NO A A PROFESSIONAL PAPER 11 



flocculent aggregate. This floe was seen at various times 

 and places during July and August, but, by far, most was 

 at the thermocline (where the C. tripos bloom population 

 had previously concentrated) and on the bottom. In the 

 Manasquan area, less than 20 km from shore on July 4, 

 nearly all of the C. tripos seen at the bottom were dead 

 and these, broken or fragmented, composed most of the 

 floe biomass (fig. 9.2-3). In the same area, less than a 

 week later, the C. tripos dominance had become less clear; 

 increased disruption of the cells was evident and the floe 

 had darkened (fig. 9.2-4). With further decomposition 

 (fig. 9.2-5), the material became even darker and far 

 fewer C. tripos fragments were identifiable. By August 2, 

 no C tripos were seen in the inshore bottom floe off Man- 

 asquan (fig. 9.2-6). Therefore, in this area, except for 

 refractory constituents, decomposition at the bottom of 

 massive numbers of C. tripos, which presumably had be- 

 gun in June, was complete by late July or early August. 

 Temporal and geographical differences in the C. tripos 

 decomposition are discussed in the next section. Figures 

 9.2-7 and 9.2-8 show microbial decomposition of the C. 

 tripos. Figures 9.2-9 and 9.2-10 show one effect of the 

 bloom decomposition: the gill of the mud shrimp, Axiiis 

 serratus, is partially occluded with floe material. A con- 

 centration of these animals, dead or dying, was found out 

 of the substrate around 18 km off Barnegat on July 15. 



CONCLUSIONS 



C. tripos remained a significant portion of the bottom 

 floe in the oxygen-deficient area between Manasquan and 

 Barnegat at least until mid-July. Around the end of July, 

 no C tripos were seen in bottom samples from off Sandy 

 Hook and it had almost disappeared from the bottom floe 

 off Manasquan, but it was still evident in the Barnegat 

 area. The floe from the Manasquan area at this time was 

 about equally black and white under the microscope, but 

 the Barnegat floe retained much of the earlier yellow- 

 brown appearance. By mid-August, the bottom samples 

 from off Barnegat had no C. tripos and little floe; what 

 was present appeared generally decayed. Bottom samples 

 from off Atlantic City still contained abundant yellow- 

 brown floe. Vaughan (1977) surveyed the C. tripos pop- 

 ulation in southern New Jersey coastal waters between 

 Great Bay and Cape May from July 21 to its complete 

 disappearance around August 20. The decline of C. tripos 

 abundance he observed had a pattern similar to that seen 

 in the more northerly regions, but occurred later. In ad- 

 dition, during late July and the first half of August, 

 Vaughan (personal communication) found C. tripos pre- 

 sent nearly always, even inshore, as individual, intact cells 

 retaining cytoplasmic contents. Because a preservative 

 was used, he was not able to determine whether the cells 



were alive when collected. However, the cells were at 

 least not disrupted or aggregated in a detrital mass as they 

 were to the north when the first samples were examined 

 on July 4. The combined observations indicate that the 

 decomposition proceeded earlier or at a more rapid rate 

 in the Sandy Hook — Manasquan area and progressed 

 southward. 



Some C. tripos concentrations, alive and apparently 

 vigorous, were found around middepth between the mid- 

 dle of July and early August off Sandy Hook, Manasquan, 

 and Barnegat. They were all at stations 20 km or greater 

 from the shore. During the same period, intact but non- 

 motile cells and fragments of cells, but no live cells, were 

 found at various depths less than 20 km from shore (table 

 9.2-1). This suggests that C. tripos survived better in off- 

 shore waters. If so, a possible explanation (ch. 9, pt. 1) 

 is that by May and June, the C. tripos population within 

 20 km of the shoreline between the Bight Apex and Bar- 

 negat Inlet was light limited. 



Based on microscopic observations, some bacterial 

 presence was associated with aggregates of phytoplankton 

 material in the water column, but it was greatest at or 

 near the bottom where most of the floe was also found. 

 Also, general bacterial presence seemed to be associated 

 with the presence of C. tripos (the notable exception was 

 in the August 16 Atlantic City bottom sample in which 

 abundant bacteria but no C. tripos were seen). Unmis- 

 takable bacterial decomposition of C. tripos cells (fig. 

 9.2-7) was observed several times; fungus attack on C. 

 tripos was also seen (fig. 9.2-8). Protozoans and small 

 nematodes were fairly numerous in some samples and may 

 have been feeding on the floe material, although this was 

 not determined. Vigorous activity and clustering around 

 the floe by ciliate protozoans seen in a number of samples 

 did suggest feeding behavior. All these forms probably 

 contributed to the decomposition process. The cell wall 

 of C. tripos is cellulosic. In the Gulf of Maine and Georges 

 Bank, Waksman et al. (1933) found extensive populations 

 of bacteria able to use cellulose and hemicelluloses, al- 

 though cellulose-decomposing marine bacteria were less 

 abundant than species not having this capability. Bar- 

 ghoorn and Linder (cited in Zobell 1945) found several 

 species of marine fungi able to use cellulose. Marine cil- 

 iates have been known to feed on bacteria, diatoms, or 

 other protozoa (Lackey 1936). 



The presence of numerous O. luteiis (many individuals 

 apparently in a senescent state) as a floe constituent in 

 locations from Sandy Hook to Sea Girt, N.J., between 

 July 22 and August 4 is interesting. This species bloomed 

 intensely throughout the southern half of Lower New 

 York Bay between June 6 and 13, 1976. Tidal action grad- 

 ually washed the bloom water to the ocean. If we assume 

 that the Olisthodiscus concentrations in the bottom floe 

 originated in the bay, then inshore along the New Jersey 



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