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Ecosystem engineers are organisms that modulate natural resources enabling the survival of other species. They drive environmental change and contribute to several coastal functional attributes such as landscape heterogeneity, sedimentary processes, and coastal protection. Our study focuses on the case of Lanice conchilega, a tube-building ecosystem engineer whose aggregations impact sedimentary processes. This polychaete forms biogenic tube aggregations distributed on the coasts of the northern hemisphere from the shallow intertidal to depths of 1900 m. The aggregations engineer sedimentary processes autogenically by altering water flow at the benthic-boundary layer, and harbor highly diverse infaunal communities as a consequence. This study evaluates the relationships between intertidal L. conchilega aggregations and sedimentary processes at the intertidal zone of a sandy beach in northern France. Three experiments were executed to investigate (1) the effects of L. conchilega presence on sedimentary processes, as well as (2) the impacts of sedimentation on L. conchilega survival and patch growth, and (3) assess small-scale spatial heterogeneity in density and ecosystem engineering in L. conchilega aggregations. Weekly estimations of sedimentary properties in-situ showed that net deposition is significantly higher inside L. conchilega aggregations than in bare sand; whereas sediment mixing depth is noticeably reduced in comparison and regardless of patch tidal height. Variations in tube density above 3200 ind m-2 did not significantly impact sedimentary properties suggesting that the relationship between flow attenuation and tube density is nonlinear. In-situ monitoring of L. conchilega aggregations revealed different temporal trends for tube density and EPS content at the sediment surface between the center and edges of patches. This hints at the presence of environmental gradients within ag

Ecosystem engineers are organisms that modulate natural resources enabling the survival of other species. They drive environmental change and contribute to several coastal functional attributes such as landscape heterogeneity, sedimentary processes, and coastal protection. Our study focuses on the case of Lanice conchilega, a tube-building ecosystem engineer whose aggregations impact sedimentary processes. This polychaete forms biogenic tube aggregations distributed on the coasts of the northern hemisphere from the shallow intertidal to depths of 1900 m. The aggregations engineer sedimentary processes autogenically by altering water flow at the benthic-boundary layer, and harbor highly diverse infaunal communities as a consequence. This study evaluates the relationships between intertidal L. conchilega aggregations and sedimentary processes at the intertidal zone of a sandy beach in northern France. Three experiments were executed to investigate (1) the effects of L. conchilega presence on sedimentary processes, as well as (2) the impacts of sedimentation on L. conchilega survival and patch growth, and (3) assess small-scale spatial heterogeneity in density and ecosystem engineering in L. conchilega aggregations. Weekly estimations of sedimentary properties in-situ showed that net deposition is significantly higher inside L. conchilega aggregations than in bare sand; whereas sediment mixing depth is noticeably reduced in comparison and regardless of patch tidal height. Variations in tube density above 3200 ind m-2 did not significantly impact sedimentary properties suggesting that the relationship between flow attenuation and tube density is nonlinear. In-situ monitoring of L. conchilega aggregations revealed different temporal trends for tube density and EPS content at the sediment surface between the center and edges of patches. This hints at the presence of environmental gradients within ag

Contains fulltext : 137299.pdf (publisher's version ) (Closed access)

We study how organism traits and population densities of ecosystem engineering species, in combination with environmental factors, affect the formation and erosion rates of biogeomorphological structures, and focus on the widely distributed marine tube-building polychaete Lanice conchilega, which lives in patches that form mounds up to 80 cm high in soft-bottom sediments. We modeled the tube-building worms as thin solid piles that affect drag and turbulence, and thereby the local sediment dynamics and thus mound dynamics. Hydrodynamic model predictions showed good agreement with flume experiments for flow-velocity adaptations both within and in front of a patch of tube-building worms. The modeled equilibrium mound height increased with the organism trait "tube length," and with population density, but was only little affected by the strength of the tidal current, water depth, and grain size. In all cases, the modeled mound heights were within the range of the mound heights observed in the field. The effect of the tube-building worm L. conchilega reached beyond the spatial scale of their biogenic structures, and persisted longer than the lifetime of the engineering organism itself.

