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Sometimes a disaster can be a good thing

It is that time again, hurricane season that is and most of us are thinking about how we are going to deal with the potential threat of another Ivan. In our personal lives things like accidents, fire and illness make things uncomfortable if not down right dangerous. Out in nature it is much the same only what we see as a disaster is in reality just a part of the natural cycle of life.For instance, take a look at some of those really large brush fires they have out west every year. Before man began helping things along with his campfires and broken glass, lightening was nature’s way of helping the forest ecosystems stay health. The fires clear out large amounts of underbrush that has grown in the under-story of the forests. This burning releases nutrients that were tied up in the brush for use by the forest. Some species of fir trees require the heat from forest fires to release seeds from their cones. These trees would not be able to reproduce without a forest fire. So, for those trees what we see as a disaster is just another round of their reproductive cycle.Hurricanes are their own renewing force in the marine world also. Strong currents created by storm surge from a hurricane act as a liquid scouring pad. When these currents move across oyster reefs the hydrological forces that they apply to these shallow reefs are tremendous. Large amounts of sand and debris carried by the currents and the force of the water itself just about completely wash all the oysters off the reefs or cover them up. If you look at the commercial oyster landings for a year or two after a hurricane you will see a very strong decline in production.If left to their own designs the reefs will come back on their own. The shells from several generations of oysters would serve to build the reefs back up. In order to help things also the federal government has responded to this crisis by authorizing grants to the States for the purchase oyster shells from commercial dealers and the funds to plant them on the reefs. This is necessary a process in order to rebuild the reefs quickly.Shrimp is another species that is negatively impacted by the effects of a hurricane. Large amounts of freshwater are generated by hurricanes both on the coastline and inland. This water flows down the river systems, through the delta and out into the Gulf. If this happens during the larval stages that shrimp go through in May and early June it will kill them all if the salinity drops too low. Later in the shrimp season, most mature shrimp will either be killed or forced out into the Gulf by the retreating storm surge.The storm surge that causes so much havoc along the coast brings with it some inshore biological consequences. The saltwater the makes up the surge ‘salts the earth’ as it passes north from the shore. This will kill salt intolerant plants, shrubs and some trees and if the water from the surge stays around to awhile it will impair new plant growth.The surge pushes saltwater fish far up the coastal rivers and streams with mullet and some sharks being found as far north as Montgomery. Saltwater fish populations are not the only ones affected.The saline water from the surge negatively impacts freshwater species like largemouth bass, crappie, bream, striped mullet, carp and many others. It destroys their eggs and larvae and will killed the adults if they do not move into fresher water.The freshwater also washes tremendous amounts of debris down the rivers into the coastal waters. Along with trees, cars and paper cups large amounts of nutrients wash into local waters. This can cause massive algal blooms, even red tide. When these blooms die off they cause oxygen depletion and result in fish kills. The dead fish then add to the oxygen problem as they decay. This is all part of what we smell in the days following a hurricane’s departure.It is ironic that all this death is the seed for the new growth that comes after a hurricane. Nutrients that were not useable in the estuary mud bottom are recycled into the ecosystem along with those from the dead fish. The debris that is washed into the bay forms artificial reefs and adds to the productivity of the coastal ecosystems. Life comes from death in the biological world. Normal 0

Think Global – Act Local!


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