Tropical Marine Ecology 2013

Project abstract: Coral disease and wave action

Megan Bednarz and Rachel Morrison

Abstract

The prominence of diseased coral, or lack of large and healthy corals, is notable when snorkeling around Discovery Bay, Jamaica. The purpose of this study was to take a closer look at the relationship between the distribution of diseased coral and the wave action at six sites in the bay. Our study was narrowed to a select few physical factors including wave action and turbidity in the sea grass, mangroves, boat channel, jetty, back reef and reef crest. A survey of twenty corals at each site was completed to quantify the presence of disease. Three sets of clod cards were placed at each site, at two depths, for twenty-four hours to determine a percent loss due to water dissolving Plaster of Paris cubes.  In an area with maximum wave action, like the reef crest, abundance and diversity will be negatively impacted. In an area with low wave action, like the sea grass, there will be an increase in sedimentation, which will also negatively impact corals.  Other factors like depth, light, and salinity and anthropogenic forces were not measured but contribute to the presence and spread of disease. There was no direct correlation between a specific disease and wave action.

Project abstract: Sponge Reattachment on Different Substrates

Allegra Waters and Sarah Song

Abstract

Sponges are vital to the marine system because they can attach and grow on just about anything allowing for niche specialization among organisms. The objective of this study was to observe the reattachment rates of different species of sponges on different substrates. Amphimedon compressa, Aplysina fistularis, and Iotrochota birotulata were all placed on rock, sand, coral, and garbage. Each species was cut up into three different sizes; 1cm, 5cm, 10cm. The attachment rate depending on size was also tested. Each sponge was gently poked after given 48 hours to attach. This process was repeated for 6 days giving the sponge’s ample time to attach. The 10cm fragments attached best in all three species of sponge. A. fistularis had the overall best attachment but I. birotulata had the most attach first. This data means I. birotulata would be the most successful in the ocean. Because of the constant disturbance of wave action the shorter the time the sponge takes to attach the more successful it would be in a real life situation.

Project abstract: Effects of the feeding habits of Aplysia dactylomela resultant from changes in photoperiods and thermal variation

Bryan Hadler and Jason Kahen

Abstract

Feeding habits of the Aplysia dactylomela were observed under varied conditions of light and temperature. The A. dactylomela were subjected to twenty-hour hour cycles of complete darkness, light and a 2° C increase in the water temperature. Statistical analysis of the data was unable to be preformed due to faulty data collection and test methods. The raw data appears to indicate that there is no significant difference in the herbivory rates when the light or temperature is changed. The total amounts eaten the control and the experimental groups were within one percent of each other for the dark treatment and within five percent of each other for the light treatment. The heat treatment had vastly different results for both the control and experimental compared to the other two tests and should be discounted because of this. These experiments provided general observations about the feeding behavior of A. dactylomela though and a lesson in laboratory procedures.

Project abstract: Algal Feeding Preferences and Grazing Patterns of Diadema antillarum Under Varying Light/Dark Cycles

Deborah Aller and Ian Martin

Abstract

As one of the biggest providers of environmental complexity in tropical marine ecosystems, it is crucial that researchers continue to compile as much information as possible about coral reefs and their high fragility, diversity, and productivity. One of the biggest staples in the study of reefs and their conservation is the balance between spatial partitioning between algae and corals and the constant competition for limiting resources, such as light. Since algae tends to grow and spread much faster than reef building corals, herbivory by sea urchins, specifically Diadema antillarum, is essential for maintaining coral colonies and thus an array of environmental complexity. The current study examines how D. antillarum grazing patterns are affected by varying light/dark cycles as well as algal feeding preferences of D. antillarum. Twelve D. antillarum were divided in to groups of four and placed in three separate tanks which received varying amount of light. Additionally each tank received three different algal genera for grazing in equal amounts. Algal samples were weighed and information was compiled to determine which light treatment caused the urchins to graze more as well as which algal genera was preferred by the urchins for grazing. It was found that there was no significant difference in mean algal percent mass consumption between the groups under differing light/dark cycles. Similarly it was also found that the D. antillarum used for this study had no feeding preferences based on the three algal genera provided to them; Dictyota sp., Enteromorpha sp., and Wrightiella blodgettii. Possible factors that may have contributed to the gathering of skewed data which lead to insignificant results could include but are not limited to a lack of acclimation of the urchins to the testing tanks that were used, the use of unfamiliar algal genera that are not normally a part of the D. antillarum diet, and a natural homing behavior of sea urchins. Because of limited supplies and time, further investigation is then called for and more research is needed to solidify more concretely the findings of this study.

Project abstract: Behavioral response of O. echinata and O. reticulate to chemical compounds

Jean Tremmel

My experiment was conducted to see if brittle stars, because they posses chemoreceptor’s would be able to detect sunscreen SPF 30 in water and remove themselves from the affected area. I had mixed results with this experiment. There are a lot of different aspects that come into play and I did a large amount of research to determine the reason for my results. Sunscreen has been shown to cause coral bleaching and I thought it would be a great research project to see if the sunscreen would have an effect on brittle stars.

