TY - JOUR
T1 - The impact of hurricanes on sedimenting particulate matter in the semi-arid Bahía de La Paz, Gulf of California
AU - Silverberg, Norman
AU - Shumilin, Evgueni
AU - Aguirre-Bahena, Fernando
AU - Rodríguez-Castañeda, Ana Patricia
AU - Sapozhnikov, Dmitry
N1 - Funding Information:
We thank the captain and crew of the B.O. Francisco de Ulloa for their help during the sampling program, and are grateful for the participation of various students and colleagues. This study was supported by the following grants from the Instituto Politécnico Nacional of Mexico: “Monitoreo ecológico continuo en Bahía de La Paz” CGPI 20-02; 20030351; 20040095; 20050274 and “Biogeoquímica de los elementos traza en el Golfo de California” CGPI 20040093, 20050113.
PY - 2007/11/15
Y1 - 2007/11/15
N2 - From 2002 through 2004, time-series sediment trap samples were collected from a depth of 410 m in Cuenca Alfonso, Bahía de La Paz, on the SW coast of the Gulf of California. The instrument recorded the impact of the local passage of hurricanes "Ignacio" (24-26 August) and "Marty" (21-23 September) in 2003. These two events accounted for 82% of the total rainfall measured in 2003, equivalent to the annual average precipitation in years without hurricanes. Mean total mass fluxes (TMFs) of 2.88 and 3.58 g m-2 d-1 were measured during the week of each hurricane as well as the following week. This may have been enough to produce a lamina in the underlying sediment with characteristics peculiar to such events. The terrigenous component was particularly abundant, with notably higher concentrations of Fe, Sc, Co and Cs and REEs. In contrast, TMFs throughout 2002-2004 (excluding the hurricane periods) averaged only 0.73 g m-2 d-1 and had a larger marine biogenic component. The extraordinary elemental fluxes during the 29 days of hurricane-influenced sedimentation represented a great proportion of the totals over an entire "normal" year: Co (67.8%) >Sc (62.6) >Fe (59.6) >Cs (53.4)>Lu (51.5)>La (51.3)>Yb (51.0)>Ce (49.5) >Tb (48.4) >Sm (44.7)>Cr (36.5) >Ca (31.0)>Eu (25.4%). The terrigenous fraction was calculated using (a) TMF minus the sum of CaCO3, biogenic silica and organic matter and (b) the ratio of Sc in the trap samples to the average in the Earth's crust. The latter was consistently smaller, but the two methods offered similar results following hurricanes (78% vs. 63%, respectively). For normal sedimentation, however, the difference method yielded values twice as large as the Sc method (58% vs. 30%) This suggests that the mineralogy of the terrigenous fraction may also vary, with unsorted dessert soil being carried to sea by the powerful flash floods associated with hurricanes. Eolian supply of particles, particularly Sc-free quartz grains, possibly from beyond the limited fluvial drainage basin, apparently dominates normal sedimentation.
AB - From 2002 through 2004, time-series sediment trap samples were collected from a depth of 410 m in Cuenca Alfonso, Bahía de La Paz, on the SW coast of the Gulf of California. The instrument recorded the impact of the local passage of hurricanes "Ignacio" (24-26 August) and "Marty" (21-23 September) in 2003. These two events accounted for 82% of the total rainfall measured in 2003, equivalent to the annual average precipitation in years without hurricanes. Mean total mass fluxes (TMFs) of 2.88 and 3.58 g m-2 d-1 were measured during the week of each hurricane as well as the following week. This may have been enough to produce a lamina in the underlying sediment with characteristics peculiar to such events. The terrigenous component was particularly abundant, with notably higher concentrations of Fe, Sc, Co and Cs and REEs. In contrast, TMFs throughout 2002-2004 (excluding the hurricane periods) averaged only 0.73 g m-2 d-1 and had a larger marine biogenic component. The extraordinary elemental fluxes during the 29 days of hurricane-influenced sedimentation represented a great proportion of the totals over an entire "normal" year: Co (67.8%) >Sc (62.6) >Fe (59.6) >Cs (53.4)>Lu (51.5)>La (51.3)>Yb (51.0)>Ce (49.5) >Tb (48.4) >Sm (44.7)>Cr (36.5) >Ca (31.0)>Eu (25.4%). The terrigenous fraction was calculated using (a) TMF minus the sum of CaCO3, biogenic silica and organic matter and (b) the ratio of Sc in the trap samples to the average in the Earth's crust. The latter was consistently smaller, but the two methods offered similar results following hurricanes (78% vs. 63%, respectively). For normal sedimentation, however, the difference method yielded values twice as large as the Sc method (58% vs. 30%) This suggests that the mineralogy of the terrigenous fraction may also vary, with unsorted dessert soil being carried to sea by the powerful flash floods associated with hurricanes. Eolian supply of particles, particularly Sc-free quartz grains, possibly from beyond the limited fluvial drainage basin, apparently dominates normal sedimentation.
KW - "Ignacio"
KW - "Marty"
KW - Alfonso Basin
KW - Major and trace particulate metal fluxes
KW - Mexico Baja California Sur
KW - Sediment traps
UR - http://www.scopus.com/inward/record.url?scp=35648967037&partnerID=8YFLogxK
U2 - 10.1016/j.csr.2007.06.016
DO - 10.1016/j.csr.2007.06.016
M3 - Artículo
SN - 0278-4343
VL - 27
SP - 2513
EP - 2522
JO - Continental Shelf Research
JF - Continental Shelf Research
IS - 19
ER -