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The Ecological Genomic Basis Of Salinity Adaptation In Tunisian Medicago Truncatula, Maren L. Friesen, Eric J.B. Von Wettberg, Mounawer Badri, Ken S. Moriuchi, Fathi Barhoumi, Peter L. Chang, Sonia Cuellar-Ortiz, Matilde A. Cordeiro, Wendy T. Vu, Soumaya Arraouadi, Naceur Djebali, Kais Zribi, Yazid Badri, Stephanie S. Porter, Mohammed Elarbi Aouani, Douglas R. Cook, Sharon Y. Strauss, Sergey V. Nuzhdin Dec 2014

The Ecological Genomic Basis Of Salinity Adaptation In Tunisian Medicago Truncatula, Maren L. Friesen, Eric J.B. Von Wettberg, Mounawer Badri, Ken S. Moriuchi, Fathi Barhoumi, Peter L. Chang, Sonia Cuellar-Ortiz, Matilde A. Cordeiro, Wendy T. Vu, Soumaya Arraouadi, Naceur Djebali, Kais Zribi, Yazid Badri, Stephanie S. Porter, Mohammed Elarbi Aouani, Douglas R. Cook, Sharon Y. Strauss, Sergey V. Nuzhdin

Department of Biological Sciences

Background: As our world becomes warmer, agriculture is increasingly impacted by rising soil salinity and understanding plant adaptation to salt stress can help enable effective crop breeding. Salt tolerance is a complex plant phenotype and we know little about the pathways utilized by naturally tolerant plants. Legumes are important species in agricultural and natural ecosystems, since they engage in symbiotic nitrogen-fixation, but are especially vulnerable to salinity stress. Results: Our studies of the model legume Medicago truncatula in field and greenhouse settings demonstrate that Tunisian populations are locally adapted to saline soils at the metapopulation level and that saline origin …


El Nino Southern Oscillation (Enso) Enhances Co2 Exchange Rates In Freshwater Marsh Ecosystems In The Florida Everglades, Sparkle L. Malone, Christina L. Staudhammer, Steven F. Oberbauer, Paulo Olivas, Michael G. Ryan, Jessica L. Schedlbauer, Henry W. Loescher, Gregory Starr Dec 2014

El Nino Southern Oscillation (Enso) Enhances Co2 Exchange Rates In Freshwater Marsh Ecosystems In The Florida Everglades, Sparkle L. Malone, Christina L. Staudhammer, Steven F. Oberbauer, Paulo Olivas, Michael G. Ryan, Jessica L. Schedlbauer, Henry W. Loescher, Gregory Starr

Department of Biological Sciences

This research examines the relationships between El Nino Southern Oscillation (ENSO), water level, precipitation patterns and carbon dioxide (CO2) exchange rates in the freshwater wetland ecosystems of the Florida Everglades. Data was obtained over a 5-year study period (2009-2013) from two freshwater marsh sites located in Everglades National Park that differ in hydrology. At the short-hydroperiod site (Taylor Slough; TS) and the long-hydroperiod site (Shark River Slough; SRS) fluctuations in precipitation patterns occurred with changes in ENSO phase, suggesting that extreme ENSO phases alter Everglades hydrology which is known to have a substantial influence on ecosystem carbon dynamics. Variations in …


Ecology And Physiology Of The Pathogenic Cyanobacterium Roseofilum Reptotaenium, Laurie L. Richardson, Dina Stanic, Amanda May, Abigael Brownell, Miroslav Gantar, Shawn R. Campagna Dec 2014

Ecology And Physiology Of The Pathogenic Cyanobacterium Roseofilum Reptotaenium, Laurie L. Richardson, Dina Stanic, Amanda May, Abigael Brownell, Miroslav Gantar, Shawn R. Campagna

Department of Biological Sciences

Roseofilum reptotaenium is a gliding, filamentous, phycoerythrin-rich cyanobacterium that has been found only in the horizontally migrating, pathogenic microbial mat, black band disease (BBD) on Caribbean corals. R. reptotaenium dominates the BBD mat in terms of biomass and motility, and the filaments form the mat fabric. This cyanobacterium produces the cyanotoxin microcystin, predominately MC-LR, and can tolerate high levels of sulfide produced by sulfate reducing bacteria (SRB) that are also associated with BBD. Laboratory cultures of R. reptotaenium infect coral fragments, suggesting that the cyanobacterium is the primary pathogen of BBD, but since this species cannot grow axenically and Koch’s …


