, capable of withstanding a wide range of salinity. Continue reading