Maverick Science mag 2013-14

While small-scale experiments are important to science and often lead to major discoveries, when
it comes to ecology it’s often necessary to take a wide-ranging and all-inclusive look at things
to find solutions to complex problems.
Macroecology — the study of relationships between organisms and their environment at
large spatial scales to characterize and explain statistical patterns of species abundance, distribution
and diversity — is what Sophia Passy uses to show how nature works. Passy, a UT Arlington associate professor
of biology, has used the “big picture” approach in her research and it has helped lead to a better understanding
of how one facet of a subject can affect many others.
Passy has led numerous
research projects utilizing a
macro approach, including
many environmental ecology
studies which explore
the response of algal communities
to anthropogenic
acidification, or acid deposition
caused by human activities.
One such study is
an assessment of the effects
of acidic deposition on
streams in the eastern and
central parts of the Adirondack
Park in upstate New
York. Passy is co-principal
investigator of a three-year,
$187,224 grant by the New
York State Energy Research
and Development
Authority.
The project’s principal
investigator is Gregory
Lawrence, a physical scientist
with the U.S. Geological
Survey’s New York Water
Science Center with whom
Passy has worked for years
on several acid-related
projects in the Adirondacks.
One of Passy’s doctoral students, Katrina Pound, was lead author of a
paper the team wrote about the research which was published in the September
2013 edition of the leading environmental and biodiversity conservation
journal Global Change Biology. The study set out to determine
if watershed wetlands can play a role in remediating the damage done to
streams by acidification.
“For over 40 years, acid deposition has been recognized as a serious international
environmental problem, but efforts to restore acidified streams
and biota have had limited success,” the researchers said in the Global
Change Biology article. “The need to better understand the effects of different
sources of acidity on streams has become more pressing with the
recent increases in surface water organic acids, or ‘brownification,’ associated
with climate change and decreased inorganic acid deposition.”
“Acidification of surface waters from acid deposition is one of the most
serious environmental problems in the northeast United States and northern
Europe,” Passy said. “It is associated with biodiversity loss, elevated
mortality, and simplified food webs. Despite numerous state and federal
actions to reduce acid emissions, streams continue to experience acidification
and biological communities have not returned to their pre-acidification
state.”
Passy, Pound and Lawrence, working with the USGS, carried out a
large-scale study showing that wetlands are capable of improving stream
ecosystem health in the Adirondacks, which is one of the most acid-impacted
regions in the United States.
“Wetlands are important
not only for wellbuffered
stream ecosystems
as sources of iron,
but also for acid-impacted
streams because they contribute
to the neutralization
of aluminum, which
reaches highly toxic concentrations
in acid
streams,” Passy said. “This
research has far-reaching
consequences for biodiversity
conservation and
stream management. It
suggests that wetlands can
be used in acid stream
restoration and offers a viable
alternative to the current
approach for
acidification remediation
through liming, which is
ineffective and even harmful.”
For her dissertation research,
Pound analyzed diatom
communities from
around 200 Adirondack
streams that were sampled
over four sampling periods.
Diatoms are an environmentally
sensitive group of algae and the most diverse microbial
producers. Pound successfully defended her dissertation in August and received
her Ph.D. in December 2013. She is working as a biology lecturer
and continuing to do research in Passy’s lab during the Spring 2014 semester.
“Studying this region is challenging because streams are acidified by
both inorganic acid deposition and natural organic acidity originating from
soils and wetlands,” Pound said. “My job was to count and identify the diatom
species in each of the stream samples and examine the impact of
these two sources of acidity on diatom diversity.”
The current study is an extension of the 2003-05 Western Adirondack
Stream Survey (WASS), a project for which Passy and her USGS collaborators
received $486,000 from the New York State Energy Research and
Development Authority. According to the USGS, the study found that acid
rain had acidified soils resulting in toxic aluminum levels in two-thirds of
565 assessed streams. It also found that diatoms were moderately to severely
affected by acid rain in 80 percent of assessed streams; aquatic insects
and related organisms referred to as macroinvertebrates were
moderately to severely affected in over half of assessed streams; and recovery
from acidification had been minimal in 11 of 12 Adirondack streams
sampled in the early 1980s.
“By teaming up, we are able to address the problem of acid rain from a
truly interdisciplinary perspective, myself being the soil and water chemist
and Sophia being the expert in aquatic ecology, and in particular, diatoms,”
Passy and her students analyzed water samples from streams such as this one in
the Adirondack Forest Preserve. Photo courtesy of Sophia Passy.
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