Savannah, GA, United States
Savannah, GA, United States

The Skidaway Institute of Oceanography is an internationally renowned marine science research institute located on the northern end of Skidaway Island near Savannah, Georgia, USA. Founded in 1968, it is now a research unit of the University of Georgia. It does not grant degrees, but its faculty serve as adjuncts to universities, and as mentors and advisors for visiting students and interns. SkIO faculty also frequently collaborate with marine scientists of other institutes both nationally and internationally. In 2012, It was announced that SkIO would be put under the management of the University of Georgia as part of an effort to streamline the University System of Georgia, the realignment with the University of Georgia being completed in July 2013. Wikipedia.


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Verity P.G.,Skidaway Institute of Oceanography | Borkman D.G.,University of Rhode Island
Estuaries and Coasts | Year: 2010

The Skidaway River estuary, GA (USA), a tidally dominated subtropical system surrounded by extensive Spartina salt marshes, is experiencing steady increases in nutrients, chlorophyll, and particulate matter and decline in dissolved oxygen, associated with cultural eutrophication. A long-term study is documenting changes in these parameters: previous papers Verity (Estuaries 25:944-960, 2002a, Estuaries 25:961-975, b) reported on hydrography, nutrients, chlorophyll, and particulate matter during 1986-1996; plankton community responses are reported here. Phytoplankton, bacteria, heterotrophic nanoplankton and dinoflagellates, ciliates, and copepods exhibited strong seasonal cycles in abundance driven by temperature and resource availability, typically with summer maxima and winter minima. However, cultural eutrophication coincided with altered planktonic food webs as autotrophic and heterotrophic communities responded to increasing concentrations and changing ratios of inorganic and organic nutrients, potential prey, and predators. Small (<8 μm) photosynthetic nanoplankton increased in absolute concentration and also relative to larger cells. In contrast, diatoms did not show consistent increases in abundance, despite significant long-term increases in ambient silicate concentrations. Mean annual bacteria concentrations approximately doubled, and eukaryotic organisms in the microbial food web (heterotrophic and mixotrophic flagellates, dinoflagellates, ciliates, and metazoan zooplankton) also increased. All plankton groups except copepods showed trends of increasing annual amplitudes between seasonal high and low values, with higher peak concentrations each year. These observations suggest that the eutrophication signal was gradually becoming uncoupled from regulatory mechanisms. Theory and evidence from other more impacted waters suggest that, if these patterns continue, changes in the structure and function of higher trophic levels will ensue. © Coastal and Estuarine Research Federation 2009.


Borrett S.R.,University of North Carolina at Wilmington | Whipple S.J.,Skidaway Institute of Oceanography | Patten B.C.,University of Georgia
Oikos | Year: 2010

Indirect effects are important components of ecological and evolutionary interactions that may maintain biodiversity, enable or inhibit invasive species, and challenge ecosystem assessment and management. A central hypothesis of Network Environ Analysis (NEA), one type of ecological network analysis, is that indirect flows tend to dominate direct flows in ecosystem networks of conservative substance exchanges. However, current NEA methods assume that these ecosystems are stationary (i.e. time invariant exchange rates), which is unlikely to be true for many ecosystems for interesting time and space scales. For the work reported here, we investigated the sensitivity of the dominance of indirect effects hypothesis to the stationary modeling assumption by determining the development rate of indirect effects and flow intensity, as expressed as the number of transfer steps, in thirty-one ecosystem models. We hypothesized that indirect effects develop rapidly in ecological networks, but that they would develop faster in biogeochemically based models than in trophically based models. In contrast, our results show that indirect effects develop rapidly in all thirty-one models examined. In 94% of the models, indirect flows exceeded direct flows by a pathway length of 3. This indicates that ecological systems do not need to maintain a particular configuration for long for indirect effects to dominate. Thus, the dominance of indirect effects hypothesis remains plausible. We also found that biogeochemical models tended to require more of the extended path network than the trophic models to account for 50% and 95% of the total system activity, but that both types of models required more of the power series than is typically considered in engineered systems. These results succinctly illustrate the complexity of ecological systems and help explain why they are challenging to assess and manage. © 2009 The Authors.


Paffenhofer G.-A.,Skidaway Institute of Oceanography
Journal of Plankton Research | Year: 2013

There are repeated reports in the literature of the sudden appearance and disappearance of dolioid blooms. While there is ample information on parasites and predators of salps, such information is rare for doliolids. While other variables like food organisms of different quality and their supply cannot be excluded, parasites and predators may have a major impact on bloom persistence. From 2009 to 2012 large nurses of Dolioletta gegenbauri with only short cadophores were found during 16 cruises. This observation suggested the hypothesis that the removal by predators of longer cadophores, with their trophozooids and budding phorozooids, often prevents the development or maintenance of doliolid blooms on subtropical continental shelves. © 2013 The Author.


