Local hydrodynamics at edges of marine canopies under oscillatory flows

Serra, Teresa; Oldham, Carolyn; Colomer, Jordi

doi:10.1371/journal.pone.0201737

Cited by 15 publications

(5 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Taxa that were positively associated with higher seagrass biomass included polychaetes from the families Eunicidae and Syllidae (mostly mobile and carnivores) as well as Terebellidae and Capitellidae (sessile or of limited mobility, mostly suspension feeders/detritivores). The increase in the trophic trait suspension feeders/detritivores in areas of higher seagrass was not surprising as flow rates within seagrass meadows have been demonstrated to be reduced resulting in higher rates of deposition of organic matter providing food source for these organisms 98 – 100 . The analysis of the exclusive species associated with each treatment also showed a prevalence of gammarid amphipods associated with high density of seagrasses.…”

Section: Discussionmentioning

confidence: 99%

The role of seagrass vegetation and local environmental conditions in shaping benthic bacterial and macroinvertebrate communities in a tropical coastal lagoon

Alsaffar

Pearman

Cúrdia

et al. 2020

Sci Rep

View full text Add to dashboard Cite

We investigated the influence of seagrass canopies on the benthic biodiversity of bacteria and macroinvertebrates in a Red Sea tropical lagoon. Changes in abundance, number of taxa and assemblage structure were analyzed in response to seagrass densities (low, SLD; high, SHD; seagrasses with algae, SA), and compared with unvegetated sediments. Biological and environmental variables were examined in these four habitats (hereafter called treatments), both in the underlaying sediments and overlaying waters, at three randomly picked locations in March 2017. Differences between treatments were more apparent in the benthic habitat than in the overlaying waters. The presence of vegetation (more than its cover) and changes in sedimentary features (grain size and metals) at local scales influenced the observed biological patterns, particularly for macroinvertebrates. Of note, the highest percentage of exclusive macroinvertebrate taxa (18% of the gamma diversity) was observed in the SHD treatment peaking in the SA for bacteria. Benthic macroinvertebrates and bacteria shared a generally low number of taxa across treatments and locations; approximately, 25% of the gamma diversity was shared among all treatments and locations for macrofauna, dropping to 11% for bacteria. Given the low overlap in the species distribution across the lagoon, sustaining the connectivity among heterogeneous soft sediment habitats appears to be essential for maintaining regional biodiversity. This study addresses a current scientific gap related to the relative contributions of vegetated and unvegetated habitats to biodiversity in tropical regions. In tropical coastal waters, seagrass beds, mangroves and coral reefs are often linked through physical, chemical and biological processes 1-4. These interconnected habitats form what is often referred to as "the tropical seascape" 5 , which contributes to a variety of ecosystem goods and services essential for human well-being 2,6,7. Among the typical triad of tropical key marine habitats, seagrass meadows are considered one of the most productive 8,9. Their presence increases habitat complexity and ecological niches 10-12 , enhancing biodiversity. By reducing current velocity and wave action, seagrasses promote organic and inorganic matter deposition 13,14 .

show abstract

Section: Discussionmentioning

confidence: 99%

The role of seagrass vegetation and local environmental conditions in shaping benthic bacterial and macroinvertebrate communities in a tropical coastal lagoon

Alsaffar

Pearman

Cúrdia

et al. 2020

Sci Rep

View full text Add to dashboard Cite

show abstract

“…Gaps with widths less than twice the leaf length exhibited 8% wave attenuation and 11% turbulent kinetic energy attenuation, confirming that vegetation shelters, at least, small gaps [52]. Under oscillatory flows, vegetation in the vicinity of a longitudinal gap (i.e., with its main axis aligned to wave direction) may reduce wave velocity and the turbulent kinetic energy at the edge with distance into the canopy, with the attenuation increasing as the density of the vegetation increases [169]. Compared to flexible plants, an edge of plants with high rigidity would present even higher wave velocity attenuation but with an increase in the turbulent kinetic energy with distance into the canopy [169].…”

Section: Hydrodynamics Of the Edges In Gaps Within Canopiesmentioning

confidence: 76%

“…Under oscillatory flows, vegetation in the vicinity of a longitudinal gap (i.e., with its main axis aligned to wave direction) may reduce wave velocity and the turbulent kinetic energy at the edge with distance into the canopy, with the attenuation increasing as the density of the vegetation increases [169]. Compared to flexible plants, an edge of plants with high rigidity would present even higher wave velocity attenuation but with an increase in the turbulent kinetic energy with distance into the canopy [169]. In canopies with rigid plants, the lateral vegetation may modify the wave attenuation in the nearby gap, while there is no attenuation in the gap for flexible plants in the vicinity of the gap [170].…”

Section: Hydrodynamics Of the Edges In Gaps Within Canopiesmentioning

confidence: 99%

The World of Edges in Submerged Vegetated Marine Canopies: From Patch to Canopy Scale

