Chapter 4 



Recent Foraminifera and Nonplanktonic Protozoans' 



E. H. CHAVEt and 



DENNIS M. DEVANEY (dcceased)t 



f University of Hawaii. Hawaii Undersea 



Research Laboratory/, Honolulu, Hawaii 96822 

 fBernice P. Bishop Museum, Honolulu, Hawaii 9681 7 



FORAMINIFERA 



In 1946, during Operation Crossroads, 45 samples 

 containing Recent Foraminifera were obtained in the 

 Enewetak Lagoon from the shore to depths of 62 m (204 

 feet) and on the outer slopes at depths from 44 to 914 m 

 (144 to 3000 feet) (Cushman et al., 1954). Of the 204 

 species of foraminifera recorded at Enewetak, approxi- 

 mately 60% were also collected from the reef flats, 

 lagoons, and outer slof)es of other Marshall Island atolls 

 (Rongerik, Rongelap, Bikini) and Sylvania Guyot. Fourteen 

 of the 18 new species and two new varieties described at 

 that time from the Marshall Islands were found at 

 Enewetak. 



In the 1954 study, the Marshall Island foraminiferal 

 fauna was composed of nearly 85% species characteristic 

 of the tropical Pacific, 6% new to science, and the balance 

 undetermined. No significant differences in the foraminif- 

 eral composition were evident between the four atolls sam- 

 pled during the study. Compared with other unspecified 

 Pacific islands, the absence of Baculogxjpsina spp., 

 Calcahna calcar, and medium-to-large Rotalia, as well as 

 the presence of a greater variety of miliolid species, was 

 apparent (Cushman et al., 1954). 



General features of specific biotopes (reef flat, lagoon, 

 outer slope, and deep waters) with their dominant or re- 

 stricted foraminiferal components were given, together 

 with specific station localities (op. cit.). 



Foraminifera from Enewetak were also recorded from 

 borings at two drill sites on the atoll (Cole, 1957; Todd 

 and Low, 1960). These sites include a large number of 

 extant species. In fact. Cole (op. cit.) reported that samples 



'With the exception of planktonic foranniniferans, which are 

 included in this chapter, other planktonic protozoans (dinoflagel- 

 lates, radiolarians. and tintinnids) are presented in Chapter 20 

 (this volume). 



from the surface to about 186 m (610 feet) contained only 

 Recent species. The present list of Recent Enewetak 

 Foraminifera recorded from these two papers includes 23 

 additional species that were listed among Recent Marshall 

 Island species by Cushman et al. (1954). 



Todd (1960) included Enewetak among localities dis- 

 cussed in the distribution of Calcarina spengleri and 

 absence of members of the genus Baculogvpsina. 



Lacking a representative identified collection of Fora- 

 minifera and other protozoans at Enewetak, Mid-Pacific 

 Research Laboratory (MPRL) contracted for such a collec- 

 tion to be made in 1956. Approximately 140 foraminiferal 

 species were determined from the 142 samples obtained 

 from shallow water throughout the atoll. The seaward reef 

 and reef flat genera were compared with those found in 

 beach sands and plankton tows (Hirshfield et al., 1968). 

 This work also compared the foraminiferal genera of 

 Enewetak with that from smaller samples taken in Hawaii, 

 Kwajalein, and the Solomon and Caroline Islands. The 

 species list (unpublished report to MPRL by Hirshfield, 

 Helson, and Charmatz, 1957) included several additions to 

 the Enewetak fauna, six of which were also found by 

 Chavc in 1981. 



Subsequent work on Foraminifera at Enewetak 

 included studies on the fine structure and morphology of 

 Carterina spiculotesta (Lipps and Enrico, 1973; Deutsch 

 and Lipps, 1976; Conger et al., 1977). Foraminiferan pre- 

 dation by fishes and the methods of feeding by foraminif- 

 erans were also investigated at Enewetak (Lipps and 

 Delaca, 1980). The species, Amphistegina lessonii and A. 

 obijera, reviewed by Halloch and Larsen (1979) included 

 material from Enewetak. Showers and Atkinson (1979) 

 worked at the atoll on the different forms of Rosalina 

 globularis. 



The checklist of Recent Foraminifera and nonplank- 

 tonic protozoans from Enewetak is presented in Table 1 

 and contains 280 species. The above-mentioned publica- 

 tions list 233 of these species. Forty-seven new Enewetak 

 records have been added to this list by Chave (Table 2). 

 Fourteen of these species were listed by Cushman et al. 

 (1954) from other Marshall Island atolls; 33 species arc 

 new to Enewetak and the Marshall Islands. 



37 



