Salty Beans: The Effects of Moderate Salt Stress on Nodule Formation in Medicago truncatula

Nitrogen is the most limiting resource for plant growth. Legumes have evolved a symbiosis with a soil bacterium that converts atmospheric nitrogen into a plant available form. This symbiosis involves chemical communication, coordinated growth, and the creation of a new root organ, the nodule. Previous research has shown that this symbiosis is particularly sensitive to salt stress, resulting in dramatic reductions in nodulation, even at levels that do not significantly reduce plant biomass. I investigated the underlying cause of this reduction and will determine if it is a result of reduced initiation of nodules, disrupted or abnormal development, or both. Plants were grown in a controlled environment, in a defined medium, with the treatment group receiving 100mM NaCl. Roots were harvested 7 days post-bacterial-inoculation and stained using a modified Pseudo-Schiff method. Data was gathered via whole-mount, confocal scanning laser microscopy, which allowed for faster and more accurate data collection. Using previously defined stages of nodule primordia development, I categorized each nodule primordia across treatments. In this way, I intend to determine if there is a significant reduction in the number of initiated nodules, significant differences in the distribution of nodule stages, and if there is any abnormal development across treatments

A National Status Report on United States Coral Reefs Based on 2012-2018 Data From National Oceanic and Atmospheric Administration's National Coral Reef Monitoring Program

National Oceanic and Atmospheric Administration's Coral Reef Conservation Program supports the National Coral Reef Monitoring Program (NCRMP) in the United States Pacific, Atlantic, Caribbean, and Gulf of Mexico. NCRMP conducts standardized observations of biological, climatic, and socioeconomic indicators across American Samoa, Guam, the Main Hawaiian Islands, the Northwestern Hawaiian Islands, the Northern Mariana Islands, the Pacific Remote Islands, Florida, the Flower Garden Banks, Puerto Rico, and the United States Virgin Islands. NCRMP provides periodic, national-level assessments of the status of United States coral reef ecosystems and communities connected to them. In 2014, NCRMP partnered with the University of Maryland Center for Environmental Science on an unprecedented collaboration between federal and jurisdictional/state agencies, academia, and non-governmental organizations to synthesize NCRMP data into a reporting format designed to be accessible and relevant to the public and policy makers. The process involved multi-year data analyses of key benthic, fish, and climate indicators. In populated jurisdictions, socioeconomic data were integrated to assess public support for management actions, participation in pro-environmental behaviors, and awareness of threats to coral reefs. Jurisdictions were scored using a report-card scale (0-100%) by establishing references for each indicator using best-available historical data or expert opinion where historical data did not exist or were not statistically comparable. Despite overall ecosystem scores of Fair for all combined Atlantic (70%) and Pacific (74%) jurisdictions, the current trend is downward with a majority of United States coral reefs declining and vulnerable to further degradation. Remote, uninhabited reefs had an advantage with respect to reef fish population scores, i.e., Flower Garden Banks (85%) and Pacific Remote Islands (93%), when compared to populated location scores, i.e., Puerto Rico (63%) and Main Hawaiian Islands (66%). All coral reefs are highly impacted by climate change, and climate impacts were more pronounced than expected on remote reefs, i.e., the Northwestern Hawaiian Islands (58%). Presenting results in a report-card style facilitates communication to the public and policy makers, and provides a useful mechanism to garner support for management actions such as expanding protected areas; enforcing existing regulations; increasing climate change education; reducing land-based sources of pollution; and other actions to improve the trajectory of coral reef ecosystem conditions