Screening Of Cyanobacteria And Microalgae For Their Ability To Synthesize Silver Nanoparticles With Antibacterial Activity, Vijay Patel, David Berthold, Pravin Puranik, Miroslav Gantar Dec 2014

Screening Of Cyanobacteria And Microalgae For Their Ability To Synthesize Silver Nanoparticles With Antibacterial Activity, Vijay Patel, David Berthold, Pravin Puranik, Miroslav Gantar

Department of Biological Sciences

The aim of this study was to assess the ability of selected strains of cyanobacteria and microalgae to biosynthesize silver nanoparticles (Ag-NPs) by using two procedures; (i) suspending the live andwashed biomass of microalgae and cyanobacteria into the AgNO3 solution and (ii) by adding AgNO3 into a cellfree culture liquid. Ag-NPs were biosynthesized by 14 out of 16 tested strains. In most of the cases Ag-NPs were formed both in the presence of biomass as well as in the cell-free culture liquid. This indicates that the process of Ag-NPs formation involves an extracellular compound such as polysaccharide. TEM analysis showed …


Morphological And Physiological Responses Of Seagrasses (Alismatales) To Grazers (Testudines: Cheloniidae) And The Role Of These Responses As Grazing Patch Abandonment Cues, Elizabeth A. Lacey, Ligia Collado-Vides, James W. Fourqurean Dec 2014

Morphological And Physiological Responses Of Seagrasses (Alismatales) To Grazers (Testudines: Cheloniidae) And The Role Of These Responses As Grazing Patch Abandonment Cues, Elizabeth A. Lacey, Ligia Collado-Vides, James W. Fourqurean

Department of Biological Sciences

Green sea turtles, Chelonia mydas, are grazers influencing the distribution of seagrass within shallow coastal ecosystems, yet the drivers behind C. mydas patch use within seagrass beds are largely unknown. Current theories center on food quality (nutrient content) as the plant responds to grazing disturbances; however, no study has monitored these parameters in a natural setting without grazer manipulation. To determine the morphological and physiological responses potentially influencing seagrass recovery from grazing disturbances, seagrasses were monitored for one year under three different gazing scenarios (turtle grazed, fish grazed and ungrazed) in a tropical ecosystem in Alcumal Bay, Quintana Roo, Mexico. …


Using Phylogenetically-Informed Annotation (Pia) To Search For Light-Interacting Genes In Transcriptomes From Non-Model Organisms, Daniel I. Speiser, M. Sabrina Pankey, Alexander K. Zaharoff, Barbara A. Battelle, Heather D. Bracken-Grissom, Jesse W. Breinholt, Seth M. Bybee, Thomas W. Cronin, Anders Garm, Annie R. Lindgren, Nipam H. Patel, Megan L. Porter, Meredith E. Protas, Ajna S. Rivera, Jeanne M. Serb, Kirk S. Zigler, Keith A. Crandall, Todd H. Oakley Nov 2014

Using Phylogenetically-Informed Annotation (Pia) To Search For Light-Interacting Genes In Transcriptomes From Non-Model Organisms, Daniel I. Speiser, M. Sabrina Pankey, Alexander K. Zaharoff, Barbara A. Battelle, Heather D. Bracken-Grissom, Jesse W. Breinholt, Seth M. Bybee, Thomas W. Cronin, Anders Garm, Annie R. Lindgren, Nipam H. Patel, Megan L. Porter, Meredith E. Protas, Ajna S. Rivera, Jeanne M. Serb, Kirk S. Zigler, Keith A. Crandall, Todd H. Oakley

Department of Biological Sciences

Background: Tools for high throughput sequencing and de novo assembly make the analysis of transcriptomes (i.e. the suite of genes expressed in a tissue) feasible for almost any organism. Yet a challenge for biologists is that it can be difficult to assign identities to gene sequences, especially from non-model organisms. Phylogenetic analyses are one useful method for assigning identities to these sequences, but such methods tend to be time-consuming because of the need to re-calculate trees for every gene of interest and each time a new data set is analyzed. In response, we employed existing tools for phylogenetic analysis to …


Two Distinct Microbial Communities Revealed In The Sponge Cinachyrella, Marie L. Cuvelier, Emily Blake, Rebecca Mulheron, Peter J. Mccarthy, Patricia Blackwelder, Rebecca L. Vega Thurber, Jose V. Lopez Nov 2014

