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OSCAR video: “What’s in Our Water?”

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George Mason (https://www2.gmu.edu/) undergraduate research, led by principal investigators Amy Fowler and Kim de Mutsert, who are researchers at the Potomac Environmental Research and Education Center (Perec.gmu.edu). In the summer of 2017, this team project looked at the effects of micropollutants on the Potomac River watershed. Students and faculty discuss some of the results of the study and the future of this work. Projects were funded by the Students as Scholars at Mason (https://oscar.gmu.edu/) as well as the Patriot Green Fund (https://green.gmu.edu/patriot-green/) , and the videos were produced by graduate student, Chelsea Gray, thanks to the Virginia Sea Grant (https://vaseagrant.org/).

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Summer Impact Grant Postings

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OSCAR video: “Micropollutants in the Potomac River”

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George Mason (https://www2.gmu.edu/) undergraduate research, led by principal investigators Amy Fowler and Kim de Mutsert, who are researchers at the Potomac Environmental Research and Education Center (Perec.gmu.edu). In the summer of 2017, this team project looked at the effects of micropollutants on the Potomac River watershed. Projects were funded by the Students as Scholars at Mason (https://oscar.gmu.edu/) as well as the Patriot Green Fund (https://green.gmu.edu/patriot-green/) , and the videos were produced by graduate student, Chelsea Gray, thanks to the Virginia Sea Grant (https://vaseagrant.org/).

Graduate Student Research Highlight: It’s a penguin eat krill world: using dynamic food web modeling to help design a new Antarctic Marine Protected Area

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Student: Adrian Dahood, PhD Candidate

Affiliation: De Mutsert Fish Ecology Lab

Webpage: http://adrian.fritztech.com

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Gentoo penguins porpoising in the Antarctic Sound.

In 2014-2016, recent De Mutsert Lab PhD graduate Adrian Dahood, spent the month of August at sea in Antarctic waters. She set zooplankton nets and identified critters as part of a National Oceanic and Atmospheric Administration Antarctic Marine Living Resources (NOAA-AMLR) project. The NOAA-AMLR team is particularly interested in understanding how one zooplankton species, Antarctic krill, populations change over time. NOAA-AMLR uses these data to help inform management decisions for the krill fishery. Adrian uses the same data to develop dynamic food web models to aid in the design process for a new Antarctic Marine Protected Area (MPA). Because Antarctica is so remote, you may wonder why we need to establish an MPA in a place that experiences relatively few human impacts.

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Adrian at an Adélie penguin colony in the Western Arctic Peninsula that has just suffered significant chick deaths due to excessive breeding season snow fall and and subsequent melt streams.

Well, the Western Antarctic Peninsula (WAP) region, where NOAA-AMLR conducts its krill surveys, has been significantly impacted by climate change. It is one of the fastest warming regions in the world; the average annual temperature has already increased 7oC since 1950 (Ducklow et al. 2013). Increased temperatures have led to significant sea ice loss (Ducklow et al. 2013). Antarctic krill, an ice dependent species, is an important prey item for many species including fish, birds, seals and whales. As the ice retreats, krill lose habitat and the areas accessible to the fishery expand. These pressures on krill could lead to declines in krill and krill predators.

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Getting ready to set the zooplankton net.

Indeed, we have already seen that populations of ice-dependent species that primarily eat krill, such as Adélie penguins, are in decline, while populations of more flexible species such as Gentoo penguins, are increasing. The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), the international body responsible for managing Antarctic marine ecosystems, is in the process of designing and establishing MPAs throughout the Antarctic. CCAMLR recognizes that MPAs can help buffer the ecosystem from the increasing pressure of climate change and facilitate sustainable fisheries. Traditional methods for designing MPAs rely on static maps of animal distribution and human use patterns. The assumption is that if you protect the areas where animals have been sighted, you will protect the processes that lead to them being sighted there. This may not be a valid assumption for the WAP where both the physical environment and availability of the main prey item, Antarctic krill, are changing rapidly.

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Identifying zooplankton in the shipboard lab.

