Estuarine areas occupy about .25 percent of the earth's surface. 

 About 20 percent of the estuarine area is marsh, and the other 80 per- 

 cent is open water. Thus, world net production of estuarine areas 

 is probably about 3.1 x 10^ metric tons of organic matter annually, 

 or about two percent of the world net production. 



Research at Flax Pond, a 50 hectare marsh open to Long Island 

 Sound, suggests that there is no significant outwelling of fixed 

 carbon from estuarine marshes into coastal waters. In fact, the 

 flux may be in the opposite direction, with the marsh removing fixed 

 carbon from tidal waters. If this relationship applies generally 

 and sediments are accumulating, net ecosystem production (defined 

 as gross production and net production in minus total respiration 

 and net production out) must be positive for the estuaries of the 

 world. Estuaries appear to oe centers of high primary production, 

 high metabolism, and centers of sedimentation; they may not normally 

 be centers of outwelling of fixed carbon into coastal waters. (J.B.) 



Keywords: carbon, estuaries, tidal marshes, primary productivity, 

 outwelling. Long Island, U.S. coastal regions 



Detritus Feeders 



III-E-1 



Odum, W.E. 1968. The ecological significance of fine particle selection 



by striped mullet, Mugil cephalus . Limnology and Oceanography 



13:92-98. 



By tracer experiments and a comparison of sediment and stomach content 

 particle sizes, Mugil cephalus Linnaeus is shown to prefer very fine 

 particles wherever sediments are involved in feeding. It is suggested 

 that these small inorganic and plant detrital sediment particles 

 are much richer both in absorbed organic material and in absorbed 

 bacteria, protozoa, and other microorganisms than the coarser material 

 that the mullet rejects. This selectivity results in substantially 

 higher organic value of the stomach contents than of the sediments. 



It has been established that the major contents of the stomach comprise 

 three categories: 1) microalgae including epiphytic and benthic 

 diatoms, dinoflagellates, green and blue-green algae, 2) decaying plant 

 detritus, and 3) inorganic sediment particles. Microalgae are regarded 

 as the primary source of nutrition, although plant detritus appears 

 to be quite important in estuarine areas. (A, A. -expanded) 



Keywords: striped mullet, detritus, microalgae 



120 



