1. Primary Production. 
Primary production on sandy beaches is very low. Cox (1976) reported that 
plant biomass was low compared to most littoral and sublittoral systems, and 
that diatoms were of small consequence as a food energy source. Leach (1970) 
measured primary production of intertidal sediments and found the sand beach 
to be the least productive substrate in the Ythan estuary. He estimated total 
annual primary production of the sand beach to be less than 5 grams organic 
carbon per square meter per year. Steele and Baird (1968) measured the pri- 
mary production occurring in the top 20 centimeters and estimated subtidal 
sand beach production to be only 4 to 9 grams organic carbon per Square meter 
per year. When they measured the total production for the intertidal part 
of the beach, they found negligible production. Low productivity was attrib- 
uted to constant sorting and mixing of the substrate, which buried diatoms 
or otherwise kept them out of the photic zone. 
Amspoker (1977) found diatoms on Scripps Beach at La Jolla, California, 
to have high diversity, uniform distribution, and no stratification. He 
attributed this distribution pattern to tidal mixing. Pearse, Humm, and 
Wharton (1942) found diatoms associated with sandy beaches inside the Beaufort 
Inlet; however, they reported none from the sands at Fort Macon. Although 
production seems to be low, a wide range of primary producers have been 
reported for sandy beaches, including blue-green algae, diatoms, and early 
stages of brown algae (Meadows, 1965). 
Figure A-l presents an energy flow diagram for primary production on a 
sandy beach. The producers are dependent on input of mineral nutrients from 
offshore sources, and remineralization of organic compounds by the meiofauna 
decomposer-bacteria complex. The greatest loss of energy from this system 
results from the sorting, mixing, and scouring action of the surf. Primary 
production is inherently low, and most of what is produced is lost as near- 
shore particulate matter. Only a small fraction of the total production 
becomes available to epistrate browsers and lickers in the meiofaunal commu- 
nity. Virtually none of the primary production on sandy beaches is available 
to macrofauna. 
2. Bacteria. 
Bacteria serve an important function on sandy beaches where they constitute 
an important food source for the meiofauna (McIntyre and Murison, 1973; Cox, 
1976). The major input into the bacterial community of the sandy beach is 
dissolved organic matter derived from tidal influx from coastal waters which 
is either absorbed to substrate or formed into microparticles by bubbling and 
surface phenomena (Cox, 1976). 
Elmgren (1976) and Gerlach (1978) demonstrated that bacterial production 
is enhanced by the mechanical and metabolic activities of the meiofauna, 
although bacteria and meiofauna compete for the same food resources. At the 
same time the meiofauna utilizes this increased bacterial production as a 
food source. Thus, the meiofauna-bacteria community represents an essentially 
closed or self-contained system having minimal interaction with surrounding 
communities. 
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