Two Distinct Microbial Communities Revealed In The Sponge Cinachyrella, Marie L. Cuvelier, Emily Blake, Rebecca Mulheron, Peter J. Mccarthy, Patricia Blackwelder, Rebecca L. Vega Thurber, Jose V. Lopez

Department of Biological Sciences

Marine sponges are vital components of benthic and coral reef ecosystems, providing shelter and nutrition for many organisms. In addition, sponges act as an essential carbon and nutrient link between the pelagic and benthic environment by filtering large quantities of seawater. Many sponge species harbor a diverse microbial community (including Archaea, Bacteria and Eukaryotes), which can constitute up to 50% of the sponge biomass. Sponges of the genus Cinachyrella are common in Caribbean and Floridian reefs and their archaeal and bacterial microbiomes were explored here using 16S rRNA gene tag pyrosequencing. Cinachyrella specimens and seawater samples were collected from the …


Regional Differences In The Age And Growth Of Red Snapper (Lutjanus Campechanus) In The Us Gulf Of Mexico, Courtney R. Saari, James H. Cowan Jr., Kevin M. Boswell Oct 2014

Regional Differences In The Age And Growth Of Red Snapper (Lutjanus Campechanus) In The Us Gulf Of Mexico, Courtney R. Saari, James H. Cowan Jr., Kevin M. Boswell

Department of Biological Sciences

In the U.S. Gulf of Mexico (GOM), red snapper (Lutjanus campechanus) are managed as a unit stock, although the stock is assessed as subunits east and west of the Mississippi River. Differences were examined between management subunits by comparison of the size and age structure and growth rates of red snapper among recreational catches from 6 regions of the GOM: South Texas, North Texas, Louisiana, Alabama, Northwest Florida, and Central Florida. In all of these regions, red snapper sampled in 2009 and 2010 were small and predominantly from age classes that represented the strong recruitment for the year classes of …


Quorum Sensing Signal Production And Microbial Interactions In A Polymicrobial Disease Of Corals And The Coral Surface Mucopolysaccharide Layer, Beth L. Zimmer, Amanda L. May, Chinmayee D. Bhedi, Stephen P. Dearth, Carson W. Prevatte, Zoe Pratte, Shawn R. Campagna, Laurie L. Richardson Sep 2014

Quorum Sensing Signal Production And Microbial Interactions In A Polymicrobial Disease Of Corals And The Coral Surface Mucopolysaccharide Layer, Beth L. Zimmer, Amanda L. May, Chinmayee D. Bhedi, Stephen P. Dearth, Carson W. Prevatte, Zoe Pratte, Shawn R. Campagna, Laurie L. Richardson

Department of Biological Sciences

Black band disease (BBD) of corals is a complex polymicrobial disease considered to be a threat to coral reef health, as it can lead to mortality of massive reef-building corals. The BBD community is dominated by gliding, filamentous cyanobacteria with a highly diverse population of heterotrophic bacteria. Microbial interactions such as quorum sensing (QS) and antimicrobial production may be involved in BBD disease pathogenesis. In this study, BBD (whole community) samples, as well as 199 bacterial isolates from BBD, the surface mucopolysaccharide layer (SML) of apparently healthy corals, and SML of apparently healthy areas of BBD-infected corals were screened for …


Unprecedented Evidence For High Viral Abundance And Lytic Activity In Coral Reef Waters Of The South Pacific Ocean, Jerome P. Payet, Ryan Mcminds, Deron E. Burkepile, Rebecca L. Thurber Vega Sep 2014

Unprecedented Evidence For High Viral Abundance And Lytic Activity In Coral Reef Waters Of The South Pacific Ocean, Jerome P. Payet, Ryan Mcminds, Deron E. Burkepile, Rebecca L. Thurber Vega

Department of Biological Sciences

Despite nutrient-depleted conditions, coral reef waters harbor abundant and diverse microbes; as major agents of microbial mortality, viruses are likely to influence microbial processes in these ecosystems. However, little is known about marine viruses in these rapidly changing ecosystems. Here we examined spatial and short-term temporal variability in marine viral abundance (VA) and viral lytic activity across various reef habitats surrounding Moorea Island (French Polynesia) in the South Pacific. Water samples were collected along four regional cross-reef transects and during a time-series in Opunohu Bay. Results revealed high VA (range: 5.6 x 10(6)-3.6 x 10(7) viruses ml(-1)) and lytic viral …


