Oceanography and Atmospheric Sciences and Meteorology Commons^™

Optical Detection And Classification Of Phytoplankton Taxa Through Spectral Analysis, Daniel Tyler Sensi

USF Tampa Graduate Theses and Dissertations

Phytoplankton serve as the bottom of the marine food web and therefore play an essential role in marine ecosystems. On the other hand, coastal phytoplankton communities can adversely affect the marine ecosystem and humans. A variety of techniques have been developed to measure and study phytoplankton, including in situ methods (e.g., flow cytometry) and laboratory methods (e.g., microscopic taxonomy). These provide accurate measurements of phytoplankton taxa and concentrations, yet they are limited in space and time, and synoptic information is difficult to obtain with these techniques.

Optical remote sensing may provide complementary information for its synoptic nature, as demonstrated by …

High Resolution Determination Of Nanomolar Concentrations Of Dissolved Reactive Phosphate In Ocean Surface Waters Using Long Path Liquid Waveguide Capillary Cells (Lwcc) And Spectrometric Detection, Louise A. Zimmer, Gregory A. Cutter

OES Faculty Publications

In the last decade, long path length, low volume, liquid waveguide capillary cells (LWCC) in conjunction with conventional nutrient auto-analyzers have been applied to determinations of nanomolar levels of phosphate, nitrate, and nitrite in oligotrophic waters. This article reports a high resolution, real-time, continuous method for nanomolar dissolved reactive phosphate measurements in ocean surface waters with data logging every 30 seconds for up to 16 consecutive hours. Surface seawater is pumped continuously from a shipboard underway tow-fish unit to a helium gas-segmented, continuous-flow, nutrient auto-analyzer modified with a 250 cm LWCC. To circumvent baseline instability due to reagents, a parallel …

Rapid And Noncontaminating Sampling System For Trace Elements In Global Ocean Surveys, Gregory A. Cutter, Kenneth W. Bruland

OES Faculty Publications

A system for the rapid and noncontaminating sampling of trace elements with volumes of up to 36 L per depth and including the dissolved and particulate phases has been developed for ocean sections that are a crucial part of programs such as International GEOTRACES. The system uses commercially available components, including an aluminum Seabird Carousel with all titanium pressure housings for electronics and sensors to eliminate zinc sacrificial anodes and holding twenty-four 12 L GO-FLO bottles, and a 7500 m, 14 mm Vectran conducting cable (passing over an A-frame with nonmetallic sheave) spooled onto a traction winch. The GO-FLO bottles …

Δ13c Is A Signature Of Light Availability And Photosynthesis In Seagrass, Xingping Hu, David J. Burdige, Richard C. Zimmerman

OES Faculty Publications

We explored the role of light-saturated (carbon-limited) photosynthesis on δ¹³C of turtlegrass (Thalassia testudinum Banks ex Konig) populations from the clear, blue waters of the Great Bahama Bank and the turbid, green waters of Florida Bay using field observations and radiative transfer models. Consistent with numerous previous observations, leaf δ¹³C decreased significantly with water depth in both regions. However the δ¹³C for Bahamas turtlegrass was 3 parts per thousand heavier than that for Florida Bay turtlegrass at equivalent depths, and broadband irradiance explained even less of the δ¹³C variations than depth. Instead, leaf δ¹³C showed a stronger relationship to …

Controls On Dissolved Cobalt In Surface Waters Of The Sargasso Sea: Comparisons With Iron And Aluminum, R. U. Shelley, Peter N. Sedwick, T. S. Bibby, P. Cabedo-Sanz, T. M. Church, R. J. Johnson, A. I. Macey, C. M. Marsay, E. R. Sholkovitz, S. J. Ussher, P. J. Worsfold, M. C. Lohan

OES Faculty Publications

Dissolved cobalt (dCo), iron (dFe) and aluminum (dAl) were determined in water column samples along a meridional transect (∼31°N to 24°N) south of Bermuda in June 2008. A general north-to-south increase in surface concentrations of dFe (0.3-1.6 nM) and dAl (14-42 nM) was observed, suggesting that aerosol deposition is a significant source of dFe and dAl, whereas no clear trend was observed. for near-surface dCo concentrations. Shipboard aerosol samples indicate fractional solubility values of 8-100% for aerosol Co, which are significantly higher than corresponding estimates of the solubility of aerosol Fe (0.44-45%). Hydrographic observations and analysis of time series rain …

