TABLE 3.

Rates of bacterial carbon production and DMSP turnover and the potential contribution of DMSP turnover and incorporation to bacterial sulfur demand in surface waters of the Gulf of Mexico^a

Station no.	Date (mo/day/yr)	LATb	LONc	Total depth (m)	Bacterial carbon production (nM day−1)	Calculated bacterial sulfur demand (nM day−1)	Dissolved DMSP turnover rate (nM day−1)	Calculated DMSP incorporation rated rate (nM day−1)	Potential contribution to bacterial sulfur demand (%) by:
									DMSP turnover	DMSP incorporation
2	9/24/97	28 22.82	88 17.97	2,280	140	0.6	2.8	0.7	496	123
5	9/24/97	28 23.02	88 19.94	143	156	0.6	3.2	0.8	518	129
8	9/25/97	27 54.14	83 32.63	35	420	1.7	12.8	3.2	759	188
10	9/26/97	27 04.72	85 19.56	3,184	413	1.7	4.9	1.2	297	74
12	9/27/97	26 21.57	87 25.28	2,964	148	0.6	2.8	0.7	475	118
14	9/28/97	27 35.76	88 50.99	1,833	293	1.2	9.9	2.5	842	209
18	9/29/97	28 36.54	90 29.19	27	1,225	4.9	10.9	2.7	223	55
23	9/30/97	28 53.12	89 26.20	15	8,219	32.9	31.0	7.8	94	23
Mean									463	115

^aAll samples were collected from a 1-m depth by using a Niskin bottle attached to a CTD. DMSP turnover was estimated with nonperturbing tracer additions of [³⁵S]DMSP to 50-ml water samples. Incubation times were less than 1 h. Bacterial carbon production levels were estimated from [³H]thymidine incorporation by assuming that 2 × 10¹⁸ cells were produced per mol of thymidine incorporated and that each cell contained 20 fg of C. Sulfur demand was estimated by using a value of 248 for the molar C/S ratio in marine bacteria (10). 

^bLAT, latitude (N, degree and minute). 

^cLON, longitude (W, degree and minute). 

^dAt 25% efficiency.