March 7, 2005
Scientists concerned about potentially harmful
algae persisting in Monterey Bay
By Tim Stephens
A species of microscopic algae that caused "red tides"
in Monterey Bay last summer, discoloring the water and killing
mussels, is still present in water samples from the bay and
has the potential to cause more serious problems, according
to scientists involved in a Central Coast ocean monitoring program.
Cochlodinium catenatum, a species of microscopic
algae that caused "red tides" in Monterey Bay
last summer, discoloring the water and killing mussels,
is a type of dinoflagellate.
UCSC researchers Atma Roberts and
Itchung Cheung collect water samples from Monterey Bay
during a ship survey in August 2004 on the R/V John
Photo: Rondi Robison
"This species has been seen before on the Central Coast,
but never in the numbers we've seen in the past year, and we
are still seeing it now. Its presence is so unusual and persistent,
and its blooms so dense, we suspect it is signaling a change
in our coastal waters," said Mary Silver, professor of
ocean sciences at UCSC.
While Silver and other scientists around Monterey Bay are keeping
a close eye on the situation, they noted that federal funding
for the programs that support this kind of monitoring effort
is increasingly uncertain.
The alga has been tentatively identified as Cochlodinium
catenatum, a species that has caused fish kills and other
damage in the coastal Pacific waters of Mexico and Central America.
A closely related species, C. polykrikoides, has killed
fish in salmon farms in Vancouver, British Columbia, and has
caused severe damage to fish farms in the coastal waters of
Korea, China, and Japan.
Silver's lab has been monitoring Cochlodinium in Monterey
Bay since first noticing it in July 2004. The researchers measured
concentrations of the algae as high as 50,000 cells per liter
in water samples taken last summer. Where dense blooms of the
algae occurred, the waters were "slimy" and foul-smelling.
Although toxicologists have not isolated a specific toxin from
C. catenatum, the slime it produces has been associated
with the deaths of fish and corals in Pacific waters of Panama
and Costa Rica, where blooms occurred in the 1980s, Silver said.
Records from the 1960s and 1970s indicate that blooms of this
organism were also noted in the San Diego area, she said.
Gregg Langlois, who oversees the California Department of Health
Services (CDHS) marine biotoxin monitoring program, said C.
catenatum was first identified on the Central Coast in 1997
when it bloomed near San Luis Obispo. The recent findings in
Monterey Bay were confirmed by Chris Scholin, an expert on toxic
algae at the Monterey Bay Aquarium Research Institute, and scientists
at the Moss Landing Marine Laboratories.
As part of Silver's monitoring efforts, carried out in conjunction
with Langlois's statewide program, bags of mussels are hung
in the water below the Santa Cruz Wharf and checked every week
to monitor for toxicity. The mussels began to die when C.
catenatum showed up, and continued dying for about five
months, Silver said.
"Up until about a month ago we were still getting dead
mussels," she said. "The algae produces some substance
that is nasty, but it is likely to take a while for scientists
to nail down exactly what that is."
Langlois said there is no evidence of any human health effects
associated with Cochlodinium blooms. Analyses of tissue
samples from affected mussels have not indicated the presence
of any known algal toxins, he said.
"We're not certain what the mechanism is for the deaths
of mussels, but there is no evidence that these algae produce
a toxin that affects mammals or birds," Langlois said.
Kenneth Coale, director of Moss Landing Marine Laboratories,
said the Cochlodinium bloom provides a good illustration
of the need for coordinated efforts to monitor ocean conditions
along the coast.
"Without coastal observatories, we might have missed this
until we had a major fish kill or other type of ecological damage,"
Coale said. "What is striking to me is that these blooms
may signal coastal climate change, invasion of new species,
or both. We need long-term measurements in order to understand
what factors contribute to these blooms, whether they are natural
or the result of human activity, and what might be done about
Silver's monitoring work is supported by UCSC's Center for
Integrated Marine Technologies (CIMT), funded through the National
Oceanic and Atmospheric Administration (NOAA) as part of the
agency's Coastal Ocean Technology System (COTS). But funding
for CIMT, an interdisciplinary effort involving five partner
institutions around Monterey Bay, has not been renewed for next
"The marine science institutions all around Monterey Bay
are working together to organize an integrated ocean observing
system for the Central Coast, and we are trying to move forward
in a very uncertain funding climate," said Donald Croll,
assistant professor of ecology and evolutionary biology at UCSC
and codirector of CIMT.
Moss Landing's Coale is involved in CIMT and also oversees
a related NOAA-funded program, the Center for Integrative Coastal
Observation, Research, and Education (CICORE). CIMT and CICORE
are developing complementary ocean monitoring technologies as
part of NOAA's efforts to establish a Central and Northern California
Ocean Observing System (CeNCOOS). Establishing an integrated
ocean observing system is among the key recommendations of a
major report issued last year by the U.S. Commission on Ocean
Policy, but funding to implement the commission's recommendations
has not yet been authorized.
According to Croll, the need to implement the commission's
recommendations on ocean policy will only become more urgent
with increasing coastal development and growing human impacts
on coastal waters.
"With a harmful algal bloom, you can't see how it develops
over time unless you're out there sampling all the time,"
Croll said. "Because of the coordinated efforts of marine
scientists around Monterey Bay, this is probably one of the
most closely observed ocean ecosystems anywhere, and we want
to see that continue."
Silver will be discussing her research on harmful algal blooms
in a public lecture at UCSC on Thursday, March 10. (See
On Saturday, March 12, the Monterey Bay National Marine Sanctuary
holds its annual Sanctuary Currents Symposium at California
State University, Monterey Bay. This year's theme is "Tracking
the Health of Our Sanctuary."
For more information, see http://www.mbnms-simon.org.
This sanctuary web site also has links to additional information
about monitoring programs in the sanctuary and harmful algal
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