Marine Biology Commons^™

Interactive Effects Of Herbivory And Substrate Orientation On Algal Community Dynamics On A Coral Reef, Alain Duran, Ligia Collado-Vides, L. Palma, D. E. Burkepile

Department of Biological Sciences

Herbivory is a significant driver of algal community dynamics on coral reefs. However, abiotic factors such as the complexity and orientation of the benthos often mediate the impact of herbivores on benthic communities. We experimentally evaluated the independent and interactive effects of substrate orientation and herbivorous fishes on algal community dynamics on a coral reef in the Florida Keys, USA. We created horizontal and vertical substrates, mimicking the trend in the reduction of vertical surfaces of coral reefs, to assess how algal communities developed either with herbivory (open areas) or without herbivory (herbivore exclosures). We found that substrate orientation was …

Seagrasses In The Age Of Sea Turtle Conservation And Shark Overfishing, Michael R. Heithaus, Teresa Allcoverro, Rohan Arthur, Derek Burkholder, Kathryn A. Coates, Marjolijn J.A. Christianen, Nachiket Kelkar, Sarah A. Manuel, Aaron J. Wirsing, W. Judson Kenworthy, James W. Fourqurean

Department of Biological Sciences

Efforts to conserve globally declining herbivorous green sea turtles have resulted in promising growth of some populations. These trends could significantly impact critical ecosystem services provided by seagrass meadows on which turtles feed. Expanding turtle populations could improve seagrass ecosystem health by removing seagrass biomass and preventing of the formation of sediment anoxia. However, overfishing of large sharks, the primary green turtle predators, could facilitate turtle populations growing beyond historical sizes and trigger detrimental ecosystem impacts mirroring those on land when top predators were extirpated. Experimental data from multiple ocean basins suggest that increasing turtle populations can negatively impact seagrasses, …

A Comprehensive And Integrative Reconstruction Of Evolutionary History For Anomura (Crustacea: Decapoda), Heather D. Bracken-Grissom, Maren E. Cannon, Patricia Cabezas, Rodney M. Feldmann, Carrie E. Schweitzer, Shane T. Ahyong, Darryl L. Felder, Rafael Lemaitre

Department of Biological Sciences

Background

The infraorder Anomura has long captivated the attention of evolutionary biologists due to its impressive morphological diversity and ecological adaptations. To date, 2500 extant species have been described but phylogenetic relationships at high taxonomic levels remain unresolved. Here, we reconstruct the evolutionary history—phylogeny, divergence times, character evolution and diversification—of this speciose clade. For this purpose, we sequenced two mitochondrial (16S and 12S) and three nuclear (H3, 18S and 28S) markers for 19 of the 20 extant families, using traditional Sanger and next-generation 454 sequencing methods. Molecular data were combined with 156 morphological characters in order to estimate the largest …

Microhabitat Selection By Marine Mesoconsumers In A Thermally Heterogeneous Habitat: Behavioral Thermoregulation Or Avoiding Predation Risk?, Jeremy J. Vaudo, Michael R. Heithaus

Department of Biological Sciences

Habitat selection decisions by consumers has the potential to shape ecosystems. Understanding the factors that influence habitat selection is therefore critical to understanding ecosystem function. This is especially true of mesoconsumers because they provide the link between upper and lower tropic levels. We examined the factors influencing microhabitat selection of marine mesoconsumers – juvenile giant shovelnose rays (Glaucostegus typus), reticulate whiprays (Himantura uarnak), and pink whiprays (H. fai) – in a coastal ecosystem with intact predator and prey populations and marked spatial and temporal thermal heterogeneity. Using a combination of belt transects and data …

Could Relatedness Help Explain Why Individuals Lead In Bottlenose Dolphin Groups?, Jennifer S. Lewis, Douglas Wartzok, Michael R. Heithaus, Michael Krützen

Department of Biological Sciences

In many species, particular individuals consistently lead group travel. While benefits to followers often are relatively obvious, including access to resources, benefits to leaders are often less obvious. This is especially true for species that feed on patchy mobile resources where all group members may locate prey simultaneously and food intake likely decreases with increasing group size. Leaders in highly complex habitats, however, could provide access to foraging resources for less informed relatives, thereby gaining indirect benefits by helping kin. Recently, leadership has been documented in a population of bottlenose dolphins (Tursiops truncatus) where direct benefits to leaders …

Disturbance Driven Colony Fragmentation As A Driver Of A Coral Disease Outbreak, Marilyn E. Brandt, Tyler B. Smith, Adrienne M.S. Correa, Rebecca Vega-Thurber

Department of Biological Sciences

In September of 2010, Brewer's Bay reef, located in St. Thomas (U.S. Virgin Islands), was simultaneously affected by abnormally high temperatures and the passage of a hurricane that resulted in the mass bleaching and fragmentation of its coral community. An outbreak of a rapid tissue loss disease among coral colonies was associated with these two disturbances. Gross lesion signs and lesion progression rates indicated that the disease was most similar to the Caribbean coral disease white plague type 1. Experiments indicated that the disease was transmissible through direct contact between colonies, and five-meter radial transects showed a clustered spatial distribution …