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 Aug 2014

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, …


Ecosystem Fragmentation Drives Increased Diet Variation In An Endemic Livebearing Fish Of The Bahamas, Marcio S. Araujo, R. Brian Langerhans, Sean T. Giery, Craig A. Layman Aug 2014

Ecosystem Fragmentation Drives Increased Diet Variation In An Endemic Livebearing Fish Of The Bahamas, Marcio S. Araujo, R. Brian Langerhans, Sean T. Giery, Craig A. Layman

Department of Biological Sciences

One consequence of human-driven habitat degradation in general, and habitat fragmentation in particular, is loss of biodiversity. An often-underappreciated aspect of habitat fragmentation relates to changes in the ecology of species that persist in altered habitats. In Bahamian wetlands, ecosystem fragmentation causes disruption of hydrological connectivity between inland fragmented wetlands and adjacent marine areas, with the consequent loss of marine piscivores from fragmented sections. We took advantage of this environmental gradient to investigate effects of ecosystem fragmentation on patterns of resource use in the livebearing fish Gambusia hubbsi (Family Poeciliidae), using both population- and individual-level perspectives. We show that fragmentation-induced …


Exploring Germplasm Diversity To Understand The Domestication Process In Cicer Spp. Using Snp And Dart Markers, Manish Roorkiwal, Eric J. Von Wettberg, Hari D. Upadhyaya, Emily Warschefsky, Abhishek Rathore, Rajeev K. Varshney Jul 2014

Exploring Germplasm Diversity To Understand The Domestication Process In Cicer Spp. Using Snp And Dart Markers, Manish Roorkiwal, Eric J. Von Wettberg, Hari D. Upadhyaya, Emily Warschefsky, Abhishek Rathore, Rajeev K. Varshney

Department of Biological Sciences

To estimate genetic diversity within and between 10 interfertile Cicer species (94 genotypes) from the primary, secondary and tertiary gene pool, we analysed 5,257 DArT markers and 651 KASPar SNP markers. Based on successful allele calling in the tertiary gene pool, 2,763 DArT and 624 SNP markers that are polymorphic between genotypes from the gene pools were analyzed further. STRUCTURE analyses were consistent with 3 cultivated populations, representing kabuli, desi and pea-shaped seed types, with substantial admixture among these groups, while two wild populations were observed using DArT markers. AMOVA was used to partition variance among hierarchical sets of landraces …


Variable Effects Of Temperature On Insect Herbivory, Nathan P. Lemoine, Deron E. Burkepile, John D. Parker Jul 2014

Variable Effects Of Temperature On Insect Herbivory, Nathan P. Lemoine, Deron E. Burkepile, John D. Parker

Department of Biological Sciences

Rising temperatures can influence the top-down control of plant biomass by increasing herbivore metabolic demands. Unfortunately, we know relatively little about the effects of temperature on herbivory rates for most insect herbivores in a given community. Evolutionary history, adaptation to local environments, and dietary factors may lead to variable thermal response curves across different species. Here we characterized the effect of temperature on herbivory rates for 21 herbivore-plant pairs, encompassing 14 herbivore and 12 plant species. We show that overall consumption rates increase with temperature between 20 and 30 degrees C but do not increase further with increasing temperature. However, …


Effect Of Beta 1,3 Glucan In Stress Responses Of The Pencilfish (Nannostomus Trifasciatus) During Transport Within The Rio Negro Basin, Janessa S. Abreu, Richard P. Brinn, Levy C. Gomes, Dawn Michelle Mccomb, Bernardo Baldisserott, Sérgio F. Zaiden, Elisabeth C. Urbinati, Jaydione L. Marcon Jun 2014

Effect Of Beta 1,3 Glucan In Stress Responses Of The Pencilfish (Nannostomus Trifasciatus) During Transport Within The Rio Negro Basin, Janessa S. Abreu, Richard P. Brinn, Levy C. Gomes, Dawn Michelle Mccomb, Bernardo Baldisserott, Sérgio F. Zaiden, Elisabeth C. Urbinati, Jaydione L. Marcon

Department of Biological Sciences

We investigated the use of beta 1,3 glucan as an imunostimulant during a transport experiment to determine the effects upon the stress response of the pencilfish (Nannostomus trifasciatus). Pencilfish were fed for seven days with different concentrations of beta 1,3 glucan: 0.0% (control); 0.01%; 0.1% and 0.5% of beta 1,3 glucan per kg of feed-1. Fish were then transported for 24 hours by boat from Barcelos to Manaus. The highest dose of beta 1,3 glucan in the food increased Na+ influx after 12 hours of transport and 0.1 and 0.5% beta 1,3 glucan maintained the flux of …


