Florida Bay is a shallow subtropical estuary, which experiences highly variable environmental fluctuations due to natural forces (hurricanes, climatic variations and sea level rise) and anthropogenic influences (agricultural activity, water management and urbanization). Study of short time-scale variability in benthic community population structure and synchronous environmental change is essential to understanding forcing relationships between environment and its effects on population. Benthic foraminifera assemblage variability is an excellent indicator of environmental change in estuarine and coastal areas because populations may respond relatively quickly on spatial and temporal scales (Alve, 1995). Temporal resolution is enhanced because foraminifera may reproduce as often as 3 months to one year (Murray, 1991).
Monthly population sampling from 15 stations throughout Florida Bay is being conducted in a multi-year program begun in January 2004. This includes collection of sediment samples containing benthic foraminifera as well as site measurement of environmental parameters (salinity, temperature, suspended particulate matter, chlorophyll, nutrients, and dissolved organic matter).
The objectives of the current study are to examine sites in Florida Bay with enhanced temporal resolution and determine (1) monthly variability in benthic foraminifera species composition, diversity, dominance and abundance; and (2) provide data on the relationship between water quality parameters and these measures of benthic foraminifera community structure.
In northeastern Florida Bay (station 1), preliminary results from monthly sampling indicate a temporal inverse relationship between the relative abundance of particular species and increasing salinity to hyper saline (40 o/oo) conditions. The benthic foraminifera community is predominately Ammonia sp., Elphidium sps. and Peneroplis sps. (greater than 60%). Quinqueloculina sps. and Triloculina sps. contribute 40% or less to the total population during each month sampled. Over a twelve month interval an inverse relationship is evident between Peneropolis sps. and Ammonia sp. Peneroplis sps.are more abundant under normal marine conditions, while Ammonia sp. is dominant during low and hyper saline conditions. Elphidium sps. decreased with increasing salinity.
Sample collection during 2005, foraminifera enumeration, and data processing is in progress and benthic foraminifera population characteristics are being compared with environmental parameters. These data sets will provide a fundamental baseline from which to evaluate long-term environmental change in Florida Bay and facilitate utilization of benthic foraminifera as proxies of environmental change.
Available at: http://works.bepress.com/patricia-blackwelder/22/