Contains fulltext : 137299.pdf (publisher's version ) (Closed access)

Contains fulltext : 137299.pdf (publisher's version ) (Closed access)

We study how organism traits and population densities of ecosystem engineering species, in combination with environmental factors, affect the formation and erosion rates of biogeomorphological structures, and focus on the widely distributed marine tube-building polychaete Lanice conchilega, which lives in patches that form mounds up to 80 cm high in soft-bottom sediments. We modeled the tube-building worms as thin solid piles that affect drag and turbulence, and thereby the local sediment dynamics and thus mound dynamics. Hydrodynamic model predictions showed good agreement with flume experiments for flow-velocity adaptations both within and in front of a patch of tube-building worms. The modeled equilibrium mound height increased with the organism trait "tube length," and with population density, but was only little affected by the strength of the tidal current, water depth, and grain size. In all cases, the modeled mound heights were within the range of the mound heights observed in the field. The effect of the tube-building worm L. conchilega reached beyond the spatial scale of their biogenic structures, and persisted longer than the lifetime of the engineering organism itself.

Within coastal nurseries, the distribution of juvenile flatfish may depend on small-scale habitat variability. The presence of ecosystem engineers is known to have important impacts in coastal sediments. Lanice conchilega is a well-known marine ecosystem engineer of shallow soft bottom ecosystems, shaping the macrobenthic community and attracting flatfish. The present study examines the relation between juvenile flatfish and L conchilega reefs through two experiments. In a field experiment in the Dutch part of the North Sea, the benthic habitat is evaluated by comparing relative differences in numbers of juvenile flatfish between ecosystem engineered habitats and adjacent bare sand (i.e. non-ecosystem engineered) habitats. The hypothetical shelter seeking behaviour was further examined using stomach content analyses. Results show that juvenile plaice Pleuronectes platessa was the dominant species within the tube worm habitat and the species selects specifically for this biogenic habitat. This selection was explained as feeding behaviour. In a complementary laboratory study, food was excluded and the shelter function of the ecosystem engineered habitat was investigated. This experiment quantifies the selection for this habitat by juveniles of the common sole Solea solea. Results from the flume experiment, manipulating the number of tube worms, show that distribution of sole was not random when current velocities are high. The selected habitat is the one with low density tube worm aggregations. Overall, we conclude that structuring benthos plays an important role for juvenile flatfish, both as refuge and as feeding ground.

Within coastal nurseries, the distribution of juvenile flatfish may depend on small-scale habitat variability. The presence of ecosystem engineers is known to have important impacts in coastal sediments. Lanice conchilega is a well-known marine ecosystem engineer of shallow soft bottom ecosystems, shaping the macrobenthic community and attracting flatfish. The present study examines the relation between juvenile flatfish and L conchilega reefs through two experiments. In a field experiment in the Dutch part of the North Sea, the benthic habitat is evaluated by comparing relative differences in numbers of juvenile flatfish between ecosystem engineered habitats and adjacent bare sand (i.e. non-ecosystem engineered) habitats. The hypothetical shelter seeking behaviour was further examined using stomach content analyses. Results show that juvenile plaice Pleuronectes platessa was the dominant species within the tube worm habitat and the species selects specifically for this biogenic habitat. This selection was explained as feeding behaviour. In a complementary laboratory study, food was excluded and the shelter function of the ecosystem engineered habitat was investigated. This experiment quantifies the selection for this habitat by juveniles of the common sole Solea solea. Results from the flume experiment, manipulating the number of tube worms, show that distribution of sole was not random when current velocities are high. The selected habitat is the one with low density tube worm aggregations. Overall, we conclude that structuring benthos plays an important role for juvenile flatfish, both as refuge and as feeding ground.

Within coastal nurseries, the distribution of juvenile flatfish may depend on small-scale habitat variability. The presence of ecosystem engineers is known to have important impacts in coastal sediments. Lanice conchilega is a well-known marine ecosystem engineer of shallow soft bottom ecosystems, shaping the macrobenthic community and attracting flatfish. The present study examines the relation between juvenile flatfish and L conchilega reefs through two experiments. In a field experiment in the Dutch part of the North Sea, the benthic habitat is evaluated by comparing relative differences in numbers of juvenile flatfish between ecosystem engineered habitats and adjacent bare sand (i.e. non-ecosystem engineered) habitats. The hypothetical shelter seeking behaviour was further examined using stomach content analyses. Results show that juvenile plaice Pleuronectes platessa was the dominant species within the tube worm habitat and the species selects specifically for this biogenic habitat. This selection was explained as feeding behaviour. In a complementary laboratory study, food was excluded and the shelter function of the ecosystem engineered habitat was investigated. This experiment quantifies the selection for this habitat by juveniles of the common sole Solea solea. Results from the flume experiment, manipulating the number of tube worms, show that distribution of sole was not random when current velocities are high. The selected habitat is the one with low density tube worm aggregations. Overall, we conclude that structuring benthos plays an important role for juvenile flatfish, both as refuge and as feeding ground.

