Category: Research Blog

Quiz: Non-point source pollution. Are you part of the problem?

Quiz: Non-point source pollution. Are you part of the problem?

Could your daily activities be polluting your neighborhood stream? Answer a few questions to see!

1. Do you clean up pet waste from your lawn?

YES       Great job for being a responsible pet owner!

NO         When it rains, pet waste can be washed into a nearby stream and cause E. coli and other bacteria to increase in numbers in the streams. By walking through your yard a couple of times a week to clean up after your animals, your yard will not only smell nicer, you can know you are not contributing to increased pathogen levels in the stream.

2. Do you read and follow the instructions when applying fertilizers to your lawn?

YES        Awesome! So, you already know that more does not equal better, and to never, ever apply fertilizers before it rains.

NO         If excess fertilizer is applied to your lawn, or if applied just before it rains, the nutrients are washed into the stream and becomes food for algae. This can cause algal blooms and lead to depleted oxygen levels in the stream, often times causing other wildlife in the stream to die. Next time, read the label for application instructions.

3. Do you blow your leaves or yard clippings into the storm drains on your street?

YES       Storm drains lead to the closest creek or stream, so when you put yard waste into your storm drain, you are contributing lots of organic matter into the stream. When this extra organic matter in the stream begins to break down, it will use oxygen from the stream, and can contribute to depleted oxygen levels in the stream. Again, this can cause organisms in the stream to die if oxygen levels drop too low.

NO         You rock! Want to be really awesome? – Use your yard clippings to create a compost pile in your yard to simply return those nutrients back into the soil in your own yard! Or use the compost for your own garden next year.

Just a few small changes to our daily activities can help keep our streams happy and healthy! Stay informed and educate your neighbors to keep our local environment clean.

The Rambur’s Forktail

The Rambur’s Forktail

By Liam Wolff, Phinizy Research Intern

Male Nominate, Female Blue Male-Like; Photo by Liam Wolff

Male Nominate, Female Blue Male-Like; Photo by Liam Wolff

Male Nominate, Photo by Liam Wolff

Male Nominate, Photo by Liam Wolff

The Rambur’s Forktail, Ischnura ramburii, is the most abundant species of damselfly at Phinizy Swamp and probably the most common wetland damselfly across the Southeast United States as a whole. Its range expands west to California into Mexico with an isolated population in Hawaii. One of the most interesting features of the Rambur’s Forktail is its polymorphic variation. Polymorphism is the occurrence of a species that displays two or more forms. These forms are determined by dominant and recessive alleles that are inherited at fertilization. Rambur’s Forktails, like many insects, demonstrate this polymorphism on top of sexual dimorphism. With sexual dimorphism, the males and females of the species are apparently dissimilar – they differ in appearance. To make things even more complicated, the color morphs are different at varying ages.

Rambur's Female Orange

Rambur’s Female Orange, Photo by Liam Wolff

Rambur's Female Green Male-like; Photo by Liam Wolff

Rambur’s Female Green Male-like; Photo by Liam Wolff

Nominate form males are light green on the thorax with similar coloration on the abdomen and a blue terminal end. Nominate females tend to be olive in coloration across the abdomen and thorax. As immatures, female Rambur’s Forktails are a bright orange. There are two female morphs that are very similar to males, though. One form is bright green like the male, but the colors are less defined. The other has a green abdomen with a blue terminal segment like the male, but the thorax is a sky blue. At Phinizy, most of the damselflies we study are in their larval stage. However, at this age it is very difficult to differentiate between species. Unlike many macroinvertebrates in the Savannah River which are scrapers or filter-feeders, the suborder Zygoptera (damsels) consists of predators.

Rambur's Female Olive

Rambur’s Female Olive; Photo by Liam Wolff

River Research & the Boat that Makes a Difference

Lagrangian Houseboat

The Original Houseboat

There are two different ways to measure and assess water quality in river systems: one way is to measure continuously from fixed locations along a river, and the other is to measure continuously from a location that moves downstream with the river current. Through generous contributions from public and private partners, Phinizy Center has been measuring water quality since 2006 from 9 locations along the Savannah River, starting seven miles below Thurmond Dam (River Mile 214) to the I-95 bridge (River Mile 27) (see Continuous River Monitoring). In 2012, we began measuring water quality using the “river current” perspective by equipping a 30-foot houseboat with scientific instrumentation and floating, at river speed (about 3 feet per second), for over 145 river miles, which took about 5 days. That river expedition allowed us to capture very important data related to how quickly bacteria in the river process wastewater from Augusta to a few river miles above Savannah. The boat we used to do that important research was rather old, but it allowed us to do this important work, once!

