Indian River (Lagoon)

Macroalgal blooms are responses to nutrient enrichment in shallow seagrass ecosystems like the Indian River Lagoon (IRL), Florida. Little is known about nitrogen (N) and phosphorus (P) limitation or the importance of morphological/physiological characteristics of bloom-forming macroalgae (Ulva lactuca, Hypnea musciformis, and Gracilaria tikvahiae) in the IRL. We hypothesized: 1) all species would proliferate in nutrient-rich Titusville, 2) opportunistic U. lactuca would dominate, 3) Rapid Light Curves (RLCs) would assess nutrient status, and 4) nutrient concentrations would regulate growth more than N:P ratios. Field studies showed rapid biomass doubling times of 2 days (U. lactuca; November 2012) in urbanized Titusville. RLCs in a guano-enriched island off Big Pine Key (BPK) and Titusville (Ulva spp.) were similar due to P-saturation. Laboratory studies showed three-fold higher RLCs and two-fold faster growth at high nutrient concentrations of N and P. Reductions of both N and P will be required to moderate future blooms.

Nineteenth century settlers in Florida's Indian River Lagoon (IRL) region created an isolated fringe culture wholly dependent on the instable hydrological forces of the shallow lagoon system. These settlers were among the first to construct a built environment market by the dredging and filling that would define much of the twentieth century Sunshine State. There has been no period when the liminal IRL ecosystem was not without shifting barrier islands and dramatically varying salinity levels due primarily to the oceanic interchange following the opening and closing of natural inlets. This paper suggests that attempts to "restore" the lagoon will necessarily declare an arbitrary historical form to be normative for the system. The first and last chapters provide an overview of the system's origins and recent history, while the core of the paper focuses on human-environment interaction of the lagoon in the late nineteenth and early twentieth century.

In estuaries, like the Indian River Lagoon, mesozooplankton have a vital role in the food web by connecting trophic levels. In this study, mesozooplankton abundance and species composition were monitored weekly on the incoming and outgoing tides from September 2006 to May 2009. For the incoming tide, the mean abundance was 2298.2 mesozooplankton/m3 (+/-325.2), and for the outgoing tide the mean abundance was 1180.0 mesozooplankton/m3 (+/-153.1). The mesozooplankton abundance on the incoming tide was significantly greater than on the outgoing tide. The most abundant type of mesozooplankton was the copepod Acartia tonsa, representing 35.0% and 52.1% of the individuals on the incoming and outgoing tides respectively. Mesozooplankton abundance values were compared with environmental data obtained from the South Florida Water Management District. The strongest positive correlation was found between chlorophyll a concentrations and A. tonsa abundance, likely due to phytoplankton being the primary food source for A. tonsa.

Sorites dominicensis is a common Foraminifera living on Thalassia testudinum seagrass blades in the Indian River Lagoon. This locality is unique because epiphytic diatoms, characteristic of Caribbean and temperate environments, are expected to make up the biofilm community. Diatoms compose a large part of the Foraminiferan diet. It is important to understand the cause and effect relationship of population variation between S. dominicensis and its preferred food source, since both are valuable bioindicators. We examined the selective feeding of S. dominicensis by first, identifying the diatom assemblage. Second, we utilized scanning electron microscopy (SEM) in order to identifying the remains of diatoms entrapped in pseudopodial nets and in debris piles. We found that Mastogloia and Cocconeis were the most prominent genera in the overall diatom assemblage. The food preference of S. dominicensis included Amphora, Berkeleya rutilans,Cocconeis, Licmophora dalmatica, Mastogloia, Odontella rhombus, Plagiogramma pulchellum var. pygmaeum, and Skeletonema.