Several studies have found separation of biogeographic provinces on the West Florida Shelf (WFS), but the location of this separation differs depending on different organisms with faunal boundaries proposed at Apalachicola, Cedar Key, Anclote Key. Tampa Bay, Charlotte Harbor, Cape Romano, or Cape Sable. Biogeographic boundaries can be gradual over a given space and are often species-specific. Analyses of marine benthic mapping and community characterization of Florida’s West-central coast shallow water (depth) hardbottom habitats indicate a major shift in the benthos across Tampa Bay. Quantitative benthic surveys of 29 sites yielded a total of 4,079 individuals of nine stony coral species and 1,918 soft coral colonies. Populations were dominated by four species of corals: Siderastrea radians, Oculina robusta, Solenastrea hyades, and Cladacora arbuscula. Most corals were less than 10 cm in diameter. Cluster analyses of coral density and major functional group percent cover showed distinct differences in hard and soft coral densities and species demographics from south to north with clear spatial patterns between regions. These benthic hardbottom coral communities change over a relatively small spatial scale (10’s of km), indicating a biogeographical province or ecosystem region boundary in marine benthic communities at, or very near, the mouth of Tampa Bay. Broader studies are needed to identify the shifts in benthic community biogeography along the West Florida Shelf.

Information on habitat preferences is critical for the successful conservation of endangered species. For many species, especially those living in remote areas, we currently lack this information. Time and financial resources to analyze habitat use are limited. We aimed to develop a method to describe habitat preferences based on a combination of bird surveys with remotely sensed fine-scale land cover maps. We created a blended multiband remote sensing product from SPOT 6 and Landsat 8 data with a high spatial resolution. We surveyed populations of three bird species (Yellow-breasted Bunting Emberiza aureola, Ochre-rumped Bunting Emberiza yessoensis, and Black-faced Bunting Emberiza spodocephala) at a study site in the Russian Far East using hierarchical distance sampling, a survey method that allows to correct for varying detection probability. Combining the bird survey data and land cover variables from the remote sensing product allowed us to model population density as a function of environmental variables. We found that even small-scale land cover characteristics were predictable using remote sensing data with sufficient accuracy. The overall classification accuracy with pansharpened SPOT 6 data alone amounted to 71.3%. Higher accuracies were reached via the additional integration of SWIR bands (overall accuracy = 73.21%), especially for complex small-scale land cover types such as shrubby areas. This helped to reach a high accuracy in the habitat models. Abundances of the three studied bird species were closely linked to the proportion of wetland, willow shrubs, and habitat heterogeneity. Habitat requirements and population sizes of species of interest are valuable information for stakeholders and decision-makers to maximize the potential success of habitat management measures.

Anthropogenic changes to the landscape, storm events and sea level rise are contributing to the erosion of beaches leading to an increase of the sediment load in near shore marine environments. Palm Beach, Florida is host to unique near shore hardbottom habitats. These areas are distinct from the vast expanses of surrounding sediments and play and important role of habitat and shelter for many different species. In this study, remotely sensed images from 2000-2015 were used to look at the movement of sediment and how it contributes to exposure rates of near shore hardbottom habitats in Palm Beach, Florida and how these factors affect the benthic community. GIS was used to determine areas of hardbottom with high exposure (exposed in >60% of aerial images), medium exposure (40-60%), and low exposure ( I strived to determine if one can detect a successional relationship of benthic communities in a dynamic environment with annual mapping. I also examined if areas with higher exposure rates have more complex successive communities than those with lower exposure rates, and what implications this has on near shore benthic communities. In situ surveys conducted at 117 sites determined the community structure (corals, octocorals, macroalgae, and hydroids). This study confirmed that periodic mapping was successful in identifying hardbottom burial and exposure, which fluctuate both spatially and temporally. This periodic mapping along with manual delineation did identify hardbottom burials and exposures that fluctuate between years and relate to benthic community differences. The near shore hardbottom coral reef communities aligned with the observed exposure categories with the greater coral species richness and octocoral morphologies found at sites classified as highly exposed. Statistical analyses showed differences in communities shallower and deeper than three meters’ depth. Increasing the frequency of imagery captures and in situ observation would further increase our comprehension of the metrics of hardbottom exposures in reference to community structure.

