NO A A PROFESSIONAL PAPER 11 



On July 9, bottom samples from the same area, about 

 3 and 15 km, off Manasquan, also contained abundant 

 floe. The general phytoplankton composition of the ma- 

 terial was similar to that of the first samples, but further 

 decomposition of the C tripos cells and a change from 

 yellow to predominantly brown was evident. Live C. tripos 

 were not seen. Bacteria appeared more abundant; ciliate 

 protozoans were also abundant. 



On July 15, C. tripos still dominated the phytoplankton 

 on the bottom in locations 6 to 7 km off Manasquan. 

 About twice as many fragmented as intact C. tripos cells 

 were seen; C. tripos appeared to make up 25 to 50 percent 

 of the floe volume. Coscinodiscus excentricus was second 

 in importance. The floe retained the brownish color. Be- 

 cause these samples were treated with preservative, bac- 

 terial presence was not estimated. 



C. tripos was absent in the bottom floe 3.7 km off Man- 

 asquan by August 2; however, a few C. tripos cells and 

 broken tests were present in the water column. The phy- 

 toplankton, from the surface to the bottom, was domi- 

 nated by S. costatum and L. danicus, followed by Ceratium 

 minutum, Peridinium trochoideum, Dinophysis spp., and 

 Prorocentrum micans. These were all numerous at the 

 surface, but most were in decreased abundance at the 

 other depths. P. trochoideum and small nonmotile chlo- 

 rophytes, however, were also abundant at the bottom. 

 The amount of floe in the water column and on the bottom 

 appeared greatly reduced compared to the amount seen 

 previously. The color of the floe was changed; under the 

 microscope, white and black portions were about equal. 

 Only a few bacteria were seen. 



Farther offshore (20 km) on August 2, in definite con- 

 trast to the inshore location, all depths except the bottom 

 had abundant intact or fragmented C. tripos. At 20 m, 

 there was an increased amount of intact, and for about 

 half the cells, motile C tripos. At 22 m, there were nu- 

 merous, nearly all vigorously motile, C. tripos ceils. Ap- 

 parent bacterial digestion of some of the fragmented 

 C. tripos cells was observed. S. costatum and small non- 

 motile chlorophytes were numerically dominant through 

 the water column. O. luteus and P. trochoideum were 

 abundant at the surface; O. luteus was also very abundant 

 at the bottom. 



Barnegat — Atlantic City 



Three locations, about 18, 28, and 37 km off Barnegat. 

 N.J., were sampled on July 15. Because divers found the 

 floe to be primarily in the bottom waters, sampling was 

 at 6 and 9 m off the bottom. At the 18- and 28-km stations, 

 samples from both depths contained floe that was yellow 

 or yellow-green with some blackish spots. Many of the C. 

 tripos cells were disrupted. Bacteria in chains or as motile 

 individuals were most evident in the samples collected 6 

 m off the bottom. At the farthest offshore station, decom- 



position did not appear as advanced. The floe was pre- 

 dominantly yellow. Most C. tripos cells were intact; dis- 

 rupted cells were in large fragments. Some motile C. tripos 

 were observed. Again, bacteria were more evident in the 

 lower depth sample. 



At 10 m, 5 km off Barnegat on July 21, only a small 

 amount of fine floe particles and a sparse phytoplankton, 

 including just a few C. tripos, were present. At 15 m, 

 however, a fairly abundant, by comparison, floe was com- 

 posed almost entirely of C. tripos. 



On July 30, 13 km off Barnegat, the surface had a mod- 

 erate abundance of free, intact C tripos cells. At mid- 

 depth, around 11 m, C tripos cells, most without cyto- 

 plasm, were numerous; broken tests were more numerous 

 than intact ones. The bottom had fewer and more decayed 

 C. tripos. The floe was abundant only at the bottom. The 

 floe ranged from yellow to dark brown or black. Much of 

 the material was unstructured; diatoms, especially S. cos- 

 tatum and L. danicus, composed most of the identifiable 

 phytoplankton; bacteria were moderately abundant. 



At 20 km off Barnegat on July 30, C. tripos was absent 

 at the surface. At middepth, numerous free, intact C. 

 tripos cells dominated the phytoplankton (a mixed group 

 of diatoms and dinoflagellates). At the bottom, a smaller 

 abundance of intact and disrupted C. tripos was evident. 

 The floe was most abundant, although moderately so, at 

 the bottom. Various diatoms, especially S. costatum. were 

 abundant in the floe. Apparent vigorous swarming of bac- 

 teria around partially digested C. tripos and fungus dis- 

 persed throughout the floe were observed. 



C. tripos was absent at two locations, about 22 and 37 

 km, off Barnegat on August 16. 5. costatum dominated 

 the generally sparse phytoplankton, which also included 

 a mixture of other diatoms, dinoflagellates, and smaller 

 nannoplankton. On the bottom, the diatoms appeared to 

 be in a state of advanced decomposition, judging from the 

 appearance of the cells. Only a small amount of blackish 

 floe was present. At the same time, however, farther to 

 the south, 11 km off Atlantic City, C. tripos was moder- 

 ately abundant at middepth although it was not seen in 

 the rest of the water column. S. costatum was numerically 

 dominant at all depths. Floe, yellow to greenish-brown, 

 was abundant at the bottom. Bacteria appeared abundant 

 in the floe. 



At locations 18.5 and 93 km off Atlantic City on Sep- 

 tember 2, the bottom and middepth samples contained 

 only a sparse amount of flne floe, at least 50 percent of 

 which was black. A few diatoms were present, but no C. 

 tripos. The phytoplankton was even less abundant in the 

 surface samples; again no Ceratium spp. were seen. 



C. tripos Decomposition Sequence and the Floe 



With the decline of the bloom, the C. tripos cells, in 

 senescence or death (flgs. 9.2-1, 9.2-2), formed into a 



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