COI Funded Project: Geomicrobiology of an Anthropogenically Altered Subterranean Estuary
Project Funded 2007:
Human activities have undoubtedly altered the ecology of coastal
waters. Much of the alteration is due to the addition of excess
nutrients, primarily nitrogen. Thirty years of effort aimed at stemming
this problem (eg. The Clean Water Act) has been unable to sufficiently
reduce the anthropogenic flux of nitrogen to coastal waters resulting
in the deterioration of coastal waters. Having been unable to
adequately reduce the supply of nitrogen, we must now also strive to
better understand the natural processes that remove nitrogen from
affected systems. Groundwater is one of the significant transport
pathways of nitrogen to the coastal water and may harbor much different
chemical conditions than traditional riverine inputs. Many of the
processes that transform nitrogen in this groundwater system are
microbially-mediated. We propose to carefully examine the potential of
natural populations of microorganisms to attenuate the flux of nitrogen
from groundwater to the coastal waters. We will combine the use of
microbiological, molecular and chemical techniques to examine the
biogeochemical cycling of nitrogen in a groundwater estuary. We will
strive to understand (i) which populations are active, and under what
condition are they active, (ii) what community function is served by
archaea in the system, (iii) at what rate is nitrogen removed from the
system by different populations. This work will address all three
themes of the Coastal Ocean Institute. First, this work will provide
insight into the fate of an anthropogenic pollutant on the micron to
centimeter scale by describing which organisms are important in the
groundwater nitrogen cycle as well as the organism’s activity,
distribution and abundance. Second, we propose to examine the
biogeochemical processes within the groundwater that control speciation
and transport of nitrogen to the coastal waters. Finally, we propose to
implement new tools by combining molecular methods, including the first
metagenomic study of a groundwater system, and stable isotope
techniques to elucidate the dominant biochemical processes controlling
the nitrogen cycle in the groundwater estuary.