Citation:

PANGAEA.930796

Name: Biomarkers of sediment core POS362-2_99
Published: 2021-04-26
License: https://creativecommons.org/licenses/by/4.0/
Keywords: deoxygenation; Geochemistry; Nile River; Sapropel S1

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Abstract:

Ocean deoxygenation is a rising threat to marine ecosystems and food resources under present climate warming conditions. Organic-rich sapropel layers deposited in the Mediterranean Sea provide a natural laboratory to study the processes that have controlled the changes in seawater oxygen levels in the recent geological past. Our study is based on three sediment cores spanning the last 10 thousand years (10 kyr BP) and located on a bathymetric transect offshore the western distributaries of the Nile delta. These cores are partly to continuously laminated in the sections recording sapropel S1, which is indicative of bottom-water anoxia above the western Nile deep-sea fan. We used a combination of microfacies analyses and inorganic and organic geochemical measurements to reconstruct changes in oxygenation conditions at seasonal to millennial time-scales. The regular alternations of detrital, biogenic and chemogenic sublayers in the laminated sequences are interpreted in terms of seasonal changes. Our microfacies analyses reveal distinct summer floods and subsequent plankton blooms preceding the deposition of inorganic carbonates formed in the water-column during spring-early summer. The isotopic signature of these carbonates suggests year-round anoxic to euxinic bottom waters resulting in high levels of anaerobic remineralisation of organic matter and highlights their potential to reconstruct seawater chemistry at times when benthic fauna was absent. Synchronous changes in terrigenous input, primary productivity and past oxygenation dynamics on millennial time-scales obtained by our multi-proxy study show that runoff-driven eutrophication played a central role in driving rapid changes in oxygenation state of the entire Levantine Basin. Rapid fluctuations of oxygenation conditions in the upper 700 m water depth occurred above the Nile deep-sea fan between 10 and 6.5 ka BP while deeper cores recorded more stable anoxic conditions. These findings are further supported by other regional records and reveal time-transgressive changes in oxygenation state driven by rapid changes in primary productivity during a period of long-term deep-water stagnation.

Keyword(s):

deoxygenation; Geochemistry; Nile River; Sapropel S1

Supplement to:

Blanchet, Cécile L; Tjallingii, Rik; Schleicher, Anja Maria; Schouten, Stefan; Frank, Martin; Brauer, Achim (accepted): Deoxygenation dynamics above the western Nile deep-sea fan during sapropel S1 at seasonal to millenial time-scales. Climate of the Past, https://doi.org/10.5194/cp-2020-114

Coverage:

Latitude: 31.945320 * Longitude: 30.149180

Date/Time Start: 2008-02-22T06:26:00 * Date/Time End: 2008-02-22T06:26:00

Minimum DEPTH, sediment/rock: 0.000 m * Maximum DEPTH, sediment/rock: 5.285 m

Event(s):

POS362-2_99 * Latitude: 31.945320 * Longitude: 30.149180 * Date/Time: 2008-02-22T06:26:00 * Elevation: 396.0 m * Campaign: * Basis: * Method/Device: Gravity corer (GC)

Parameter(s):

