GEOLOGIST FOLLOWS IN HIS MENTOR'S FOOTSTEPS TO FIGHT CLIMATE CHANGE
The same week one of his undergraduate mentors passed away, Kent State Geology Professor, Dr. Joseph Ortiz received a grant that will allow him to use the techniques that his mentor taught him in an innovative way to research harmful algae blooms (HAB). The $10,000 in funds from Ohio Sea Grant will let Ortiz partner with Bowling Green State University, NASA-Glenn, and the United States Geologic Survey’s Lake Erie Biological Station to study to study the differences the between growth and presence of large cyanoHAB toxic blooms in the Maumee River.
Ortiz has been working on cyanoHABs in Lake Erie with NASA Glenn and Ohio View* partners for several years. In 2014, the City of Toledo’s drinking water was contaminated by toxic algae in Lake Erie and the Maumee River. Scientists and city and state officials want to know what causes the toxic algae to grow where it does, in the hope that they can stop it, or get more advanced warning as problems develop.
Ortiz will work with biologists Dr. George Bullerjahn and Dr. Mike McKay at BGSU to find out how an increase in agricultural runoff and climate change may be contributing to the growing problem.
He will accomplish this work using remote sensory equipment, and multivariate statistical techniques he learned while studying at Brown University under Professor John Imbrie, who died May 13, three days before Ortiz received notice of the grant award.
“I was saddened to learn that Imbrie had passed away,” he said. “Like many others, John Imbrie had a profound impact on my development as a scientist.”
Imbrie, who co-founded the field of paleoclimatology, is probably best known as a co-author of a 1976 paper in “Science,” “Variations in the Earth's orbit: Pacemaker of the Ice Ages.” Through the use of ocean sediment cores, the Science paper confirmed the hypotheses of Milutin Milanković that oscillations in climate over the past few million years are correlated with variations of Earth's eccentricity, axial tilt, and precession as it orbits around the sun. These changes are now known as the Milankovitch cycles.
Making use of a multivariate statistical technique called “factor analysis” to separate complex, correlated signals, the paper observed that because microfossils in deep-sea sediment reflect the environment in which they grew, their signal can be used to reconstruct the climate response to variations in Earth’s orbit through time.
In the years since leaving Brown, Ortiz has refined his own approach to the use of this technique, with a variant known as varimax-rotated, principal component analysis.
“I’ve spent my career taking methods from one field and using them to address problems in another,” he said. “When I realized there was a HAB problem on Lake Erie, I took the tools I’d developed for my paleoclimate research, that were similar to Imbrie’s methods, and applied them to remote sensing.”
Ortiz’s approach is based on the fact that color-producing agents in the water have different absorption and scattering effects on light.
“Any material that absorbs or scatters light is going to produce a reflective spectrum that is indicative of what is present,” Ortiz said. “We can determine the different types of algae, sediment, and colored dissolve organic matter (decomposed algae) that are present in the water, based on the shape of the resulting spectrum. The trick is to have a method that can objectively untangle the mixed signal generated by multiple constituents.”
That is where the methods that Ortiz learned from John Imbrie come in handy.
Ortiz said there are marked differences between the Maumee and Detroit River Plumes. The Maumee has suffered severe blooms of harmful algae, while the blooms are almost non-existent in the Detroit.
There are many questions surrounding the relationship between the two rivers.
“We’re interested in the role that nutrient dynamics might play in the spread of the bloom, and why the response of the two rivers is so different,” he said.
Scientists assume nutrient concentrations in the Detroit are too low, or that the water flow is too great to support a bloom, but some public groups think the Detroit might indirectly contribute to the problems in Lake Erie, by delivering nutrients that may ultimately lead to production in the lake as the Detroit plume mixes with water from the Maumee Plume.
Ortiz’s project will help to better quantify the reasons for the differences in the two plumes.
“If we understand what drives the differences, that information may suggest how we could implement new management strategies,” he said. “We could also identify potential vulnerabilities to future changes that may occur as a result of climate change.”
*OhioView is a consortium of Ohio universities that collaborate to develop a broad range of research expertise in the fields of agriculture, geology, geography, civil engineering, computer science, library science, environmental science, and urban studies.
For more information on Kent State Research, contact Dan Pompili, at 330-672-0731 or firstname.lastname@example.org