Colomer

Serra

2021

Water

Self Cite

View full text Add to dashboard Cite

This review describes the world of edges in submerged vegetated marine canopies (seagrasses, saltmarshes, and seaweeds) where an edge is a boundary with a frontal area separating the vegetation from the adjacent non-vegetated zones. Plants within the vegetation are made of flexible elements pronating in the direction of the flow and oscillating back and forth in response to wave forcing. Some of them also occupy the full height within the water body. The analysis focuses on both the canopy- and local-patch scales to acquire knowledge about the hydrodynamics and the biophysical interactions in the structural shallows and deep limits of the canopies as well as on the structural edges of vegetation patches and the edges in the gaps within the canopies. The spatial arrangements of both canopy and patch edges are not only well imposed through the modification of hydrodynamics, but so too through small-scale interactions from internal structural causes and modifications. The continuous fragmentation of coastal marine habitats has reduced their structural complexity, thus making habitat edges a prevalent seascape feature, including in the shallow (or upper) and deep (or lower) limits of the canopies, the patch edges, and the edges in the gaps within the canopies. Canopy patches represent a region of high flow resistance where flow deflects and accelerates above and/or next to the canopy, resulting in an increase in water velocity and turbulence, especially at the edges of the patch. At the edges, energy transfer is found in spectral wave velocities from the longer to shorter wave period components. Likewise, at the edges, the net deposition of sediments decreases over a distance to a certain length, relative to the bare bed, which is associated with a region of vertical updraft and elevated turbulent kinetic energy. The edge effects also relate to the influence that a patch edge can have on determining species composition and predation risk, which is additionally mediated by the effect the edges have on habitat complexity within the vegetated patch. Organism feedback within the edges does not simply follow the canopy and local features and, in fact, the intricate interaction between biogeophysical processes is key in explaining the complexity of coastal submerged canopy landscapes. For example, proximity to patch edges has a greater influence on epifaunal density and community structure than structural complexity or predation do. The extent to which edges reduce predation risk depends on the extent to which they support higher structural complexities compared to patch interiors. The canopies’ shallow limits and their position in the underwater beach profile are mostly limited by light availability, the intensity of the wave action, and the local nearshore hydrodynamics, but they also depend on the local structural conditions at the vegetated side. The deep limits of the canopies, however, mainly depend on the availability of light and research findings support migration both to the deeper and shallower layers. All structural edges face changes caused by increasing nutrient inputs, development of coastal zones and the increasing impact of climate change. A considerable challenge to managing, restoring, and conserving coastal marine ecosystems stems from understanding how the canopies are able to cope with these natural and anthropogenic disturbances.

show abstract

“…4). This is probably related to the transitional flow near the low marsh edge, where the higher (compared to neap tide) spring tidal currents are expected to become significantly more turbulent at the transition from the flexible Zostera seagrass meadow to the more rigid Spartina vegetation 49 . A similar pattern of peak velocities and turbulent kinetic energy identified at the edge of a Spartina patch decreasing values with the distance from the www.nature.com/scientificreports/ vegetation edge was observed by 10 , when the water flow could not move above the canopy but is forced through the canopy.…”

Section: Discussionmentioning

confidence: 99%

Short-term sedimentation dynamics in mesotidal marshes

Carrasco

Kombiadou

Matias

2023

Sci Rep

View full text Add to dashboard Cite

One of the key questions about wetlands resilience to sea-level rise is whether sediment supply will be enough to keep them coping with growing inundation levels. To address this question, researchers have put a lot of effort into field data collection and ecogeomorphic modelling, in an attempt to identify the tipping points of marsh survival. This study uses fieldwork data to characterize the sediment fluxes between the tidal flats and salt marshes, in the Ria Formosa lagoon (Portugal). Sediment fluxes were measured from the tidal channel towards the mid-upper marsh, during neap and spring tide conditions. The flow magnitude was measured, and induced transport was determined based on shear velocities. Deposition rates, instantaneous suspended sediment and near-bed velocities were linked through theoretical formulas and used to characterize time-averaged conditions for sediment delivery and deposition to the site. The results showed that suspended sediment concentrations and sediment deposition varied across the transect with no specific relation to elevation. Maximum water depths were recorded in the vegetated tidal flat, and the maximum currents were flood dominated, in the order of 0.20 m/s, in the low marsh due to flow-plant interactions and an increase of turbulence. Deposition rates ranged between 20 to 45 g/m2/hr, after a complete tidal cycle, and were higher in the mid-upper marsh. Hydroperiod was not the main contributor to sediment deposition in the study area. Sediment transport was tidally driven, strongly two-dimension during the cycle, and highly influenced by the vegetation. Measurements of marsh sediment flux obtained in our work are diverse from the ones found in the literature and evidence the importance of considering spatio-temporal variability of vegetated platforms in assessing overall marsh bed level changes.

show abstract

Local hydrodynamics at edges of marine canopies under oscillatory flows

Cited by 15 publications

References 56 publications

The role of seagrass vegetation and local environmental conditions in shaping benthic bacterial and macroinvertebrate communities in a tropical coastal lagoon

The role of seagrass vegetation and local environmental conditions in shaping benthic bacterial and macroinvertebrate communities in a tropical coastal lagoon

The World of Edges in Submerged Vegetated Marine Canopies: From Patch to Canopy Scale

Short-term sedimentation dynamics in mesotidal marshes

Contact Info

Product

Resources

About