In 2014, a conversation between Mr. Gary Swiggett, a boat insurance agent, and one of our Board members, Dr. Michael Ash, resulted in an excellent opportunity to purchase a boat better suited for our needs. Through a generous price reduction from the boat manufacturer, Premier in Wyoming, Minnesota, and generous philanthropic contributions from The Knox Charity Fund, Creel-Harison Foundation, and Wells Fargo, we were able to purchase the boat which arrived a week ago from Minnesota.


We would again like to thank all of those who made this opportunity happen and we look forward to sharing the data with all of you from the river!

Life History of the Larva of the Glassworm

Life History of the Larva of the Glassworm (Chaoboridae)

By Liam Wolff, Phinizy Research Intern

Phantom Midge by Peter Maguire

Phantom Midges by Peter Maguire

The Phinizy Center for Water Science’s research projects often includes studying the diversity and abundance of certain macroinvertebrates. In the Oxbow Lakes left behind by the Savannah River, one type of midge larva is particularly common in the sediment samples that are collected. In fact, this midge makes up a large percentage of organisms found and counted in the sediments of the Oxbow Lakes.

The Glassworm, also known as the Phantom Midge due to its transparency, is a small insect from the family Chaoboridae. Closely related to the ever-ubiquitous Chironomidae, it is small and worm-like in its larval stage, inhabiting rivers and other natural water sources, such as the Oxbow Lakes along the Savannah River. However, the glassworm has a fascinating life history – one unlike most other insects.

Phantom Midge by Peter Maguire

Phantom Midges by Peter Maguire

One of the main things that sets the glassworm apart is its diel vertical migration. This transparent creature spends the daytime in the depths of the hypolimnion – the bottom layer of the lake – poking its head out of the dense sediment, feeding on zooplankton swimming by. However, after twilight the glassworm migrates from the sediment to the epilimnion – the uppermost layer of the lake. Two pairs of air sacs control the larva’s bouyancy and are used to move up or down the stratification zones. The exchange of gases from these airsacs are actually audible, taking up much of the perceptible frequencies underwater at dusk. One of the reasons Chaoboridae exhibits this behavior is because its prey does as well. Zooplankton migrate to the epilimnion at night due to changes in temperature and light.

Microscope photo of two glassworms dyed with rose bengal dye from the oxbow lake Possum Eddy. Photo by Liam Wolff.

Microscope photo of two glassworms dyed with rose bengal dye from the oxbow lake Possum Eddy. Photo by Liam Wolff.

Another motive for the Phantom Midge larva to return back to its abode in the hypolimnion at dawn is to escape predation from fish. In fact, some claim this is the primary reason that Chaboridae display diel vertical migration (DVM). One study showed that glassworms in the genus Chaoborus only partook in DVM in the presence of fish (Larson 2016). In a pond devoid of fish, no glassworms were found to demonstrate their nightly migration. How the larvae are aware of the prevalance of fish is explained by chemicals signals sent out by fish called Kairomones that the glassworms can detect. Since fish cannot tolerate the low levels of oxygen in the sediments of lakes, the glassworm hides in the hypolimnion from dawn until dusk. In fact, with the exception of zooplankton, most organisms cannot tolerate the anoxic waters of the sediment. The only way the glassworm can survive is by producing energy (ATP) through an alternate route (anaerobic malate cycle). This makes them tolerable to more polluted, less healthy water bodies.

One other reason the glassworm is unique is because it has a huge impact on the community of zooplankton. Although Chaoboridae feeds mostly on rotifers, copepods and cladocerans make up a large percentage of its diet as well. During its various instar stages, the glassworm tends to prefer different types of zooplankton. This helps regulate the abundance and diversity of zooplankton in lakes, rivers, and streams.

See more photos of the Phantom Midge by Peter Maguire in his online album.