The aim of this study was to develop and examine the use of backscatter data collected with multibeam sonar (MBS) systems for benthic habitat mapping. Backscatter data were collected from six sites around the Australian coastal zone using the Reson SeaBat 8125 MBS system operating at 455 kHz. Benthic habitats surveyed in this study included: seagrass meadows, rhodolith beds, coral reef, rock, gravel, sand, muddy sand, and mixtures of those habitats. Methods for processing MBS backscatter data were developed for the Coastal Water Habitat Mapping (CWHM) project by a team from the Centre for Marine Science and Technology (CMST). The CMST algorithm calculates the seafloor backscatter strength derived from the peak and integral (or average) intensity of backscattered signals for each beam. The seafloor backscatter strength estimated from the mean value of the integral backscatter intensity was shown in this study to provide an accurate measurement of the actual backscatter strength of the seafloor and its angular dependence. However, the seafloor backscatter strength derived from the peak intensity was found to be overestimated when the sonar insonification area is significantly smaller than the footprint of receive beams, which occurs primarily at oblique angles. The angular dependence of the mean backscatter strength showed distinct differences between hard rough substrates (such as rock and coral reef), seagrass, coarse sediments and fine sediments. The highest backscatter strength was observed not only for the hard and rough substrate, but also for marine vegetation, such as rhodolith and seagrass. The main difference in acoustic backscatter from the different habitats was the mean level, or angle-average backscatter strength. However, additional information can also be obtained from the slope of the angular dependence of backscatter strength. / It was shown that the distribution of the backscatter. The shape parameter was shown to relate to the ratio of the insonification area (which can be interpreted as an elementary scattering cell) to the footprint size rather than to the angular dependence of backscatter strength. When this ratio is less than 5, the gamma shape parameter is very similar for different habitats and is nearly linearly proportional to the ratio. Above a ratio of 5, the gamma shape parameter is not significantly dependent on the ratio and there is a noticeable difference in this parameter between different seafloor types. A new approach to producing images of backscatter properties, introduced and referred to as the angle cube method, was developed. The angle cube method uses spatial interpolation to construct a three-dimensional array of backscatter data that is a function of X-Y coordinates and the incidence angle. This allows the spatial visualisation of backscatter properties to be free from artefacts of the angular dependence and provides satisfactory estimates of the backscatter characteristics. / Using the angle-average backscatter strength and slope of the angular dependence, derived by the angle cube method, in addition to seafloor terrain parameters, habitat probability and classification maps were produced to show distributions of sand, marine vegetation (e.g. seagrass and rhodolith) and hard substrate (e.g. coral and bedrock) for five different survey areas. Ultimately, this study demonstrated that the combination of high-resolution bathymetry and backscatter strength data, as collected by MBS, is an efficient and cost-effective tool for benthic habitat mapping in costal zones.

There is a need to define a more efficient and accurate approach to aquatic habitat mapping. Traditional approaches have focused on intense biological/non-biological sampling and observation analysis within specific and restrained scales. Therefore, an underwater video mapping system (UVMS) has been developed in efforts to identify federally protected aquatic species’ habitats within the Obed Wild and Scenic River (OBRI). The UVMS kayak apparatus provides georeferenced video footage correlated with GPS (global positioning systems) for GIS (geographic information systems) mapping applications. Based on its fluvial and geomorphological trends, OBRI was dissected quantitatively and integrated into databases for species-specific GIS habitat queries. Substrate type, depth, above water river characteristics (pool/riffle/run), and substrate embeddedness were extracted to access specific habitats. To better pinpoint optimal microhabitat locations, a physical habitat suitability model was developed to rank preferred habitat locales. Rankings were sequentially broken into five categories: optimal, sub-optimal, marginal, sub-marginal, and poor habitat criteria. Habitat suitability findings for the interested species habitats varied tremendously, favoring fish species. Spotfin chub, Erimonax monacha, optimal habitat was found to cover 22.14 km of river length within OBRI (30 % of OBRI’s spatial extent). The blackside dace, Phoxinus cumberlandensis, (38.9 km) and the duskytail darter, Etheostoma percnurum, (50.9 km) met optimal habitat conditions that yielded 51% and 69% of OBRI’s spatial extent, respectively. In general, optimal habitats for the six mussels were sporadically distributed and had low occurrences. Primarily, these mussel species prefer highly embedded areas with very specific depths and pool/riffle/run conditions. Cumberland elktoe, Alasmidonta atropurea, optimal habitat ranges spanned across 4.32 km (6% of OBRI’s spatial extent) with most of the habitat characteristics in OBRI being marginal. The purple bean, Villosa perpurpurea, optimal habitat was identified within 2.61 km of OBRI (3.5% of OBRI’s spatial extent). Most of the physical conditions of OBRI supplied poor to sub-marginal habitat for the purple bean, at least from a thalweg perspective. Only 385 m coincided with optimal habitat for the cumberland bean, Villosa trabalis, (0.5% of OBRI’s spatial extent) with most habitats in long sub-marginal reaches. Optimal habitats for the cumberlandian combshell, Epioblasma brevidens, the tan riffleshell, Epioblasma florentina walkeri, and the littlewing pearlymussel, Pegias fibula, were deficient, only occurring in 484 m, 276 m, and 252 m of OBRI, respectively (0.7%, 0.4%, and 0.3% of OBRI’s spatial extent). Marginal to sub-marginal habitats dominated the park for these three mussel species.

