Citation:

0967-0637(93)90040-A

Name: (Table 2) Distribution of alkenone unsaturation index UK37 of the eastern North Atlantic
Published: 1993
License: https://creativecommons.org/licenses/by/3.0/

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Abstract:

This paper reports the concentrations and within-class distributions of long-chain alkenones and alkyl alkenoates in the surface waters (0–50 m) of the eastern North Atlantic, and correlates their abundance and distribution with those of source organisms and with water temperature and other environmental variables. We collected these samples of >0.8 µm particulate material from the euphotic zone along the JGOFS 20°W longitude transect, from 61°N to 24°N, during seven cruises of the UK-JGOFS Biogeochemical Ocean Flux Study (BOFS) in 1989-1991; the biogeographical range of our 53 samples extends from the cold (<10°C), nutrient-rich and highly productive subarctic waters of the Iceland Basin to the warm (>25°C) oligotrophic subtropical waters off Africa. Surface water concentrations of total alkenone and alkenoates ranged from <50 ng/l in oligotrophic waters below 40°N to 2000-4500 ng/l in high latitude E. huxleyi blooms, and were well correlated with E. huxleyi cell densities, supporting the assumption that E. huxleyi is the predominant source of these compounds in the present day North Atlantic.

The within-class distribution of the C37 and C38 alkenones and C36 alkenoates varied strongly as a function of temperature, and was largely unaffected by nutrient concentration, bloom status and other surface water properties. The biosynthetic response of the source organisms to growth temperature differed between the cold (<16°C) waters above 47°N and the warmer waters to the south. In cold (<16°C) waters above 47°N, the relative amounts of alkenoates and C38 alkenones synthesized was a strong function of growth temperature, while the unsaturation ratio of the alkenones (C37 and C38) was uncorrelated with temperature. Conversely, in warm (>16°C) waters below 47°N, the relative proportions of alkenoates and alkenones synthesized remained constant with increasing temperature while the unsaturation ratios of the C37 and C38 methyl alkenones (Uk37 and Uk38Me, respectively) increased linearly. The fitted regressions of Uk37 and Uk38Me versus temperature for waters >16°C were both highly significant (r**2 > 0.96) and had identical slopes (0.057) that were 50% higher than the slope (0.034) of the temperature calibration of Uk37 reported by Prahl and Wakeham (1987; doi:10.1038/330367a0) over the same temperature range. These observations suggest either a physiological adjustment in biochemical response to growth temperature above a 16-17°C threshold and/or variation between different E. huxleyi strains and/or related species inhabiting the cold and warm water regions of the eastern North Atlantic.

Using our North Atlantic data set, we have produced multivariate temperature calibrations incorporating all major features of the alkenone and alkenoate data set. Predicted temperatures using multivariate calibrations are largely unbiased, with a standard error of approximately ±1°C over the entire data range. In contrast, simpler calibration models cannot adequately incorporate regional diversity and nonlinear trends with temperature. Our results indicate that calibrations based upon single variables, such as Uk37, can be strongly biased by unknown systematic errors arising from natural variability in the biosynthetic response of the source organisms to growth temperature. Multivariate temperature calibration can be expected to give more precise estimates of Integrated Production Temperatures (IPT) in the sedimentary record over a wider range of paleoenvironmental conditions, when derived using a calibration data set incorporating a similar range of natural variability in biosynthetic response.

Project(s):

Joint Global Ocean Flux Study (JGOFS)

Coverage:

Median Latitude: 49.925858 * Median Longitude: -19.526316 * South-bound Latitude: 24.455000 * West-bound Longitude: -22.583300 * North-bound Latitude: 61.281700 * East-bound Longitude: -14.833300

Date/Time Start: 1989-06-14T00:00:00 * Date/Time End: 1991-07-25T00:00:00

Minimum DEPTH, water: 4 m * Maximum DEPTH, water: 50 m

Event(s):

CD46_PUMP1 * Latitude: 49.846700 * Longitude: -18.531700 * Date/Time: 1990-05-04T00:00:00 * Method/Device: Water pump (PUMP)

