Marine Biology Commons^™

Photorespiration In Eelgrass (Zostera Marina L.): A Photoprotection Mechanism For Survival In A Co₂-Limited World, Billur Celebi-Ergin, Richard C. Zimmerman, Victoria J. Hill

OES Faculty Publications

Photorespiration, commonly viewed as a loss in photosynthetic productivity of C3 plants, is expected to decline with increasing atmospheric CO₂, even though photorespiration plays an important role in the oxidative stress responses. This study aimed to quantify the role of photorespiration and alternative photoprotection mechanisms in Zostera marina L. (eelgrass), a carbon-limited marine C3 plant, in response to ocean acidification. Plants were grown in controlled outdoor aquaria at different [CO₂]aq ranging from ~55 (ambient) to ~2121 μM for 13 months and compared for differences in leaf photochemistry by simultaneous measurements of O₂ flux and …

Simulated Response Of St. Joseph Bay, Florida, Seagrass Meadows And Their Belowground Carbon To Anthropogenic And Climate Impacts, Marie Cindy Lebrasse, Blake A. Schaeffer, Richard C. Zimmerman, Victoria J. Hill, Megan M. Coffer, Peter J. Whitman, Wilson B. Salls, David D. Graybill, Christopher L. Osburn

OES Faculty Publications

Seagrass meadows are degraded globally and continue to decline in areal extent due to human pressures and climate change. This study used the bio-optical model GrassLight to explore the impact of climate change and anthropogenic stressors on seagrass extent, leaf area index (LAI) and belowground organic carbon (BGC) in St. Joseph Bay, Florida, using water quality data and remotely-sensed sea surface temperature (SST) from 2002 to 2020. Model predictions were compared with satellite-derived measurements of seagrass extent and shoot density from the Landsat images for the same period. The GrassLight-derived area of potential seagrass habitat ranged from 36.2 km2 …

Tropicalization Of Seagrass Macrophytodetritus Accumulations And Associated Food Webs, Gilles Lepoint, Glenn A. Hyndes

Research outputs 2022 to 2026

Seagrass, systems export significant amounts of their primary production as large detritus (i.e. macrophytodetritus). Accumulations of exported macrophytodetritus (AEM) are found in many areas in coastal environment. Dead seagrass leaves are often a dominant component of these accumulations, offering shelter and/or food to numerous organisms. AEM are particular habitats, different from donor habitats (i.e. seagrass meadow, kelp or macroalgae habitats) and with their own characteristics and dynamics. They have received less attention than donor habitats despite the fact they often connect different coastal habitats, are the place of intense remineralization processes and shelter associated detritus food web. As for seagrass …

Patterns Of Habitat Use And Trophic Structure In Turtle Grass (Thalassia Testudinum)-Dominated Systems Across The Northern Gulf Of Mexico, Christian Hayes

Dissertations

Seagrass structural complexity is a primary driver of nekton recruitment and faunal community structure. Few studies, however, have quantified the role of seagrass complexity on habitat use and trophic structures over large spatial scales. A large-scale simultaneous survey was conducted to assess relationships of multiple seagrass morphological complexity metrics to nekton habitat use, trophic dynamics, and blue crab (Callinectes sapidus) growth and mortality across the Northern Gulf of Mexico. Seagrass morphological and nekton community characteristics depended on site and season, and regional variation in seagrass morphology was an important driver of juvenile nekton abundance, species richness, beta diversity, …

Fisheries Food Webs: Quantifying Habitat-Use, Trophic Structure, And Energetic Pathways In Coastal Tanzania, Mario Fernando Hernandez

LSU Doctoral Dissertations

Commercial and recreational fisheries are a valuable resource to millions of people around the world. Developing countries are particularly dependent on the revenue provided by locally harvested fish with total exports from these nations valued at $80 billion USD. For Tanzania, fisheries provide not only a source of revenue but an important source of protein with an estimated 25 to 30kg of fish consumed per person every year. There is no doubt that high fisheries production is critical to the well-being of millions of livelihoods along the Tanzanian coast. An important but poorly understood driver of fisheries production is the …

Photographs Of Seaweeds In Intertidal Monitoring Plots, 2020, David M. Burdick, Gregg Moore

Jackson Estuarine Laboratory

Records of photographs of intertidal seaweed sampling plots for cover (50 by 50 cm) and biomass (25 by 25 cm) collected by Jackson Estuarine Laboratory research staff in 2020.

