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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

Changes in final root morphology across oil treatments [none (white), low (gray), medium (dark gray), and high (black)] for root mass (A), root length (B), root diameter (C), and root area (D).Letters indicate statistically-significant results (N = 12 per treatment).
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pone.0138797.g003: Changes in final root morphology across oil treatments [none (white), low (gray), medium (dark gray), and high (black)] for root mass (A), root length (B), root diameter (C), and root area (D).Letters indicate statistically-significant results (N = 12 per treatment).

Mentions: The root morphology also changed significantly with oil exposure (Table 2, Fig 3). While root mass did not vary (Fig 3A), root length marginally decreased with increasing oil (Fig 3B). Roots were shortest in the high oil treatment (~0.58 mm), and increased in length in the medium (~0.65 mm), low (~0.80 mm), and no oil treatments (~0.83 mm). Conversely, roots were wider with increasing oil concentrations, with the average diameters ranging from 0.34 mm in the no oil treatment to 0.40 mm and 0.35 mm in low and medium treatments, and the largest diameters of 0.43 mm were in the high oil treatment (Fig 3C). This difference was driven by the diameters in the none and high oil treatments (p = 0.027; Table 3). Root area similarly increased across oiling, with areas of 0.09 mm2 in the none, 0.14 mm2 in low, 0.11 mm2 in medium, and 0.15 mm2 in high oil treatments (Fig 3D). Again, this increase was statistically driven by the significant difference between none and high oil (p = 0.017; Table 3).


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

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

Changes in final root morphology across oil treatments [none (white), low (gray), medium (dark gray), and high (black)] for root mass (A), root length (B), root diameter (C), and root area (D).Letters indicate statistically-significant results (N = 12 per treatment).
© Copyright Policy
Related In: Results  -  Collection

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

pone.0138797.g003: Changes in final root morphology across oil treatments [none (white), low (gray), medium (dark gray), and high (black)] for root mass (A), root length (B), root diameter (C), and root area (D).Letters indicate statistically-significant results (N = 12 per treatment).
Mentions: The root morphology also changed significantly with oil exposure (Table 2, Fig 3). While root mass did not vary (Fig 3A), root length marginally decreased with increasing oil (Fig 3B). Roots were shortest in the high oil treatment (~0.58 mm), and increased in length in the medium (~0.65 mm), low (~0.80 mm), and no oil treatments (~0.83 mm). Conversely, roots were wider with increasing oil concentrations, with the average diameters ranging from 0.34 mm in the no oil treatment to 0.40 mm and 0.35 mm in low and medium treatments, and the largest diameters of 0.43 mm were in the high oil treatment (Fig 3C). This difference was driven by the diameters in the none and high oil treatments (p = 0.027; Table 3). Root area similarly increased across oiling, with areas of 0.09 mm2 in the none, 0.14 mm2 in low, 0.11 mm2 in medium, and 0.15 mm2 in high oil treatments (Fig 3D). Again, this increase was statistically driven by the significant difference between none and high oil (p = 0.017; Table 3).

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