#	Name	Short Name	Unit	Principal Investigator	Comment
1	DEPTH, sediment/rock	Depth sed	m	Blanchet, Cécile L	Geocode
2	AGE	Age	ka BP	Blanchet, Cécile L	Geocode
3	Age, error	Age e	±	Blanchet, Cécile L	2s
4	Mass	Mass	g	Blanchet, Cécile L	weight sediment
5	Density, wet bulk	WBD	g/cm³	Blanchet, Cécile L
6	Linear sedimentation rate	LSR	cm/ka	Blanchet, Cécile L
7	Mass	Mass	µg	Blanchet, Cécile L	weigh of the C37 Alkenone
8	C37:2-, C37:3-Alkenone	C37:2, C37:3	µg/g	Blanchet, Cécile L
9	Accumulation rate, alkenones	Acc rate alk	µg/cm²/ka	Blanchet, Cécile L	mass accumulation rate of the C37 Alkenone
10	Mass	Mass	µg	Blanchet, Cécile L	weight odd n-alkanes (µg)
11	Mass	Mass	µg	Blanchet, Cécile L	weight lycopane (µg)
12	Mass	Mass	µg	Blanchet, Cécile L	weight triterpenoids (µg)
13	Concentration	Conc	µg/g	Blanchet, Cécile L	conc odd n-alkanes (µg/g)
14	Concentration	Conc	µg/g	Blanchet, Cécile L	conc lycopane (µg/g)
15	Concentration	Conc	µg/g	Blanchet, Cécile L	conc triterpenoids (µg/g)
16	Accumulation rate, mass	MAR	g/cm²/ka	Blanchet, Cécile L	MAR odd n-alkanes (µg/cm2.a)
17	Accumulation rate, mass	MAR	g/cm²/ka	Blanchet, Cécile L	MAR lycopane (µg/cm2.a)
18	Accumulation rate, mass	MAR	g/cm²/ka	Blanchet, Cécile L	MAR triterpenoids (µg/cm2.a)
19	Carbon Preference Index	CPI		Blanchet, Cécile L
20	Mass	Mass	µg	Blanchet, Cécile L	Weight cren (µg)
21	Standard deviation	Std dev	±	Blanchet, Cécile L	weight cren
22	Mass	Mass	µg	Blanchet, Cécile L	Weight brGDGTs (µg)
23	Standard deviation	Std dev	±	Blanchet, Cécile L	Weight brGDGTs (µg)
24	Concentration	Conc	µg/g	Blanchet, Cécile L	Conc cren (µg/g)
25	Standard deviation	Std dev	±	Blanchet, Cécile L	Conc cren (µg/g)
26	Concentration	Conc	µg/g	Blanchet, Cécile L	Conc brGDGTs (µg/g)
27	Standard deviation	Std dev	±	Blanchet, Cécile L	Conc brGDGTs (µg/g)
28	Accumulation rate, mass	MAR	g/cm²/ka	Blanchet, Cécile L	MAR Cren (µg/cm2.a)
29	Standard deviation	Std dev	±	Blanchet, Cécile L	MAR Cren (µg/cm2.a)
30	Accumulation rate, mass	MAR	g/cm²/ka	Blanchet, Cécile L	MAR brGDGTs (µg/cm2.a)
31	Standard deviation	Std dev	±	Blanchet, Cécile L	MAR brGDGTs (µg/cm2.a)

License:

Creative Commons Attribution 4.0 International (CC-BY-4.0)

Status:

Curation Level: Enhanced curation (CurationLevelC)

Size:

503 data points

Data

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

1 Depth sed [m]	2 Age [ka BP]	3 Age e [±] (2s)	4 Mass [g] (weight sediment)	5 WBD [g/cm³]	6 LSR [cm/ka]	7 Mass [µg] (weigh of the C37 Alkenone)	8 C37:2, C37:3 [µg/g]	9 Acc rate alk [µg/cm²/ka] (mass accumulation rate of the...)	10 Mass [µg] (weight odd n-alkanes (µg))	11 Mass [µg] (weight lycopane (µg))	12 Mass [µg] (weight triterpenoids (µg))	13 Conc [µg/g] (conc odd n-alkanes (µg/g))	14 Conc [µg/g] (conc lycopane (µg/g))	15 Conc [µg/g] (conc triterpenoids (µg/g))	16 MAR [g/cm²/ka] (MAR odd n-alkanes (µg/cm2.a))	17 MAR [g/cm²/ka] (MAR lycopane (µg/cm2.a))	18 MAR [g/cm²/ka] (MAR triterpenoids (µg/cm2.a))	19 CPI	20 Mass [µg] (Weight cren (µg))	21 Std dev [±] (weight cren)	22 Mass [µg] (Weight brGDGTs (µg))	23 Std dev [±] (Weight brGDGTs (µg))	24 Conc [µg/g] (Conc cren (µg/g))	25 Std dev [±] (Conc cren (µg/g))	26 Conc [µg/g] (Conc brGDGTs (µg/g))	27 Std dev [±] (Conc brGDGTs (µg/g))	28 MAR [g/cm²/ka] (MAR Cren (µg/cm2.a))	29 Std dev [±] (MAR Cren (µg/cm2.a))	30 MAR [g/cm²/ka] (MAR brGDGTs (µg/cm2.a))	31 Std dev [±] (MAR brGDGTs (µg/cm2.a))
0.000	0.0000	0.0000	6.2	2.010	28.25	0.15	0.02	0.001	5.46		0.58	0.88	0.00	0.09	0.05	0.00	0.01	7.82	9.05	0.29	1.95	0.11	1.46	0.05	0.31	0.02	0.08	0.00	0.04	0.00
0.300	1.0620	0.0300	6.3	2.140	28.25	0.13	0.02	0.001	3.64		1.07	0.58	0.00	0.17	0.03	0.00	0.01	7.83	5.87	0.03	4.97	0.19	0.93	0.01	0.79	0.03	0.06	0.00	0.03	0.00
0.865	5.9410	0.0865	6.6	2.270	11.58	0.88	0.13	0.003	1.69		0.44	0.26	0.00	0.07	0.01	0.00	0.00	4.23	1.61	0.09	0.89	0.03	0.24	0.01	0.13	0.01	0.01	0.00	0.01	0.00
1.265	7.2440	0.1265	6.5	2.170	30.70	1.21	0.19	0.012	2.96	0.08	1.17	0.46	0.01	0.18	0.03	0.00	0.01	6.38	14.99	0.44	3.61	0.33	2.27	0.07	0.55	0.05	0.06	0.00	0.03	0.00
1.565	7.3905	0.1565	6.4	1.985	204.78	0.51	0.08	0.032	0.30	0.01	0.23	0.05	0.00	0.04	0.02	0.00	0.01	5.31	35.42	1.92	16.76	1.04	5.45	0.30	2.58	0.16	0.33	0.02	0.15	0.01
1.880	7.5460	0.1880	6.1	1.945	202.57	1.53	0.25	0.099	4.09	0.20	1.57	0.67	0.03	0.26	0.27	0.01	0.10	6.32	18.45	1.21	10.83	1.12	2.88	0.19	1.69	0.17	1.15	0.08	0.60	0.05
2.280	7.7390	0.2280	6.2	1.970	207.25	0.68	0.11	0.045	3.32	0.10	1.37	0.54	0.02	0.22	0.23	0.01	0.09	7.97	28.05	1.36	16.97	1.13	4.62	0.22	2.80	0.19	1.84	0.09	0.94	0.05
2.580	7.8860	0.2580							0.82	0.02	0.25	0.13	0.00	0.04	0.05	0.00	0.02	3.20	14.93	7.49	19.19	9.40	2.41	1.21	3.09	1.52	1.01	0.51	0.58	0.28
2.580	7.8860	0.2580	6.4	2.030	204.08	0.72	0.11	0.047	0.93	0.02	0.26	0.14	0.00	0.04	0.06	0.00	0.02	3.37	19.22	1.14	11.60	0.63	3.00	0.18	1.81	0.10	1.24	0.07	0.66	0.05
2.895	8.0400	0.2895	6.2	2.015	204.55	4.01	0.65	0.266	7.60		3.20	1.23	0.00	0.52	0.50	0.00	0.21	7.87	35.61	3.28	24.24	2.64	5.74	0.53	3.91	0.43	2.37	0.22	1.23	0.13
3.295	8.2355	0.3295	6.4	2.110	204.60	2.29	0.36	0.155	8.41		4.44	1.31	0.00	0.69	0.57	0.00	0.30	12.59	28.83	0.72	25.72	1.10	4.50	0.11	4.02	0.17	1.94	0.05	1.22	0.04
3.595	8.3665	0.3595	6.5	2.015	229.01	0.66	0.10	0.047	7.64		0.00	1.18	0.00	0.00	0.55	0.00	0.00		17.57	1.01	17.84	1.48	2.72	0.16	2.77	0.23	1.26	0.07	0.93	0.08
3.900	8.5020	0.3900	6.5	2.040	225.09	0.77	0.12	0.055	3.68		1.47	0.57	0.00	0.23	0.26	0.00	0.10	8.59	37.81	2.01	30.88	1.80	5.82	0.31	4.75	0.28	2.67	0.14	1.73	0.08
4.300	8.6800	0.4300	6.4	2.040	224.72	0.60	0.09	0.043	3.72		1.06	0.58	0.00	0.17	0.27	0.00	0.08	9.40	27.02	0.07	25.33	0.26	4.22	0.01	3.95	0.04	1.93	0.01	1.41	0.03
4.600	8.8130	0.4600	6.6	2.090	225.56	0.43	0.07	0.031	5.20		1.14	0.79	0.00	0.17	0.37	0.00	0.08	9.20	31.93	2.21	30.65	2.76	4.87	0.34	4.67	0.42	2.29	0.16	1.61	0.13
4.810	8.9030	0.4810	6.3	0.710	233.33	0.82	0.13	0.021	3.56		1.13	0.57	0.00	0.18	0.09	0.00	0.03	9.78	33.76	0.36	32.83	0.85	5.36	0.06	5.21	0.13	0.89	0.01	0.53	0.01
5.010	8.9920	0.5010	6.2	2.130	224.72	0.50	0.08	0.039	3.75		1.00	0.61	0.00	0.16	0.29	0.00	0.08	6.81	14.22	0.69	25.58	1.42	2.29	0.11	4.13	0.23	1.10	0.05	0.81	0.05
5.285	9.0670	0.5285	6.4	2.055	366.67	0.30	0.05	0.036	4.12		1.11	0.64	0.00	0.17	0.48	0.00	0.13	10.27	27.10	0.69	28.18	0.76	4.21	0.11	4.38	0.12	3.17	0.08	1.81	0.02