CD46_PUMP2 * Latitude: 48.896700 * Longitude: -17.016700 * Date/Time: 1990-05-17T00:00:00 * Method/Device: Water pump (PUMP)

CD47_PUMP1 * Latitude: 48.435000 * Longitude: -17.490000 * Date/Time: 1990-05-28T00:00:00 * Method/Device: Water pump (PUMP)

Parameter(s):

#	Name	Short Name	Unit	Principal Investigator	Comment
1	Event label	Event
2	Latitude of event	Latitude
3	Longitude of event	Longitude
4	Date/Time of event	Date/Time
5	DEPTH, water	Depth water	m		Geocode
6	Temperature, water	Temp	°C	Conte, Maureen H
7	Heptatriaconta-8E,15E,22E-trien-2-one	C37:3Me	%	Conte, Maureen H
8	Methyl hexatriaconta-7E,14E,21E-trienoate	Methyl hexatriaconta-7E 14E 21E-tri	%	Conte, Maureen H
9	Heptatriaconta-15E,22E-dien-2-one	C37:2Me	%	Conte, Maureen H
10	Methyl hexatriaconta-14E,21E-dienoate	Methyl hexatriaconta-14E 21E-die	%	Conte, Maureen H
11	Methyl hexatriaconta-14E,21E-dienoate	Methyl hexatriaconta-14E 21E-die	%	Conte, Maureen H
12	Octatriaconta-9E,16E,23E-trien-2-one	C38:3Me	%	Conte, Maureen H
13	Octatriaconta-16E,23E-dien-3-one	C38:2Et	%	Conte, Maureen H
14	Octatriaconta-16E,23E-dien-2-one	C38:2Me	%	Conte, Maureen H
15	Alkenone, unsaturation index UK37	UK37		Conte, Maureen H
16	Alkenoate index	AA36		Conte, Maureen H

License:

Creative Commons Attribution 3.0 Unported (CC-BY-3.0)

Size:

582 data points

Data

Download dataset as tab-delimited text — use the following character encoding:

