Oxygen Depletion and Associated Benthic Mortalities in New York Bight, 1976 



Chapter 15. A Perspective on Natural and 



Human Factors 



Joel S. O'Connor^ 



CONTENTS 



Page 



323 Global and Regional Patterns 



324 The New York Bight Case 

 324 Overview 



324 Nitrogen Loadings 



327 Carbon Loadings 



329 Physical and Biochemical Processes 



331 Conclusions 



331 Acknowledgments 



' MESA New York Bight Project, Office of Marine 

 Pollution Assessment, NOAA, Vc State University of 

 New York, Stony Brook, NY 11794 



GLOBAL AND REGIONAL PATTERNS 



Human activities had not been suggested as significant 

 factors in any large-scale anoxic events of open coastal 

 ocean waters until the 1976 event in the New York Bight. 

 Large-scale mortalities in shallow productive seas and es- 

 tuaries had been attributed to anoxia and hydrogen sulfide 

 (Brongersma-Sanders 1957), and waste nutrient and car- 

 bonaceous contributions from human activities clearly 

 contributed to the severity of many such anoxic events 

 (National Academy of Sciences 1969, 1971). However, 

 anoxia along open coasts of the world oceans has been 

 attributed consistently and exclusively to upwelling (Deu- 

 ser 1975). Related phenomena are the "oxygen minimum 

 layers," which are most pronounced at tropical latitudes. 

 These also are attributed to natural factors in open oceans 

 (Richards 1957; Kester et al. 1973; Lambert et al. 1973; 

 Deuser 1975) and are less relevant here. 



Extensive coastal enrichment by riverborne material has 

 been discussed: off the Mississippi by Riley (1937); off the 

 Amazon by Ryther et al. (1967) and Gibbs (1976); and 

 off the Hudson-Raritan estuary by Ketchum (1967), Ry- 

 ther and Dunstan (1971), and Malone (1976a). Yentsch 

 (1975) developed a model implying significant estuarine 

 phosphate enrichment to the edge of the entire north- 

 eastern U.S. continental shelf. Recommendations, based 

 upon simplified models of eutrophication in estuaries and 

 marine waters with restricted circulation, have been made 

 for much more serious consideration of ocean outfalls to 

 carry domestic wastes to open coastal waters (Officer and 

 Ryther 1977). Some investigators feel that "the concen- 

 tration of nutrient elements in much of the coastal waters 

 near urban regions of the world is now excessive" (Ket- 

 chum 1972). This assertion remains debatable because 

 effects of nutrient contributions by humans are so difficult 



323 