Adrian’s research uses dynamic food web modeling to help identify areas most important for hungry animals. She employs a wide variety of data including zooplankton data collected on the NOAA-AMLR cruises, penguin and other predator population estimates, and spatial and temporal information about sea ice to build the models. While she spends one month a year in Antarctica counting animals, most of her time is spent searching the literature and speaking with Antarctic ecologists to parameterize her models. By studying predator prey interactions, and how they change over time and space in response retreating sea ice, Adrian hopes to help CCAMLR design an MPA for the WAP that will provide meaningful protection for years to come.

Ducklow, H. W., W. R. Fraser, M. P. Meredith, S. E. Stammerjohn, S. C. Doney, D. G. Martinson, S. F. Sailley, O. M. Schofield, D. K. Steinberg, H. J. Venables, and C. D. Amsler. 2013. West Antarctic Peninsula: An Ice-Dependent Coastal Marine Ecosystem in Transition. Oceanography 26:190-203.

 

 

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What are Local Fish Eating?

By: Sammie Alexander

As a member of the ecology team for the Potomac Environmental Research and Education Center’s (PEREC) summer OSCAR team project, my research goal is to investigate the predator-prey dynamics between fish and macroinvertebrates in two freshwater tidal Potomac River tributaries, Gunston Cove and Hunting Creek. This means, I examine the stomach content of 15 fish species known to inhabit both embayments in order to construct a food web for each location.
Due to variations in aquatic habitat types within the embayments (i.e., vegetated and non-vegetated), I use three different methods to collect my fish samples: fyke nets, seine nets, and otter trawls.

A fyke net is a passive collection technique in which fish are guided into a funnel shaped net by three leads, or guide nets. Once fish enter the funnel through narrow openings, they are unable to return to the outside of the net. The funnels on the fyke net are comprised of subsequently narrower openings that make exiting the net difficult for many fish. This method is implemented in heavily vegetated habitats where the submerged aquatic vegetation is so dense it is impossible to actively pull other types of net through.

The second method, seine nets, are an active collection technique in which two people extend a long net perpendicular to the shore and then drag it parallel to the shore for approximately 100 feet. This targets fish along the shoreline and can be used in vegetated and non-vegetated habitat. However, seine nets become very difficult or even impossible to use effectively once the vegetation reaches a certain density.

The third method, otter trawls, are another active collection technique in which a weighted net is dropped off the back of the boat and dragged at a constant speed for 5 minutes. Like the seine net, this method can be used in vegetated habitats to an extent. If there is too much vegetation, the trawl will become clogged or too heavy and will have to be reset, so it is best used in open water.

Once my fish samples are collected, I take them back to the lab to remove their stomachs for examination. I then sort the contents of their stomach into groups based on the lowest possible taxonomic level, which can be challenging if the organisms in the stomach have already begun to digest.

While there are published studies focused on the diet of many of the fish species I am studying this summer, none of the studies focus on populations in these specific tributaries of the Potomac River. The species found in these systems are unique, in a way, due to their close relationship with wastewater treatment plants upstream. These treatment plants feed nutrient rich effluent (i.e., discharge water) into the streams that then flow into these embayments. Adding additional nutrients to an aquatic system has the potential to influence the type of organisms that can live there.

I will use the organisms I identify in the fish stomachs to construct a food web, which will allow me to compare the diets of fish communities that reside in non-vegetated habitats, such as shorelines and open water, to the fish communities that reside in vegetated habitats, such as the submerged aquatic vegetation (SAV) beds.

Pursuing this question is interesting because in the 1980’s Gunston Cove was a hypereutrophic (i.e., very nutrient rich) system, due to the nutrient rich effluent released from the Noman M. Cole, Jr. Pollution Control Plant (NCPCP), which provided ample nutrient resources for phytoplankton algae to grow. Eventually, the algae became so abundant that it formed a thick green layer over much of Gunston Cove, which blocked the sunlight from reaching the streambed, preventing the growth of SAV. However, in an effort to reduce the occurrence of these harmful algal blooms, NCPCP reduced the amount of nutrients released in their effluent and after many years SAV beds began to reestablish (like they were prior to the 1980’s).

Now that nutrients, such as phosphorus (the first nutrient that was reduced in the wastewater effluent) and nitrogen, are better regulated, light is able to penetrate the surface and in turn SAV is able to grow. The food webs I construct will compare the potential impacts shifting from the historically non-vegetated habitat to the emerging vegetated habitat may have on the diets of fish in Gunston Cove and Hunting Creek.

