Bacterial properties in discrete water column samples collected during Palmer LTER station seasons at Palmer Station Antarctica, 2002 - 2019.

• Main Authors: LTER, Palmer Station Antarctica, Ducklow, Hugh
• Format: Dataset
• Language: English
• Published: Environmental Data Initiative 2019
• Subjects: Palmer Station; Palmer-Station; Antarc*; Antarctica; polar night
• Online Access: https://dx.doi.org/10.6073/pasta/8168e51daba2b7f7a978d2f6a27e22a4; https://portal.edirepository.org/nis/mapbrowse?packageid=knb-lter-pal.47.6

The microbial biogeochemistry component of PAL focuses on marine bacterioplankton, and is thus a counterpart to the phytoplankton and zooplankton components, which together provide a detailed and comprehensive description of plankton ecology in PAL-LTER. Bacteria and Archaea (hereafter called "bacteria") are taxonomically and metabolically diverse. In coastal and offshore surface waters Bacteria generally predominate over Archaea, but Archaea are equal or greater in abundance in the mesopelagic layer below the euphoric zone. We focus on aerobic, heterotrophic bacteria in the upper 65 m at Palmer Station which oxidize recently-produced low molecular weight dissolved organic compounds released by phytoplankton and zooplankton, decomposing them back into CO2 and inorganic nutrients. Globally, marine bacteria respire an amount of carbon roughly equal to about half the daily photosynthetic production. In cold polar waters, relative bacterial activity is lower, with bacterial biomass production being equal to <5% of the daily photosynthesis. The ratio at lower latitudes is 10-20%. The factors responsible for this contrast are not entirely clear. Resolving this pattern is a key aim of the PAL microbial component. At Palmer Station, bacterial production is low (< 10 mgC/m2/d) in the winter (polar night) when there is little if any photosynthesis. There is a climatological (2003-14 average) summer peak of 50-60 mgC/m2/d in January-February but with considerable seasonal and annual variability. The 2016/2017 season data contains bacteria abundances for preserved samples for comparison to abundances from live samples. See the documentation for this in the accompanying file, 2016_live_vs_preserved.pdf.