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Effects of Oil-Contaminated Sediments on Submerged Vegetation: An Experimental Assessment of Ruppia maritima.

Martin CW, Hollis LO, Turner RE - PLoS ONE (2015)

Bottom Line: We found significant reductions in inflorescences and fruiting bodies at higher oil concentrations.A second experiment was performed to separate the effects of root morphology and oiled sediment properties and indicated that there were also changes to sediment cohesion that contributed to a reduction in uprooting forces in medium and high oil.Moreover, areas containing buried oil may be more susceptible to high energy storm events due to the reduction in uprooting force of foundation species such as R. maritima.

View Article: PubMed Central - PubMed

Affiliation: Department of Oceanography & Coastal Sciences, School of the Coast and Environment, Louisiana State University, Baton Rouge, Louisiana, United States of America.

ABSTRACT
Oil spills threaten the productivity of ecosystems through the degradation of coastal flora and the ecosystem services these plants provide. While lab and field investigations have quantified the response of numerous species of emergent vegetation to oil, the effects on submerged vegetation remain uncertain. Here, we discuss the implications of oil exposure for Ruppia maritima, one of the most common species of submerged vegetation found in the region affected by the recent Deepwater Horizon oil spill. We grew R. maritima in a range of manipulated sediment oil concentrations: 0, 0.26, 0.53, and 1.05 mL oil /L tank volume, and tracked changes in growth (wet weight and shoot density/length), reproductive activity (inflorescence and seed production), root characteristics (mass, length, diameter, and area), and uprooting force of plants. While no statistical differences were detected in growth, plants exhibited significant changes to reproductive output, root morphology, and uprooting force. We found significant reductions in inflorescences and fruiting bodies at higher oil concentrations. In addition, the roots growing in the high oil were shorter and wider. Plants in medium and high oil required less force to uproot. A second experiment was performed to separate the effects of root morphology and oiled sediment properties and indicated that there were also changes to sediment cohesion that contributed to a reduction in uprooting forces in medium and high oil. Given the importance of sexual reproduction for these plants, oil contamination may have substantial population-level effects. Moreover, areas containing buried oil may be more susceptible to high energy storm events due to the reduction in uprooting force of foundation species such as R. maritima.

No MeSH data available.


Related in: MedlinePlus

Daily proportional change for (A) wet weight, which increased from an initial average biomass of 0.31 g to 1.09 g, and (B) stem density, which increased from 3.7 to over 5 shoots per tank, for plants grown in the four different oil treatments: none (white), low (gray), medium (dark gray), and high (black).Letters indicate statistically-significant results. There were no statistically-significant differences among treatments (N = 12 per treatment).
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pone.0138797.g001: Daily proportional change for (A) wet weight, which increased from an initial average biomass of 0.31 g to 1.09 g, and (B) stem density, which increased from 3.7 to over 5 shoots per tank, for plants grown in the four different oil treatments: none (white), low (gray), medium (dark gray), and high (black).Letters indicate statistically-significant results. There were no statistically-significant differences among treatments (N = 12 per treatment).

Mentions: Ruppia grew in all treatments, with little differences found in growth (Table 1). Plants grew from an initial biomass of approximately 0.31 g to an average of 1.09 g over the course of the experiment. This growth rate is a daily proportional change of approximately 0.07, with no significant difference among oil treatments (Fig 1A). Likewise, stem density per plant increased from around 3.7 shoots initially to over 5 at the end of the experiment, which is a daily proportional change of approximately 0.17, with a tendency of decreasing density with increasing oil, although this trend was not significant (Fig 1B). Stem length was highly variable and not significant across treatments, with average tank stem length increasing from 15.0 cm to 21.7 cm over the experiment duration. This translates to a 69% increase in shoot length with an average growth rate of 0.2 cm per day.


Effects of Oil-Contaminated Sediments on Submerged Vegetation: An Experimental Assessment of Ruppia maritima.

Martin CW, Hollis LO, Turner RE - PLoS ONE (2015)

Daily proportional change for (A) wet weight, which increased from an initial average biomass of 0.31 g to 1.09 g, and (B) stem density, which increased from 3.7 to over 5 shoots per tank, for plants grown in the four different oil treatments: none (white), low (gray), medium (dark gray), and high (black).Letters indicate statistically-significant results. There were no statistically-significant differences among treatments (N = 12 per treatment).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4592016&req=5

pone.0138797.g001: Daily proportional change for (A) wet weight, which increased from an initial average biomass of 0.31 g to 1.09 g, and (B) stem density, which increased from 3.7 to over 5 shoots per tank, for plants grown in the four different oil treatments: none (white), low (gray), medium (dark gray), and high (black).Letters indicate statistically-significant results. There were no statistically-significant differences among treatments (N = 12 per treatment).
Mentions: Ruppia grew in all treatments, with little differences found in growth (Table 1). Plants grew from an initial biomass of approximately 0.31 g to an average of 1.09 g over the course of the experiment. This growth rate is a daily proportional change of approximately 0.07, with no significant difference among oil treatments (Fig 1A). Likewise, stem density per plant increased from around 3.7 shoots initially to over 5 at the end of the experiment, which is a daily proportional change of approximately 0.17, with a tendency of decreasing density with increasing oil, although this trend was not significant (Fig 1B). Stem length was highly variable and not significant across treatments, with average tank stem length increasing from 15.0 cm to 21.7 cm over the experiment duration. This translates to a 69% increase in shoot length with an average growth rate of 0.2 cm per day.

Bottom Line: We found significant reductions in inflorescences and fruiting bodies at higher oil concentrations.A second experiment was performed to separate the effects of root morphology and oiled sediment properties and indicated that there were also changes to sediment cohesion that contributed to a reduction in uprooting forces in medium and high oil.Moreover, areas containing buried oil may be more susceptible to high energy storm events due to the reduction in uprooting force of foundation species such as R. maritima.

View Article: PubMed Central - PubMed

Affiliation: Department of Oceanography & Coastal Sciences, School of the Coast and Environment, Louisiana State University, Baton Rouge, Louisiana, United States of America.

ABSTRACT
Oil spills threaten the productivity of ecosystems through the degradation of coastal flora and the ecosystem services these plants provide. While lab and field investigations have quantified the response of numerous species of emergent vegetation to oil, the effects on submerged vegetation remain uncertain. Here, we discuss the implications of oil exposure for Ruppia maritima, one of the most common species of submerged vegetation found in the region affected by the recent Deepwater Horizon oil spill. We grew R. maritima in a range of manipulated sediment oil concentrations: 0, 0.26, 0.53, and 1.05 mL oil /L tank volume, and tracked changes in growth (wet weight and shoot density/length), reproductive activity (inflorescence and seed production), root characteristics (mass, length, diameter, and area), and uprooting force of plants. While no statistical differences were detected in growth, plants exhibited significant changes to reproductive output, root morphology, and uprooting force. We found significant reductions in inflorescences and fruiting bodies at higher oil concentrations. In addition, the roots growing in the high oil were shorter and wider. Plants in medium and high oil required less force to uproot. A second experiment was performed to separate the effects of root morphology and oiled sediment properties and indicated that there were also changes to sediment cohesion that contributed to a reduction in uprooting forces in medium and high oil. Given the importance of sexual reproduction for these plants, oil contamination may have substantial population-level effects. Moreover, areas containing buried oil may be more susceptible to high energy storm events due to the reduction in uprooting force of foundation species such as R. maritima.

No MeSH data available.


Related in: MedlinePlus