Impact Of Ocean Carbonation On Long-Term Regulation Of Light Harvesting In Eelgrass Zostera Marina, Billur Celebi-Ergin, Richard C. Zimmerman, Victoria J. Hill

OES Faculty Publications

Seagrasses account for approximately 10% of the total carbon stored in the ocean, although photosynthesis of seagrasses is carbon-limited at present oceanic pH levels. Therefore, increasing atmospheric CO₂ concentration, which results in ocean acidification/carbonation, is predicted to have a positive impact on seagrass productivity. Previous studies have confirmed the positive influence of increasing CO₂ on photosynthesis and survival of the temperate eelgrass Zostera marina, but the acclimation of photoprotective mechanisms in this context has not been characterized. We aimed to quantify the long-term impacts of ocean acidification on photochemical control mechanisms that promote photosynthesis while simultaneously protecting …

What Lies Beneath: Predicting Seagrass Below-Ground Biomass From Above-Ground Biomass, Environmental Conditions And Seagrass Community Composition, C. J. Collier, L. M. Langlois, Kathryn M. Mcmahon, J. Udy, M. Rasheed, E. Lawrence, A. B. Carter, M. W. Fraser, L. J. Mckenzie

Research outputs 2014 to 2021

© 2020 Seagrass condition, resilience and ecosystem services are affected by the below-ground tissues (BGr) but these are rarely monitored. In this study we compiled historical data across northern Australia to investigate biomass allocation strategies in 13 tropical seagrass species. There was sufficient data to undertake statistical analysis for five species: Cymodocea serrulata, Halophila ovalis, Halodule uninervis, Thalassia hemprichii, and Zostera muelleri. The response of below-ground biomass (BGr) to above-ground biomass (AGr) and other environmental and seagrass community composition predictor variables were assessed using Generalized Linear Models. Environmental data included: region, season, sediment type, water depth, proximity to land-based sources …

Snp Population Genetic Data For The Seagrass Halodule Uninervis From Pilbara Region, Western Australia, Kathryn Margaret Mcmahon, Richard Evans

Research Datasets

This dataset contains 80 SNP loci from 15 locations with 25-47 samples per locations. Each column contains data from two alleles. All genotyped samples are included. Prior to population genetic analysis clone mates were identified and removed.

Conserving Critical Seagrass Habitat For Dugong. Dugong Seagrass Associations Summary Data., Kathryn M. Mcmahon, Paul Lavery, Nicole Said, Chris Cleguer, Amanda Hodgson

Research Datasets

This is the summary dataset of the dugong seagrass associations data containing dugong counts, benthic habitat cover, seagrass nutrient content, water temperature, water current speed, water depth and water transparency from three locations in the Pilbara over 3 time periods in 2018-2019.

Conserving Critical Seagrass Habitat For Dugong. Seagrass Network Monitoring Data Summary, Kathryn M. Mcmahon, Paul Lavery, Nicole Said

Research Datasets

This is the summary dataset of the seagrass monitoring data containing benthic habitat, seagrass meadow characteristics, seed density and environmental variables from three locations in the Pilbara over 3-4 time periods in 2018-2019.

Developing Multispectral Imaging Techniques To Determine Canopy Coverage And Carbon Storage Of Seagrasses In The Gulf Of Mexico, Ivy Michelle Hinson

Theses and Dissertations

Although seagrass beds provide global ecosystem services, coverage is in rapid decline, with the capacity of seagrasses to sequester carbon of special concern. Current seagrass monitoring methods are labor intensive and may not offer a complete picture of coverage. Remote sensing offers the ability to oversee landscapes but water in coastal environments presents challenges, as the commonly used near-infrared wavelength dissipates in water.

This project aimed to provide reliable methodology to assess seagrass coverage using multispectral imagery taken from an unmanned aerial vehicle and to provide evidence for the link between seagrass coverage and stored belowground carbon for common seagrasses …

Effects Of Reduced Ph On Health Biomarkers Of The Seagrass Cymodocea Nodosa, Regan A. Mcenaney

DePaul Discoveries

Ocean acidification is a growing problem that may affect many marine organisms in the future. Within 100 years the pH of the ocean is predicted to decrease to 7.8, from the current ocean pH of around 8.1. Using phenolic acid levels as a stress indicator as well as respiration and chlorophyll content as a measure of health, the effect of lowering pH was tested on the seagrass, Cymodocea nodosa, in a controlled environment. Plant samples, water, and soil were taken from the Bay of Cádiz, Spain, and placed in aquaria in a temperature-controlled room. One control group was left …

On The Composistion Of Cymodocea Nodosa Root Exudate Under Artificial Blue, Green And Natural Light Conditions, Armand Martin, Ben Manriquez, Christian Pompa, Aaron Saper, Kyle A. Grice, Jason Bystriansky