1 Event	2 Latitude	3 Longitude	4 Date/Time	5 Depth water [m]	6 Temp [°C]	7 C37:3Me [%]	8 Methyl hexatriaconta-7E 14E 21E-tri [%]	9 C37:2Me [%]	10 Methyl hexatriaconta-14E 21E-die [%]	11 Methyl hexatriaconta-14E 21E-die [%]	12 C38:3Me [%]	13 C38:2Et [%]	14 C38:2Me [%]	15 UK37	16 AA36
D183_PUMP1	59.4150	-20.9883	1989-06-14	20	9.8	33.64	7.26	10.72	19.60	9.72	11.22	5.75	2.08	0.242	0.266
D183_PUMP2	59.6967	-21.2533	1989-06-15	5	10.2	21.36	13.96	18.28	19.19	12.70	9.15	3.94	1.42	0.461	0.277
D183_PUMP3	59.6967	-21.2533	1989-06-15	4	10.2	28.28	11.98	17.29	21.39	9.40	8.47	2.04	1.15	0.379	0.282
D183_PUMP3	59.6967	-21.2533	1989-06-15	4	10.2	26.76	8.28	11.30	15.13	17.55	10.81	6.49	3.68	0.299	0.422
D183_PUMP3	59.6967	-21.2533	1989-06-15	10	10.0	27.37	13.01	16.32	17.49	10.99	8.66	4.86	1.29	0.374	0.265
D183_PUMP3	59.6967	-21.2533	1989-06-15	25	9.7	28.19	7.71	14.03	16.48	11.74	11.74	7.24	2.88	0.332	0.327
D183_PUMP4	59.8000	-21.1683	1989-06-16	20	10.2	30.09	7.45	9.95	21.21	10.19	11.20	7.18	2.74	0.249	0.262
D183_PUMP4	59.8000	-21.1683	1989-06-16	30	10.0	22.94	8.25	23.95	16.35	12.48	7.38	7.61	1.05	0.511	0.338
D183_PUMP4	59.8000	-21.1683	1989-06-16	50	9.7	26.32	9.27	10.12	20.86	12.87	9.65	8.43	2.50	0.278	0.299
D183_PUMP5	55.9750	-19.8183	1989-06-25	4	11.7	20.17	5.84	21.94	19.01	13.39	7.48	9.91	2.26	0.521	0.352
D183_PUMP5	55.9750	-19.8183	1989-06-25	10	11.7	23.60	7.48	21.06	17.47	12.91	6.62	8.70	2.17	0.472	0.341
D183_PUMP5	55.9750	-19.8183	1989-06-25	30	11.6	20.62	9.87	17.74	18.17	14.84	7.73	9.40	1.63	0.462	0.346
D183_PUMP6	55.9800	-19.9250	1989-06-26	30	11.6	25.10	5.44	16.72	21.05	8.30	7.05	11.36	4.98	0.400	0.238
D183_PUMP7	51.9567	-19.8450	1989-06-27	30	14.0	19.03	8.48	19.07	12.12	19.19	7.17	10.30	4.64	0.500	0.482
D183_PUMP8	51.8000	-19.4333	1989-06-28	40	12.4	24.83	4.50	16.04	17.08	14.08	7.16	13.08	3.24	0.393	0.395
D183_PUMP9	46.9217	-20.0350	1989-07-02	30	14.5	22.62	1.87	17.24	13.49	13.74	12.86	15.21	2.97	0.431	0.474
D183_PUMP10	46.8400	-20.0367	1989-07-02	4	16.9	25.93	2.11	22.26	6.06	13.87	11.92	12.98	4.88	0.462	0.628
D183_PUMP10	46.8400	-20.0367	1989-07-02	15	15.5	28.69	0.99	23.59	6.24	14.54	9.61	12.33	4.01	0.452	0.668
D183_PUMP12	46.7533	-19.8683	1989-07-07	10	17.2	24.58	0.84	20.14	6.77	13.64	12.22	15.55	6.27	0.450	0.642
CD46_PUMP1	49.8467	-18.5317	1990-05-04	15	12.4	27.01	3.21	13.72	16.87	10.44	13.04	11.56	4.16	0.337	0.342
CD46_PUMP2	48.8967	-17.0167	1990-05-17	15	12.9	25.61	4.12	16.02	16.52	11.20	9.34	13.10	4.10	0.385	0.352
D191_PUMP1	48.4967	-17.7983	1990-05-21	10	13.9	26.19	3.00	23.01	11.59	10.74	11.06	9.52	4.89	0.468	0.424
D191_PUMP2	48.4900	-17.8033	1990-05-23	10	13.7	21.41	3.54	22.57	14.90	12.53	9.96	12.81	2.29	0.512	0.404
D191_PUMP3	48.4683	-17.5617	1990-05-25	10	14.3	21.94	2.84	22.13	13.45	12.73	10.41	10.98	5.51	0.502	0.439
D191_PUMP4	48.4483	-17.4917	1990-05-27	10	14.3	24.46	3.82	21.50	11.75	12.47	10.61	9.91	5.48	0.469	0.445
