A Review of Salinity Problems of Organisms in United States Coastal Areas Subject to the Effects of Engineering Works

Abstract

The nongaseous substances that normally move in and out of cells are metabolites, water and salts. The common salts in water determine its salinity, and the definition of sea water salinity and its composition are discussed. The relationships of salinity to all phyla of animals living in the coastal waters are reviewed, with emphasis on the estuaries of the Gulf and Atlantic coasts of the United States, which are particularly influenced by coastal engineering works and changes of salinity caused thereby.The fauna of estuaries is made up of a few brackish water species which complete their life cycles there, marine species which spend only a part of their life cycles there and which have definite low-salinity limits, a few anadromous species passing through, and a few fresh water species with high salinity limits. Organisms of marine origin are dominant. Floods and drought periods, resulting in severe osmotic changes, may kill organisms or result in drastic changes of the biota, which may take extended time to reestablish itself, if the conditions return to normal.Many invertebrate animals have few mechanisms for controlling the movement of waters and salts across their external membranes and thus are osmotic conformers. Species that cannot withstand wide salinity change are said to be stenohaline, but many species can tolerate rather wide changes; they have broad tolerance at a cellular level. Osmoregulators exhibit considerable control of their internal salinity by excretory mechanisms and permeability control of the body surface to water and salts. In general, the worms and molluscs are more often osmoconformers than the crustaceans, the latter having greater control over their internal osmotic environment than other invertebrate groups. Effects upon different stages of life history are different, but in general the limiting effects of salinity and other environmental factors bear upon the reproductive stages or the young. The limits of salinities are nearly always on the lower side with regard to estuarine organisms. Aside from osmotic adjustments, animals react to salinity changes by closing their shells, closing their burrows, burying in the bottom where interstitial water has higher salinity, or motile forms simply move out. In spite of these adjustments, none may be successful during large floods.The salinity relationships of all phyla are reviewed, even though some of them are unimportant parts of the marine populations. Dinoflagellate Protozoa which cause red tides 'This paper is modified from a report that was prepared by the Gulf Coast Research Laboratory under Contract No. DACW39-72C-0003 with the U. S. Army Engineer Waterways Experiment Station (WES) and Contract No. DACW73-70-C-0004 with the Department of the Army, Office of the Chief of Engineers (OCE) (Gunter, Ballard and Venkataramiah 1973). Preparation of that state-of-knowledge summary was initiated on the recommendation of the W E Estuarine Ecological Consultants Board in an Interim Report entitled "Effects of Engineering Activities o...

Dynamics of Mesozooplankton Assemblage in Relation to Environmental Factors in the Maryland Coastal Bays

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