indicated that species composition shows 

 geographical, salinity and local intra- 

 marsh patterns. The southern and Baja 

 California assemblage identified by 

 Phleger (1967, in Macdonald 1977b) had 

 several dominants ( Trochammina inflata , 

 Miliammina fusca , Jadammina polystoma ) in 

 common with more northern Foraminiferan 

 communities, but included more species 

 ( Ammonia beccarii , Arenoparrella mexicana , 

 Cellanthus discoidale , Discor inopsis 

 aguayoi , Glabratella sp., and Protoschista 

 findens) . As with the marsh flora, 

 dominant Foraminiferan species extend over 

 a broad latitude, but southern California 

 has additional species of more tropical 

 distribution. 



Phleger (1970, 1977) provided lists 

 of species which have been classified 

 according to their general ecological 

 distribution. Scott's (1976) data on live 

 specimens from Mission Bay and Tijuana 

 Estuary include two of the four species 

 listed as common in marshes, three of the 

 five hypersaline species, but no brackish 

 forms (Table 9) . 



Comparisons of low and high marsh at 

 Mission Bay and Tijuana Estuary (Scott 

 1976) showed distinctive communities, with 

 higher densities above MHHW in the upper 

 marsh. Species characteristic of the 

 upper marsh were T. inflata , J_. polystoma , 

 D. aguayoi , and Quinqueloculina seminulum 

 at both locations. However, low marsh 

 habitats were characterized by high 

 percentages of Cribroelphidium spinatum 

 translucens and Cellanthus tumidum at 

 Mission Bay and Protoschista findens at 

 Tijuana Estuary, where calcareous species 

 were generally less common. 



Using the relatively high consistency 

 of composition and marsh type, Scott 

 (1976) interpreted the history of Mission 

 Bay and Tijuana Estuary from auger cores 

 taken within each marsh. The Mission Bay 

 core was dated with carbon-14 to be 2380 + 

 60 years at 3.1 m. At that time, the 

 Foraminifera indicate that the present 

 high marsh was an intertidal mudflat, 

 which subsequently changed to low and then 

 high marsh as sediments and organic 



Table 9. Foraminiferal categories (from 

 Phleger 1977) and occurrences in Mission 

 Bay (MB) and Tijuana Estuary (TE) (from 

 Scott 1976). 



Categories 



Lower Higher 

 Marsh Marsh 



Abundant and dominant cosmopolitan spp. 

 Miliammina fusca x 



Trochammina inflata x 



X 



dom. 



Jadammina polystoma x v.abun. 



Spp. confined to hypersaline marshes 



Discorinopsis aguayoi x x 

 Textularia earlandi x 



Spp. common in marshes 



Protoschista findens dom. 



Ammonia beccarii 



@ TE 

 x 



Additional abundant species found by 

 Scott (1976) 



Quinqueloculina spp. x x 



Cellanthus tumidum x 



Cribroelphidium dom. 



spinatum translucens § MB 



dom.r dominant; v. abun. = very abundant 



material accumulated. At Tijuana Estuary, 

 material at 1.1 m was dated at 1180 + 50 

 years B. P. with carbon-14, at which time 

 the core location was a mudflat. The 

 sequence from that time on was similar to 

 that at Mission Bay. However, a thick 

 layer of sediments below 1.1 m was 

 depauperate in Foraminifera, and Scott 

 suggested the area may have been a closed, 

 brackish lagoon at the time. This 

 suggestion is difficult to reconcile with 

 modern - day observations of water 

 accumulation patterns in southern 

 California lagoons. Usually, only the 

 lagoons with relatively small watersheds 



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