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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.

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. Source

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. Source

Paffenhofer G.-A.,Skidaway Institute of Oceanography | Koster M.,University of Greifswald
Journal of Plankton Research | Year: 2011

The life cycle of Dolioletta gegenbauri is presented photographically with comments on the features and development of the various zooid stages. Special attention is paid to nurse colonies with their associated zooids, including colony growth and rates of feeding. © The Author 2011. Published by Oxford University Press. All rights reserved. Source

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. Source

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. Source

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