Introduction To Special Section On Recent Advances In The Study Of Optical Variability In The Near-Surface And Upper Ocean, T. Dickey, M. L. Banner, P. Bhandari, T. Boyd, L. Carvalho, O. Wurl

OES Faculty Publications

Optical variability occurs in the near-surface and upper ocean on very short time and space scales (e.g., milliseconds and millimeters and less) as well as greater scales. This variability is caused by solar, meteorological, and other physical forcing as well as biological and chemical processes that affect optical properties and their distributions, which in turn control the propagation of light across the air-sea interface and within the upper ocean. Recent developments in several technologies and modeling capabilities have enabled the investigation of a variety of fundamental and applied problems related to upper ocean physics, chemistry, and light propagation and utilization …

Novel Lineages Of Prochlorococcus And Synechococcus In The Global Oceans, Sijun Huang, Steven W. Wilhelm, H. Rodger Harvey, Karen Taylor, Nianzhi Jiao, Feng Chen

OES Faculty Publications

Picocyanobacteria represented by Prochlorococcus and Synechococcus have an important role in oceanic carbon fixation and nutrient cycling. In this study, we compared the community composition of picocyanobacteria from diverse marine ecosystems ranging from estuary to open oceans, tropical to polar oceans and surface to deep water, based on the sequences of 16S-23S rRNA internal transcribed spacer (ITS). A total of 1339 ITS sequences recovered from 20 samples unveiled diverse and several previously unknown clades of Prochlorococcus and Synechococcus. Six high-light (HL)-adapted Prochlorococcus clades were identified, among which clade HLVI had not been described previously. Prochlorococcus clades HLIII, HLIV and …

Diversity, Distribution, And Expression Of Diazotroph Nifh Genes In Oxygen-Deficient Waters Of The Arabian Sea, Amal Jayakumar, Mamoon M. D. Al-Rshadat, Bess B. Ward, Margaret R. Mulholland

OES Faculty Publications

The Arabian Sea oxygen minimum zone (OMZ), the largest suboxic region in the world's oceans, is responsible for up to half of the global mesopelagic fixed nitrogen ( N ) loss from the ocean via denitrification and anammox. Dinitrogen (N₂) fixation is usually attributed to cyanobacteria in the surface ocean. Model prediction and physiological inhibition of N₂ fixation by oxygen, however, suggest that N₂ fixation should be enhanced near the oxygen-deficient zone (ODZ) of the Arabian Sea. N₂ fixation and cyanobacterial nifH genes (the gene encoding dinitrogenase reductase) have been reported in surface waters overlying …

Database Of Diazotrophs In Global Ocean: Abundance, Biomass, And Nitrogen Fixation Rates, Y. W. Luo, S. C. Doney, L. A. Anderson, M. Benavides, I. Berman-Frank, A. Bode, S. Bonnet, K. H. Boström, D. Böttjer, D. G. Capone, M. R. Mulholland

OES Faculty Publications

Marine N₂ fixing microorganisms, termed di-azotrophs, are a key functional group in marine pelagic ecosystems. The biological fixation of dinitrogen (N₂) to bioavailable nitrogen provides an important new source of nitrogen for pelagic marine ecosystems and influences primary productivity and organic matter export to the deep ocean. As one of a series of efforts to collect biomass and rates specific to different phytoplankton functional groups, we have constructed a database on diazotrophic organisms in the global pelagic upper ocean by compiling about 12 000 direct field measurements of cyanobacterial diazotroph abundances (based on microscopic cell counts or …

The Role Of Larval Dispersal In Metapopulation Gene Flow: Local Population Dynamics Matter, Daphne M. Munroe, John M. Klinck, Eileen E. Hofmann, Eric N. Powell