DePaul Discoveries

Seagrasses are identified as a sentinel species: a good indicator of overall marine ecosystem health and function. At the rhizome, they are known to interact with marine bacteria by exchanging energy in the form of glucose and free amino acids secreted through root exudate in exchange for microbe-fixated nitrogen that can be utilized for plant growth. To analyze potential outcomes of possible future changes in light availability, an experiment was designed to collect and analyze the root exudate of Cymodocea nodosa under three light conditions (standard fluorescent light, blue LED, and green LED light). After 72 hours of treatment, the …

Toward The Ultrasonic Sensing Of Organic Carbon In Seagrass-Bearing Sediments, Gabriel R. Venegas, Abdullah Rahman, Kevin M. Lee, Megan S. Ballard, Preston S. Wilson

School of Earth, Environmental, & Marine Sciences Faculty Publications

Ten percent of all organic carbon (Corg) absorbed by the ocean each year is stored in seagrass-bearing sediments. The preservation of these carbon stores is considered a vital method to mitigate climate change. Seagrass-bearing sediments have been correlated with sediment geophysical properties yet have not been related to sediment acoustic properties. For this purpose, sediment cores were collected from a Thalassia testudinum seagrass meadow in South Texas, USA, where geophysical, acoustical, and Corg properties were measured. It is hypothesized that when deposits of Corg adsorb onto mineral surfaces and are stored in pore spaces, compliant layers between grain contacts and …

Techniques Used To Increase Recapture Rates Of Dwarf Seahorses (Hippocampus Zosterae) In Tampa Bay: Implications For Population Estimates And Movement Patterns, Heather D. Masonjones, Emily Rose, Michael C. Masonjones

Gulf and Caribbean Research

Mark-recapture techniques were used to estimate population size and movement patterns of the Dwarf Seahorse (Hippocampus zosterae, Syngnathidae), a species native to the Gulf of Mexico and under review by the National Marine Fisheries Service (NMFS, USA) for consideration under the Endangered Species Act (ESA). Previous collection methods have failed to yield recapture rates high enough to use for population estimation, hypothesized to be a result of longer time durations between collections and large distances surveyed in previous studies. In this report, Dwarf Seahorses in Tampa Bay, Florida (USA) were sampled with a pushnet in a small, well-marked …

Seagrass Ecosystems: A Career-Long Quest To Understand Their Inner Workings, Kenneth L. Heck Jr

Gulf and Caribbean Research

Four decades of research findings associates on the ecology of seagrasses and their animal and plant associates are described here, along with some of the major changes and advances that have taken place in our understanding of the inner workings of these amazingly productive and diverse ecosystems. Of primary importance are shifts in the recognition of: 1) the importance of the nursery role of seagrasses and how it can be quantified; 2) the importance of direct herbivory in the trophic ecology of seagrass-dominated ecosystems; and 3) the primacy of consumer effects in determining the abundance of algal epiphytes that colonize …

Seagrass Sedimentary Deposits As Security Vaults And Time Capsules Of The Human Past, Dorte Krause-Jensen, Oscar Serrano, Eugenia T. Apostolaki, David J. Gregory, Carlos M. Duarte

Research outputs 2014 to 2021

Seagrass meadows form valuable ecosystems, but are considered to have low cultural value due to limited research efforts in this field. We provide evidence that seagrass deposits play a hitherto unrealized central role in preserving valuable submerged archaeological and historical heritage across the world, while also providing an historical archive of human cultural development over time. We highlight three case studies showing the significance of seagrass in protecting underwater cultural heritage in Denmark, the Mediterranean and Australia. Moreover, we present an overview of additional evidence compiled from the literature. We emphasize that this important role of seagrasses is linked to …

Role Of Carbonate Burial In Blue Carbon Budgets, V. Saderne, N.R. Geraldi, P.I. Macreadie, D.T. Maher, J.J. Middelburg, O. Serrano, H. Almahasheer, A. Arias-Ortiz, M. Cusack, B.D. Eyre, J.W. Fourqurean, H. Kennedy, D. Krause-Jensen, T. Kuwae, P.S. Lavery, C.E. Lovelock, N. Marba, P. Masqué, M.A. Mateo, I. Mazarrasa, K.J. Mcglathery, M.P.J. Oreska, C.J. Sanders, I.R. Santos

Research outputs 2014 to 2021

Calcium carbonates (CaCO 3 ) often accumulate in mangrove and seagrass sediments. As CaCO 3 production emits CO 2 , there is concern that this may partially offset the role of Blue Carbon ecosystems as CO 2 sinks through the burial of organic carbon (C org ). A global collection of data on inorganic carbon burial rates (C inorg , 12% of CaCO 3 mass) revealed global rates of 0.8 TgC inorg yr −1 and 15–62 TgC inorg yr −1 in mangrove and seagrass ecosystems, respectively. In seagrass, CaCO 3 burial may correspond to an offset of 30% of the …

