The genesis of scientific collaboration and its big impacts

The words science and progress often conjure images of sterile laboratories and white coats, not dimly lit bars and pints of beer. However, both are common breeding grounds for scientific research and collaboration.

When graduate students have time to turn their heads away from their computer screens or escape the lab, they gather at coffee shops and bars, venting frustrations and hashing out ideas. This is an important component of scientific research: Communication with peers.
In academia, we often are so focused on our specific research question that we lose perspective and put our blinders on. Peer-to-peer communication provides an opportunity to regain perspective and can be the foundation for collaboration.

At the local graduate student watering hole, the Mews Tavern in downtown Wakefield, we launched a collaborative research project early last spring to help address the question of how interacting climate change impacts alter salt marsh functioning.

In the past 300 years, 53 percent of Rhode Island salt marshes have been lost to development, and our remaining marshes are threatened by a combination of nutrient pollution, invasive species, and sea level rise.

We both are Ph.D. candidates in the biology department at the University of Rhode Island, but our research focuses are quite different: Rose studies salt marsh ecology and biogeochemical cycling; Gordon works with marine communities and food web interactions.

Despite the research differences, we found common ground as Rhode Island NSF EPSCoR graduate fellows, studying the impacts of climate change on coastal ecosystems. Throughout the course of a few pints, we first jokingly talked about how climate change would cause our respective ecosystems to merge.

But then, we pondered a serious question: Given distinct, but complementary skillsets, would it be possible to combine forces to address questions about the response of salt marshes to climate change in novel ways?

Salt marshes, with their characteristic expanses of grassy meadows and glistening mudflats, are defining features of our coastal landscape in the Ocean State. In addition to their beauty, these marshes provide critically important services including habitat for commercially important fish and wildlife, protection against storm surges, trapping land-derived pollutants such as fertilizer before they enter Narragansett Bay, and reducing climate change by absorbing and storing atmospheric carbon.

The importance of salt marshes to the health of the environment and society is clear now, but this has not always been the case. In the past 300 years, 53 percent of Rhode Island salt marshes have been lost to development, and our remaining marshes are threatened by a combination of nutrient pollution, invasive species, and sea level rise.

Increasing sea level will present a particularly difficult management challenge, since marshes moving landward to escape rising tides will meet with resistance in the form of shoreline development. As Rhode Island coastal communities prepare to deal with effects of climate change, understanding the ways that salt marshes respond to sea level rise will be an important tool for management and planning.

Salt marsh response to sea level rise has been investigated throughout the past few decades, in a variety of methods. From modeling to field studies and laboratory-based projects, scientists have been able to show the negative effects of sea level rise on marsh ecosystems, structure, and productivity.

However, rising seas alone do not stress marsh ecosystems: There are a number of other factors that could work in concert with sea level rise to exacerbating impacts to marshes.

Our findings suggest that the low marsh species first to feel the impact of sea level rise may find itself stressed to the point of significant die-back, a phenomenon that would have severe repercussions for coastal marsh stability and productivity.

Testing multiple factors of climate change on marsh responses is not only relevant; it is necessary. Teasing out which factors are the most important or most influential often poses the greatest challenge, but if we ask the right questions, science has the tools to provide answers.

After deciding to combine our perspectives, we began a flurry of brainstorming as we sought the main research question.

There are many facets of climate change, and many of them act in conjunction with one another to impact species and ecosystems. Sea level rise was the main focus, as this is the force joining marine and marsh systems, but we added the addition of algal blooms as a factor of global change.

Algal blooms occur due in part to nutrient loading along the coast, and if occurring alongside sea level rise, their presence in salt marshes could affect ecosystem function. Salt marshes are not only under pressure from rising seas on one side, but on the upland side they are being squeezed by development and invasive species. This has resulted in merging of plant communities that, in marshes not impacted by human activities, are usually distinct from one another. Since plants are responsible for many of the important functions of marshes, changes to plant communities may have profound impacts for the salt marsh ecosystem.

