Redondo Beach King Harbor
News Releases
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King Harbor, located in the South
Bay
area of Los Angeles County, is highly frequented by
boaters and surrounded by businesses, restaurants and private
residencies. The harbor waters are busy with an array of fish species,
invertebrates and occasionally
visited by mammals. In 2005 the development of red tides
led to fish
kills in certain areas of the harbor which prompted the city of Redondo
Beach to form the Redondo
Beach Water Quality
Task
Force.
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In collaboration with the
city of Redondo Beach USC
started a weekly sampling program in early 2006 to determine
algal species composition and algal biomass dynamics. Red tides
were
observed during
spring and early summer of 2006 with maximal chlorophyll a concentrations of up to 647 μg
per
L (see graph below). However, no
fish kills occurred possibly due to the briefness of bloom periods
(left: King Harbor Marina in May
2006 during a red tide
dominated  by Prorocentrum spp.; right: whole seawater
collected from
the same location). Analyses of algae species composition
revealed
the presence of an array of potentially harmful
species in King Harbor.
In collaboration with Dr. Carmelo Tomas
from the University of North Carolina Wilmington several of the algal
species were successfully isolated and cultures established.
Experimental work with these cultures focuses on examining the
physiology and ecology of the most dominant species and examines
the
trophic dynamics that explain rapid shifts in the succession of
algal community composition in situ.
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| Phytoplankton Dynamics
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Concentrations of
chlorophyll a
varied tremendously during 2006 inside the King Harbor Marina.
Discoloration of the water was caused by different algal
assemblages. Several Prorocentrum species
(P. micans, P. gracile and P. triestetum) dominated the
assemblage in May and raphidophytes were abundant during June of
2006 (Chattonella marina, Heterosigma akashiwo and Fibrocapsa jabonica).
Intermittently Scrippsiella spp.
co-dominated
the algae assemblage and several other
species were present during
these red tide events. The Prorocentrum
bloom
in May was immediately followed by high abundances of the heterotrophic
dinoflagellate Noctiluca scintillans which was
observed with ingested Prorocentrum cells.
Rapid changes in phytoplankton biomass and
species composition were also accompanied by strong temporal diel
variability
in algal
distribution. Many dinoflagellate species are known to undergo diel
vertical
migration and the same phenomenon was suspected for the
raphidophyte-dominated assemblage in June when highest biomass
concentrations in surface waters were detected during mid-day (see
graph on the left). The average water depth within the harbor area
is 3-4m.
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| NAMOS:
or Networked Aquatic
Microbial Observing System |
Complex algal
bloom dynamics and the re-occurrence of potentially
harmful species have made King Harbor in Redondo Beach
an
interesting case study to examine how changes in the physical and
chemical environment control plankton biology in coastal ecosystems. NAMOS, a
collaborative project
between
USC and UCLA and part of the NSF-funded CENS (Center of Embedded Network Sensing) program,
provides the platform to address these issues. Multiple deployments of stationary
sensor
buoys and a mobile sensing unit (Q-boat) during
winter 2006
and spring 2007 have characterized
physical, chemical and biological parameters in King Harbor. High
resolution sampling of physiochemical factors at different locations in
the harbor, in combination with data collected on algal species
composition and abundances, is being employed to
identify the factors that trigger algal blooms. All
information collected by the program is
open to the public,
and will assist the city of Redondo Beach with management
decision regarding mitigation and ultimately prevention of red tides in
King Harbor.
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