The Dangers Of Carbon-Centric Conservation For Biodiversity: A Case Study In The Andes, Alvaro Duque, Kenneth J. Feeley, Edersson Cabrera, Ricardo Callejas, Alvaro Idarraga Jun 2014

The Dangers Of Carbon-Centric Conservation For Biodiversity: A Case Study In The Andes, Alvaro Duque, Kenneth J. Feeley, Edersson Cabrera, Ricardo Callejas, Alvaro Idarraga

Department of Biological Sciences

Carbon-centric conservation strategies such as the United Nation’s program to Reduce CO2 Emissions from Deforestation and Degradation (REDD+), are expected to simultaneously reduce net global CO2 emissions and mitigate species extinctions in regions with high endemism and diversity, such as the Tropical Andes Biodiversity Hotspot. Using data from the northern Andes, we show, however, that carbon-focused conservation strategies may potentially lead to increased risks of species extinctions if there is displacement (i.e., “leakage”) of land-use changes from forests with large aboveground biomass stocks but relatively poor species richness and low levels of endemism, to forests with lower biomass stocks but …


Cascading Effects Of A Highly Specialized Beech-Aphid-Fungus Interaction On Forest Regeneration, Susan C. Cook-Patton, Lauren Maynard, Nathan P. Lemoine, Jessica Shue, John D. Parker Jun 2014

Cascading Effects Of A Highly Specialized Beech-Aphid-Fungus Interaction On Forest Regeneration, Susan C. Cook-Patton, Lauren Maynard, Nathan P. Lemoine, Jessica Shue, John D. Parker

Department of Biological Sciences

Specialist herbivores are thought to often enhance or maintain plant diversity within ecosystems, because they prevent their host species from becoming competitively dominant. In contrast, specialist herbivores are not generally expected to have negative impacts on non-hosts. However, we describe a cascade of indirect interactions whereby a specialist sooty mold (Scorias spongiosa) colonizes the honeydew from a specialist beech aphid (Grylloprociphilus imbricator), ultimately decreasing the survival of seedlings beneath American beech trees (Fagus grandifolia). A common garden experiment indicated that this mortality resulted from moldy honeydew impairing leaf function rather than from chemical or microbial changes to the soil. In …


Provision Of Ecosystem Services By Human-Made Structures In A Highly Impacted Estuary, Craig A. Layman, Zachary R. Jud, Stephanie K. Archer, David Riera Apr 2014

Provision Of Ecosystem Services By Human-Made Structures In A Highly Impacted Estuary, Craig A. Layman, Zachary R. Jud, Stephanie K. Archer, David Riera

Department of Biological Sciences

Water filtration is one of the most important ecosystem services provided by sessile organisms in coastal ecosystems. As a consequence of increased coastal development, human-made shoreline structures (e.g., docks and bulkheads) are now common, providing extensive surface area for colonization by filter feeders. We estimate that in a highly urbanized sub-tropical estuary, water filtration capacity supported by filter feeding assemblages on dock pilings accounts for 11.7 million liters of water h−1, or ~30% of the filtration provided by all natural oyster reef throughout the estuary. Assemblage composition, and thus filtration capacity, varied as a function of piling type, …


Genetic Diversity And Demographic History Of Cajanus Spp. Illustrated From Genome-Wide Snps, Rachit K. Saxena, Eric Von Wettberg, Hari D. Upadhyaya, Vanessa Sanchez, Serah Songok, Kulbhushan Saxena, Paul Kimurto, Rajeev K. Varshney Feb 2014

Genetic Diversity And Demographic History Of Cajanus Spp. Illustrated From Genome-Wide Snps, Rachit K. Saxena, Eric Von Wettberg, Hari D. Upadhyaya, Vanessa Sanchez, Serah Songok, Kulbhushan Saxena, Paul Kimurto, Rajeev K. Varshney