A Comparison of Aquatic Insects Colonizing leaf, Wood, and Artificial Substrates in Two Southeastern Coastal Plain Rivers

A Comparison of Aquatic Insects Colonizing leaf, Wood, and
Artificial Substrates
in Two Southeastern Coastal Plain Rivers

By Damon Mullis, Phinizy Research Scientis

Substrate 1.1Despite their widespread use in wadeable streams, aquatic insects are less frequently incorporated into formal assessments of large rivers. The size, depth, and unstable substrates of large rivers make many sampling techniques difficult. As a result, passive samplers of natural or artificial materials are commonly used. These samplers are placed in the water for a predetermined period of time to allow for colonization by macroinvertebrate communities. We designed an experiment to compare aquatic insect communities collected from two passive samplers made of  natural substrates (leaves and woody debris) and one made from an artificial substrate (masonite board; i.e., Hester-Dendy samplers). In this experiment we placed three replicates of each sampler type (Hester-Dendy samplers, mesh bags filled with leaves, and mesh bags filled with woody debris) at 4 sites on the Savannah River and 3 sites of the Ogeechee River. After 30 days, samplers were retrieved and aquatic insect communities were assessed for differences in composition. Preliminary results indicate that there is a difference in the communities collected from each substrate, but these differences are small and each sampler was able to detect site specific differences in aquatic insect communities within each river (Fig. 1). As a result, all three substrate types provide an efficient mean for collecting macroinvertebrates as part of bioassessment practices. These results will be presented at the joint meetings of the Georgia and Alabama chapters of The American Fisheries Society to be held February 9-11 in Columbus, GA.

Figure 1- Non-metric multi-dimensional Scaling (NMDS) plot using a Bray Curtis Similarity matrix. Each symbol represents one sampler. The distance between each symbol represents how similar aquatic insect communities are to one another.

Figure 1- Non-metric multi-dimensional Scaling (NMDS) plot using a Bray Curtis Similarity matrix. Each symbol represents one sampler. The distance between each symbol represents how similar aquatic insect communities are to one another.

Net Spinning Caddisflies

Net Spinning Caddisflies

by Kelsey Laymon, Research Scientist

Fire 1: Example of Hydropsychidae Net

Fire 1: Example of Hydropsychidae Net

One of the coolest things I have come to learn while working at Phinizy Center is the life cycle of the net spinning caddisfly larvae. These aquatic insects reside in the family of Hydropsychidae and occupy freshwater systems. Usually positioned at the large end of their retreats, the Hydropsychid spin an elaborate net or sieve made of silk, which is similar to that of a caterpillar. These nets are constructed to catch their food, which consists of algae, small invertebrates and detritus. Different types of caddisflies will spin different mesh sizes and shapes based on which type of food they are targeting.

Figure 2: Hydropsychidae Caddisfly

Figure 2: Hydropsychidae Caddisfly

To collect what they have caught in their nets, some genus like Macrostemum, will utilize their hairy forelegs and hairy mouth parts. The hair collects while they walk over the net and then they are able to eat it. Most caddisflies in Hydropsychidae need flowing current to capture food, however caddisflies in another genus, Neureclipsis can utilize weak flowing water by building a large cornucopia shaped net and eating what collects at the smaller end.

Figure 3: Cornucopia Shaped Net of Neureclipsis on Bottom Right

Figure 3: Cornucopia Shaped Net of Neureclipsis on Bottom Right

Another interesting aspect of caddisflies are that some species can actually produce a sound by rubbing their femurs across their heads, just like a grasshopper rubbing its back legs together. This noise is used as a defense from other caddisflies that might try to steal their net retreats. Caddisflies that don’t have a retreat will try to seek out already built retreats and the sound will warn foes that the retreat is already occupied. These amazing creatures make their own silk, build their own nets to capture food and create underwater noises! Learn more about them here.