There is a need to define a more efficient and accurate approach to aquatic habitat mapping. Traditional approaches have focused on intense biological/non-biological sampling and observation analysis within specific and restrained scales. Therefore, an underwater video mapping system (UVMS) has been developed in efforts to identify federally protected aquatic species’ habitats within the Obed Wild and Scenic River (OBRI). The UVMS kayak apparatus provides georeferenced video footage correlated with GPS (global positioning systems) for GIS (geographic information systems) mapping applications. Based on its fluvial and geomorphological trends, OBRI was dissected quantitatively and integrated into databases for species-specific GIS habitat queries. Substrate type, depth, above water river characteristics (pool/riffle/run), and substrate embeddedness were extracted to access specific habitats. To better pinpoint optimal microhabitat locations, a physical habitat suitability model was developed to rank preferred habitat locales. Rankings were sequentially broken into five categories: optimal, sub-optimal, marginal, sub-marginal, and poor habitat criteria. Habitat suitability findings for the interested species habitats varied tremendously, favoring fish species. Spotfin chub, Erimonax monacha, optimal habitat was found to cover 22.14 km of river length within OBRI (30 % of OBRI’s spatial extent). The blackside dace, Phoxinus cumberlandensis, (38.9 km) and the duskytail darter, Etheostoma percnurum, (50.9 km) met optimal habitat conditions that yielded 51% and 69% of OBRI’s spatial extent, respectively. In general, optimal habitats for the six mussels were sporadically distributed and had low occurrences. Primarily, these mussel species prefer highly embedded areas with very specific depths and pool/riffle/run conditions. Cumberland elktoe, Alasmidonta atropurea, optimal habitat ranges spanned across 4.32 km (6% of OBRI’s spatial extent) with most of the habitat characteristics in OBRI being marginal. The purple bean, Villosa perpurpurea, optimal habitat was identified within 2.61 km of OBRI (3.5% of OBRI’s spatial extent). Most of the physical conditions of OBRI supplied poor to sub-marginal habitat for the purple bean, at least from a thalweg perspective. Only 385 m coincided with optimal habitat for the cumberland bean, Villosa trabalis, (0.5% of OBRI’s spatial extent) with most habitats in long sub-marginal reaches. Optimal habitats for the cumberlandian combshell, Epioblasma brevidens, the tan riffleshell, Epioblasma florentina walkeri, and the littlewing pearlymussel, Pegias fibula, were deficient, only occurring in 484 m, 276 m, and 252 m of OBRI, respectively (0.7%, 0.4%, and 0.3% of OBRI’s spatial extent). Marginal to sub-marginal habitats dominated the park for these three mussel species.