OES Faculty Publications

The degree of genetic connectivity among populations in a metapopulation has direct consequences for species evolution, development of disease resistance, and capacity of a metapopulation to adapt to climate change. This study used a metapopulation model that integrates population dynamics, dispersal, and genetics within an individual-based model framework to examine the mechanisms and dynamics of genetic connectivity within a metapopulation. The model was parameterized to simulate four populations of oysters (Crassostrea virginica) from Delaware Bay on the mid-Atlantic coast of the United States. Differences among the four populations include a strong spatial gradient in mortality, a spatial gradient …

Impact Of Abrupt Deglacial Climate Change On Tropical Atlantic Subsurface Temperatures, Matthew W. Schmidt, Ping Chang, Jennifer E. Hertzberg, Theodore R. Them Ii, Link Li, Bette L. Otto-Bliesner

OES Faculty Publications

Both instrumental data analyses and coupled ocean-atmosphere models indicate that Atlantic meridional overturning circulation (AMOC) variability is tightly linked to abrupt tropical North Atlantic (TNA) climate change through both atmospheric and oceanic processes. Although a slowdown of AMOC results in an atmospheric-induced surface cooling in the entire TNA, the subsurface experiences an even larger warming because of rapid reorganizations of ocean circulation patterns at intermediate water depths. Here, we reconstruct high-resolution temperature records using oxygen isotope values and Mg/Ca ratios in both surface- and sub-thermocline-dwelling planktonic foraminifera from a sediment core located in the TNA over the last 22 ky. …

Deglacial Variability Of Antarctic Intermediate Water Penetration Into The North Atlantic From Authigenic Neodymium Isotope Ratios, Ruifang C. Xie, Franco Marcantonio, Matthew W. Schmidt

OES Faculty Publications

Understanding intermediate water circulation across the last deglacial is critical in assessing the role of oceanic heat transport associated with Atlantic Meridional Overturning Circulation variability across abrupt climate events. However, the links between intermediate water circulation and abrupt climate events such as the Younger Dryas (YD) and Heinrich Event 1 (H1) are still poorly constrained. Here, we reconstruct changes in Antarctic Intermediate Water (AAIW) circulation in the subtropical North Atlantic over the past 25 kyr by measuring authigenic neodymium isotope ratios in sediments from two sites in the Florida Straits. Our authigenic Nd isotope records suggest that there was little …

Solar Forcing Of Florida Straits Surface Salinity During The Early Holocene, Matthew W. Schmidt, William A. Weinlein, Franco Marcantonio, Jean Lynch-Stieglitz

OES Faculty Publications

Previous studies showed that sea surface salinity (SSS) in the Florida Straits as well as Florida Current transport covaried with changes in North Atlantic climate over the past two millennia. However, little is known about earlier Holocene hydrographic variability in the Florida Straits. Here, we combine Mg/Ca-paleothermometry and stable oxygen isotope measurements on the planktonic foraminifera Globigerinoides ruber (white variety) from Florida Straits sediment core KNR166-2 JPC 51 (24° 24.70' N, 83° 13.14' W, 198 m deep) to reconstruct a high-resolution (~25 yr/sample) early to mid Holocene record of sea surface temperature and δ¹⁸O_SW)(a …

Antarctic Surface Melting Dynamics: Enhanced Perspectives From Radar Scatterometer Data, L. D. Trusel, K. E. Frey, S. B. Das

Geography

Antarctic ice sheet surface melting can regionally influence ice shelf stability, mass balance, and glacier dynamics, in addition to modulating near-surface physical and chemical properties over wide areas. Here, we investigate variability in surface melting from 1999 to 2009 using radar backscatter time series from the SeaWinds scatterometer aboard the QuikSCAT satellite. These daily, continent-wide observations are explored in concert with in situ meteorological records to validate a threshold-based melt detection method. Radar backscatter decreases during melting are significantly correlated with in situ positive degree-days as well as meltwater production determined from energy balance modeling at Neumayer Station, East Antarctica. …

Adaptation Of Sea Level Rise In Nile Delta Due To Climate Change, Ayman F. Batisha

