flow of water within intake and effluent pipes, and 

 interfere with navigation. This category of nuisance 

 organisms should also include those organisms that 

 interfere with the growth and reproduction of or- 

 ganisms important to man. For example, excessive 

 populations of boring sponge or oyster drills, 

 rooted and floating aquatics can interfere with the 

 movement and reproduction of fish; bacteria and 

 red tide organisms such as Gymnodinium and 

 Gonyaulax may have toxic effects on other orga- 

 nisms, including man (Rounsefell and Nelson, 

 1966;Felsing, 1966). 



The groups of organisms that may cause nui- 

 sances or become severe pests include algae (in- 

 cluding red tide organisms), coelenterates, 

 sponges, mollusks, such as oyster driUs and mus- 

 sels, and Crustacea. These organisms are com- 

 monly encountered in the natural marine environ- 

 ment. Organisms may become nuisances because 

 of excessive growth and changes in distribution 

 patterns and predator-prey relationships. The main 

 causative factors are excessive and, often, imba- 

 lanced nutrients, considerable changes in the na- 

 tural regimes of temperature, turbidity, and salin- 

 ity, and changes in current patterns. 



In some instances, nuisance growths seem to be 

 directly related to the nutrients that are available. 

 In other situations, nuisance growths may not be 

 directly affected by artificial enrichment, so far as 

 we know, and seem to be more strongly affected 

 by changes in the temperature, salinity, or turbid- 

 ity. Included here are various fouling organisms: 

 barnacles, mussels and other mollusks, polyzoa 

 tube worms, marine borers, and pests to useful 

 marine products (oyster drills, boring sponges, 

 crabs, parasitic fungi, and protozoans), and 

 swarms of jellyfish, which make bathing in some 

 coastal waters hazardous during certain seasons. 



The effect of increased nutrients may be an in- 

 crease in the populations of certain species already 

 present in the environment and a decrease of spe- 

 cies that are not tolerant of such nutrients. Exam- 

 ples of such conditions are the increase of Entero- 

 morpha and sea lettuce. Viva lactuca, in the zone 

 of mineralization of sewage which occurs in some 

 areas of the lower Potomac. In areas of higher 

 salinity, abundant growths of Ascophyllum often 

 occur in waters containing mineralized effluents 

 from sewage treatment plants. In Biscayne Bay, 

 Fla., the following organisms became abundant 

 under such conditions: the flowering plants, Halo- 

 phila baillonis and Diplanthera wrightii; and the 

 echinoderm, Amphioplus abditus. Under heavy 

 organic enrichment, the algae, Gracilaria blodgettii 

 and Agardhiella tenera, the worm, Diopatra cu- 

 pera, and the amphipods, Erichthonius brasiliensis 



and Corophium acherusicum, became very com- 

 mon (McNulty, 1955). 



In other cases, an imbalanced organic enrich- 

 ment together with changes in temperature and 

 salinity brings about an almost complete change in 

 the species composing an aquatic community plus 

 excessive growths of some species. An excellent 

 example of this type has been described by Ryther 

 (1954) in his studies of Moriches Bay and Great 

 South Bay, Long Island. In this area, duck farm 

 wastes enrich the bay waters with organic com- 

 pounds that produce a low nitrogen-to-phosphorus 

 ratio. At the times of the largest algal blooms, low 

 salinities and high temperatures exist in the area. 

 As a result, desirable marine diatom species of 

 Nitzschia which prefer cool water (5 to 25 C), ni- 

 trates, and nitrites as a source of nitrogen, and are 

 not benefited by a low N/P ratio (5:1) were re- 

 placed by Nannochloris atomus and Stichococcus 

 sp. These species can grow well in nitrates, nitrites, 

 ammonia, urea, uric acid, and cystine, and prefer 

 a N/P ratio of 5:1. As Ketchum (1967) points 

 out, these weed species are undesirable food 

 sources and the natural productivity of the estuary 

 is destroyed. Ketchum also points out that the 

 greatest amount of plankton does not always oc- 

 cur in the waters of greatest enrichment. This is 

 because the development of a maximum standing 

 crop of phytoplankton is also governed by the con- 

 centration of predators, stability of the water 

 column, transparency of the water, etc. 



Nutrient imbalance may affect the ratio of inor- 

 ganic phosphate to total phosphorus, here defined 

 as the sum of inorganic, organic, and particulate 

 phosphorus. It is known from the work of Pomeroy 

 (1960) and others that inorganic phosphorus is 

 rapidly taken up by actively growing plants. At the 

 same time, inorganic phosphorus is regenerated as 

 a result of bacterial degradation and excretion by 

 animals. The net effect over the short run is to pro- 

 duce a steady state between the various fractions 

 of phosphorus in the environment. There should 

 be some ratio of inorganic to total phosphorus in 

 the euphotic zone that would be characteristic of a 

 balanced nutrient regime and this ratio should be 

 lower than the same ratio for the imbalanced 

 system in which inorganic phosphorus can 

 accumulate. 



Data from Moriches Bay and Great South Bay 

 on Long Island, Charlestown Pond, R.I., the North 

 Atlantic, and the North Pacific have been ex- 

 amined. In the obviously poUuted portion of Mori- 

 ches Bay, the inorganic total phosphate ratio gen- 

 erally exceeds 0.6, while the Charlestown Pond, an 

 uncontaminated estuary of similar characteristics 

 to Moriches Bay, this ratio was less than 0.4. In 



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