This paper evaluates the effect of the tube-building, habitat structuring polychaete Lanice conchilega on the macrobenthic community and sediment characteristics of its habitat. To investigate which factors make species occur in a well-known bio-engineered habitat, macrofaunal and sedimentological data, gathered over a period of 10 years in a shallow, fine sediment bottom of the Belgian Part of the North Sea, were submitted to analyses. Both sediment composition and community structure of the associated macrofaunal matrix were affected by the presence of L. conchilega. The effect of the protruding tubes on hydrodynamics clearly resulted in the retention of fine sediment particles, while the increased coarse fraction was assumed to reflect a dynamic population build-up. This study confirmed that tube aggregations of L. conchilega expand the realized niche of several species without forming their own association. A species rank list was created according to each species' association with L. conchilega. This species rank list is extensively discussed based on all ecological knowledge available. Species are favoured by the habitat modifying ability of the polychaete tubes, which create and regulate refuge for species, alter the interactions between local species and change the physical factors of the environment. This descriptive and correlative data study examines the ecological importance of the bio-engineer L. conchilega on species level., This paper evaluates the effect of the tube-building, habitat structuring polychaete Lanice conchilega on the macrobenthic community and sediment characteristics of its habitat. To investigate which factors make species occur in a well-known bio-engineered habitat, macrofaunal and sedimentological data, gathered over a period of 10 years in a shallow, fine sediment bottom of the Belgian Part of the North Sea, were submitted to analyses. Both sediment composition and community structure of the associated macrofaunal matrix were affected by the presence of L. conchilega. The effect of the protruding tubes on hydrodynamics clearly resulted in the retention of fine sediment particles, while the increased coarse fraction was assumed to reflect a dynamic population build-up. This study confirmed that tube aggregations of L. conchilega expand the realized niche of several species without forming their own association. A species rank list was created according to each species' association with L. conchilega. This species rank list is extensively discussed based on all ecological knowledge available. Species are favoured by the habitat modifying ability of the polychaete tubes, which create and regulate refuge for species, alter the interactions between local species and change the physical factors of the environment. This descriptive and correlative data study examines the ecological importance of the bio-engineer L. conchilega on species level.

This paper evaluates the effect of the tube-building, habitat structuring polychaete Lanice conchilega on the macrobenthic community and sediment characteristics of its habitat. To investigate which factors make species occur in a well-known bio-engineered habitat, macrofaunal and sedimentological data, gathered over a period of 10 years in a shallow, fine sediment bottom of the Belgian Part of the North Sea, were submitted to analyses. Both sediment composition and community structure of the associated macrofaunal matrix were affected by the presence of L. conchilega. The effect of the protruding tubes on hydrodynamics clearly resulted in the retention of fine sediment particles, while the increased coarse fraction was assumed to reflect a dynamic population build-up. This study confirmed that tube aggregations of L. conchilega expand the realized niche of several species without forming their own association. A species rank list was created according to each species' association with L. conchilega. This species rank list is extensively discussed based on all ecological knowledge available. Species are favoured by the habitat modifying ability of the polychaete tubes, which create and regulate refuge for species, alter the interactions between local species and change the physical factors of the environment. This descriptive and correlative data study examines the ecological importance of the bio-engineer L. conchilega on species level., This paper evaluates the effect of the tube-building, habitat structuring polychaete Lanice conchilega on the macrobenthic community and sediment characteristics of its habitat. To investigate which factors make species occur in a well-known bio-engineered habitat, macrofaunal and sedimentological data, gathered over a period of 10 years in a shallow, fine sediment bottom of the Belgian Part of the North Sea, were submitted to analyses. Both sediment composition and community structure of the associated macrofaunal matrix were affected by the presence of L. conchilega. The effect of the protruding tubes on hydrodynamics clearly resulted in the retention of fine sediment particles, while the increased coarse fraction was assumed to reflect a dynamic population build-up. This study confirmed that tube aggregations of L. conchilega expand the realized niche of several species without forming their own association. A species rank list was created according to each species' association with L. conchilega. This species rank list is extensively discussed based on all ecological knowledge available. Species are favoured by the habitat modifying ability of the polychaete tubes, which create and regulate refuge for species, alter the interactions between local species and change the physical factors of the environment. This descriptive and correlative data study examines the ecological importance of the bio-engineer L. conchilega on species level.