Environmental sciences

Levels of the greenhouse gas carbon dioxide have been increasing dramatically in the atmosphere since the onset of the Industrial Revolution with a sharp escalation occurring due to anthropogenic causes such as the burning of fossil fuels. The ocean acts as a carbon sink for this atmospheric CO2, absorbing a large majority of it. This process causes a chemical reaction that has been increasing the acidity level of ocean water and progressively lowering the average pH value. When a carbon dioxide molecule is absorbed into sea water, two positively charged ions are produced. Because pH value is a measurement of hydrogen ion concentration in any given solution, these added hydrogen ions effectively lower the pH value of the ocean. Since these hydrogen ions are positively charged, they go on to interact with the negatively charged bases already present in the ocean. One of these bases is CaCO3, or the carbonate ion. Carbonate is essential to calcifying marine organisms, who use this ion to build and maintain their shells and skeletons. However, as atmospheric carbon dioxide levels increase and the resulting chemical reactions occur, the ocean’s carbonate saturation decreases. Coral is one such calcifying organism that essential to the aquatic ecosystem in a number of ways, most of which can be attributed to the fact that coral reefs are one of the planet’s most biodiverse ecosystems despite inhabiting only a very small portion of the ocean. Several studies have linked coral’s carbonate production to their ability to create functional skeletons. One such study was published by Kuffner et al in 2013 in the Florida Keys. Four sites ranging from Miami to the Dry Tortugas were selected, and two batches of forty Siderastrea siderea (massive starlet coral) each were selected for two experimental runs. At six-month intervals, these samples were analyzed to determine linear expansion rates and calcification levels. After analysis in both runs, a strong correlation between linear expansion rates and calcification levels was determined. Corals that experienced heightened calcification rates also experienced heightened linear expansion. This experiment solidified the negative affect ocean acidification will have in future years on coral reefs if left unacknowledged. Langdon et al also published an experiment done in the Florida Keys in 2013 that determined a relationship between increased atmospheric CO2 levels and decreased calcification rates of coral. Eleven samples of a combination of Siderastrea radians (shallow water starlet coral) and Solenastrea hyades (smooth star coral) were epoxied to cinderblocks with sensors recording environmental data at thirty-minute intervals. Random samples were incubated in tanks in situ and given a treatment regime designed to simulate increased ocean acidification conditions through chemical injections of NaHCO3 (sodium bicarbonate) and HCl (hydrogen chloride). This treatment lowered pH value in the incubation chambers by 0.1 to 0.2 units. Calcification rates of the incubated coral samples were determined through statistical analysis. Coral samples that experienced a 0.1 unit drop in pH value experienced decreased calcification rates of 50% and coral samples that experiences a 0.2 unit drop in pH value experienced a decreased calcification rate of 52%. Both of these studies combined showcases the two-part threat ocean acidification is placing on coral reefs in the Florida Keys. As the average pH of ocean water drops, corals are unable to achieve net carbonate accretion and calcification rates drop. This causes corals to experience stunted linear expansion, density, rugosity, and reproduction rates. As coral population dwindles, Florida will experience several negative socio-economic impacts such as diminished coastal protection from storms, tourism, income and jobs created by fisheries, and medicinal opportunities as new life-saving medicines will no longer be able to be harvested from dying reefs. Mitigation and adaptation methods must include reducing other local stressors to coral.

Queen conch (Lobatus gigas) have been experiencing low reproduction rates throughout their distribution. Imposex female conchs have been observed with male verges in the British Virgin Islands and have been linked to areas of high boating activity. While in the Florida Keys, reduced reproduction has been linked to Lobatus gigas located in nearshore habitats. This literature review will evaluate the most effective method to determine a cause for reproductive failure in Lobatus gigas. In the British Virgin Islands, Cassander Titley-O’Neal analyzed imposex females and performed a butylin analysis on the digestive glands and food resources within the habitat the conch were collected. Titley-O’Neal recognized imposex morphology in Lobatus gigas and collected samples based on these features in areas of high boating activity, using reproductively normal conch from areas of low boating activity as reference. Gabriel Delgado compared the gonadal tissue and cerebral ganglia cell diameter and density of non-imposex queen conch offshore and nearshore in the Florida Keys. In the La Parguera area of Puerto Rico, Shawna E. Reed compared the gonads of imposex females to normal female conch gonads. Low concentrations of Tributyltin (TBT) in the turtle grass and marine algae samples taken by Titley-O’Neal, suggested food source is not enough uptake of TBT to cause imposex in Lobatus gigas. The presence of TBT was found in both male and female digestive glands, and in all sites, except one reference site, Anegada, but was highest in boating active sites. Concentration of Tributyltin was observed to be higher in male conch compared to females of the same area. The nearshore male and female queen conch of the Florida Keys were found to have less than 50% developed gametogenic tissue resulting in more than half being sexually inactive. The offshore population were observed to be highly reproductive with over 50% developed oogenic tissue in females and over 75% spermatogenic tissue in males. Delgado concluded that there appears to be abnormalities in the cerebral ganglion (c.g. responsible for hormone production) and deficiencies in the gonads of nearshore conch, both associated with reproduction. Given there was no environmental samples taken, there is no confirmed environmental or physical source for the cause of the abnormality in nearshore conch, other than the closer geographic proximity to anthropogenic factors. Reed compared imposex gonads to the gonads of normal reproducing females and determined no difference in sexual tissue. Imposex females demonstrated no male-like behavior. One imposex female was collected near an egg mass and had emptied signet cells, indicating successful reproduction. After evaluating each method, it appears abnormalities in cerebral ganglia, and deficiencies in gonads have been more successful in providing reason for reproductive failure in Lobatus gigas, compared to looking at masculinized females. Imposex has not yet been proven to have a negative effect on conch reproduction other than hypothesized issues regarding eggs masses as of present. Further study in the spawning of normal and imposex queen conch, with specific attention to their egg masses and habits, can potentially link imposex to failing reproduction among aggregations. Butlytin analysis on the gonads of queen conch may determine a link between Tributyltin concentration and delay in gametogenic tissues. Further research in water quality and sediment sampling to detect TBT in habitats of Lobatus gigas spawning.

