Sulfidic Events in a Shallow Bay of the Central Peruvian Upwelling System

Transcription

1 Sulfidic Events in a Shallow Bay of the Central Peruvian Upwelling System FLORES E, GRACO M, MERMA, L, DIAZ R, MOREIRA M, AGUIRRE A, BÖTTCHER M, SALDARRIAGA, M, SILVA-FILHO E, ALBUQUERQUE A & MENDOZA U Instituto del Mar del Peru Oceanographic and Climatic Change Directorate

2

3 SULFATE REDUCTION 11% of the liquid primary production is decomposed by sulfate reduction at the top sediments (1 cm). Jorgensen 19

4 CRIPTIC SULFUR CYCLE NO3_ and NO_ to NHþ Reduction Oxidation HS to SO via elemental sulphur (S ) Steady-State prevent HS accumulation Inorganic carbon rich sediments with high rates of microbial sulphate reduction and underlying oxygen-depleted bottom waters, DNRA is an important sulphide detoxifying mechanism and coupling the benthic and pelagic sulphur and nitrogen cycles. DNRA in Peruvian sediments: Filamentous and nitrate-storing Sulphur oxidizing chemolithotrophs from genera Beggiatoa and Thioploca. Jørgensen & Nelson,

5 SULFIDIC EVENTS Pieterse & van der Post, 197. Reports a water mass discoloration" attribute to a turquoise discoloration, product of the hydrogen sulfide oxidation and coloidal elemental sulfur formation. Copenhague et al., Hart & Currie, Pieterse y van der Post, Bailey et al., Ferdelman et al., Emeis et al., Weeks et al., Brüchert et al., Ulloa et al., Aguirre et al., Shunck et al., 1953 South Africa 19 South Africa 197 South Africa 1991 South Africa 1999 South Africa South Africa South Africa South Africa 1 Chile & Peru 1 Peru 13 Peru Flores et al. Present Study

6 SeaWiFS-May-jun, 1 SULFUR PLUMES - NAMIBIA COAST MERIS - 1April- EVENT-5 Weeks et al., Ohde et al., Currie et al., Gaute Lavik et al.,

7 SULFUR PLUMES - PERUVIAN COAST MODIS 1-1 April- 1 S a Lima PERU c MODIS Mai-9 13 S Elemental sulfur plume Pisco 1 S Depth (m) 5 b 1 1 N km 1km km S 5 3 µm Sulfide Karhu et al., Schunk et al., 13

8 PARACAS BAY

9 SULFIDIC EVENTS DURING EL NIÑO EVENT 15 Intense Sulfidic Event 3-month time series 11 April 7 June 3 31 March Massive fisheries mortality Short-term Sulfidic Event 1 April

10 Intense Sulfidic Event Short-term Sulfidic Event 1 April-15 Normal Conditions Sulfidic Event MODIS March 17

11 MONTHLY ASCAT WINDS VARIATION (January-September 15) Summer Minimal:, m/s Maimal: 7,31 m/s Mean: 3,9 m/s calm days (1 al 19-3) <,5 m/s Spring Minimal:, m/s Maximal: 11, m/s Mean: 5,5 m/s IWinter Minimal:,7 m/s Maximal de1,5 m/s Mean:,95 m/s

12 MONTHLY WINDS AND TEMPERATURE VARIATION (February-July 15) ASCAT Satélite Winds Outside de Bay Inside de Bay

13 Winds of airport Inner-Bay Speed of w inds (m.s 1 ) Correlation Temp vs. O = w inds conditions (hours.day 1 ) Station E1 Oxygen (ml.l 1 ) Inner-Bay Hypoxic conditions (hours.day 1 ) Station E Hipoxic 1,3 ml/l ~ 3 µm (Middelburg, 9 Conolly, 1) Microxic.1 ml/l ~ µm (Naqvi et al., ) Oxygen (ml.l 1 ) Hypoxic conditions (hours.day 1 ) Middle-Bay 1.3 ml/l.1 ml/l Oxygen (ml.l 1 ) Station E Outer-Bay

14

15 Area Winds (m/s) O (ml/l) H S (mm) H S Difusive Flux (mmol.m.d -1 ) Author Namibia (3- o S) Weeks et al., Namibia (3 o S) 11. Buchert et al. Namibia (3-.5 o S) Lavik et al., 9 Peru (1-13 o S), 1 m. - Schunck et al., 13 Perú (1 o S), 7 m Paracas Bay (13 o S) 1 m Short-term Sulfidic event 5 Atypical Conditions 1 <1 Prevailed Microxic Prevailed.1 1. Dale et al., 1 Sommer et al., 1 5. Present Study

16 NORMAL SYSTEM Inner-Bay Middle-Bay Outer-Bay HS SO E1-JUNIO HS (um) SO 1 (mm) E-JUNIO HS SO H S (um) SO - (mm) E-JUNIO E-JUNIO HS SO H S (um) SO - (mm) E1-JUNIO AVS (%) CRS (%) AVS CRS AVS (%) CRS (%) AVS CRS E-JUNIO AVS (%) CRS (%) AVS CRS

17 SHORT-TERM SULFIDIC EVENT Inner-Bay Middle-Bay Outer-Bay HS SO E1-ABRIL HS (um) SO (mm) E-ABRIL HS SO H S (um) SO - (mm) E-ABRIL E-ABRIL HS SO H S (um) SO - (mm) E-ABRIL E1-ABRIL AVS (%) CRS (%) AVS CRS AVS (%) CRS (%) AVS CRS AVS (%) CRS (%) AVS CRS

18 CONCEPTUAL MODEL Winds <,5 m/s Estratificaction Concentration (µm) HS µm S S Oxygen µm S Oxygen Hipoxic 1,3 ml/l ~ 3 µm Microxic.1 ml/l ~ µm Water Column HS HS HS O O O Depth (cm) OM UPWELLING Sediment E1 E HS Flux OM E Depth (cm)