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Since then, researchers have tracked the
annual K. brevis blooms, which typically
crop up in the late summer or autumn
and vary in length.
In the FWRI lab in St. Petersburg,
Hubbard’s team of scientists is focused
on monitoring K. brevis in the Gulf.
They process water samples sent in
by citizens or fellow researchers who
notice something amiss—fish kills or
discolored water, for example. FedEx
shipments containing plastic contain-
ers of water are usually sparse in mid-
summer, but during the 2017–2019 red
tide event, Hubbard says, there was
little letup. In total, her lab processed
more than 14,000 of these samples over
a 16-month period, she says.
Currently, Hubbard’s team primarily
uses manual cell counts for state-
mandated estimates of K. brevis abun-
dance. They also occasionally hook up a
microscope to a submersible imaging flow
cytometer, an automated machine that can
process 5–8 mL samples in about 20 min-
utes, detecting a variety of phytoplankton
species including K. brevis. The group
also tracks toxins and phytoplankton
cells in water samples using chemical
analyses such as liquid chromatography
and mass spectrometry. Now, in collab-
oration with other red tide researchers,
Hubbard is working on refining a method
that can detect K. brevis RNA in water
samples, using a handheld device that is
already showing promise in field trials for
yielding quick and accurate measures of
the phyto plankton’s abundance.
“The genetic methods can be quite
tricky,” Hubbard says. “But I do foresee
[the device] could be something that’s
used to quickly scan samples.” Her team
archives water samples so that they can
be used to further develop this and other
new methods of censusing K. brevis.
With the data they gather—which
now includes inputs from an autono-
mous aquatic “glider” that samples envi-
ronmental conditions in the Gulf—Hub-
bard’s agency puts out twice-weekly
bulletins detailing which Florida beaches
are affected by red tide. People with
lung conditions such as asthma are par-ticularly vulnerable to serious adverse
effects when winds blow airborne toxins
onshore. Barbara Kirkpatrick, the execu-
tive director of the Gulf of Mexico Coastal
Ocean Observing System (GCOOS), a
nonprofit with a remit of providing infor-
mation about the Gulf coastal and ocean
waters, is working to refine that public-
facing monitoring effort. “Blooms are
patchy. Conditions can change day to day
and beach to beach,” she says. “We’re try-
ing to come up with a daily forecast that
updates every three hours.”
The complexity of the species’ biology
—and the gaping holes in scientists’
knowledge of it—presents a challenge.
“I honestly do not know if K. brevis
blooms can be ‘prevented’ based on the
level of our current knowledge,” Karen
Steidinger, the retired plankton ecol-
ogist after whom Karenia brevis was
named when its Latin binomial was
changed in 2001, writes in an email to
The Scientist.Demystifying the red tide lifecycle
Dinoflagellate life histories are noto-
riously complicated, and K. brevis’s
lifecycle in particular has been diffi-
cult to nail down. But by looking across
more than 2,000 known species of
marine dinoflagellates, scientists can
identify common strategies that could
start to fill in the missing details. For
example, more than 10 percent of spe-
cies employ a resting cyst stage,^2 and
many phytoplankton scientists suspect
that K. brevis does too. (See “Missing
Puzzle Pieces” on page 30.)
Resting cysts are analogous to seeds
in terrestrial plants: they afford dino-
flagellates the ability to deposit theirNot present/background (0-1,000)
Very low (>1,000-10,000)
Low (>10,000-100,000)
Medium (>100,000-1,000,000)
High (>1,000,000)Not present/background
Very low
Low
Medium
HighSTATEWIDE KARENIA BREVIS
CONCENTRATIONS (CELLS/LITER)
OCTOBER 1-31, 2018OrlandoTallahasseeTampaMiamiBICOASTAL BLOOM:In October 2018, at the
height of the red tide that plagued Florida for
more than 16 months, millions of the causative
dinofl agellates teemed in waters off Florida’s
panhandle, as well as on the west and east
coasts of the state.