Project abstract: Porcelain Crab Territoriality in Anemones

Benjamin Kammerman and Josh Kaufman

Abstract: There are numerous factors, both intraspecie (sex, juvenility) and environmental (host availability), influencing the territoriality of the porcelain crab species Petrolisthes armatus when utilizing the anemone Condylactus gigantea as a host. Understanding the influence of these variables on the lifestyle and behavior of Petrolisthes armatus gives an insight into this particular symbiotic relationship. We examined the effect that sex, juvenility, and host anemone abundance had on porcelain crab behavior and territoriality. The sex and juvenility tests were performed in a controlled “wet lab” setting. The host sharing tests were performed in and around the lagoon of Discovery Bay, Jamaica. We found that territoriality behavior acts independently of sex, that juvenility can affect ‘host sharing,’ and that low host abundance positively correlates with increased territoriality.

Project abstract: Observational study of root assemblage interactions

Kayla Kraker and Nicole Laible

Abstract:

An observational study of root assemblage interactions was conducted in the Rhizophora mangle forests of Discovery Bay Marine Lab, Jamaica. Symbiotic relationships in accordance to varying root structures, were monitored to denote the changes in species interactions. Two sites were chosen within the lagoon area of the property, where there were regions that had increased groundwater seepage. This allowed for physical parameters to be documented at each site. The sites were labeled according to salinity level, the Groundwater Input site and the Non-Groundwater Input site, where each site had two sections to study with different light penetration levels. Four roots were chosen at random per section. Root measurements were done for root circumference, length, and distance between each tagged root. Observations were done for ten minutes daily during high tide to note the percentage algae cover, species richness, species diversity, and species interactions. Physical parameters were measured for the last four days of the experiment at each site using the YSI. Several equations were used to determine results: the Bran-Branquet method to find the percentage algae cover on attached roots versus suspended roots, the Nearest Neighbor method measuing the root distribution, which was characterized by propagule distribution. Lastly, Simpsons Diversity Index to find the species diversity per section at each root. Overall, results showed that different mutualistic relationships occur between species and varying root assemblages. In the different sites, there was a difference in species richness, diversity, and percentage algae cover for each root.

Project abstract: The Effect of Sunscreen on Marine Sponge Filtration Rates

Melanie Lauzon

Abstract

Flow rates of the marine sponge species Aplysina fistularis were measured to determine if the presence of sunscreen in seawater has an effect on sponge filtration rates. Aplysina fistularis specimens were collected from the coral reef at Discovery Bay, Jamaica. The specimens were placed in separate tanks with continuous water flow. Sunscreens with varying sun protection factors (SPF) 30, 50 and 85 were then added to the tanks. Each specimen had a designated SPF that was tested. Flow rate measurements were taken every 20 minutes for a period of one hour of the sunscreen application, and every hour for three hours thereafter. The effects of sunscreen on the flow rates of each individual sponge proved to be inconclusive. However, the sponge treated with SPF 85 displayed a relatively lower flow rate compared to the specimens treated with the lower SPFs.

Project abstract: The Feeding Preferences of Tripneustes ventricosus

Lawrence Chong and Nicholas DaCosta

Abstract

Thalassia testudinum, which is commonly grazed by Tripneustes ventricosus, is located throughout the Caribbean. Discovery Bay, Jamaica is home to nitrogen-enriched Thalassia testudinum while in other areas of the Caribbean the Thalassia testudinum is not nitrogen-enriched. The main focus of this experiment was to see whether or not Tripneustes ventricosus would prefer to consume the nutrient rich Thalassia testudinum found in the lagoon of Discovery Bay over the Thalassia testudinum found outside the lagoon. Tripneustes ventricosus were collected for this experiment as well as Thalassia testudinum from inside and outside the lagoon of Discovery Bay and were put into artificial environments designed to test their preferences. After 3 trials, with trials 2 and 3 having a no-light factor, our data indicated that Tripneustes ventricosus does have a preference over their food consumption and that is they would prefer to consume nutrient rich Thalassia testudinum.

Project abstract: Aggressiveness of Stegastes Adustus as Observed in Discovery Bay, Jamaica

Sarah Drucker and Yelizaveta Kotlyarova

Abstract

An experiment was performed on Discovery Bay coral reef, to determine the aggressive tendencies of the damselfish Stegastes adustus. A natural setting behavior was observed and studied in four locations: within the mangroves in an area with more algal cover and an area with less algal cover, and within the jetty on the leeward and windward sides. On an aggression scale from 1 to 5, S. adustus exhibited on average an aggression level of 4 marked by chasing. The damselfish more notably chased away other damselfish that shared their area. However, Haemulon flavolineatum and Scarus taeniopterus were also chased away in the jetty leeward location where they were found sharing the habitats of the damselfish. In the mangrove area where algae was more scarce and damselfish numbers were high S. adustus were most aggressive. S. adustus were least aggressive in the jetty windward area with the least population of damselfish and the lowest species variation, although algae cover was low. It is suggested that S. adustus are a strongly aggressive fish and food supply and population count affect this level of aggression.