Scientific Papers

Using the West Indian Manatee (Trichechus manatus) as a mechanism for invasive aquatic plant managment in Florida.

NSUWorks Citation- Nova Southeastern University

Prepared by: Aarin Conrad Allen and Edward O. Keith. 2015.

Abstract: West Indian manatees (Trichechus manatus L.) are opportunistic, herbivorous aquatic mammals that occupy the warm, shallow coastal waters throughout the southeastern United States. Manatees are known to feed on large quantities of diverse plant types. Presently within the state of Florida, manatees are an endangered species facing environmental and anthropogenic threats. Several different organizations work to rescue and rehabilitate these animals for an eventual return to the wild. Also within Florida, invasive aquatic plants are becoming increasingly problematic, creating both negative economic and environmental impacts. Each year, efforts are made to control these exotic plant species through several different methods. However, physical, mechanical, chemical and biological means to contain nonindigenous plants each have their drawbacks. There is a need for a natural, integrated approach to invasive aquatic plant management. The opportunity for manatees to control exotic plant species within the Florida ecosystem exists but is improbable because of inadequate population densities. This study builds on this potential by examining the use of manatees held in captivity as a tool for management by utilizing the physical collection of targeted nonindigenous plants to supplement the diet of rehabilitated manatees.

Keep Reading —>

Widespread sewage pollution of the Indian River Lagoon system, Florida (USA) resolved by spatial analyses of macroalgal biochemistry

Prepared by: Peter J. Barile

Abstract: The Indian River Lagoon (IRL) system, a poorly flushed 240 km long estuary in east-central Florida (USA), previously received 200 MLD of point source municipal wastewater that was largely mitigated by the mid 1990’s. Since then, non-point source loads, including septic tank effluent, have become more important. Seventy sites were sampled for bloom-forming macroalgae and analyzed for δ¹⁵N, % nitrogen, % phosphorus, carbon:- nitrogen, carbon:phosphorus, and nitrogen:phosphorus ratios. Data were fitted to geospatial models showing elevated δ¹⁵N values (> +5‰), matching human wastewater in most of the IRL system, with elevated en richment (δ¹⁵N ≥ +7‰ to +10‰) in urbanized portions of the central IRL and Banana River Lagoon. Results suggest increased mobilization of OSDS NH₄⁺ during the wetter 2014 season. Resource managers must improve municipal wastewater treatment infrastructure and commence significant septic-to-sewer conversion to mitigate nitrogen over-enrichment, water quality decline and habitat loss as mandated in the Tampa and Sarasota Bays and the Florida Keys. 

Keep Reading —>

Diversity and distribution of seagrass as related to salinity, temperature and availability of light in the Indian River Lagoon, Florida.

Prepared By: Lori J Morris⁽¹⁾, Lauren M Hall⁽²⁾, Jan D Miller⁽¹⁾, Margaret A Lasi⁽¹⁾, Robert H Chamberlain⁽³⁾, Robert W Virnstein^(3,4), and Charles A Jacoby⁽¹⁾

Proceedings of Indian River Lagoon Symposium 2020

Abstract: Abstract Seven species of seagrass have been found in the Indian River Lagoon (IRL), making it an unusually diverse location at the global scale. From 1994 to 2019, the lagoon-wide distribution of these species reflected variations in temperature, salinity, and the availability of light at depth, which were related to latitudinal differences in hydrology and hydrodynamics along the IRL. In general, species richness was higher near the four southern inlets, and fewer species were found in areas with longer residence times for water. At a finer scale, the distribution of species varied among depths, with the greatest number of species found at mid-depths (~0.4–0.9 m). Prior to 2011, these patterns remained relatively consistent for ~ 40 years, but several, intense and prolonged phytoplankton blooms disrupted them. The areal extent of all seagrasses decreased by over 50%, the offshore ends of canopies moved shoreward and shallower, distributions of species along gradients of latitude and depth were disrupted, and mean percent cover decreased. Major changes in distribution and abundance of seagrasses arose when salinity, temperature, and availability of light at depth exceeded limits derived for each species. These substantial and widespread changes engendered concerns for recovery or rehabilitation of seagrasses in the lagoon.

Keep Reading —>