Egypt & Libya

Nile Delta is vulnerable due to the impact of climate change and related sea level rise. Due to low elevation in the Nile delta region, Egypt is considered one of the top five countries expected to be mostly impacted with a 1 m sea level rise resulting from global warming. Egypt is ranked as the fifth in the world concerning the impact on the total urban areas, Egypt’s GDP would be significantly impacted, and Egypt’s natural resources such as coastal zone, water resources, water quality, agricultural land, livestock and fisheries maybe subjected to vulnerability. Also, Egypt may face environmental crises …

Mangroves, Mudbanks And Seawalls: Political Ecology Of Adaptation To Sea Level Rise In Suriname, Ravic Nijbroek

USF Tampa Graduate Theses and Dissertations

This study seeks to understand how global discourses of sea level rise (SLR) and mangrove ecology influence national climate change adaptation policy to reduce coastal vulnerability in Suriname. A majority of the Surinamese population lives along the low elevation coastal zone and is highly exposed to projected SLR. Failure by the international community to reach agreement on climate change mitigation means that vulnerable coastal communities must adapt. The Suriname coast is predominantly shaped by mudbanks and mangroves which together provide protection against coastal erosion and trap sediments resulting in coastal accretion. Knowledge claims of mangrove ecology and utility in SLR …

Micronekton And Macrozooplankton Of The Western Antarctic Peninsula And The Eastern Ross Sea: Contrast Between Two Different Thermal Regimes, Melanie Leigh Parker

USF Tampa Graduate Theses and Dissertations

ABSTRACT

Micronekton and macrozooplankton were sampled from the Western Antarctic Peninsula (WAP) and eastern Ross Sea regions. Samples were collected over the course of six research cruises to the Southern Ocean. Four of those cruises were conducted in the Marguerite Bay region of the WAP during the austral fall and winter of 2001 and 2002. A fifth cruise sampled faunal assemblages at nine sites, ranging from Joinville Island at the northern tip of the WAP to Charcot Island near the southern extent of the WAP, during austral fall 2010. A sixth cruise was conducted in the pack ice within the …

Shelf-Scale Mapping Of Fish Distribution Using Active And Passive Acoustics, Carrie Christy Wall

USF Tampa Graduate Theses and Dissertations

Fish sound production has been associated with courtship and spawning behavior. Acoustic recordings of fish sounds can be used to identify distribution and behavior. Passive acoustic monitoring (PAM) can record large amounts of acoustic data in a specific area for days to years. These data can be collected in remote locations under potentially unsafe seas throughout a 24-hour period providing datasets unattainable using observer-based methods. However, the instruments must withstand the caustic ocean environment and be retrieved to obtain the recorded data. This can prove difficult due to the risk of PAMs being lost, stolen or damaged, especially in highly …

Skill Assessment And Optimization Of The Third Generation Wave Models For Applications In Gulf Of Mexico, Seyed Mostafa Siadatmousavi

LSU Doctoral Dissertations

Numerical phase-averaged wave models are the best option to obtain the spatial and temporal distribution of the wave energy over a large domain, such as the Gulf of Mexico. Parallel implementation of unstructured SWAN and WAVEWATCH-III were engaged in this research to evaluate the performance of third generation wave models for different conditions. Met-ocean data from a network of NDBC buoys and WAVCIS stations were used to assess the predictive skills of the wave models. Deep water wave energy dissipation formulations were carefully analyzed and modified to improve the accuracy of the bulk wave parameters. Moreover, the importance of the …

Greenhouse Gas Emissions And Nutrients Dynamics In Restored Wetlands Of The Mississippi River Basin, Christopher Lundberg

LSU Doctoral Dissertations

Greenhouse gases were sampled during spring and summer months in 2010 and 2011 at two sites in the Mississippi River Basin: a riparian forested wetland under restored flood pulsing near Memphis, TN and a coastal estuarine marsh complex impacted by a river diversion at Caernarvon, LA. Mean methane fluxes at Caernarvon (-0.09 g CH4-C m-2 d-1) were lower than those at Memphis (0.53 g CH4-C m-2 d-1), and did not differ between seasons. Nitrous oxide fluxes were generally below detection limits. Fluxes were uncorrelated with water depth, soil temperature, and ambient air temperature, though sampling occurred over a narrow range …