As an Environmental Science student, I am very interested in the interactions that take place between organisms within an ecosystem. One day I hope to incorporate ecosystem modeling and spatial analysis into my own research, to investigate the potential impact factors such as climate change or invasive species can have on populations of aquatic species.

When I saw that Dr. de Mutsert was looking for a student to help construct a food web, I thought that this was a great place to start. Before I can create models to predict how stressors such as climate change or invasive species will impact an ecosystem, I must first understand how the species currently interact with their environment and surrounding community.

Now, I begin week seven of attempting to answer an unanswered question with high hopes and a long to-do list. I have spent many hours this summer on a boat collecting fish for my project, and macroinvertebrates for my partner’s, trolling the internet and library for resources on how to conduct a diet study and information on the history of the fish community in the Potomac River. More recently I have begun processing my 196 fish samples to try to understand what exactly is going on in the Potomac River (i.e., who is eating whom). The past six weeks have been spent collecting my fish samples and preparing the content in their stomachs to be examined.

With only two weeks left until our results are due to our advisors, it is now time I use our data to begin connecting the dots between the inhabitants of each embayment. The only thing standing between the coveted answer and myself are approximately 190 fish stomachs, but have no fear – I’ve come prepared with my microscope, tweezers, and coffee. Stay tuned to find out what happens next.

Modeling a Coastal Environment with Human Elements

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Kim de Mutsert was one of the Keynote Speakers at the CSDMS (Community Surface Dynamics Modeling System) annual meeting “Modeling Coupled Earth and Human Systems – The Dynamic Duo.” That took place in Boulder, Colorado from May 23-25, 2017. See the presentation below entitled: “Modeling a Coastal Environment with Human Elements.”

Keynote Abstract:

If one system comes to mind where the human element is intertwined with the environment, it is the Louisiana coastal area in the Southern United States. Often referred to as the working coast, coastal Louisiana supports large industries with its ports, navigation channels, oil, and productive fisheries. In addition to that, Louisianians have a significant cultural connection to the coastal wetlands and their natural resources. Unfortunately, the land is disappearing into the sea with coastal erosion rates higher than anywhere else in the US. Due to these high rates of land loss, this system needs rigorous protection and restoration. While the restoration plans are mostly focused on building land, the effects on, for example, fisheries of proposed strategies should be estimated as well before decisions can be made on how to move forward. Through several projects I have been involved in, from small modeling projects to bold coastal design programs, I present how coupled models play a key role in science-based coastal management that considers the natural processes as well as the human element.

PEREC Represents GMU at Occoquan River Fest

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Damselfly Larvae captured from a NOVA stream

PEREC Faculty and George Mason Students spent a wonderful Saturday at the Occoquan River Fest. The festival was a great place for NOVA residents to learn about the history and environment of the Occoquan River.

PEREC’s booth was dedicated to the health and ecosystem of local Virginia streams. Students and Faculty provided some great hands on activities, by fishing out live organisms for visitors to see up close. Crayfish, amphipods, and cranefly larvae were caught from the river that day and temporarily held in a glass aquarium. Children were able to get up close and personal, using magnifying glasses to get a detailed look at the organisms from their backyard.

“It’s great seeing the excitement in young kids when they examine small critters like crayfish and cranefly larvae up close,” says Kim De Mutsert.

Crayfish

George Mason graduate and undergraduate students were able to practice their science communication skills, with children and adults alike. The students explained that the number and types of organisms found in a river help scientists determine how “healthy” (i.e. unpolluted) the waterway is.

But it wasn’t just GMU students doing to the teaching.

“It was so interesting to see how much the parents would learn from their kids,” Grad student, Jessica Melton says. “The kids would tell their parents that what we caught was only 100 meters away. They’d explain to them what a cranefly was (Parents often thought it was a nuisance or large mosquito) as it’s very common in the area. The parents realized that it’s actually a beneficial species to keep around.”

That kind of experience is what made the day a success.

An annual event, PEREC looks forward to next year’s Occoquan River River Fest!

Original post: https://cos.gmu.edu/perec/perec-represents-at-occoquan-river-fest/#