Larval fish dispersal along an estuarine-ocean gradient

The present study investigated the larval fish dispersal along an estuarine-ocean gradient to explore connectivity between ocean and estuaries. During spring 2009, a combined ocean-estuarine survey was conducted along the Lima estuarine salinity gradient and in two transects off the adjacent coast (NW Iberian Peninsula), until the 100m isobaths. Salinity, TPM, POM, TDC, DOC reached higher values at the ocean, chlorophyll a and nutrients increased at the estuary. From the total 56 taxa identified, 14 were present along the gradient, including estuarine species (ES), marine stragglers (MS) and migrants (MM). CCA analysis showed that species were separated along the gradient according to their ecological functional classification. MM associated with high salinity were separated from ES correlated with lower salinities and high chlorophyll a concentrations of inner estuary. Flounder showed a typical spatial gradient of MM, with abundance increasing from the ocean towards inner estuary. The dispersal of larvae along the Lima estuarine-ocean gradient was indicative of connectivity between habitats, emphasizing the need to consider this feature in management plans, mainly for species exploited by commercial fisheries.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Multispecies larval otolith increment data from samples collected on R/V F.G. Walton Smith cruises WS0714, WS0720, WS0809 in the Straits of Florida from 2007-2008 (FK Population Connectivity project)

Dataset: FL Multispecies Otolith DataMultispecies larval otolith increment data from samples collected on R/V F.G. Walton Smith cruises WS0714, WS0720, WS0809 in the Straits of Florida from 2007-2008. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/529658NSF Division of Ocean Sciences (NSF OCE) OCE-055073

How Do Oil, Gas, and Water Interact Near a Subsea Blowout?

Oil and gas from a subsea blowout shatter into droplets and bubbles that rise through the water column, entraining ambient seawater and forming a plume. Local density stratification and currents eventually arrest this rising plume, and the entrained water, enriched with dissolved hydrocarbons and some of the smaller oil droplets, forms one or more subsurface intrusion layers. Beyond the plume and intrusion layer(s), droplets and bubbles advect and diffuse by local currents and dissolve and biodegrade as they rise to the surface, where they are transported by wind and waves. These processes occur over a wide range of length scales that preclude simulation by any single model, but separate models of varying complexity are available to handle the different processes. Here, we summarize existing models and point out areas of ongoing and future research

Scenarios and Responses to Future Deep Oil Spills: Fighting the Next War

It has often been said that generals prepare for the next war by re-fighting the last. The Deepwater Horizon (DWH) oil spill was unlike any previous – an underwater well blowout 1,500 meters deep. Much has been learned in the wake of DWH and these lessons should in turn be applied to both similar oil spill scenarios and those arising from “frontier” explorations by the marine oil industry. The next deep oil well blowout may be at 3,000 meters or even deeper. This volume summarizes regional (Gulf of Mexico) and global megatrends in marine oil exploration and production. Research in a number of key areas including the behavior of oil and gas under extreme pressure, impacts on biological resources of the deep sea, and the fate of oil and gas released in spills is synthesized. A number of deep oil spills are simulated with detailed computer models, and the likely effects of the spills and potential mitigation measures used to combat them are compared. Recommended changes in policies governing marine oil exploration and development are proposed, as well as additional research to close critical and emerging knowledge gaps. This volume synthesizes state-of-the-art research in deep oil spill behavior and response. It is thus relevant for government and industry oil spill responders, policy formulators and implementers, and academics and students desiring an in-depth and balanced overview of key issues and uncertainties surrounding the quest for deep oil and potential impacts on the environment

Deep Oil Spills: Facts, Fate, and Effects

The demand for oil and gas has brought exploration and production to unprecedented depths of the world’s oceans. Currently, over 50% of the oil from the Gulf of Mexico now comes from waters in excess of 1,500 meters (one mile) deep, where no oil was produced just 20 years ago. The Deepwater Horizon oil spill blowout did much to change the perception of oil spills as coming just from tanker accidents, train derailments, and pipeline ruptures. In fact, beginning with the Ixtoc 1 spill off Campeche, Mexico in 1979-1980, there have been a series of large spill events originating at the sea bottom and creating a myriad of new environmental and well control challenges. This volume explores the physics, chemistry, sub-surface oil deposition and environmental impacts of deep oil spills. Key lessons learned from the responses to previous deep spills, as well as unresolved scientific questions for additional research are highlighted, all of which are appropriate for governmental regulators, politicians, industry decision-makers, first responders, researchers and students wanting an incisive overview of issues surrounding deep-water oil and gas production

BP Gulf Science Data Reveals Ineffectual Subsea Dispersant Injection for the Macondo Blowout

After the Deepwater Horizon oil platform explosion, an estimated 172.2 million gallons of gas-saturated oil was discharged uncontrollably into the Gulf of Mexico, causing the largest deep-sea blowout in history. In an attempt to keep the oil submerged, massive quantities of the chemical dispersant Corexit® 9500 were deployed 1522 m deep at the gushing riser pipe of the Macondo prospect’s wellhead. Understanding the effectiveness of this unprecedented subsea dispersant injection (SSDI) is critical because deep-water drilling is increasing worldwide. Here we use the comprehensive BP Gulf Science Data (GSD) to quantify petroleum dynamics throughout the 87-day long blowout. The spatio-temporal distribution of petroleum hydrocarbons revealed consistent higher concentrations at the sea surface and in a deep intrusion below 1000 m. The relative importance of these two layers depended on the hydrocarbon mass fractions as expected from their partitioning along temperature and pressure changes. Further, analyses of water column polycyclic aromatic hydrocarbons (PAH) of GSD extensively sampled within a 10-km radius of the blowout source demonstrated that substantial amounts of oil continued to surface near the response site, with no significant effect of SSDI volume on PAH vertical distribution and concentration. The turbulent energy associated with the spewing of gas-saturated oil at the deep-sea blowout may have minimized the effectiveness of the SSDI response approach. Given the potential for toxic chemical dispersants to cause environmental damage by increasing oil bioavailability and toxicity while suppressing its biodegradation, unrestricted SSDI application in response to deep-sea blowout is highly questionable. More efforts are required to inform response plans in future oil spills

Impacts of the Deepwater Horizon Oil Spill Evaluated Using an End-to-End Ecosystem Model

We use a spatially explicit biogeochemical end-to-end ecosystem model, Atlantis, to simulate impacts from the Deepwater Horizon oil spill and subsequent recovery of fish guilds. Dose-response relationships with expected oil concentrations were utilized to estimate the impact on fish growth and mortality rates. We also examine the effects of fisheries closures and impacts on recruitment. We validate predictions of the model by comparing population trends and age structure before and after the oil spill with fisheries independent data. The model suggests that recruitment effects and fishery closures had little influence on biomass dynamics. However, at the assumed level of oil concentrations and toxicity, impacts on fish mortality and growth rates were large and commensurate with observations. Sensitivity analysis suggests the biomass of large reef fish decreased by 25% to 50% in areas most affected by the spill, and biomass of large demersal fish decreased even more, by 40% to 70%. Impacts on reef and demersal forage caused starvation mortality in predators and increased reliance on pelagic forage. Impacts on the food web translated effects of the spill far away from the oiled area. Effects on age structure suggest possible delayed impacts on fishery yields. Recovery of high-turnover populations generally is predicted to occur within 10 years, but some slower-growing populations may take 30+ years to fully recover