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Research Highlights

2021

Emerging Wetlands from River Diversions Can Sustain High Denitrification Rates in a Coastal Delta

April 8, 2021

This project sought to evaluate the assumption that in order to treat an abundance of Nitrate in natural or restored wetland regions, a high amount of organic matter content in the soil is required to maintain high denitrification rates. Since a higher amount of Nitrate can promote a risk to these wetlands by increasing soil decomposition rates and an overall breakdown of this region, researchers evaluated these variables using techniques such as isotope pairing. Researchers evaluated the role of organic matter content and temperature interactions that control denitrification rates in eroding and emerging delta regions in coastal Louisiana. The project also assessed difference in the total and net amounts of denitrification rates among benthic and wetland habitats. As a result, environments with low carbon availability, higher rates of denitrification can be sustained as long as nitrate concentrations are high and water temperatures are greater than 50 degrees (F).


Late Pleistocene Baldcypress (Taxodium distichum) Forest Deposit on the Continental Shelf of the Northern Gulf of Mexico

March 3, 2021

Sea level rise is currently underway, but how did past climate influence ocean levels? Researchers at Louisiana State University were able to continue answering this when divers located and studied underwater forests approximately 8 miles south of Gulf Shores, Alabama. Researchers found the remains of bald cypress stumps below the ocean surface and along the continental shelf, which indicates that these trees were growing when sea levels were lower and exposed the shelf during the Pleistocene Era. Finding these well-preserved tree stumps allowed researchers to work on figuring out the possibilities and explanations of sea level rise in the past. Preserved variables such as the mud facies, wood and peats of this once swamp land were radiocarbon dated and gave a better understanding as to the age of these underwater forests. From this work, researcher’s hypothesis that rapid sea level rise provided an opportunity for local floodplain mineral deposits to bury the swamp, which results in well-preserved stumps. Additional sites in the Northern Gulf of Mexico shelf may exist as a result of this event.


Assessing the Impacts of High Nutrient Levels to Freshwater in the Northern Gulf of Mexico

February 22, 2021

Attempting to assess environmental changes over large areas is a limitation when determining the impacts of excessive nutrients from runoff from the land and the effectiveness of management strategies on coastal systems. This research used a combination of sensors at the location and satellite data to develop an algorithm and map the distribution of chlorophyll-a, which assessed the impacts of high levels of nutrients to the freshwater distributions in the Barataria Basin of the Northern Gulf of Mexico. As a result, this work demonstrated the need for large scale, continuous local (in-situ) sampling for assessing future water quality conditions.


Time lags: Insights from the U.S. Long Term Ecological Research Network

February 9, 2021

As ecosystems throughout the U.S. continue to be affected by climate change, this research aims to look at different variables to understand how changes will affect these ecosystems in the future and their role for societal needs. Part of the U.S. National Science Foundation’s Long Term Ecological Research (LTER) network, this work looks at different LTER locations and how they will change over the next 50-100 years with a changing climate. For this paper, the main focus will be on time lags from diverse climatic regions including tundra, coastal wetlands and montane forests. This work identified variables that are better indicators of lagged changes in the various sites within the network. Such indicators examined were the arctic tundra, the effect of a warming ocean on plankton off the west coast, how changes in species over decades can impact Eastern forests, and much more. The various case studies highlight the need for additional sites within the network and longer study periods to understand the complexities of time lags in ecosystems.


Hydroperiod and Salinity Interactions Control Mangrove Root Dynamics in a Karstic Oceanic Island in the Caribbean Sea (San Andres, Colombia)

January 14, 2021

Global sea levels are on the rise and this means coastal regions and ecosystems are at risk. One such ecosystem are the coastal mangroves. To better understand how mangroves will be affected by high sea levels, researchers evaluated three mangrove ecotypes in the San Andreas Island located in the Caribbean Sea. The main focus was looking at how the root system can lose nutrients with increased amounts of salinity. It was found that the mangrove roots require a balance of freshwater from the ground to maintain its nutrient efficiency. These results can assist coastal resource managers in regulating water use and coastal development in the short term to avoid loss of mangrove ecosystems.


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