Transcriptional Response Of Two Core Photosystem Genes In Symbiodinium Spp. Exposed To Thermal Stress, Michael P. Mcginley, Matthew D. Aschaffenburg, Daniel D. Pettay, Robin T. Smith, Todd C. Lajeunesse, Mark E. Warner

Department of Biological Sciences

Mutualistic symbioses between scleractinian corals and endosymbiotic dinoflagellates (Symbiodinium spp.) are the foundation of coral reef ecosystems. For many coral-algal symbioses, prolonged episodes of thermal stress damage the symbiont's photosynthetic capability, resulting in its expulsion from the host. Despite the link between photosynthetic competency and symbiont expulsion, little is known about the effect of thermal stress on the expression of photosystem genes in Symbiodinium. This study used real-time PCR to monitor the transcript abundance of two important photosynthetic reaction center genes, psbA(encoding the D1 protein of photosystem II) and psaA (encoding the P700 protein of photosystem I), …

Characterization Of Atlantic Cod Spawning Habitat And Behavior In Icelandic Coastal Waters, Timothy B. Grabowski, Kevin M. Boswell, Bruce J. Mcadam, R.J. David Wells, Guđrún Marteinsdóttir

Department of Biological Sciences

The physical habitat used during spawning may potentially be an important factor affecting reproductive output of broadcast spawning marine fishes, particularly for species with complex, substrate-oriented mating systems and behaviors, such as Atlantic cod Gadus morhua. We characterized the habitat use and behavior of spawning Atlantic cod at two locations off the coast of southwestern Iceland during a 2-d research cruise (15–16 April 2009). We simultaneously operated two different active hydroacoustic gear types, a split beam echosounder and a dual frequency imaging sonar (DIDSON), as well as a remotely operated underwater vehicle (ROV). A total of five fish species were …

Coral Thermal Tolerance: Tuning Gene Expression To Resist Thermal Stress, Anthony J. Bellatuono, Camila Granados-Cifuentes, David J. Miller, Ove Hoegh-Guldberg, Mauricio Rodriguez-Lanetty

Department of Biological Sciences

The acclimatization capacity of corals is a critical consideration in the persistence of coral reefs under stresses imposed by global climate change. The stress history of corals plays a role in subsequent response to heat stress, but the transcriptomic changes associated with these plastic changes have not been previously explored. In order to identify host transcriptomic changes associated with acquired thermal tolerance in the scleractinian coralAcropora millepora, corals preconditioned to a sub-lethal temperature of 3°C below bleaching threshold temperature were compared to both non-preconditioned corals and untreated controls using a cDNA microarray platform. After eight days of hyperthermal …

Macroalgae Decrease Growth And Alter Microbial Community Structure Of The Reef-Building Coral, Porites Astreoides, Rebecca Vega Thurber, Deron E. Burkepile, Adrienne M.S. Correa, Andrew R. Thurber, Andrew A. Schantz, Rory Welsh, Catharin Pritchard

Department of Biological Sciences

With the continued and unprecedented decline of coral reefs worldwide, evaluating the factors that contribute to coral demise is of critical importance. As coral cover declines, macroalgae are becoming more common on tropical reefs. Interactions between these macroalgae and corals may alter the coral microbiome, which is thought to play an important role in colony health and survival. Together, such changes in benthic macroalgae and in the coral microbiome may result in a feedback mechanism that contributes to additional coral cover loss. To determine if macroalgae alter the coral microbiome, we conducted a field-based experiment in which the coral Porites …

Development Of Gene Expression Markers Of Acute Heat-Light Stress In Reef-Building Corals Of The Genus Porites, Carly D. Kenkel, Galina Aglyamova, Ada Alamaru, Ranjeet Bhagooli, Roxana Capper, Ross Cunning, Amanda Devillers, Joshua A. Haslun, Laetitia Hédouin, Shashank Keshavmurthy, Kristin Kuehl, Huda Mahmoud, Elizabeth S. Mcginty, Phanor H. Montoya-Maya, Caroline V. Palmer, Raffaella Pantile, Juan A. Sánchez, Tom Schils, Rachel N. Silverstein, Logan B. Squiers, Pei-Ciao Tang, Tamar L. Goulet, Mikhail V. Matz

Department of Biological Sciences

Coral reefs are declining worldwide due to increased incidence of climate-induced coral bleaching, which will have widespread biodiversity and economic impacts. A simple method to measure the sub-bleaching level of heat-light stress experienced by corals would greatly inform reef management practices by making it possible to assess the distribution of bleaching risks among individual reef sites. Gene expression analysis based on quantitative PCR (qPCR) can be used as a diagnostic tool to determine coral condition in situ. We evaluated the expression of 13 candidate genes during heat-light stress in a common Caribbean coral Porites astreoides, and observed strong …