Space-Time variability of bio-optical properties in the Southern California Bight



12/08/2015 - 10:00am to 12/09/2015 - 9:45am


Fernanda Henderikx-Freitas
Fernanda Henderikx-Freitas Final Defense

Advisor: David Siegel


My dissertation examines the variability of particles and
phytoplankton in the Southern California Bight over various time and
space scales. In*/Chapter One/*, an underwater glider was used to
repeatedly sample the inner and mid-shelf Santa Barbara Channel (from
20 to 70m depth), providing data in detail never before observed.
Highly resolved glider data allowed answering questions such as: what
is the space-time distribution of phytoplankton and sediments in the
coastal Santa Barbara Channel? And, what are the main controls on the
variability of these properties? In*/Chapter Two/*, the capabilities
of the glider dataset were explored further to ask questions that are
in the very core of studies in upwelling environments: How important
is the cross-shelf exchange of materials to the health of nearshore
ecosystems? Is the inner-shelf a source or a sink for particles? And,
is the nearshore zone net autotrophic or net heterotrophic?
In*/Chapter Three/*, a larger scale approach is taken to determine
what drives bio-optical variability in the Southern California Bight.
This study took advantage of more than 13 years of quality optical
imagery from SeaWiFS, MODIS and MERIS sensors, which were spectrally
merged using a bio-optical algorithm to increase space-time coverage.
The data allowed the observation of daily to seasonal and inter-annual
changes in bio-optical properties, as well as long-term trends.
Controls on backscatter and chlorophyll were assessed, and surface
waves were shown to modulate the amount of suspended materials near
the coast, also confirming observations obtained with the glider dataset.