Synthesis Report: Defining Thresholds And Indicators Of Primary Producer Response To Dredging-Related Pressures: Report Of Theme 5 Prepared For The Dredging Science Node, Paul Lavery, Kathryn Mcmahon, John Statton, Mat Vanderklift, Simone Strydom, Gary Kendrick

Research outputs 2014 to 2021

Seagrasses form a small component of a diverse group of organisms termed ‘benthic primary producers’. Benthic primary producers are organisms that grow on the sea-bed that obtain some or all of their energy needs from photosynthesis. This includes animals such as scleractinian corals and some sponges that host microscopic intercellular algae, coralline and turf algae, and the larger seaweeds such as the kelps and sargassum. Seagrasses are marine flowering plants, more closely related to land plants than seaweeds and algae. Seagrasses live mostly in soft sediments, and can be found from the shallow intertidal zone through to a depth of …

The Importance Of Marine Predators In The Provisioning Of Ecosystem Services By Coastal Plant Communities, Trisha B. Atwood, Edd Hammill

Ecology Center Publications

Food web theory predicts that current global declines in marine predators could generate unwanted consequences for many marine ecosystems. In coastal plant communities (kelp, seagrass, mangroves, and salt marsh), several studies have documented the far-reaching effects of changing predator populations. Across coastal ecosystems, the loss of marine predators appears to negatively affect coastal plant communities and the ecosystem services they provide. Here, we discuss some of the documented and suspected effects of predators on coastal protection, carbon sequestration, and the stability and resilience of coastal plant communities. In addition, we present a meta-analysis to assess the strength and direction of …

Effects Of Drift Macroalgae On Sediment Nitrogen Cycling In Thalassia Testudinum Beds Of St. Joseph Bay, Fl, Erica Strope

Master of Science in Integrative Biology Theses

Anthropogenic nitrogen (N) loading and eutrophication can affect valuable ecosystem services and seagrass habitats by modifying structural and functional aspects of estuarine communities including increasing and prolonging macroalgae blooms. In some contexts, macroalgae may play a key role in N cycling pathways because they can alter sediment chemistry. Previous research has associated drift macroalgae blooms with elevated dissolved inorganic N concentrations in sediments as a result of increased remineralization of organic matter, but drift macroalgae effects on microbial N transformation pathways are not well understood. This study quantified the effects of macroalgae on estuarine N cycling in Thalassia testudinum seagrass …

Evaluating In Situ Grazing Patterns Of Lytechinus Variegatus And Their Effects On Seagrass Beds Of Thalassia Testudinum, Adrianna Parson

Master of Science in Integrative Biology Theses

The sea urchin Lytechinus variegatus is a known grazer of the seagrass Thalassia testudinum, and has been known to denude vast stands of seagrass beds at high densities. Outside of these denudation events, the effects of sea urchins on seagrass are poorly understood. This study examines the effects of L. variegatus on T. testudinum in situ, to understand how sea urchins are affecting seagrasses in situ. Results indicate that urchins were found in the offshore portion of the seagrass bed at densities up to 4 urchins/m². Changes in temperature and sediment size in the bay indicate …

Managing Seagrass Resilience Under Cumulative Dredging Affecting Light: Predicting Risk Using Dynamic Bayesian Networks, Paul Pao-Yen Wu, Kathryn Mcmahon, Michael A. Rasheed, Gary A. Kendrick, Paul H. York, Kathryn Chartrand, M. Julian Carey, Kerrie Mengerson

Research Datasets

Coastal development is contributing to ongoing declines of ecosystems globally. Consequently, understanding the risks posed to these systems, and how they respond to successive disturbances, is paramount for their improved management. We study the cumulative impacts of maintenance dredging on seagrass ecosystems as a canonical example. Maintenance dredging causes disturbances lasting weeks to months, often repeated at yearly intervals. We present a risk-based modelling framework for time varying complex systems centred around a dynamic Bayesian network (DBN). Our approach estimates the impact of a hazard on a system's response in terms of resistance, recovery and persistence, commonly used to characterise …

Effects Of Small-Scale, Shading-Induced Seagrass Loss On Blue Carbon Storage: Implications For Management Of Degraded Seagrass Ecosystems, Stacey M. Trevathan-Tackett, Caitlin Wessel, Just Cebrian, Peter J. Ralph, Pere Masque´, Peter I. Macreadie

Research Datasets

1. Seagrass meadows are important global ‘blue carbon’ sinks. Despite a 30% loss of seagrasses globally during the last century, there is limited empirical research investigating the effects of disturbance and loss of seagrass on blue carbon stocks.