The city of Hallandale Beach, Florida adopted the “Our Local Coral Reef Protection Ordinance” in June of 2019, with plans to restore their coastline and protect the community from future storm surges. Ordinance No. 2019 1- 011 added sections 5 to 8 in Chapter 13 "Health and Sanitation" of the city of Hallandale Beach code of ordinances, which outline strategies to protect and restore the resilience of the nearshore coral reef. Complex coral reef systems bring higher biodiversity and will raise the economic value of the reef to tourism. The length of Hallandale Beach shoreline is approximately 0.80mi (4200ft). Acropora cervicornis (Staghorn coral), a critically endanger species, is said to be found ½ mile off the coast of Hallandale Beach and is an important reef-building species to be monitored. This proposal will establish a long-term monitoring plan and baseline for the nearshore coral reef based on the Atlantic and Gulf Rapid Reef Assessment (AGRRA) protocols. It will briefly outline procedures needed to accomplish the three different monitoring surveys and important indicators each SCUBA diver will be required to record. Corals are the primary builders of reef habitats and they benefit from the presence of reef fish and benthic organisms. Reef fish have different eating habits that promote positive structure changes such as, keeping turf algae in check clearing room for recruitment of polyps. Benthic promotors such as, crustose coralline algae and minimal turf algae encourage a healthy reef habitat. According to a map of Broward County, Florida reef structure created by Brain Walker, the linear reef inner begins about 0.80 mi (4200ft) and the liner reef middle ends at about 1.75mi (9240ft) from the shore. There appears to be no linear outer reef off the coast of Hallandale Beach. There is no previous baseline to compare future surveyed data or confirm presence and density of diver sighted Acropora cervicornis. Baselines are important historical data that enables the city to identify changes in the complexity of the reef structure and responses to climate change to make proactive decisions. An initial baseline of Hallandale’s reef will be made to be comparable with future monitoring data, as well as determine the effectiveness of the management plans in place. AGGRA protocols require a minimum of six divers and with the use of city vendors, equipment costs can be as low as 230 dollars. Without a coral reef, the city may face costly damages from natural disasters such as hurricanes. Coral Reefs provide protection against storm surges that without, coastal erosion would increase and leave the city without an offshore defense against high energy wave action. AGRRA protocols will be applied to create a basic level survey easily adaptable, this will provide community building and outreach opportunities through citizen science and volunteering.

Dr. Von D. Mizell-Eula Johnson State Park is a barrier island off the coast of Dania Beach, Florida. Situated between the Atlantic Ocean and the Intracoastal Waterway, with the brackish Whiskey Creek transecting the park from north to south, the park is home to several coastal ecosystems and poses an unique opportunity to collect valuable data to assess the impact of sea-level rise on the distinct ecological communities within. The park is managed by the Florida Department of Environmental Protection Division of Recreation and Parks. Goals for the park management and protection include protecting the water quality and quantity in the park (including restoring hydrology to a feasible level), as well as restoring and maintaining the natural communities within the park. As studies have shown, changes of the salinity in the groundwater and surrounding soils can affect the viability of coastal forest habitats and cause a shift in ecotones. To this date, there have been no detailed studies on the extent of the groundwater dynamics within the park. With three bodies of water with differing salinity surrounding the park, the geological design should create four independent zones of saline lensing around the freshwater lenses within the two segments of the island. Installation of piezometers in east-west transects at regular increments from the north to the south could allow for the mapping of the transition from saline to freshwater within the park. Subsequent sampling and testing of temperature, salinity, and water depth, as well as other ambient factors, over a complete lunar cycle, would provide critical data in determining the extent of the tides and sea-level rise on park’s freshwater-saltwater interface. Understanding this dynamic flux is vital in preservation and restoration management plans, especially involving protection and reestablishment of at-risk or endangered species. This research will provide insight into predictable changes in the park’s communities. This knowledge can be incorporated into established Florida Department of Environmental Protection management and monitoring plan. Establishing long-term groundwater monitoring protocols can influence future protection and restoration projects with ground truth data. If successful, this type of monitoring can be expanded to other state parks of similar coastal geomorphological features.