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The Effects of Anthropogenic Structures on Habitat Connectivity and the Potential Spread of Non-Native Invertebrate Species in the Offshore Environment.

Simons RD, Page HM, Zaleski S, Miller R, Dugan JE, Schroeder DM, Doheny B - PLoS ONE (2016)

Bottom Line: Hull fouling is another possible mechanism to explain the change in distribution of Watersipora.Our results also suggest that larvae with PLDs of 24 hours or less released from offshore platforms can attain much greater dispersal distances than larvae with PLDs of 24 hours or less released from nearshore habitat.We hypothesize that the enhanced dispersal distance of larvae released from offshore platforms is driven by a combination of the offshore hydrodynamic environment, larval behavior, and larval release above the seafloor.

View Article: PubMed Central - PubMed

Affiliation: Earth Research Institute, University of California Santa Barbara, Santa Barbara, California, United States of America.

ABSTRACT
Offshore structures provide habitat that could facilitate species range expansions and the introduction of non-native species into new geographic areas. Surveys of assemblages of seven offshore oil and gas platforms in the Santa Barbara Channel revealed a change in distribution of the non-native sessile invertebrate Watersipora subtorquata, a bryozoan with a planktonic larval duration (PLD) of 24 hours or less, from one platform in 2001 to four platforms in 2013. We use a three-dimensional biophysical model to assess whether larval dispersal via currents from harbors to platforms and among platforms is a plausible mechanism to explain the change in distribution of Watersipora and to predict potential spread to other platforms in the future. Hull fouling is another possible mechanism to explain the change in distribution of Watersipora. We find that larval dispersal via currents could account for the increase in distribution of Watersipora from one to four platforms and that Watersipora is unlikely to spread from these four platforms to additional platforms through larval dispersal. Our results also suggest that larvae with PLDs of 24 hours or less released from offshore platforms can attain much greater dispersal distances than larvae with PLDs of 24 hours or less released from nearshore habitat. We hypothesize that the enhanced dispersal distance of larvae released from offshore platforms is driven by a combination of the offshore hydrodynamic environment, larval behavior, and larval release above the seafloor.

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Percent cover of Watersipora at depths of 6 m, 12 m, and 18 m on platform Gilda in 2001 and 2013 and on platforms Gail, Gina, and Grace in 2013.Watersipora was absent from platforms Gail, Gina, and Grace in 2001. The percent cover is displayed as mean values ± one standard error.
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pone.0152261.g003: Percent cover of Watersipora at depths of 6 m, 12 m, and 18 m on platform Gilda in 2001 and 2013 and on platforms Gail, Gina, and Grace in 2013.Watersipora was absent from platforms Gail, Gina, and Grace in 2001. The percent cover is displayed as mean values ± one standard error.

Mentions: Our 2001 surveys revealed Watersipora on only one of the seven study platforms, platform Gilda (Fig 3) [25]. At platform Gilda in 2001, the mean cover of Watersipora decreased with depth from 40.8% ± 9.5% SE at 6 m to 10.6% ± 3.7% SE at 18 m. An independent survey of study platforms Gail and Grace in 1998–2000 using SCUBA divers and remotely operated vehicles also failed to find Watersipora [40]. Our 2013 surveys found that the distribution of Watersipora had expanded to include 3 additional platforms, Grace, Gail and Gina, with the cover of Watersipora varying among platforms and depths (Fig 3). The highest mean percent cover occurred on platform Gail (41.1% ± 8.3% SE) at the intermediate depth of 12 m. The mean percent cover was lowest (2.0% ± 0.6% SE) on platform Grace, where only small colonies were found at a depth of 6 m. Platform Gilda, the site of the first record of Watersipora on a platform in 2001, had been recently cleaned with the invertebrate assemblage removed to a depth of approximately12 m and mean coverage at all depths had decreased to less than 6%.


The Effects of Anthropogenic Structures on Habitat Connectivity and the Potential Spread of Non-Native Invertebrate Species in the Offshore Environment.

Simons RD, Page HM, Zaleski S, Miller R, Dugan JE, Schroeder DM, Doheny B - PLoS ONE (2016)

Percent cover of Watersipora at depths of 6 m, 12 m, and 18 m on platform Gilda in 2001 and 2013 and on platforms Gail, Gina, and Grace in 2013.Watersipora was absent from platforms Gail, Gina, and Grace in 2001. The percent cover is displayed as mean values ± one standard error.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4816305&req=5

pone.0152261.g003: Percent cover of Watersipora at depths of 6 m, 12 m, and 18 m on platform Gilda in 2001 and 2013 and on platforms Gail, Gina, and Grace in 2013.Watersipora was absent from platforms Gail, Gina, and Grace in 2001. The percent cover is displayed as mean values ± one standard error.
Mentions: Our 2001 surveys revealed Watersipora on only one of the seven study platforms, platform Gilda (Fig 3) [25]. At platform Gilda in 2001, the mean cover of Watersipora decreased with depth from 40.8% ± 9.5% SE at 6 m to 10.6% ± 3.7% SE at 18 m. An independent survey of study platforms Gail and Grace in 1998–2000 using SCUBA divers and remotely operated vehicles also failed to find Watersipora [40]. Our 2013 surveys found that the distribution of Watersipora had expanded to include 3 additional platforms, Grace, Gail and Gina, with the cover of Watersipora varying among platforms and depths (Fig 3). The highest mean percent cover occurred on platform Gail (41.1% ± 8.3% SE) at the intermediate depth of 12 m. The mean percent cover was lowest (2.0% ± 0.6% SE) on platform Grace, where only small colonies were found at a depth of 6 m. Platform Gilda, the site of the first record of Watersipora on a platform in 2001, had been recently cleaned with the invertebrate assemblage removed to a depth of approximately12 m and mean coverage at all depths had decreased to less than 6%.

Bottom Line: Hull fouling is another possible mechanism to explain the change in distribution of Watersipora.Our results also suggest that larvae with PLDs of 24 hours or less released from offshore platforms can attain much greater dispersal distances than larvae with PLDs of 24 hours or less released from nearshore habitat.We hypothesize that the enhanced dispersal distance of larvae released from offshore platforms is driven by a combination of the offshore hydrodynamic environment, larval behavior, and larval release above the seafloor.

View Article: PubMed Central - PubMed

Affiliation: Earth Research Institute, University of California Santa Barbara, Santa Barbara, California, United States of America.

ABSTRACT
Offshore structures provide habitat that could facilitate species range expansions and the introduction of non-native species into new geographic areas. Surveys of assemblages of seven offshore oil and gas platforms in the Santa Barbara Channel revealed a change in distribution of the non-native sessile invertebrate Watersipora subtorquata, a bryozoan with a planktonic larval duration (PLD) of 24 hours or less, from one platform in 2001 to four platforms in 2013. We use a three-dimensional biophysical model to assess whether larval dispersal via currents from harbors to platforms and among platforms is a plausible mechanism to explain the change in distribution of Watersipora and to predict potential spread to other platforms in the future. Hull fouling is another possible mechanism to explain the change in distribution of Watersipora. We find that larval dispersal via currents could account for the increase in distribution of Watersipora from one to four platforms and that Watersipora is unlikely to spread from these four platforms to additional platforms through larval dispersal. Our results also suggest that larvae with PLDs of 24 hours or less released from offshore platforms can attain much greater dispersal distances than larvae with PLDs of 24 hours or less released from nearshore habitat. We hypothesize that the enhanced dispersal distance of larvae released from offshore platforms is driven by a combination of the offshore hydrodynamic environment, larval behavior, and larval release above the seafloor.

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