occurred when a light-dark transition was imposed at a time (18:00) to which the 
shrimp had previously been entrained to receive the onset of the dark period. 
Experiments in which shrimp, which had been fed 24 hr previously, emerged from the 
substrate and carried out food-searching movements, in the absence of food and despite 
high intensity illumination, which would normally suppress emergence, indicated the 
presence of a feeding rhythm with an approximate 24-hr periodicity. The feeding 
rhythm probably accounts for the fact that the phase of the rhythm of emergency was 
resynchronized to a shifted light-dark cycle in three days among shrimp fed 
immediately following the shifted cycle, as opposed to six days in those deprived of 
food during this time of entrainment. The phases of the two rhythms, being almost 
identical, probably supplement each other. Shrimp smaller than 4 cm (total length) 
emerged significantly earlier than larger individuals. This possibly reflects the lesser 
dependence of the early juveniles on inherent rhythms and consequently their greater 
receptivity to exogenous stimuli. The most obvious advantage of the circadian rhythm 
controlling emergence and subsequent activity is to confine the times of activity of 
shrimp to the hours of darkness when predation by fish is minimal. The proximity of the 
phase of the 24-hr feeding rhythm to the circadian rhythm of emergence and activity 
probably serves to strengthen the entrainment properties of the latter such that the 
time of emergence is further synchronized between all members of the population. The 
synchrony of the time of emergence is probably important for the maintenance of 
cohesion between aggregations of shrimp. 
1968 0 
Multer, H. G., and J. E. Hoffmeister (1968) Subaerial laminated crusts of the Florida Keys. 
Geol. Soc. Amer. Bull. . 79:183-92. 
[DATE OF SAMPLING UNKNOWN OR NOT APPLICABLE.] Exposed Pleistocene marine 
limestones of the Florida Keys are often coated with laminated 1-to-6-cm-thick calcitic 
crusts. Heretofore these crusts have locally been identified as indurated marine algal 
stromatolites similar to the soft, marine, living algal stromatolitic mats of the Florida 
Keys, which border and occasionally coat the encrusted bedrock; such juxtaposition is 
now considered merely coincidental. 14 C dating of five different crust samples reveals 
a time of formation (within the last 4395 ± 90 yrs) during which the land surface was 
above sea level. Field relationships and laboratory evidence also indicate subaerial 
origin. Three general types of crusts are: (1) microcrystalline rind, (2) dense 
laminated, and (3) porous laminated. Similar laminated crusts found in subsurface cores 
suggest emergence followed by submergence of the Key Largo reef in late Pleistocene 
time. Proper identification of such subaerially formed laminated crusts, to distinguish 
them from similar-appearing crusts formed in marine environments, is necessary for 
correct interpretation of paleoenvironments and former sea level fluctuations. Thin 
crusts may be the only evidence in recognizing some ancient unconformities. 
1968 - 1974 
Ogden, J. C. (1975) Effects of bald eagle territoriality on nesting ospreys. Wilson Bull. . 
87(4):496-505. 
Interspecific territoriality has been defined as aggressive territorial behavior 
persistently performed by individuals of a species against individuals of different 
species. Little attention has been given to documenting the effects of this behavior on 
nesting success of conflicting species. This paper is a study of the productivity and 
factors affecting nesting success in ospreys (Pandion haliaetus). It was found that 
osprey nesting success in the study area was affected by territorial behavior of bald 
eagles (Haliaeetus leucocephalus). It was also noted that the interspecific relationship 
between the ospreys and bald eagles differed in some aspects from forms of 
interspecific territoriality previously described. This paper describes the interspecific 
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