Department of Biological Sciences

Understanding genetic structure of Cajanus spp. is essential for achieving genetic improvement by quantitative trait loci (QTL) mapping or association studies and use of selected markers through genomic assisted breeding and genomic selection. After developing a comprehensive set of 1,616 single nucleotide polymorphism (SNPs) and their conversion into cost effective KASPar assays for pigeonpea (Cajanus cajan), we studied levels of genetic variability both within and between diverse set of Cajanus lines including 56 breeding lines, 21 landraces and 107 accessions from 18 wild species. These results revealed a high frequency of polymorphic SNPs and relatively high level of cross-species transferability. …


Starvation Increases Insulin Sensitivity And Reduces Juvenile Hormone Synthesis In Mosquitoes, Meritxell Perez-Hedo, Crisalejandra Rivera-Perez, Fernando G. Noriega Jan 2014

Starvation Increases Insulin Sensitivity And Reduces Juvenile Hormone Synthesis In Mosquitoes, Meritxell Perez-Hedo, Crisalejandra Rivera-Perez, Fernando G. Noriega

Department of Biological Sciences

Background: The interactions between the insulin signaling pathway (ISP) and juvenile hormone (JH) controlling reproductive trade-offs are well documented in insects. JH and insulin regulate reproductive output in mosquitoes; both hormones are involved in a complex regulatory network, in which they influence each other and in which the mosquito’s nutritional status is a crucial determinant of the network’s output. Previous studies reported that the insulin-TOR (target of rapamacyn) signaling pathway is involved in the nutritional regulation of JH synthesis in female mosquitoes. The present studies further investigate the regulatory circuitry that controls both JH synthesis and reproductive output in response …


Experimental Evidence Of Threat-Sensitive Collective Avoidance Responses In A Large Wild-Caught Herring School, Guillaume Rieucau, Kevin M. Boswell, Alex De Robertis, Gavin J. Macaulay, Nils Olav Handegard Jan 2014

Experimental Evidence Of Threat-Sensitive Collective Avoidance Responses In A Large Wild-Caught Herring School, Guillaume Rieucau, Kevin M. Boswell, Alex De Robertis, Gavin J. Macaulay, Nils Olav Handegard

Department of Biological Sciences

Aggregation is commonly thought to improve animals’ security. Within aquatic ecosystems, group-living prey can learn about immediate threats using cues perceived directly from predators, or from collective behaviours, for example, by reacting to the escape behaviours of companions. Combining cues from different modalities may improve the accuracy of prey antipredatory decisions. In this study, we explored the sensory modalities that mediate collective antipredatory responses of herring (Clupea harengus) when in a large school (approximately 60 000 individuals). By conducting a simulated predator encounter experiment in a semi-controlled environment (a sea cage), we tested the hypothesis that the collective responses of …


Photosynthetic Activity Buffers Ocean Acidification In Seagrass Meadows, I. E. Hendriks, Y. S. Olsen, L. Ramajo, L. Basso, T. S. Moore, J. Howard, C. M. Duarte Jan 2014

Photosynthetic Activity Buffers Ocean Acidification In Seagrass Meadows, I. E. Hendriks, Y. S. Olsen, L. Ramajo, L. Basso, T. S. Moore, J. Howard, C. M. Duarte

Department of Biological Sciences

Macrophytes growing in shallow coastal zones characterised by intense metabolic activity have the capacity to modify pH within their canopy and beyond. We observed diel pH changes in shallow (5–12 m) seagrass (Posidonia oceanica) meadows spanning 0.06 pH units in September to 0.24 units in June. The carbonate system (pH, DIC, and aragonite saturation state (ΩAr)) and O2 within the meadows displayed strong diel variability driven by primary productivity, and changes in chemistry were related to structural parameters of the meadow, in particular, the leaf surface area available for photosynthesis (LAI). LAI was positively correlated …


There Are Many Barriers To Species’ Migrations, Kenneth J. Feeley, Evan M. Rehm, James T. Stroud Jan 2014

There Are Many Barriers To Species’ Migrations, Kenneth J. Feeley, Evan M. Rehm, James T. Stroud

Department of Biological Sciences

Temperature-change trajectories are being used to identify the geographic barriers and thermal ‘cul-de-sacs’ that will limit the ability of many species to track climate change by migrating. We argue that there are many other potential barriers to species’ migrations. These include stable ecotones, discordant shifts in climatic variables, human land use, and species’ limited dispersal abilities. To illustrate our argument, for each 0.5° latitude/longitude grid cell of the Earth’s land surface, we mapped and tallied the number of cells for which future (2060–2080) climate represents an analog of the focal cell’s current climate. We compared results when only considering temperature …