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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

Reproductive output, expressed as daily proportional change.Fruiting bodies (A) increased from an average of 0 to 12.42 in no oil, 7.92 in low oil, 4.5 in medium oil, and 5.13 in high oil. Inflorescence production (B) increased from 1.2 flowers per tank to 3.6, 5.0, 3.2, and 2.6 inflorescences per plant in the none, low, medium, and high oil treatments, respectively, at the conclusion of the experiment. Letters indicate statistically-significant results (N = 12 per treatment).
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pone.0138797.g002: Reproductive output, expressed as daily proportional change.Fruiting bodies (A) increased from an average of 0 to 12.42 in no oil, 7.92 in low oil, 4.5 in medium oil, and 5.13 in high oil. Inflorescence production (B) increased from 1.2 flowers per tank to 3.6, 5.0, 3.2, and 2.6 inflorescences per plant in the none, low, medium, and high oil treatments, respectively, at the conclusion of the experiment. Letters indicate statistically-significant results (N = 12 per treatment).

Mentions: Reproductive output, unlike growth, did differ significantly across oiling treatments (Table 1). The presence of fruiting bodies on plants significantly declined with oil concentration (Table 1, Fig 2A). Specifically, no oil significantly differed from medium (p = 0.019) and high oil (p = 0.034), while reproductive output in the low oil treatment was not different from any of the other treatment levels (p> 0.05). At the conclusion of the experiment, the number of fruits on plants changed from an approximately zero fruits found in all treatments to 12.42 in no oil, 7.92 in low oil, 4.5 in medium oil, and 5.13 in high oil. Expressed as the proportional change per day, this decrease was approximately 1.1, 0.75, 0.4, and 0.45 in none, low, medium, and high oil treatment, respectively. Likewise, inflorescences significantly differed across oiling treatments (Table 1, Fig 2B). With an average initial number of 1.15 flowers per tank, post hoc tests indicate that there were no differences between none, low, and medium oiling (p> 0.05), but flowering in the low oil treatment differed from the flowering in the high oil treatment (p = 0.006). The highest incidence of flowering was found in the low oil treatment, with a daily proportional change of around 0.4, decreasing to 0.31 in the no oil treatment and 0.25 in the medium treatment, and the lowest 0.20 in the high oil treatment. This translated to 3.6, 5.0, 3.2, and 2.6 inflorescences per plant in the none, low, medium, and high oil treatments, respectively, at the conclusion of the experiment.


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

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

Reproductive output, expressed as daily proportional change.Fruiting bodies (A) increased from an average of 0 to 12.42 in no oil, 7.92 in low oil, 4.5 in medium oil, and 5.13 in high oil. Inflorescence production (B) increased from 1.2 flowers per tank to 3.6, 5.0, 3.2, and 2.6 inflorescences per plant in the none, low, medium, and high oil treatments, respectively, at the conclusion of the experiment. 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.g002: Reproductive output, expressed as daily proportional change.Fruiting bodies (A) increased from an average of 0 to 12.42 in no oil, 7.92 in low oil, 4.5 in medium oil, and 5.13 in high oil. Inflorescence production (B) increased from 1.2 flowers per tank to 3.6, 5.0, 3.2, and 2.6 inflorescences per plant in the none, low, medium, and high oil treatments, respectively, at the conclusion of the experiment. Letters indicate statistically-significant results (N = 12 per treatment).
Mentions: Reproductive output, unlike growth, did differ significantly across oiling treatments (Table 1). The presence of fruiting bodies on plants significantly declined with oil concentration (Table 1, Fig 2A). Specifically, no oil significantly differed from medium (p = 0.019) and high oil (p = 0.034), while reproductive output in the low oil treatment was not different from any of the other treatment levels (p> 0.05). At the conclusion of the experiment, the number of fruits on plants changed from an approximately zero fruits found in all treatments to 12.42 in no oil, 7.92 in low oil, 4.5 in medium oil, and 5.13 in high oil. Expressed as the proportional change per day, this decrease was approximately 1.1, 0.75, 0.4, and 0.45 in none, low, medium, and high oil treatment, respectively. Likewise, inflorescences significantly differed across oiling treatments (Table 1, Fig 2B). With an average initial number of 1.15 flowers per tank, post hoc tests indicate that there were no differences between none, low, and medium oiling (p> 0.05), but flowering in the low oil treatment differed from the flowering in the high oil treatment (p = 0.006). The highest incidence of flowering was found in the low oil treatment, with a daily proportional change of around 0.4, decreasing to 0.31 in the no oil treatment and 0.25 in the medium treatment, and the lowest 0.20 in the high oil treatment. This translated to 3.6, 5.0, 3.2, and 2.6 inflorescences per plant in the none, low, medium, and high oil treatments, respectively, at the conclusion of the experiment.

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