Reflections on Using Indicator Bacteria for Water Quality Impairment

Reflections on Using Indicator Bacteria for Water Quality Impairment: Results from Two Case Studies in Georgia

Oscar P. Flite III, Ph.D.
Shawn E. Rosenquist, Ph.D.
Matthew R. Erickson
Jason W. Moak

Bacteria as water indicatorThis article is featured in The Georgia Operator Winter 2016 edition, page 63, and can be read online here

Elevated fecal coliform bacteria account for the highest number of water quality impaired stream miles in Georgia (4,637 miles); this is over twice as many miles as the second highest, fish impairment (2,208 miles) and over 3.5 times that of dissolved oxygen impairment (1,291 miles) (EPA, 2015). Since fecal coliforms themselves are generally not harmful, they serve as cost effective indicator organisms (sample and identification costs) for those organisms that are known to cause diseases, such as other bacteria, viruses, and protozoans (EPA, 2015). The United States Environmental Protection Agency (USEPA) requires each state to protect surface waters from sewage contamination; currently the federal standard is either based upon fecal coliform or E. coli concentrations. Georgia Environmental Protection Division’s (GAEPD) adoption of that standard for streams designated as “fishable/swimmable” is a geometric mean of fecal coliform bacteria below 200 cfu/100mL from four samples taken within a 30-day period from May through October and a geometric mean below 1,000 cfu/100 mL from four samples taken within a 30 day period with no single sample greater than 4,000 cfu/100mL from November through April. Since most impaired stream miles in Georgia are associated with fecal coliforms, does this mean that our streams are full of raw sewage from broken sewer pipes, pet waste, and failing septic systems? In this article we will briefly discuss results of studies that we conducted over the past several years to address fecal impairment in streams and we will provide thoughts on how to improve the science, technology, monitoring, and regulation of this complex issue.

Case study 1: Augusta, Georgia

In collaboration with Augusta-Richmond County’s Engineering Department (AED), we were awarded a GAEPD 319(h) grant to address fecal coliform concentrations on sections of Rocky and Butler Creeks in Augusta, GA; these creeks were placed on the 303(d) list in 1998. We designed a sampling procedure to identify sources of bacteria, increased the number and frequency of sampling locations that AED were currently sampling, and developed materials to educate the public about fecal pollution in streams.

For Butler Creek, additional sampling showed that this creek was meeting the state’s standard for fecal coliform concentrations; it is currently being considered for delisting. For Rocky Creek, we found that concentrations of fecal coliform (and USEPA’s recommendation for E. coli of 126 cfu/ 100mL) were still not meeting the standard. However, from our increased sampling efforts there were no clear “point sources” that were causing the elevated bacteria levels. Our investigations then focused on potential diffuse, nonpoint source loadings by sampling according to travel time (Lagrangian sampling) using Rhodamine WT as a tracer, sampling stream sediment pore water for fecal coliform/E. coli concentrations, and sampling tributaries and other potential sources during storm and non-storm conditions. Our findings showed that the sediment pore water concentrations of E. coli were higher than the overlying water in nearly all cases (Figure 1), that E. coli loading increased nearly linearly with stream mile during one sampling event during the fall of 2014 (Figure 2), and E.coli concentrations exceeded 2,500 cfu/100mL in road runoff.

Figure 1

Figure 1. Results of the sediment pore water (squares) and creek water (circles) from a sampling event in Rocky Creek, Augusta, GA.

Figure 2. E. coli loading (most probable number/second) relative to creek mile; the trend shows a nearly linear increase in load in the downstream direction in Rocky Creek, Augusta, GA.

Figure 2. E. coli loading (most probable number/second) relative to creek mile; the trend shows a nearly linear increase in load in the downstream direction in Rocky Creek, Augusta, GA.

Case study 2: Thomson, Georgia

In collaboration with the City of Thomson, we were awarded a GAEPD 319(h) grant to develop a Watershed Management Plan to address elevated fecal coliform concentrations in Whites Creek, a tributary to Briar Creek; that creek was placed on the 303(d) list in 2002. For this project, we worked with the City of Thomson to identify an advisory council to guide the Watershed Management Plan process, increase the number and frequency of stream samplings to identify problem areas, and develop a Watershed Plan.

