Climatic Trends and Temporal Patterns of Phytoplankton Composition, Abundance, and Succession in the Indian River Lagoon, Florida, USA

Abstract

This paper describes the results of 10 years of water quality monitoring in the Indian River Lagoon Florida, with special emphasis on the relationships between trends in climatic conditions and the distribution, composition, and abundance of the phytoplankton community. The Indian River Lagoon, which spans 220 km of Florida's east coast, is a region of particular concern because of the rapid rate of human development throughout the region and the hydrologically restricted character of the lagoon, which heightens the potential for algal bloom. Water sampling was carried out on a monthly to twice-monthly basis at six sites located in the northern and central lagoon. The 10-year study included both extended periods of below and above average rainfall. A number of ecologically distinct regions exist within the lagoon, which differ considerably in water exchange properties and watershed inputs. The northern lagoon is characterized by longer water residence times, lower phosphorus concentrations, higher nitrogen concentrations, and more stable salinity conditions than the central lagoon. Mean phytoplankton biovolumes were substantially higher at the sites in the northern lagoon than at the sites in the central lagoon, and algal blooms were more common and intense in the former region. Inter-annual patterns of phytoplankton biovolume were also different in the northern and central lagoon. In the northern lagoon, phytoplankton biovolumes were lowest during the drought period, from the autumn of 1998 to the spring of 2001. By contrast, algal bloom events in the central lagoon were not only less frequent but were not tied to periods of high rainfall. The most widespread and common bloom formers were the potentially toxic dinoflagellate Pyrodinium bahamense var. bahamense and two centric diatoms, Dactyliosolen fragilissimus and Cerataulina pelagica. Many of the biovolume peaks observed over the study period were attributable to these three species. The results of time series modeling of phytoplankton dynamics further highlighted the disparities between the two regions of the lagoon in terms of the suite of parameters that best predict the observed trends in the biomass of phytoplankton. Overall, the outcome of this initial modeling effort in the Indian River Lagoon suggests that time series approaches can help define the factors that influence phytoplankton dynamics.

Akashiwo sanguinea (Dinophyceae) blooms in a sub-tropical estuary: An alga for all seasons

“…Corresponding salinity, temperature, total nitrogen, and total phosphorus values are reported and discussed within the context of possible factors related to A. sanguinea dynamics. The results of this study and recent observations of regular blooms of A. sanguinea in a number of other Florida estuaries, including the Indian River Lagoon (Phlips et al 2010(Phlips et al , 2011 and the St. Lucie Estuary (Phlips et al 2012), highlight the importance of this species in the subtropical environments of the Gulf of Mexico and the east coast of Florida, and provide further evidence of its tolerance to a wide range of environmental conditions.…”

“…By contrast, blooms of A. sanguinea have rarely been observed in well-flushed estuaries in Florida, such as the Suwannee River Estuary (Quinlan et al 2007), the central Indian River Lagoon (Phlips et al 2010), the southern St. Lucie Estuary (Phlips et al 2012) and the outer estuary of the St. Johns River (Cichra & Phlips, unpublished data).…”

Monitoring of the 2011 Super Algal Bloom in Indian River Lagoon, FL, USA, Using MERIS

“…Field in-situ data further supported our satellite data analysis results that the bloom began in the BR based on monthly Chl a samples collected by Philps et al [39,40]. Heavy rains can increase nutrient levels in the IRL and are thought to be a trigger for previous algal blooms of picocyanobacteria and dinoflagellates in the summer months [39][40][41]. between March and April, but these concentrations are not significantly different from their historical means since they had been decreasing in concentration over the past decade [30].…”

“…Mean water temperatures recorded at the USGS Haulover Canal dropped from 29.4 °C (30 September 2011) to 25.7 °C (3 October 2011; Figure 9). While MODIS surface temperature maps were not available for this event, all IRL segments have similar temperature fluctuations [40,41]. The initial drop in temperature coincided with the peak of the bloom between 14 September and 3 October throughout the IRL ( Figure 6).…”

Seasonal phytoplankton dynamics in the coastal waters of the north-eastern Adriatic Sea

“…Some of the ubiquitous species, namely: Dactyliosolen fragilissimus, Cerataulina pelagica and Guinardia striata are common bloom-forming taxa (Gómez and Gorsky, 2003), and it is presumed that these diatoms benefit from the ability to store nutrients and prosper in environments where nutrients are available in pulses (Phlips et al, 2010). Further, highest concentrations of another ubiquitous species, Thalassionema nitzschioides, were observed in July 2009.…”