Lee R.F.,Skidaway Institute of Oceanography | Koster M.,University of Greifswald | Paffenhofer G.-A.,Skidaway Institute of Oceanography
Journal of Plankton Research | Year: 2012

Subsurface plumes of small, stable dispersed oil droplets are a feature of oil spills treated with dispersants. The doliolid, Dolioletta gegenbauri Uljanin (Tunicata, Thaliacea), a zooplankton species abundant in the Gulf of Mexico, was observed to ingest dispersed oil droplets (1-30 m in diameter), produced by vigorous mixing of a dispersant with crude oil. Oil droplets were first observed in the doliolid stomach, followed by appearance in the fecal pellets formed within the doliolid. Released fecal pellets had numerous oil droplets. Concentrations of ingested oil droplets in doliolids, exposed to high droplet concentrations (17 000 droplets/mL), increased from 800 to 5300 droplets/doliolid after 4 and 24 h, respectively. At a lower concentration (1200 droplets/mL), the ingested droplet concentration after 12 h was 450 droplets/doliolid. Fecal pellets were an important route for the elimination of oil droplets. Oil droplet concentrations in fecal pellets were 85 droplets/fecal pellet and 10 droplets/fecal pellet at high and low concentrations of dispersed oil, respectively. A calculation of the amount of oil in doliolid fecal pellets, based on doliolid concentrations, their fecal production rates and oil concentration in the fecal pellets, indicated that 200 g oil/m3-day could be carried to the benthos via fecal pellets. © 2012 The Author.


Verity P.G.,Skidaway Institute of Oceanography
Harmful Algae | Year: 2010

Evidence is widespread that species of harmful algae are showing up in new locations and that toxic bloom events may be increasing in magnitude and frequency. These trends are sometimes but not exclusively associated with cultural eutrophication. On the southeast coast of the USA, harmful species, bloom events, and deleterious ecosystem impacts were restricted to eutrophic estuaries and adjacent shelf waters of North Carolina and Florida prior to 2000. Specifically, Georgia and South Carolina waters either lacked HAB species or contained unremarkable concentrations. Beginning in 2000, however, numerous HAB taxa were collected in South Carolina coastal ponds and estuaries, and were associated with fish kills there. The present study documents the new appearance of HAB species in Georgia, in the Skidaway estuary, which has been sampled weekly for 22 years. Four HAB taxa were initially present when sampling began in 1986-1987, five new species appeared sporadically over the next 15 years, and then seven additional new taxa appeared between 2002 and 2008. Eleven of the sixteen taxa were dinoflagellates (species of Cochlodinium, Dinophysis, Gyrodinium, Heterocapsa, Karenia, Karlodinium, Kryptoperidinium, and Prorocentrum), four were raphidophytes (Chattonella, Fibrocapsa, and Heterosigma species), with one diatom (Pseudo-nitzschia). Notably, only two species occurred at concentrations exceeding 103 cells ml-1: Heterosigma akashiwo and Heterocapsa rotundata. One species, H. akashiwo, was present every spring/summer and in sufficient concentrations to discern temporal trends. H. exhibited significant increases in annual mean and peak abundances over the 22-year sample period. This increasing trend was significantly correlated with nutrient concentrations, specifically NH4 and DON. Whereas factors responsible for the initial appearance of new HAB taxa in these waters are unknown, the evidence suggests their establishment is related to cultural eutrophication. If current trends of increasing number and abundance of HAB species continue, estuaries in Georgia can expect to exhibit the detrimental ecological manifestations commonly observed elsewhere. © 2009 Elsevier B.V. All rights reserved.


Stubbins A.,Skidaway Institute of Oceanography | Niggemann J.,Carl von Ossietzky University | Dittmar T.,Carl von Ossietzky University
Biogeosciences | Year: 2012