Since this grant was mostly focused on developing a Watershed Plan, additional sampling of this system was limited compared to the Augusta grant, so we could not perform a Lagrangian sampling scheme and were limited to two geometric mean sampling events, one in the November to April time frame, and one in the May through October time frame. Our findings were important nonetheless. The data showed that for all 88 samples analyzed during this study, not one geometric mean sampling event (16 in all) for any site (8 in all) was above the state standard for geometric mean fecal coliform concentrations. Of all 88 samples, three samples may have exceeded the single limit value of 4,000 cfu/100ml; these results were above the upper method limit for the IDEXX Colilert-18 analysis protocol used in this study (maximum 2,419 MPN/100mL) so we could not confirm the final value. Sediment pore water samples were analyzed for E. coli later in the study at 6 of the 8 sampling sites. When comparing the site-specific pore water results to the two geometric mean values for each site, the pore water had higher concentrations of E. coli 33% of the time. The ratio of sediment E. coli to water E. coli concentration for each of the six pore water sample sites ranged from 0.17 to 5.7. We also found that the wastewater treatment plant, which was suspected of causing high loading in the development of the criteria for listing the creek, was actually helping to decrease the total load to Whites Creek because the effluent had lower fecal coliform concentrations than the creek above the discharge.

What does all of this mean?

These two studies show that using indicator bacteria like fecal coliform or E. coli as a standard for protection of surface water is not straightforward or simple. We should also point out that we did not find concentrations of fecal coliform or E. coli concentrations in the tens or hundreds of thousands of bacteria per hundred milliliters; this would be indicative of a point source issue, so we were dealing with non-point or diffuse sources in these studies.

One of the most important findings was that fecal coliform, and specifically E. coli, concentrations in the sediment often exceeded concentrations in the overlying water. This suggests that bacteria associated with stream sediments may be contributing to fecal coliform loads in surface waters in some cases. The fact that fecal coliform and E. coli survive outside the gut is not a new finding; in fact, scientific literature has shown for decades that these organisms can survive in stream sediments for up to 85 days (Davies et al., 1995). If we are using these organisms as indicators of recent introduction of fecal material to water bodies, because they are assumed to only exist in the gut of warm-blooded animals, then regulating based upon their abundance in surface waters is problematic. While the use of indicator bacteria for protection of surface water quality is complex, it seems that we can do better science, monitoring, measurement, and regulation to decrease the seeming contradiction of using indicator bacteria.

Better Science

From our studies, it appears that understanding the occurrence and persistence of fecal bacteria, including E. coli, in streams needs additional research. We present two areas of potential research that we are interested in. Firstly, we found that indicator bacteria existed in the sediment. Our research in Augusta showed that E. coli loading increased linearly with increased distance downstream, which indicated a constant, low level loading along the study reach. This would have required all sources of loading (e.g. pet waste, broken sewer pipes, malfunctioning septic systems, etc.) to be contributing uniformly throughout the nearly 4 mile stream study reach! Alternatively, this particular sampling event occurred in late fall when vegetation within the stream buffer was mostly dormant for the winter. Decreased evapotranspiration of the stream buffer vegetation (corroborated with a water level logger that showed differences in diurnal water level fluctuations between leaf-on and leaf-off conditions) resulted in increased groundwater recharge to the stream. If the sediment had higher bacterial concentrations than the overlying water, then the increased groundwater pressure, through the sediment, would have flushed the sediment-laden bacteria into the stream, thereby increasing stream E.coli concentrations. This could have caused a nearly linear trend if sediment bacteria were somewhat uniformly distributed. The role of stream sediments as potential “sources” of bacteria needs to be understood for “low level” bacterial concentrations in streams. The second area of research has to do with the condition of our urban streams. The “urban stream syndrome”, characterized by high, fast storm flows and decreased stream bed stability, generally results in an altered food web (Paul and Meyer, 2001, Walsh et al., 2005). Our hypothesis is that urban streams may lack sufficient bacterial predators to keep pathogen abundance in check; in essence, bacteria may be the top of the food pyramid in urban streams. Our point here is that elevated fecal bacteria concentrations in streams may not be due to broken sewer pipes but could be due to a lack of scientific understanding.

Better Monitoring

While better science is needed, we could also apply better methods to monitoring protocols for identification of non-point source fecal contamination. Infrared thermal imaging for identification of “warm” discharges and chemical fingerprinting using caffeine and artificial sweeteners (Tran et al., 2014) are some recent advances; but what about simply adding a dye tracer such as Rhodamine WT to sewer pipes and septic systems in reaches of streams suspected of leaking? Analytical probes specific for Rhodamine and Fluorescein dyes are readily available. If failing septic tanks and broken sewer pipes are suspected of contaminating the adjacent stream, dye introduced to the suspect sewer/septic system should readily show up in the stream. Such an approach would, at least, rule out suspected raw sewage-related sources. In addition, adding tracers directly to the stream and applying a Lagrangian sampling scheme has proven useful for understanding of fecal loading to streams in our studies as well.