In this study, we decided to take our two factors of climate change (sea level rise and presence of simulated algal bloom) and measure the response of two salt marsh grasses, Spartina alterniflora and Spartina patens in terms of plant success, biomass quality, impact on soil environment, and associated greenhouse gas fluxes. These grasses, respectively, represent two marsh zones — high and low marsh. Consequently, responses of these different marsh elevations could help predict responses for the marsh system as a whole.

In order to study the impacts of sea level rise and algal blooms on salt marsh grasses, we developed an experimental setup that let us test impacts of multiple factors on plants and soil collected from a Rhode Island salt marsh. Field manipulations of sea level are difficult to recreate and the experimental setup, or mesocosm, allowed for research to be conducted in a controlled manner.

First, we determined current levels of seawater inundation in Jamestown. These levels were determined by measuring the depth of water across marsh zones at both high and low tide. These levels act as controls and were coupled with projected sea levels 50 years and 100 years from now based on accepted Intergovernmental Panel on Climate Change projections.

An ecologist’s budget often pales in comparison to those working in other fields, so that demands creativity. We developed water transport to the mesocosm tanks as well as simulated tides, but finding large enough tanks proved difficult.

Getting the project off the ground hinged on finding the appropriate vessels, and help came from an unexpected source — a restaurant supply company. This company offered large, clear trash cans that could hold the necessary levels of water and allow for light to shine through.

While we pieced together much of the setup on a shoestring budget, cutting-edge technology helped address the research questions from several angles.

Dr. Serena Moseman-Valtierra’s lab provided access to probes for measuring soil characteristics, including pH, oxidation-reduction potential, and temperature, as well as access to a Picarro Gas analyzer that uses new technology (cavity ringdown spectroscopy) to measure carbon dioxide, methane, and nitrous oxide concentrations in real-time.

The information gained from using these instruments allowed us to make observations regarding impacts of sea level rise and algal deposition on biogeochemical activity, especially carbon cycling, in the plant-soil system from high and low marsh zones. With the help of some undergraduate research assistants, we collected data and maintained the set-up through the course of the growing season.

Now sitting on top of a pile of data, we have begun to look back and analyze our findings. Weekly observations allowed us to track changes in the salt marsh grasses, and we noted that even early on in the experiment, simulated sea level rise took a toll on the health of the two grass species.

We corroborated these observations by statistical analysis, which indicated that grasses had a much poorer survival rate under sea level conditions predicted for the year 2100 than for present-day or year 2050 simulations. Gas flux measurements revealed that algal enrichment drove emission of the potent greenhouse gas methane from the low marsh mesocosms.

Based on its location in the low marsh, Spartina alterniflora will be the first salt marsh grass species to feel the effects of sea level rise. These findings show that seawater inundation causes a major decline in the density of this species. As a result of algal deposition, S. alterniflora has the potential to emit significantly more methane relative to its mid marsh counterpart.

Our findings suggest that the low marsh species first to feel the impact of sea level rise may find itself stressed to the point of significant die-back, a phenomenon that would have severe repercussions for coastal marsh stability and productivity.

Further, anthropogenically stimulated algal blooms may simultaneously drive increased fluxes of the greenhouse gas methane from the low marsh. This effect could shift coastal marshes from net sinks of greenhouse gases to net sources, with potential positive feedbacks on climate warming.

We now are at the stage of putting our analysis together and creating a narrative, which we plan to share via scientific publications and conference presentations. We hope that by shedding light on how marshes respond to sea level rise and other climate related factors, this research helps inform management decisions related to salt marsh protection and the maintenance of these ecologically critical systems and their important functions.

We also hope that a few more projects may come out of the collaboration before our respective graduations, and we look forward to hammering out the details of some budding ideas – most likely over a few pints at the Mews.

By Gordon Ober and Rose Martin | former RI EPSCoR graduate fellows