Examination of Manganese Concentrations in the Hydrothermal Vent Plume at Pele’s Pit, Hawaii
The objective of this research is to measure manganese concentrations in the neutrally buoyant plume dispersed from the hydrothermal vent field of Pele’s pit in Loihi Seamount. The field work for this research will be held during the cruise on R/V Thompson starting from December 27th 2010 and end at January 4th 2011. I will compare the collected data with preexisting data of concentration of manganese of hydrothermal plume at Juan de Fuca Mid-Ocean Ridge and previous data from the same site. Collecting of water samples and other water column data like temperature and transmissivity will be done by using CTD cast during the cruise. After the cruise, samples would be chemically analyzed to get precise concentration of manganese in a lab in NOAA. Hydrothermal vent plume tend to contain higher concentration of manganese compared to most of oceanic environment because of linear relationship between volcanic activity and manganese concentration. My hypothesis for this research is that manganese concentration of plume of hydrothermal vent of Pele’s pit would be measurably lower than recent value of manganese concentration of plume of Juan de Fuca Ridge hydrothermal vent. According to Malahoff et al. 2006, when there was strong seismic activity presented in a site, it showed significantly higher value of Mn concentration from hydrothermal plumes compared to value of Mn concentration measured during seismically inactive period from same site. The margin of difference of concentration of manganese measured from two different periods was up to a factor of 10^4. From the daily updated earthquake data provided by USGS (http://earthquake.usgs.gov/earthquakes/recenteqsww/Maps/region/N_America.php), it is noticeable that Juan De Fuca Ridge is having much active seismic activity compared to Hawaii Island. Juan de Fuca Ridge recently had earthquake of 4.2, and Hawaii Island had earthquake of 2.6. In addition, according to Malahoff et. al. 2005, since the major seismic activity that occurred at 1996, maximum temperature of hydrothermal vent plume of Loihi had been progressively decreased from 198 degree Celsius to 93 degree Celsius while concentration of Mn had been progressively decreased as well. Venting temperature at Endeavour Segment at Juan de Fuca Ridge were 290~316 degree Celsius (Bao et. al. 2008). Based on these observations, there should be measurably less concentration of manganese in plume of hydrothermal vent of Hawaiian Island compared to concentration of manganese in plume of hydrothermal vent of Juan de Fuca Ridge.