Better Measurements

One of the reasons we use fecal coliform and E. coli as indicators for other pathogens is that the test for those organisms is rapid and inexpensive relative to technologies needed to sample for all potential pathogens. This indicates a need for a new technology, one that is cost-effective and rapidly identifies all potential pathogens in a given sample. Next-generation or high throughput sequencing is a relatively new technology that allows for the analysis of millions of DNA sequences at the same time. In essence, this technology allows for the ability to sample for all pathogens in a given sample at the same time; this eliminates the need for indicator bacteria monitoring and the associated validity of the results. Unfortunately, the cost of this equipment (nearly $100,000), including the contract laboratory “per sample costs” (hundreds to thousands of dollars), are not currently feasible for conventional stream monitoring programs. The technology has been developed; we await the miniaturization and cost reduction of this important technology!

Better Regulation

All life and economic sustainability is reliant upon access to clean water, so the importance of protecting our surface waters cannot be understated. However, if the parameter being regulated is a poor indicator of the actual condition, then change can lead to a cost savings or a reallocation of local, state, and federal funds for other important projects. Since it does not seem that regulating fecal coliform and E. coli is straightforward, we may need to rethink the federal regulation; here are several observations from our studies that confound regulation of fecal indicator bacteria.

Rocky Creek in Augusta, GA is an urban stream. As we continue to build cities, it seems that some of the best remaining wildlife habitat in urban areas are stream buffer zones; does this lead to higher wildlife fecal contributions to the stream? Who is responsible for that? Currently, municipalities are required to maintain water quality according to state standards, but the default position is usually that impairments are due to failing septic systems and broken sewer pipes, not density of wildlife in the urban greenspace.

Figure 3. Photo of bridge deck drain. Samples collected below bridge during a storm event resulted in E. coli concentrations >2,500 cfu/100mL.

Figure 3. Photo of bridge deck drain. Samples collected below bridge during a storm event resulted in E. coli concentrations >2,500 cfu/100mL.

From the Rocky Creek case, we sampled during a storm event and found high concentrations of bacteria in road runoff. An interesting sample, collected from water falling through a PVC pipe bridge drain (Figure 3), exceeded the 2,419 E. coli MPN/100 mL threshold. We suspected this area, which was a unique intact urban stream forest habitat, was a common bird flyway which may have resulted in high E. coli loads in the road runoff.

Finally, on multiple occasions during the Thomson project, we found deer entrails and deer and dog carcasses in the creek. Knowing that fecal coliform and E. coli can survive in stream sediments, incidences such as a gut pile in a stream or a broken sewer pipe that was repaired 2 years ago could be viewed as a one-time “inoculation” event; these events could have lasting effects on indicator bacteria concentrations in the surface water. It is likely that the entrails go unnoticed or the repaired pipe was forgotten when regulatory sampling occurs downstream of those sites. If the results return a geometric mean of 250 cfu/100mL in the May through October timeframe, there will likely be a presumption of a failing septic system somewhere upstream.

GAEPD is required to implement a bacteria-based standard by the USEPA. The current bacteria-based approach is not conclusive enough for a municipality or industry to determine whether or not a broken pipe or failing sewer system is causing the impairment. If our approach to protecting surface waters from fecal contamination remains the same, money and effort spent in source identification and development of Total Maximum Daily Load Plans to fix those problems will fall short and the solution will remain elusive. Over time, another cost of that elusiveness will be unnecessary conflict between the regulator/regulated communities.

At this point, it seems the short-term answer might be to consider each impaired section on a case-by-case basis and be comfortable that the problem might not be a broken pipe. The long term answer is that better science will lead to better technology which will lead to better monitoring which will lead to better regulation.


Davies, C. M., Long, J. A., Donald, M., & Ashbolt, N. J. (1995). Survival of fecal microorganisms in marine and freshwater sediments. Applied and Environmental Microbiology61(5), 1888-1896.

EPA. (2015).

EPA. (2015).

