shelf and shelf-margin settings. Cyclorbiculina compressa is the most stenohaline, 
occurring in open shelf settings typically at depths of 5 - 30 m. Optimum habitat 
appears to be short (~ 1 cm) filamentous algal turf on limestone pavement reef rubble. 
Three other chlorophyte-bearing species, Broeckina/Parasorites orbitolitoides, 
Laevipeneroplis proteus and L. bradyi, are also common in this habitat. Chlorophyte- 
bearing taxa are the most abundant and diverse group of larger foraminifera in the 
Holocene western Atlantic. Despite widespread occurrence throughout the Tethyan 
region during the Miocene, this group is represented in the Holocene Indo-Pacific by 
only two species. The decline of this lineage in the Indo-Pacific and its success in the 
tropical western Atlantic is opposite of biogeographical trends typically reported for 
shallow-water tropical taxa through the Neogene. 
1993 0 
Paul, J. P., J. B. Rose, S. C. Jiang, C. A. Kellogg, and L. Dickson (1993) Distribution of 
viral abundance in the reef environment of Key Largo, Florida. Appl. Environ. Microbiol. . 
59(3) :71 8-24. 
[DATE OF SAMPLING UNKNOWN OR NOT APPLICABLE.] The distribution of viral and 
microbial abundance in the Key Largo reef environment was measured. Viral abundance 
was measured by transmission electron microscope direct counts and plaque titer on 
specific bacterial hosts in water and sediment samples from Florida Bay (Blackwater 
and Tarpon Sounds) and along a transect from Key Largo to the outer edge of the reef 
tract in Key Largo Sanctuary. Water column viral direct counts were highest in 
Blackwater Sound of Florida Bay (1.2 x 107 viruses mL* 1 ), decreased to the shelf 
break (1.7 x 106 viruses mL* 1 ), and were inversely correlated with salinity (r = 
-0.97). Viral direct counts in sediment samples ranged from 1.35 x 108 to 5.3 x 108 
cm* 3 of sediment and averaged nearly 2 orders of magnitude greater than counts in the 
water column. Viral direct counts (both sediment and water column measurements) 
exceeded plaque titers on marine bacterial hosts ( Vibrio natriegens and others) by 7 to 
8 orders of magnitude. Water column viral abundance did not correlate with bacterial 
direct counts or chlorophyll-a measurements, and sediment viral parameters did not 
correlate with water column microbial, viral, or salinity data. Coliphage, which are 
indicators of fecal pollution, were detected in two water column samples and most 
sediment samples, yet their concentrations were relatively low (<2 to 15 L* 1 for water 
column samples, and < 2 to 108 cm* 3 of sediment). Our findings indicate that viruses 
are abundant in the Key Largo environment, particularly on the Florida Bay side of Key 
Largo, and that processes governing their distribution in the water column (i.e., 
salinity and freshwater input) are independent of those governing their distribution in 
the sediment environment. 
1993 0 
Porter, D. (1993) Seagrass die-off in Florida Bay: the role of the marine slime mold, 
Labyrinthula. Bull. Ecol. Soc. Amer. . 74(Suppl. 2):397. 
[DATE OF SAMPLING UNKNOWN OR NOT APPLICABLE.] The seagrass, Thalassia 
testudinum (turtle grass) is the dominant member of the seagrass Community in Florida 
Bay, a large, carbonate sediment lagoonal system between the southern tip of 
peninsular Florida and the Florida Keys. The western portion of Florida Bay has been 
little influenced by the direct actions of human activities. However since 1988, large 
areas of dense seagrass meadows in this region have become defoliated resulting in 
massive die-off of T. testudinum. These die-off events are positively correlated with 
the presence of black, necrotic lesions in the leaves of the seagrass prior to die-off. 
The leaf necrosis is caused by a species of the marine slime mold Labyrinthula. As of 
January 1993, there have been no observed seagrass die-off episodes on the Atlantic 
Ocean side of the Florida Keys. However, similar leaf necrosis symptoms have been 
357 