2. In this study, we hypothesised that seagrass loss would reduce blue carbon stocks. Using shading cloth, we simulated small-scale die-offs of two subtropical seagrass species, Halodule wrightii and Thalassia testudinum, in a dynamic northern Gulf of Mexico lagoon. The change in quantity and quality of sediment organic matter and organic carbon were compared among kill, control and bare plots before the …

Latitudinal Variation In Seagrass Herbivory: Global Patterns And Explanatory Mechanisms, Adriana Vergés, Christopher Doropoulos, Robert Czarnik, Kathryn Mcmahon, Nil Llonch, Alistair G. B. Poore

Research Datasets

Aim: The aim was to quantify latitudinal patterns in seagrass–herbivore interactions in the context of a warming climate.

Location: We carried out a global meta‐analysis combined with a field experiment across 1,700 km and 12° of latitude in Western Australia.

Time period: 1984–2014. Major taxa studied: Seagrasses.

Methods: We first synthesized the global literature on herbivore exclusion experiments in seagrasses to test whether differences in herbivore impacts are related to latitude and sea surface temperature. We then quantified leaf production and consumption rates in the field at nine meadows of the seagrass Amphibolis antarctica across 1,700 km, from tropical to …

Microorganisms Facilitate Uptake Of Dissolved Organic Nitrogen By Seagrass Leaves, Flavia Tarquinio, Jeremy Bourgoure, Annette Koenders, Bonnie Laverock, Christin Säwström, Glenn A. Hyndes

Research Datasets

The database compiles data (used in Tarquinio et al. 2018, ISME Journal, accepted for publication) obtained from nitrogen stable isotope analysis (IRMS) and Nanoscale secondary ion mass spectrometry (NanoSIMS) of seagrass (Posidonia sinuosa) leaves and associated microorganisms. Row data (IRMS) are presented for bulk tissue ¹⁵N enrichment of P. sinuosa leaves at different times of incubation (plotted as bar chart in the manuscript), as well as the enrichment detected through the drawing of regions of interest (ROI) from NanoSIMS image analysis and plotted as box plots in the manuscript.

Short-Term Responses Of Posidonia Australis To Changes In Light Quality, Simone Strydom, Kathryn M. Mcmahon, Gary A. Kendrick, John Stratton, Paul S. Lavery

Research outputs 2014 to 2021

Seagrass meadows are highly productive ecosystems that provide ecosystem services to the coastal zone but are declining globally, particularly due to anthropogenic activities that reduce the quantity of light reaching seagrasses, such as dredging, river discharge and eutrophication. Light quality (the spectral composition of the light) is also altered by these anthropogenic stressors as the differential attenuation of wavelengths of light is caused by materials within the water column. This study addressed the effect of altered light quality on different life-history stages of the seagrass Posidonia australis, a persistent, habitat-forming species in Australia. Aquarium-based experiments were conducted to determine …

Historical Change Of Seagrasses In The Mississippi And Chandeleur Sounds, Linh Thuy Pham

Dissertations

Seagrasses are important coastal resources facing numerous stressors, and losses have been documented from local to global assessments. Under the broad theme of habitat loss and fragmentation, a study of historical change in total area and landscape configuration of seagrasses in the Mississippi and Chandeleur Sounds was conducted. Mapping data was collated from a multitude of previous projects from 1940 to 2011.

Comparisons of seagrass area among various studies that used different mapping methods can result in overestimation of area change and misleading conclusions of change over time. The vegetated seagrass area (VSA) data were generalized to a common resolution …

Hardbottom Mapping And Community Characterization Of The West-Central Florida Gulf Coast, December 2011 - June 2016, Brian K. Walker, Rene Baumstark, Sean Keenan, Cory Ames

Marine & Environmental Sciences Faculty Datasets

The continental shelf off Florida’s west coast is a mosaic of fish habitats including seagrass beds and carbonate reef outcroppings (hard bottom) classified by the National Marine Fisheries Service (NMFS) as Essential Fish Habitat. Habitat maps and community baseline data, however, are nonexistent for a majority of the region. This collaborative effort between Nova Southeastern University, Florida Fish and Wildlife Conservation Commission, NMFS and other scientists will characterize and map continental shelf seagrass and hard bottom habitats in nearshore areas fished by many recreational fishermen. Objectives include: 1) map hard bottom and seagrass beds using various data types including sonar …