CD47_PUMP1	48.4350	-17.4900	1990-05-28	10	14.6	26.68	2.85	16.23	13.48	12.72	10.89	12.07	5.08	0.378	0.438
CD47_PUMP2	48.2800	-17.3133	1990-06-01	10	14.9	26.11	3.70	15.92	14.47	11.14	10.63	12.20	5.81	0.379	0.380
CD47_PUMP2	48.2800	-17.3133	1990-06-01	25	12.5	25.23	3.52	15.03	16.76	12.87	10.36	11.94	4.30	0.373	0.388
CD47_PUMP3	47.9283	-16.8233	1990-06-02	10	14.9	26.52	2.90	15.63	14.90	12.59	10.43	12.41	4.62	0.371	0.414
CD53_PUMP1	47.0600	-19.7267	1990-09-22	4	17.4	26.31	1.32	20.94	7.30	10.94	11.40	14.35	7.44	0.443	0.558
CD53_PUMP2	44.6550	-20.5617	1990-09-22	4	18.7	23.54	0.57	27.47	5.56	7.61	9.38	17.11	8.75	0.539	0.554
CD53_PUMP3	47.8050	-19.4367	1990-09-22	10	18.0	23.09	0.67	23.14	6.66	8.64	11.08	17.39	9.32	0.501	0.541
CD53_PUMP3	47.8050	-19.4367	1990-09-22	30	18.0	23.54	1.99	24.05	6.61	9.91	9.92	15.71	8.27	0.505	0.536
CD53_PUMP4	42.1617	-21.4617	1990-09-23	4	20.6	17.38	1.32	30.22	5.07	10.11	7.74	16.96	11.20	0.635	0.613
CD53_PUMP5	41.1317	-20.7050	1990-09-25	4	20.9	14.09	0.84	31.53	5.78	10.54	6.74	21.55	8.94	0.691	0.615
CD53_PUMP6	42.1617	-21.4617	1990-09-24	10	20.7	14.97	3.15	35.68	3.57	16.17	4.71	14.68	7.07	0.704	0.706
CD53_PUMP7	38.7983	-19.8867	1990-09-26	4	21.6	15.70	3.36	35.43	3.69	12.86	5.33	15.89	7.74	0.693	0.648
CD53_PUMP8	35.1100	-19.2383	1990-09-27	4	22.7	9.43	7.45	36.99	6.83	18.16	2.94	12.05	6.14	0.797	0.560
CD53_PUMP9	32.9017	-18.9417	1990-09-29	4	23.4	7.63	3.88	39.31	2.36	10.41	4.08	20.39	11.93	0.837	0.623
CD53_PUMP10	32.8650	-19.2900	1990-09-30	4	23.5	8.31	3.92	38.28	2.82	12.72	3.35	19.62	10.98	0.822	0.653
CD53_PUMP11	32.4733	-20.4933	1990-10-02	10	24.9	6.36	10.86	34.67	2.84	13.20	2.97	18.70	10.41	0.845
CD53_PUMP12	24.4550	-20.4067	1990-10-08	10	24.7	6.12	7.58	42.83	2.12	13.54	1.99	17.02	8.80	0.875	0.583
CD60_PUMP1	60.1667	-20.0000	1991-06-20	8	10.8	29.29	6.33	10.99	19.93	9.08	13.57	6.95	3.86	0.273	0.257
CD60_PUMP2	60.6667	-22.5833	1991-06-22	8	11.0	27.63	9.00	11.50	21.66	9.97	9.83	7.77	2.64	0.294	0.245
CD60_PUMP3	60.4167	-14.8333	1991-06-30	5	12.5	22.09	5.29	14.67	19.61	11.97	8.96	6.69	1.71	0.399	0.325
CD61_PUMP1	61.0817	-19.9917	1991-07-12	10	12.3	25.01	5.46	21.03	19.28	11.31	6.81	9.38	1.72	0.457	0.314
CD61_PUMP2	61.2817	-19.7850	1991-07-14	15	12.4	25.41	4.91	16.42	20.71	8.88	7.81	11.90	3.96	0.393	0.257
CD61_PUMP3	60.5450	-20.1533	1991-07-12	4	12.3	24.31	5.25	18.07	19.67	10.59	6.65	12.35	3.11	0.426	0.298
CD61_PUMP4	60.5483	-19.5467	1991-07-12	4	12.6	23.78	4.64	19.14	19.73	10.93	6.79	12.13	2.87	0.446	0.310
CD61_PUMP5	60.7833	-19.6783	1991-07-14	4	13.1	25.67	5.83	16.55	19.49	12.07	7.12	10.11	3.16	0.392	0.323
CD61_PUMP6	56.0600	-19.9750	1991-07-25	4	13.9	26.56	3.51	14.72	18.46	11.02	10.88	10.41	4.43	0.357	0.334
CD61_PUMP7	55.9300	-20.0133	1991-07-25	4	13.9	26.78	2.93	15.96	16.41	10.28	10.92	11.37	5.35	0.373	0.347
CD61_PUMP8	55.6283	-20.0067	1991-07-25	4	14.0	27.67	2.30	15.36	15.91	9.88	12.19	11.31	5.38	0.357	0.352