Dissolved black carbon (DBC), defined here as condensed aromatics isolated from seawater via PPL solid phase extraction and quantified as benzenepolycarboxylic acid (BPCA) oxidation products, is a significant component of the oceanic dissolved organic carbon (DOC) pool. These condensed aromatics are widely distributed in the open ocean and appear to be tens of thousands of years old. As such DBC is regarded as highly refractory. In the current study, the photo-lability of DBC, DOC and coloured dissolved organic matter (CDOM; ultraviolet-visible absorbance) were determined over the course of a 28 day irradiation of North Atlantic Deep Water under a solar simulator. During the irradiation DBC fell from 1044 ± 164 nM-C to 55 ± 15 nM-C, a 20-fold decrease in concentration. Dissolved black carbon photo-degradation was more rapid and more extensive than for bulk CDOM and DOC. The concentration of DBC correlated with CDOM absorbance and the quality of DBC indicated by the ratios of different BPCAs correlated with CDOM absorbance spectral slope, suggesting the optical properties of CDOM may provide a proxy for both DBC concentrations and quality in natural waters. Further, the photo-lability of components of the DBC pool increased with their degree of aromatic condensation. These trends indicate that a continuum of compounds of varying photo-lability exists within the marine DOC pool. In this continuum, photo-lability scales with aromatic character, specifically the degree of condensation. Scaling the rapid photo-degradation of DBC to rates of DOC photo-mineralisation for the global ocean leads to an estimated photo-chemical half-life for oceanic DBC of less than 800 years. This is more than an order of magnitude shorter than the apparent age of DBC in the ocean. Consequently, photo-degradation is posited as the primary sink for oceanic DBC and the apparent survival of DBC molecules in the oceans for millennia appears to be facilitated not by their inherent inertness but by the rate at which they are cycled through the surface ocean's photic zone. © Author(s) 2012. CC Attribution 3.0 License.


Savidge D.K.,Skidaway Institute of Oceanography
Deep-Sea Research Part I: Oceanographic Research Papers | Year: 2016

Remarkably low vertical coherences in downstream velocities have been reported recently for three alongstream locations in the Gulf Stream, a Western Boundary Current with known three-dimensional dynamics of a baroclinically and barotropically unstable jet. This comment addresses the possibility that spatial averaging of coherences may be contributing to the low values estimated. © 2016 Elsevier Ltd.


Grant
Agency: NSF | Branch: Standard Grant | Program: | Phase: OCEANOGRAPHIC INSTRUMENTATION | Award Amount: 31.39K | Year: 2011

A request is made to fund additional and back-up instrumentation for the R/V Savannah. The R/V Savannah is a 92 foot coastal research vessel operated by Skidaway Institute of Oceanography as part of the University-National Oceanographic Laboratory System (UNOLS) research fleet. The request includes three items listed by priority:

1) Upgrade of Data Acquisition System
2) Sampling components for multi-corer system
3) Acoustic deck unit

Broader Impacts:
The principal impact of the present proposal is under criterion two, providing infrastructure support for scientists to use the vessel and its shared-use instrumentation in support of their NSF-funded oceanographic research projects (which individually undergo separate review by the relevant research program of NSF). The acquisition, maintenance and operation of shared-use instrumentation allows NSF-funded researchers from any US university or lab access to working, calibrated instruments for their research, reducing the cost of that research, and expanding the base of potential researchers.


Grant
Agency: NSF | Branch: Standard Grant | Program: | Phase: | Award Amount: 35.10K | Year: 2010

ABSTRACT

25 July 2010
Proposal Number: 1012818
Institution: Skidaway Institute of Oceanography
PI: J. Sanders

The proposal requests several Shipboard Scientific Support Equipment (SSSE) items for the R/V SAVANNAH operated by Skidaway Institute of Oceanography; namely portable deck capstans, navigational echo sounders and trawl blocks. These items will improve safety, bring the vessel into compliance with latest UNOLS standards, and enhance science support capabilities.


Broader Impacts: The R/V SAVANNAH supports federally funded scientific research in the southeast Atlantic in order to expand human knowledge of the ocean environment. During operations, the vessel routinely exposes graduate and undergraduate students to seagoing oceanography. Pubic outreach is also achieved through open house events and educational cruises funded by both NSF and the State of Georgia. The SAVANNAH is scheduled to complete approximately 60 NSF sponsored days in 2010.


Grant
Agency: NSF | Branch: Standard Grant | Program: | Phase: OCEANOGRAPHIC INSTRUMENTATION | Award Amount: 48.25K | Year: 2010

A request is made to fund additional and back-up instrumentation for the R/V Savannah. The R/V Savannah is a 92 foot coastal research vessel operated by Skidaway Institute of Oceanography as part of the University-National Oceanographic Laboratory System (UNOLS) research fleet. The request includes four items listed by priority:

1) Acrobat Towed Vehicle
2) Optical Nitrate Sensor
3) Deck Incubation Units
4) Stereo Microscope

Broader Impacts: The acquisition, maintenance and operation of shared-use instrumentation allows NSF-funded researchers from any US university or lab access to working, calibrated instruments for their research, reducing the cost of that research, and expanding the base of potential researchers.

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