Details
| Original language | English |
|---|---|
| Article number | 808018 |
| Journal | Frontiers in Marine Science |
| Volume | 9 |
| Publication status | Published - 9 Mar 2022 |
Abstract
Keywords
- bed roughness, current attenuation, ecosystem engineer, field study, invasive species, Magallana gigas, oyster reef, wave attenuation
ASJC Scopus subject areas
- Environmental Science(all)
- Water Science and Technology
- Environmental Science(all)
- Environmental Science (miscellaneous)
- Engineering(all)
- Ocean Engineering
- Agricultural and Biological Sciences(all)
- Aquatic Science
- Earth and Planetary Sciences(all)
- Oceanography
- Environmental Science(all)
- Global and Planetary Change
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In: Frontiers in Marine Science, Vol. 9, 808018, 09.03.2022.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Oyster Reef Surfaces in the Central Wadden Sea: Intra-Reef Classification and Comprehensive Statistical Description
AU - Hitzegrad, Jan
AU - Brohmann, Leon
AU - Pfennings, Kai
AU - Hoffmann, Tom Kristian
AU - Eilrich, Anne K.
AU - Paul, Maike
AU - Welzel, Kim Mario
AU - Schlurmann, Torsten
AU - Aberle, Jochen
AU - Wehrmann, Achim
AU - Goseberg, Nils
N1 - Funding information: This project “BIVA-WATT” on which this work is based was funded by the Federal Ministry of Education and Research of Germany (BMBF) under the funding code 03KIS127.
PY - 2022/3/9
Y1 - 2022/3/9
N2 - The Pacific oyster (Magallana gigas) is an invasive species in the Wadden Sea transforming parts of it permanently. M. gigas, as an ecosystem engineer, builds reef structures that are characterized by highly complex and variable surfaces consisting of densely packed, sharp-edged individuals connected with cement-like bonds. To investigate the interactions between reef structure, shape and formation and wave as well as tidal currents, an understanding of the surface roughness is essential. This work reports on observations of oyster reefs for which seven new structural classes (Central Reef, Transitional Zone, Cluster I, Cluster II, Patch I, Patch II, and Garland) are proposed. For each class, high resolution Digital Elevation Models (DEMs) have been elaborated based on Structure-from-Motion (SfM) photogrammetry and analyzed using spatial statistics. By determining probability density functions (PDFs), vertical porosity distributions, abundances, orientations and second-order structure functions (SSFs), topographical parameters that influence the hydraulic bed roughness have been determined. The results suggest, that by applying the structural classification and their distinct topographical roughness parameters, the oyster reef surfaces can be described appropriately accounting for their complexity. The roughness accounts to a total roughness height kt = 103 ± 15 mm and root-mean-square roughness height krms = 23 ± 5 mm. These values were found similar across all structural classes, yet the shape of the PDFs reveal differences. With decreasing abundance, the distributions become more positively skewed and are characterized by more extreme outliers. This is reflected in the higher statistical moments, as the skewness ranges between Sk = 0.4–2.1 and the kurtosis between Ku = 2.2–11.5. The analysis of the orientations and the SSFs confirms anisotropic behavior across all structural classes. Further, the SSFs reveal the oyster shells as significant roughness elements with exception of Cluster I and II, where the clusters are identified as significant roughness elements. The provided set of topographical roughness parameters enhances the knowledge of oyster reef surfaces and gives insights into the interactions between biogenic structure and surrounding hydrodynamics. The new intra-reef classification allows for more accurate determination of the overall roughness as well as the population dynamics of the habitat forming oyster. Combined with hydraulic measurements, the results can be used to estimate the hydraulic bed roughness induced by the oyster reef surfaces.
AB - The Pacific oyster (Magallana gigas) is an invasive species in the Wadden Sea transforming parts of it permanently. M. gigas, as an ecosystem engineer, builds reef structures that are characterized by highly complex and variable surfaces consisting of densely packed, sharp-edged individuals connected with cement-like bonds. To investigate the interactions between reef structure, shape and formation and wave as well as tidal currents, an understanding of the surface roughness is essential. This work reports on observations of oyster reefs for which seven new structural classes (Central Reef, Transitional Zone, Cluster I, Cluster II, Patch I, Patch II, and Garland) are proposed. For each class, high resolution Digital Elevation Models (DEMs) have been elaborated based on Structure-from-Motion (SfM) photogrammetry and analyzed using spatial statistics. By determining probability density functions (PDFs), vertical porosity distributions, abundances, orientations and second-order structure functions (SSFs), topographical parameters that influence the hydraulic bed roughness have been determined. The results suggest, that by applying the structural classification and their distinct topographical roughness parameters, the oyster reef surfaces can be described appropriately accounting for their complexity. The roughness accounts to a total roughness height kt = 103 ± 15 mm and root-mean-square roughness height krms = 23 ± 5 mm. These values were found similar across all structural classes, yet the shape of the PDFs reveal differences. With decreasing abundance, the distributions become more positively skewed and are characterized by more extreme outliers. This is reflected in the higher statistical moments, as the skewness ranges between Sk = 0.4–2.1 and the kurtosis between Ku = 2.2–11.5. The analysis of the orientations and the SSFs confirms anisotropic behavior across all structural classes. Further, the SSFs reveal the oyster shells as significant roughness elements with exception of Cluster I and II, where the clusters are identified as significant roughness elements. The provided set of topographical roughness parameters enhances the knowledge of oyster reef surfaces and gives insights into the interactions between biogenic structure and surrounding hydrodynamics. The new intra-reef classification allows for more accurate determination of the overall roughness as well as the population dynamics of the habitat forming oyster. Combined with hydraulic measurements, the results can be used to estimate the hydraulic bed roughness induced by the oyster reef surfaces.
KW - bed roughness
KW - current attenuation
KW - ecosystem engineer
KW - field study
KW - invasive species
KW - Magallana gigas
KW - oyster reef
KW - wave attenuation
UR - http://www.scopus.com/inward/record.url?scp=85127344787&partnerID=8YFLogxK
U2 - 10.3389/fmars.2022.808018
DO - 10.3389/fmars.2022.808018
M3 - Article
VL - 9
JO - Frontiers in Marine Science
JF - Frontiers in Marine Science
SN - 2296-7745
M1 - 808018
ER -