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Science Office Response
Perspective on the 2007 pilot-study of SolarBee Long-Distance Circulation (LDC) to
inhibit harmful algal blooms (HABs) in St. Albans Bay, Lake Champlain (Vermont)
Overview. A pilot study of SolarBee solar-powered, LDC technology to inhibit HABs in the
north end of St. Albans Bay, Lake Champlain (Vermont) was conducted during May to
August, 2007. Both SolarBee and the Vermont Agency of Natural Resources (VANR)
issued reports on the study results. Different interpretations of the data led to diametrically
opposed conclusions in those reports. The SolarBee report concluded “We believe the
data unequivocally demonstrate beneficial impacts….”, whereas the VNAR report
concluded “…there was no evidence that the SolarBees in St. Albans Bay reduced algal
concentrations, improved water clarity, or inhibited blue-green algae in the bay.” SolarBee
acknowledges that the interpretation of scientific data can be complex, and that well-
intentioned individuals can reach different conclusions. We also believe that issues
concerning study design and control over its development, and vested interests in
methodologies used for HAB prevention, may impact the conclusions reached by those
individuals. Those issues are briefly discussed below. SolarBee strongly supports the
scientific peer-review process as a means for reaching unbiased conclusions concerning
scientific studies. Therefore, we call for the VANR to join SolarBee in obtaining reports on
the pilot study results from a panel of three independent and mutually agreed upon experts
in the field of freshwater HABs. A majority of the panel would likely reach one of three
conclusions: 1) LDC inhibited HABs; 2) LDC did not inhibit HABs, or; 3) the study design
was insufficient for reaching a definitive conclusion. We agree to accept the panel’s
opinion, and expect the VANR to do likewise.
Study Design and Its Control. The study design, described in the Monitoring Workplan
(May 4, 2007), was developed by VNAR. SolarBee was given an opportunity to comment
on a draft Workplan, but most of our comments were not incorporated into the final
Workplan. The Workplan did not address the need to determine the time period, number
of units or unit spacing needed for the ecological approach of LDC to control HABs given
the unique characteristics of the bay. Furthermore, we believe that the data analysis plan
was fundamentally flawed due to the following considerations.
Three watersheds with high phosphorus and other nutrient levels drain into the
northern shore of St. Albans Bay. HABs apparently initiate along the northern wetlands
and shore due to high nutrient levels and vertically unmixed water. The Workplan states
that phosphorus, algal biomass and water clarity typically have a very strong horizontal,
north-south gradient in summer months, implying that statistical analyses would show
significantly higher nutrient and algal-biomass levels in waters along the northern shore than in areas to the south. The Workplan called for LDC unit deployment along the
northern shore of the bay. The Workplan’s data analysis plan states that significantly
lower algal-biomass (chlorophyll-a) and higher water clarity levels (Secchi depths) must be
observed along the northern shore, within the areas of LDC influence (treated zone – 3
congruent, circular areas of 35 acres each), than at points south for an effect of LDC on
HAB inhibition to be indicated. These criteria implicitly assume that the baseline conditions
are typically uniform within the bay, an assumption that is inconsistent with the statement
that a very strong horizontal, north-south gradient typically exists. Therefore, the
observation of no statistically significant difference in algal-biomass or water clarity levels
between the northern treated zone and points south can be interpreted to indicate LDC
inhibited HABs rather than failed to do so, particularly during a summer when overall algal
biomass levels were much lower in the bay than in previous years.
The LDC HAB inhibition interpretation is supported by a finer-scale analysis of the
data. Both reports show that algal biomass was higher and water clarity was lower in the
northern portion of the treated zone than in its southern portion. Because LDC can not be
expected to prevent algal cells from washing into the bay from the northern wetlands, or to
completely inhibit cell growth and division in the northern area of high nutrient input, it is
not unexpected that algal biomass and water clarity would be worse in the northern portion
of the treated zone than its southern portion. Improvements seen in the southern portion
of the treated zone and at points farther south may indicate that LDC inhibited HABs as the
northern input waters moved southward.
Vested Interests in HAB Prevention Methodologies. Neither SolarBee nor the VANR
can be viewed as unbiased parties whose pilot-study report writers are free of all potential
conflicts of interest. SolarBee designs and manufactures LDC technology that we believe
provides the most effective, environmentally benign, sustainable and low-cost solution for
HAB prevention. The first author of the VANR report, Eric Smeltzer, wrote his masters
thesis on the chemical approach of alum application to reduce phosphorus levels in the
water column and inhibit HAB occurrence. During the pilot study and report preparation
period, the VANR continued consultations with Dr. Ken Wagner, ENSR, Inc., on alum
applications in the bay and sought funding for a multi-million dollar alum project. Although
Mr. Smeltzer recently stated that there hasn't been enough time to judge the effectiveness
of his 2004 Clean and Clear multi-million dollar watershed-management program to reduce
phosphorus inputs and inhibit HABs, he was very quick to judge the efficacy of the
ecological and low-cost LDC approach. After leading a Federal interagency effort to
address freshwater HABs, I left the US EPA to join SolarBee because I believe LDC is the
best solution for HAB prevention, and chemical/alum applications for HAB control are
detrimental to the aquatic environment, often ineffective for HAB prevention particularly in
areas having high phosphorus input levels, usually require reapplication every few years
and are very expensive over the long term. Therefore, a panel of independent experts is
needed to obtain an unbiased opinion on the outcome of the pilot study. We hope the
VANR will join us in this effort.
H Kenneth Hudnell, PhD
Director of Science, SolarBee Inc.
Read the original report here.
Read the SolarBee Response here.
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