Effects of seagrasses and algae of the Caulerpa family on hydrodynamics and particle-trapping rates

By I. Hendriks, Tjeerd Joris Bouma, E. Charles Morris, Carlos M. Duarte. 2010

130 citations recorded by the source corpus.

The widespread decline of seagrass beds within the Mediterranean often results in the replacement of seagrasses by opportunistic green algae of the Caulerpa family. Because Caulerpa beds have a different height, stiffness and density compared to seagrasses, these changes in habitat type modify the interaction of the seafloor with hydrodynamics, influencing key processes such as sediment resuspension and particle trapping. Here, we compare the effects on hydrodynamics and particle trapping of Caulerpa taxifolia, C. racemosa, and C. prolifera with the Mediterranean seagrasses Cymodocea nodosa and Posidonia oceanica. All macrophyte canopies reduced near-bed volumetric flow rates compared to bare sediment, vertical profiles of turbulent kinetic energy revealed peak values around the top of the canopies, and maximum values of Reynolds stress increased by a factor of between 1.4 (C. nodosa) and 324.1 (P. oceanica) when vegetation was present. All canopies enhanced particle retention rates compared to bare sediment. The experimental C. prolifera canopy was the most effective at particle retention (m2 habitat); however, C. racemosa had the largest particle retention capacity per structure surface area. Hence, in terms of enhancing particle trapping and reducing hydrodynamic forces at the sediment surface, Caulerpa beds provided a similar or enhanced function compared to P.oceanica and C. nodosa. However, strong seasonality in the leaf area index of C. racemosa and C. taxifolia within the Mediterranean, combined with a weak rhizome structure, suggests that sediments maybe unprotected during winter storms, when most erosion occurs. Hence, replacement of seagrass beds with Caulerpa is likely to have a major influence on annual sediment dynamics at ecosystem scales.

Subfields: Ecology, Oceanography

View Paper: https://www.semanticscholar.org/paper/cdcb6ab4f0c64faf5beb282774be4194da46d53f

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In Ecology

1. B. Nolet
2. Luis Santamaría
3. Sabine Hilt
4. E. S. Bakker
5. A. Green
6. M. Klaassen

In Oceanography

1. Sabine Hilt
2. Marjolijn J. A. Christianen
3. Luis Santamaría

Citations in the corpus

• Potential for landscape-scale positive interactions among tropical marine ecosystems (2014, unknown): “(Hendriks et al. 2008, 2010).”
• Herbivory on freshwater and marine macrophytes: A review and perspective (2016, background): “Herbivory in tropical seagrasses (e.g. by sea urchins and green turtles) can influence species composition (Vonk et al., 2008b; Kelkar et al., 2013b; Hernandez and van Tussenbroek, 2014), but often in contrasting ways.”