277 



Along the Miami shoreline was a zone of red algae, which can survive 

 in low light intensities, and most of the surrounding bay was a zone 

 of grasses and other vegetation requiring much sunlight. No life was 

 found at locations above the Miami River mouth in areas near sewage 

 outfalls, and there was a zone in midbay containing no fixed vegetation. 



The softest sediments were found along the Miami shoreline just 

 north of the Miami River mouth. Soft sediments also occurred in mid- 

 bay with harder sediments along the shores of Miami and Miami Beach 

 w^here the currents are stronger. 



The oxygen consumption of the sediments was highest in the softest 

 sediments just north of the Miami River mouth, in the northwestern 

 portion of the bay, and in the deep water south of the Miami River 

 mouth. These zones were relatively deep, had poor bottom circulation, 

 and were zones of major deposition of organic-rich material. 



Both harmful and fertilizing effects w^ere observed in Biscayne Bay. 

 The harmful effects were indicated by the absence of life. These areas 

 were within 200 yards of sewage outfalls, were greater than average 

 depth and had soft, sticky mud with high amounts of oxidizable organic 

 matter. The fertilizing effects were most pronounced in areas 200-600 

 yards from outfalls in shallow water with good tidal circulation in 

 firm sandy mud. Species associations within definite communities were 

 fomid to be indicative of both the harmful and fertilizing effects 

 (IV-5-10). 



INDUSTRIAL WASTES 



Los Angeles Harbor^ Calif. 



The Los Angeles Harbor portion of San Pedro Bay, Calif., provides 

 an example of an estuarine system receiving oil refinery wastes. These 

 wastes were discharged intO' enclosed basins or slips which had very 

 limited tidal circulation and flushing. The effects on the receiving sys- 

 tem were reflected in progressive studies of the benthic bilogical com- 

 munity. Initial investigations showed the bottom to be composed of 

 black oily material with the odor of hydrogen sulfied, a characteristic of 

 anaerobic conditions. The receiving area was subsequently bridged, 

 and a diverse population of bottom organisms began to populate the 

 area. The continuous discharge of the refinery waste, however, elimi- 

 nated the biota after a relatively short time. This example demonstrates 

 the ability to recover if proper management techniques are utilized 

 (IV-5-10). 



Silver Bay., Alaska 



Another example of the water quality changes caused by industrial 

 wastes is the Silver Bay system of Alaska, A paper pulp mill located 

 on the bay discharges sulfite waste liquor to the waste surface. Water 

 quality sampling of the bay demonstrated extensive degradation of 

 the surface water stratum as indicated by depressed dissolved oxygen 

 concentrations, changes in pH (hydrogen ion concentration), and in- 

 crease in turbidity. Vertical profiles of these water quality parameters 

 indicated that the waste materials remained on or near the surface in 

 a low-density layer. The concentrations of the sulfite waste liquor were 

 sufficient to be toxic to many of the natural food chain organisms and to 

 cause abnormalities to oyster larvae and fish eggs (IV-5-10). 