Our planet is traversing the age of human-induced climate change and biodiversity loss. Projected global warming of 1.5 ºC above pre-industrial levels and related greenhouse gas emission pathways will bring about detrimental and irreversible impacts on the interconnected natural and human ecosystem. A global warming of 2 ºC could further exacerbate the risks across the sectors of biodiversity, energy, food, and water. Time- and cost-effective solutions and strategies are required for strengthening humanity’s response to the present environmental and societal challenges. Coastal seascape ecosystems including seagrasses, corals, mangrove forests, tidal flats, and salt marshes have been more recently heralded as nature-based solutions for mitigating and adapting to the climate-related impacts. This is due to their ability to absorb and store large quantities of carbon from the atmosphere. Focusing on seagrass habitats, although occupying only 0.2% of the world’s oceans, they can sequestrate up to 10% of the total oceanic carbon pool, all the while providing important food security, biodiversity, and coastal protection. But seagrass ecosystems, as all of their blue carbon seascape neighbors, are losing 1.5% of their extent per year due to anthropogenic activities. This has adverse implications for global carbon stocks, coastal protection, and marine biodiversity. Seagrass and seascape recession necessitates their science and policy-based management, protection, conservation which will ensure that our planet will remain within its sustainable boundaries in the age of climate change. The present PhD Thesis and research aim is to develop algorithms for seagrass mapping and monitoring leveraging the recent emergences in remote sensing technology―new satellite image archives, machine learning frameworks, and cloud computing―with field data from multiple sources. The main PhD findings are the demonstration of the suitability of Sentinel-2, RapidEye, and PlanetScope satellite imagery for regional to large-scale seagrass mapping; the introduction and incorporation of machine learning frameworks in the context of seagrass remote sensing and data analytics; the development of a semi-analytical model to invert the bottom reflectance of seagrasses; the design and implementation of multi-temporal satellite image approaches in coastal aquatic remote sensing; and the introduction, design and application of a scalable cloud-based tool to scale up seagrass mapping across large spatial and temporal dimensions. The approaches of the present PhD cover the gaps of the existing scientific literature of seagrass mapping in terms of the lack of spatial and temporal scalability and adaptability; the infancy in seagrass and seascape-related artificial intelligence endeavours; the restrictions of local server and mono-temporal approaches; and the absence of new methodological developments and applications using new (mainly open) satellite image archives. I anticipate and envisage that the near-future steps after the completion of my PhD will address the scalability of the designed cloud-native, data-driven mapping tool to standardise, automate, commercialise and democratise mapping and monitoring of seagrass and seascape ecosystems globally. The synergy of the developed momentum around the global seascape with the technological potential of Earth Observation can contribute to humanity’s race to adapt to and mitigate the climate change impacts and avoid cross tipping points in climate patterns, and biodiversity and ecosystem functions.

Graduation date: 2006 / Structure-forming invertebrates belong to a polyphyletic group of primarily sessile and sedentary megafauna that can significantly enhance the complexity of physical habitats. A number of these organisms, including cold-water corals and sponges, are known to be slow growing and vulnerable to physical disturbance. In addition, as filter feeders, these invertebrates can indicate areas of consistently favorable conditions for feeding and growth. This study provides the first quantitative analysis of structure-forming invertebrate communities in many areas along the continental margin of Oregon and Washington. Geological surveys during 1992-95, using the occupied submersible, Delta, sampled an extensive area in this region, primarily on and around rock outcrops. The videos from these surveys were analyzed to inventory and catalog sessile structure-forming invertebrates and to document their associations with geological habitat types. Detailed data on geological substrate, invertebrate diversity, abundance, and density were compiled and analyzed. It was found that geological substrate and depth were reliable indicators of suitable habitat for most species included in the study. Gorgonian corals tended to concentrate in high densities in depths between 200-250m, at the southern edges of submerged rocky banks, and where hard rocky substrate was covered with a thick layer of sediment. Because of recent fishery regulation changes, this information can be used as baseline data for future studies on the effectiveness of closed areas on the recovery of structure-forming invertebrates from disturbance, particularly bottom trawling.

A growing number of scientists are investigating applications of landscape ecology principles to marine studies, yet few coral reef scientists have examined spatial patterns across entire reefscapes with a holistic ecosystem-based view. This study was an effort to better understand reefscape ecology by quantitatively assessing spatial structures and habitat arrangements using remote sensing and geographic information systems (GIS). Quantifying recurring patterns in reef systems has implications for improving the efficiency of mapping efforts and lowering costs associated with collecting field data and acquiring satellite imagery. If a representative example of a reef is mapped with high accuracy, the data derived from habitat configurations could be extrapolated over a larger region to aid management decisions and focus conservation efforts. The aim of this project was to measure repeating spatial patterns at multiple scales (10s m2 to 10s km2) and to explain the environmental mechanisms which have formed the observed patterns. Because power laws have been recognized in size-frequency distributions of reef habitat patches, this study further investigated whether the property exists for expansive reefs with diverse geologic histories. Intra- and inter-reef patch relationships were studied at three sites: Andavadoaka (Madagascar), Vieques (Puerto Rico), and Saipan (Commonwealth of the Northern Mariana Islands). In situ ecological information, including benthic species composition and abundance, as well as substrate type, was collected with georeferenced video transects. LiDAR (Light Detection and Ranging) surveys were assembled into digital elevation models (DEMs), while vessel-based acoustic surveys were utilized to empirically tune bathymetry models where LiDAR data were unavailable. A GIS for each site was compiled by overlying groundtruth data, classifications, DEMs, and satellite images. Benthic cover classes were then digitized and analyzed based on a suite of metrics (e.g. patch complexity, principle axes ratio, and neighborhood transitions). Results from metric analyses were extremely comparable between sites suggesting that spatial prediction of habitat arrangements is very plausible. Further implications discussed include developing an automated habitat mapping technique and improving conservation planning and delimitation of marine protected areas.