Paul, M. J., & Meyer, J. L. (2001). Streams in the urban landscape. Annual Review of Ecology and Systematics, 333-365.

Walsh, C. J., Roy, A. H., Feminella, J. W., Cottingham, P. D., Groffman, P. M., & Morgan, R. P. (2005). The urban stream syndrome: current knowledge and the search for a cure. Journal of the North American Benthological Society,24(3), 706-723.

Tran, N. H., Hu, J., Li, J., & Ong, S. L. (2014). Suitability of artificial sweeteners as indicators of raw wastewater contamination in surface water and groundwater. water research48, 443-456.

Water as a Medium

Water as a Medium

by Chalisa Fabillar, Research Scientist

One of water’s most amazing characteristics is its ability to act as a medium. No I’m not talking about the size of your French fry order or the ostentatiously dressed palm reader. I’m referring to the ability to carry or convey materials, like oxygen, nutrients, minerals, proteins, and other materials which our bodies require. Plants also use water to move minerals and nutrients through their tissues. In addition to our biological requirements, we humans have capitalized on water’s ability to act as a medium for thousands of years and still use it today. We use water to transport people and cargo in ships, clean and carry the dirt away from things being cleaned, carry our physical wastes away through sewage lines, and industries use it to carry (treated) waste from their facilities. These are just a few examples of the way we and the environment use water.

guitar in the waterWhile we need water to perform all these functions for us, we don’t need a flood of it. In case you hadn’t noticed, we’ve had a lot of rain recently. So much so that we are well above average for this time of year. The result is that the lakes of the Savannah River are filled above winter guidelines and the river itself is running high to try to get rid of some of that excess water. We’ve also had a lot of water running over the land. Since water acts as a medium, it’s picks up everything in its path that isn’t secured or rooted down. This means that all the trash carelessly discarded on roadways, parking lots, and everywhere else people leave their garbage, is ending up in storm drains, creeks, and eventually the Savannah River. There it becomes flotsam or floating debris. When trash collects in the woody debris on the sides of the river it often gets washed all the way downstream and out to sea (think North Atlantic Garbage Patch).

holding flotsam guitarI find myself looking at these collections of trash whenever I go to collect water samples or equipment maintenance. As much as they disturb me, I find them strangely fascinating. The type and amount of the trash tells something about the way people use and care for both the river and the land surrounding the river. Most of the time the trash is plastic bottles, old beer cans, single use plastic shopping bags, and Styrofoam. Usually cheap items, bought and sold everywhere. But every now and again you find something a little different. Like a guitar for example. Can someone please tell me how and why a guitar ended up in the Savannah River? Perhaps it had something to do with those old beer cans?

The Secret Life of Mistletoe

The Secret Life of Mistletoe

Author: Kelsey Laymon, Research Scientist

Photo Credit

Photo Credit

The trees are starting change color and drop their leaves and you might be asking yourself, “What is that ball of green still left?” That ball of green is actually Mistletoe. Long before mistletoe became an excuse to steal a kiss, it became a widespread and important species in ecology. Mistletoe is a diverse group of flowering plants with over 1,300 species that reside in habitats all across the world. They use a unique growth form called obligate hemiparasitism, meaning they attach to a host through a vascularized root called a haustorium to obtain water and nutrients. They perform about 40% of their own photosynthesis, which is why they are only hemiparasitic and not fully parasitic. They can infect a wide variety of hosts including coniferous trees, cacti, succulents, orchids, ferns and even grasses.

Photo Credit:

Photo Credit:

The mistletoe’s seeds are deposited with a sticky material that helps adhere onto a branch of a tree or shrub. The seed germinates and produces a hypocotyl, or stem of a seedling, which grows towards the bark of the host depending on gravity and light. After about a full year, the hypocotyl penetrates the bark to reach the conductive tissues of its host. Often when mistletoe attaches to its host tree, they will stunt the growth of the tree and a heavy infestation can actually kill the tree. However, mistletoe fruits are high in soluble carbohydrates, minerals and amino acids and therefore are an excellent food source for birds and mammals. Because the fruits are available year round, 66 families of birds and 30 families of mammals have been recorded as eating mistletoe fruit. Furthermore, mistletoe flowers provide nectar that many insects and mammals consume.

