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 JFMAMJJASOND 



TIME 



Figure 35. Numerical abundance and 

 SHPcies richness of invertebrates taken in 

 leaf-litter baskets at various permanent 

 sampling sites in the Apalachicola 

 estuary, monthly from January, 1976, 

 through Pecember, 1976. After Livingston 

 (1978) and Livingston et al. (1977). 



State University researchers indicate that 

 biological associations are also 



important. Macroinvertebrates appear to 

 utilize the detritus as shelter and a 

 source of food (White in press). In a 

 series of experiments with the leaf litter 

 community. White et al. (1979a) found 

 that, whereas the biomass (as measured 

 bv lipid phosphate and 

 poly-beta-hydroxybutyrate), nutritional 

 history, and respiratory activity of 

 microbes are correlated with substrate 

 type, the macrofaunal populations are more 

 often associated with specific water 

 quality features such as salinity. 

 Numbers, biomass, and species richness of 

 detritus-associated microfauna are 

 associated with the mass and community 

 structure of the macrofaunal food web. 

 These macroinvertebrates apparently seek 

 out microbial populations rich in 



5 10 15 20 25 30 35 



SALINITY 



Figure 36. Regression of numbers of 

 species of litter-associated 

 macroinvertebrates on salinity at three 

 stations in the Apalachicola estuary. 

 Samples were taken over a 12-month period 

 in oligohaline (stations 5A, 3) and 

 mesohaline (station IX) areas. 



anaerobic or microaerophi 1 ic bacteria. 

 The data siiggest that distinct populations 

 may choose different microbes. The 

 component energy linkages are poorly 

 understood, however. Little is known 

 concerning the protozoan components of 

 litter associations, although preliminary 

 analyses in East Bay indicate that 

 ciliates constitute the dominant protozoan 

 inhabitants of the litter assemblages (D. 

 Cairns, pers. comm.). 



In summary, phvsical/chemical 

 features such as temperature and salinity 

 influence the spatial-temporal 

 distribution of litter-associated 

 macroinvertebrates in the estuary. Such 

 distribution is also determined by 

 productivity trends and the biochemical 

 features of the microbial communities. 

 The detri ti vorous macroinvertebrates serve 

 as a link between the microbial producers 

 and important estuarine fishes and 

 invertebrates that feed on these species 

 (Laughlin 1979; Livingston et al. 1977; 

 Sheridan 1978, 1979; Sheridan and 

 Livingston 197Q). 



78 