Η παρούσα μεταπτυχιακή διατριβή επικεντρώνεται στην μελέτη της παράκτιας ζώνης της νήσου Λέρου στο Νοτιοανατολικό Αιγαίο, παρουσιάζοντας τα αποτελέσματα της ερμηνείας των γεωφυσικών στοιχείων που συλλέχθηκαν από το Εργαστήριο Θαλάσσιας Γεωλογίας και Φυσικής Ωκεανογραφίας (Ε.ΘΑ.ΓΕ.Φ.Ω.) τον Ιούνιο του 2011. Η έρευνα φιλοδοξεί να συνεισφέρει στην ανάδειξη της υποθαλάσσιας πολιτιστικής και φυσικής κληρονομιάς του νησιού, καθώς η συλλογή, επεξεργασία και ερμηνεία του συνόλου των δεδομένων επέτρεψε την αναγνώριση και την λεπτομερή χαρτογράφηση υποθαλάσσιων στόχων μεγάλης ιστορικής και περιβαλλοντικής σημασίας. Ως εκ τούτου, η διατριβή κινείται σε δύο κατευθύνσεις. Η πρώτη κατεύθυνση αφορά στον εντοπισμό στόχων πιθανής ιστορικής σπουδαιότητας που εντοπίστηκαν στην επιφάνεια του πυθμένα ενώ η δεύτερη κατεύθυνση αφορά στον εντοπισμό και την αποτύπωση βιογενών σχηματισμών και συγκεκριμένα λειμώνων P. Oceanica και ασβεστιτικών ροδοφυκών (corallegene formations). Οι θαλάσσιες έρευνες πραγματοποιήθηκαν σε δύο διακριτά στάδια, στην συστηματική αποτύπωση του πυθμένα με ηχοβολιστή πλευρικής σάρωσης (EG&G 272 TD) και την οπτική επιβεβαίωση των αποτελεσμάτων της ηχοβολιστικής αποτύπωσης με σύστημα συρόμενης υποβρύχιας κάμερας. Η ανάλυση και επεξεργασία των ηχογραφιών οδήγησε στον εντοπισμό ναυαγίων που συνδέονται με τη Μάχη της Λέρου (9-10/1943), ένα από τα σημαντικότερα πολεμικά γεγονότα που έλαβαν χώρα κατά τη διάρκεια του Δευτέρου Παγκοσμίου πολέμου, στην ανατολική Μεσόγειο και τα οποία αποτελούν πολύτιμα ιστορικά στοιχεία σε παγκόσμια κλίμακα, μεταξύ των οποίων το βυθισμένο ελληνικό αντιτορπιλικό Βασίλισσα ‘Ολγα (D15). Στο πλαίσιο της δεύτερης κατεύθυνσης εντοπίστηκαν και χαρτογραφήθηκαν οι λειμώνες P. Oceanica και οι σχηματισμοί των ασβεστιτικών ροδοφυκών σχεδόν ανά όρμο περιμετρικά της νήσου. Η σχεδίαση των αντιστοίχων υποθαλάσσιων θεματικών χαρτών της παράκτιας ζώνης της Λέρου αναμένεται να αποτελέσουν ένα σημαντικό εργαλείο στην προστασία και στην ανάδειξη της σημαντικής υποθαλάσσιας ιστορικής και φυσικής κληρονομιάς του νησιού / The present study describes the submarine geophysical survey which was carried out in Leros Island, Aegean Sea and presents the results of the geophysical data analysis. The data were collected by the Laboratory of Marine Geology & Physical Oceanography, department of Geology, University of Patras during the period 11-17 June 2011. The research aims to contribute to the enhancement of underwater cultural and natural heritage of the island, as the collection, processing and interpretation of all of the data has allowed the identification of underwater targets of great historic and environmental importance. Geophysical survey in Leros Island, using a side scan sonar (EG&G 272 TD), coupled with ground-truthing by deploying a Towing Camera System of historic shipwrecks from World War II and of the major seabed habitats, namely Posidonia oceanica and coralligène formations. The survey revealed a great number of shipwrecks associated with the Battle of Leros (9-10/1943), one of the most important military events that took place during the World War II, in the Eastern Mediterranean which are considered as valuable historic data on a global scale, including the sunken Greek destroyer Queen Olga (D15). The design of the thematic maps of the coastal zone of Leros is expected to become an important tool in both protecting and promoting the significant underwater cultural and natural heritage of the island.