In addition to providing food sources to a number of species, mistletoe is used for nesting and roosting sites for over 43 families of birds and 7 families of mammals. The Long-eared Owl uses mistletoe clumps as a structural foundation for their stick nests. Other birds use mistletoe to help conceal their nests from predators. In addition, mistletoe clumps are used as a hiding place from predators, and a shelter from hot temperatures. Interestingly it has been documented that fresh mistletoe sprigs are used as nest linings and can play a key role in the hygiene of the nests because the sprigs have antibacterial properties.

Mistletoe 3David M. Watson suggested that mistletoe functions as a keystone species, or a species that has a large effect on its environment relative to its abundance. Through two case studies, one a semiarid shrub habitat and the other a temperate forest, Watson found that mistletoe has a large impact on the biomass, species abundance, nutrient resources and nesting sites in these environments. Watson suggests due to his findings that mistletoe should be considered a keystone resource. Although mistletoe is a hemiparasitic plant and could be deadly to a tree, it actually helps to enhance the surrounding environment in most cases. Many animals use mistletoe for its unique properties and can be useful for its antibacterial properties. Mistletoe


For The American Heritage® Medical Dictionary:
immunostimulant. (n.d.) The American Heritage® Medical Dictionary. (2007). Retrieved December 18 2014 from

“haustorium”. Encyclopædia Britannica. Encyclopædia Britannica Online.
Encyclopædia Britannica Inc., 2014. Web. 18 Dec. 2014

“Keystone Species.” National Geographic. Web. 18 Dec. 2014. <>.

Tainter, Frank H. “What Does Mistletoe Have To Do With Christmas?” APS. Clemson University. Web. 18 Dec. 2014.

Watson, David M. “Mistletoe-A Keystone Resource in Forests and Woodlands Worldwide.” Annu. Rev. Ecol. Syst. 2001 (2001): 219-47. Print.

Common Names and Fish Talk

Common Names and Fish Talk

by Chalisa Fabillar, Research Scientist

A week or so ago, one of my co-workers was holding a catfish on a measuring board, when it loudly grunted. It surprised her and brought an old memory back to mind for me.

Oyster Toadfish

Oyster Toadfish, Photo by Amanda Hurst

Several years ago, I caught a small fish while fishing off a Savannah pier. Nearby, an old Gullah man guffawed and poo-poo’ed my little fish, saying it wasn’t anything special and called it a “dogfish.” When asked why he called what I knew to be an oyster toadfish by another name, he simply said, ”because they bark and they bite!”

This brief encounter has stuck with me for all these years for a couple of reasons.


Oystercatcher, Photo by Amanda Hurst

First, it helps to illustrate the need for scientific names. In the Gullah man’s community, the common name of dogfish applies singularly to the oyster toadfish. However, outside the Gullah community, dogfish usually means a type of shark. (Notice the emphasis on usually, as I can’t say what other fish have been labelled dogfish by people who encounter them.) But the problem with common names isn’t limited to local populations: it can also cross major taxonomic divisions. The oyster toadfish has other common names like oyster cracker and bar dog, but also oyster catcher. The oyster catcher is also a type of bird. Imagine the confusion that could ensue if one side of a conversation was talking about the fish and the other the bird! To avoid this confusion and create a standard for naming organisms, science has long used the binomial nomenclature, or a two name system. Using this system, there is only one fish scientifically named as Opsanus tau, and this will not change no matter where you are in the world. Period.

Second, the man said they bark. Fish bark? Yes, they do, and they grunt, growl, purr, and chirp too!

They vocalize to establish territory, in mating rituals, to stun prey, and to alert others to danger. Scientists have found multiple uses for these vocalizations in research. The amorous grunts of several species of fish are recorded to know when spawning is most likely to occur. This information is very important for economically important fisheries such as haddock, salmon, and sea trout to name a few. Scientists can also record fish vocalizations to know when certain species are present and what activities the fish are ‘talking about.”.

I don’t think many people think of fish as great communicators. But a brief google search shows a wealth of published and ongoing research demonstrating a surprising complexity to fish vocalizations. As research continues and we learn more about this topic, it will be interesting to discover what fish find worthy of talking about. In the case of my co-worker’s grunting catfish however, I do believe it was simply expressing its dislike of being out of water.

For more information on the mechanisms behind the noises and the reasons fish use sound: