Disturbed Zone Research Articles

Functional adaptations of benthic communities to organic matter enrichment at the edge of an allowable zone of effect (AZE)

In a changing environment, it is important to understand the contribution of faunal and microbial communities to ecosystem functioning. In this context, the present study aimed to explore the effect of organic matter inputs due to aquaculture on the interaction between microphytobenthos and macrofaunal traits related to bioturbation. The study was conducted in the vicinity of a fish farm in a semi-enclosed bay in Cephalonia (Eastern Mediterranean). Two different disturbance zones were compared – a control area and an area close to fish cages and, more specifically, at the edge of the Allowable Zone of Effect (AZE) subject to intermediate stress from aquaculture waste discharge. Bioturbation potential was the main driver shaping microphytobenthic community composition. While Euglenophytes prevailed in the benthic communities close to fish farms, Cyanobacteria were more abundant in the control area, indicating a shift from a microbially driven functioning to a more macrofaunal one near fish cages. Indeed, a shift from suspension feeding to predation and scavenging was recorded close to fish cages. This shift was caused by the interaction of different trophic groups, food availability, as well as the interference of the increased bioturbation in suspension feeding near fish cages. High bioturbation and bioirrigation potentials recorded near fish cages probably acted as moderators of the negative effects of organic matter deposition caused by fish farming. In conclusion, the benthic community close to fish cages was more diverse in terms of biological traits than at the control sites. This indicated the co-existence of species with different ecological strategies near fish cages.

Effects of different hole structures of pre-chamber with turbulent jet ignition on the flame propagation and lean combustion performance of a single-cylinder engine

Turbulent jet ignition is an advanced pre-chamber approach for improving combustion rates and extending lean burn limitations. The hot flows jetted from the pre-chamber through jet hole act as a distributed ignition source, igniting the mixture in the main chamber. In this paper, the effects of structures on flame propagation and engine performance are systematically studied based on an optical constant volume combustion chamber and a single cylinder engine. Firstly, the visualization of the effects of pre-chamber hole apertures and jet hole numbers on flame propagation is realized. Then, the effects of pre-chamber hole structures on engine performance are studied. The results show that small jet hole aperture could lead to flame quenching while too large aperture may cause low flame speed, both of which will decrease combustion rates. Moreover, the disturbance zone formed by cold jet flow could help maintain the jet flame speed induced by hot jet. Meanwhile, adopting multi jet hole structure could improve combustion in main chamber while modifying jet hole structure considering combustion chamber of real engine helps to achieve lower fuel consumption and emissions. TJI engine has great potential for achieving low fuel consumption and low NOx emissions without severe engine knock when the excess air coefficient ranges from 1.4 to 1.7.

INFLUENCE OF TECTONIC DISTURBANCES OF COAL LAYER ON HIS GAS DYNAMIC STATE

Problem Statement and Purpose. At one of the coal mines of the Donetsk basin, there was a sudden release of coal and gas. The peculiarity of this case is that the accident happened in the place of the alleged development of a geological disturbance, but without any visible signs of this. Inspection of the ejection site and adjacent horizons made it possible to conclude that the emergency site is located in the place of the plicative disturbance development. Thus, it is necessary to study in more detail the influence of disturbed zones hidden nature on the gas-dynamic state of the reservoir, as well as to develop and implement methods for determining such zones. Data & Methods. To achieve this goal, a new method was tested, based on the property of structureless substances to form crystal-like units. This phenomenon has been studied for decades; therefore, such new formations have long been given the name quasicrystals. It was noted that the increase in the concentration of such forms is associated with the presence of geological disturbances. Consequently, the increase in quasicrystals in the rock is an indicator of its disturbance due to the influence of tectonic pressure. Thus, in order to test the technique and reveal the hidden geological disturbance of the coal seam, coal samples were taken, microstructural features were studied, and the strength of the coal seam was measured at 56 points. Result. As a result the values of the concentration of quasicrystals, data on the strength of the formation were obtained, a schematic map of the development of the disturbance in this area was built, its contours were determined, the center of the disturbed zone was identified and the role of such disturbances in the outburst hazard of the formation was substantiated. It has been established that geological disturbances, even of plicative nature, have a high degree of fracturing. Such pores and cracks in coal reduce the strength properties and are able to concentrate sufficient volumes of gas for manifestation of GDP.

The Study of Transformed Herbaceous Vegetation in the Area Flooded Due to Coal Mine Workings

Abstract The spontaneous vegetation in permanent flooding zone around technogenic water bodies arising on former pastures due to underground coal mining in the Western Donbass basin (steppe zone of Ukraine) was studied in 2018–2019. Occurrence and abundance of herbaceous plants were taken into account in 36 vegetation plots over a total area of 0.8 km2 in different habitats: dry, wet and flooded. In total, 83 plant species belonging to 31 families and 66 genera were identified, among which perennials dominated. Strong negative Pearson’s correlation was found between the amount and abundance of plant species and soil characteristics across the studied habitats, where the joint action of all edaphic factors determined the mosaic appearance of transformed vegetation. The spontaneous vegetation of the least disturbed xero-mesophilic habitats was most similar to (semi)natural grasslands, while the vegetation of hygrophilic habitats had a complete mismatch. Surrounding grasslands were not the most important diasporas’ source for spontaneous succession in the disturbed zone, and many species were supposed to come from the more remote areas. Recovery of target vegetation did not occur for 25 years of permanent subsidence and flooding due to radical transformation of landscape and soil and appearance of completely inappropriate habitats. At the same time, the unusual species composition of spontaneous vegetation and significant number of rare and endangered plants indicate the formation of valuable biotopes in the subsidence and flooding zone.

Consolidation Theory of Unsaturated Soils with Vertical Drains Considering Well Resistance and Smear Effect under Time-Dependent Loading

In this investigation, an approximate analytical solution to the axisymmetric consolidation problem of unsaturated soils improved with vertical drain is presented under the equal-strain condition. The smear effect of soil, the well resistance of vertical drain, and the application of time-dependent loading are considered in the solution. Matrix analysis is used to solve the solution under constant loading for comparison against the available solution. The influence of soil parameters, smear parameters, and well resistance parameters on the consolidation behavior is investigated under ramp loading. Moreover, two types of loading which are noncyclic forms (i.e., instantaneous, multistage ramp, and exponential loading) and cyclic forms (i.e., triangular, sinusoidal, and cosine cyclic loading) are incorporated in the analyses. It is found that a higher hydraulic conductivity ratio in the undisturbed zone and a larger radius of the influence zone can speed up the consolidation process. The consolidation process is slowed down by increasing the radius of the disturbed zone and reducing its hydraulic conductivity, and the influence of hydraulic conductivity is more significant. The effect of radius and hydraulic conductivity of vertical drain on the consolidation behavior is similar. The consolidation behavior generally follows the pattern of the applied loading apparently.

An integrated fluid-chemical model toward modeling the thrombus formation in an idealized model of aortic dissection.

Type B aortic dissection is a major aortic catastrophe that can be acutely complicated by rapid expansion, rupture, and malperfusion syndromes. The separation of the intima from aortic walls will form a second blood-filled lumen defined as "false lumen (FL)", where the thrombus is more likely to form due to the local stasis hemodynamic conditions. Complete thrombosis of FL is associated with a beneficial outcome while patency and partial thrombosis will lead to later complications. However, the thrombosis mechanism is still unclear and little is known about the impact of chemical species transported by blood flow on this process. The proteins involved in the coagulation cascade (CC) may play an important role in the process of thrombosis, especially in the activation and stabilization of platelets. Based on this hypothesis, a reduced-order fluid-chemical model was established to simulate CC in an aortic dissection phantom with two tears. A high level of fibrin is continuously observed at the top of the FL and some time-varying areas between two tears, indicating a high likelihood of thrombus formation there. This finding is consistent with the clinical observation. The time evolution of coagulation factors is greatly affected by local hemodynamics, especially in the high disturbance zone where the evolution has characteristics of periodic changes consistent with the flow field. The ability of the proposed model to reproduce the CC response provides a potential application to integrate with a model that can simulate platelet activities, forming a biochemical-based model which would help unveil the mechanisms of thrombosis in FL and the clinical decision of appropriate treatment.

Coupled wellbore–reservoir heat and mass transfer model for horizontal drilling through hydrate reservoir and application in wellbore stability analysis

To address the wellbore instability risk during drilling in hydrate reservoirs, a fully coupled wellbore–reservoir model for horizontal drilling through a hydrate reservoir is presented, which considers the dynamic heat and mass transfer between the wellbore and reservoir and the coupling interactions between the fluid flow, heat transfer, and evolution of mechanical properties in hydrate-bearing sediments. A numerical method based on COMSOL Multiphysics + MATLAB was first proposed, and the accuracy of this model was verified by comparing it with experimental data and another mathematical model. The rules of heat and mass transfer between the wellbore and reservoir and the yield failure behaviors of the wellbore are thoroughly analyzed based on the data of hydrate-bearing sediments in the Shenhu area. The simulation results indicate that the temperature of the hydrate reservoir increases with the invasion of drilling fluid. The radii of the thermal disturbance zone at the toe and heel of the horizontal well are approximately 0.48 m and 0.64 m after 20 h, respectively. The formation shear strength near the wellbore gradually decreases from the initial 3.24 MPa–2.09 MPa due to hydrate decomposition; then, the formation begins to yield, and the yield ratio of the borehole reaches 92.56% after 20 h. Compared with the drilling fluid displacement and density, the inlet temperature of the drilling fluid plays an absolute leading role in the wellbore extension length. When the inlet temperature is less than 22.5 °C, the reservoir hydrate will not decompose. This work can provide a theoretical reference for the design of drilling fluids aimed at controlling borehole stability issues and for the design of the length of horizontal wells during drilling in hydrate reservoirs.

Observer-based semi-global containment of saturated multi-agent systems with uncertainties

In this article, the robust semi-global containment control for multi-agent systems affected by uncertainties, such as input additive disturbance, input saturation and dead zone is addressed. An observer-based control algorithm is designed by combining the high-gain observer approach and the low-and-high gain feedback technique. Under the assumption that all agents are asymptotically null controllable with bounded controls and each follower can access the information of at least one leader through a directed path, sufficient conditions for the semi-global output feedback containment control are provided. Finally, numerical simulations are proposed to verify the main theoretical results.

Investigation of the Fracturing Effect Induced by the Disturbing Stress of Hydrofracturing Using the Bonded-Particle Model

Hydraulic fracturing applications have shown a stress disturbance effect during hydraulic fracture propagation, which is often ignored. Using laboratory and discrete element numerical simulation tests, hydraulic fracture propagation under this stress disturbance is systematically studied. The results show that during hydraulic fracturing, the bedding plane is damaged by the stress disturbance, forming a bedding fracture zone (BFZ). The nonlinear fracture characteristics of the formation process of the disturbed fracture zone are revealed, and two indexes (the number of fractures in the disturbed fracture zone and the size of the disturbed fracture zone) are proposed to evaluate the fracturing effect of the stress disturbance. Based on these indexes, multifactor sensitivity tests are conducted under different geological conditions and operational factors. When the principal stress ( σ 1 ) difference is large, the number of hydraulic fractures gradually decreases from many to one, and the direction of the hydraulic fractures gradually approaches the vertical direction of σ 3 , but the change in the in situ stress condition has no obvious effect on the stress disturbance effect. The weaker the bonding strength of the bedding plane, the more significant the stress disturbance effect is, and the easier it is for the fractures to expand along the bedding plane. With increasing injection rate, the stress disturbance effect first increases and then decreases, and the hydraulic fracture propagates from along the bedding plane to cross the bedding plane. With increasing relative distance between the injection hole and bedding plane, the stress disturbance effect presents a linearly increasing trend, and the hydraulic fractures along the bedding planes extend. Based on the experimental results, the relationship between the fracturing effect of the stress disturbance and the extension mode of the hydraulic fracture is determined, and an optimization method for hydraulic fracturing in composite rock reservoirs is given. The research results can provide a theoretical basis for controlling the formation of complex fracture networks in composite rock reservoirs.

Fracturing behaviors of soil subjected to monotonic and fatigue pneumatic loading

The mechanical behaviors of soil exposed to monotonic and cyclic pneumatic loading are investigated through laboratory testing. The fracture morphology, air pressure, and earth pressure (EP) were monitored and analyzed. In monotonic pneumatic fracturing, pressure of air is the crucial factor that determines the length and number of fractures. In cyclic pneumatic fracturing, the number and propagation of fractures is greater than that under the monotonic loading, as well as the disturbance zone of the pressurized air to the soil. It is found that high-frequency injection maintains higher air pressure inside the soil, coupled with the cyclic loading, the fatigue fracturing effect is much better than that under monotonic loading. The patterns of fractures subjected to monotonic and cyclic loading are presented. It is concluded that the higher the injection frequency and air pressure, the larger the number and propagation range of fractures.

Experimental and Numerical Investigation on Basic Law of Dense Linear Multihole Directional Hydraulic Fracturing

Using the dense linear multihole to control the directional hydraulic fracturing is a significant technical method to realize roof control in mining engineering. By combining the large-scale true triaxial directional hydraulic fracturing experiment with the discrete element numerical simulation experiment, the basic law of dense linear holes controlling directional hydraulic fracturing was studied. The results show the following: (1) Using the dense linear holes to control directional hydraulic fracturing can effectively form directional hydraulic fractures extending along the borehole line. (2) The hydraulic fracturing simulation program is very suitable for studying the basic law of directional hydraulic fracturing. (3) The reason why the hydraulic fracture can be controlled and oriented is that firstly, due to the mutual compression between the dense holes, the maximum effective tangential tensile stress appears on the connecting line of the drilling hole, where the hydraulic fracture is easy to be initiated. Secondly, due to the effect of pore water pressure, the disturbed stress zone appears at the tip of the hydraulic fracture, and the stress concentration zone overlaps with each other to form the stress guiding strip, which controls the propagation and formation of directional hydraulic fractures. (4) The angle between the drilling line and the direction of the maximum principal stress, the in situ stress, and the hole spacing has significant effects on the directional hydraulic fracturing effect. The smaller the angle, the difference of the in situ stress, and the hole spacing, the better the directional hydraulic fracturing effect. (5) The directional effect of synchronous hydraulic fracturing is better than that of sequential hydraulic fracturing. (6) According to the multihole linear codirectional hydraulic fracturing experiments, five typical directional hydraulic fracture propagation modes are summarized.

Reduced-order modeling of near-field THMC coupled processes for nuclear waste repositories in shale

Performance assessment (PA) of geologic radioactive waste repositories requires three-dimensional simulation of highly nonlinear, thermo-hydro-mechanical-chemical (THMC), multiphase flow and transport processes across many kilometers and over tens to hundreds of thousands of years. Integrating the effects of a near-field geomechanical process (i.e. buffer swelling) into coupled THC simulations through reduced-order modeling, rather than through fully coupled geomechanics, can reduce the dimensionality of the problem and improve computational efficiency. In this study, PFLOTRAN simulations model a single waste package in a shale host rock repository, where re-saturation of a bentonite buffer causes the buffer to swell and exert stress on a highly fractured disturbed rock zone (DRZ). Three types of stress-dependent permeability functions (exponential, modified cubic, and Two-part Hooke’s law models) are implemented to describe mechanical characteristics of the system. Our modeling study suggests that compressing fractures reduces DRZ permeability, which could influence the rate of radionuclide transport and exchange with corrosive species in host rock groundwater that could accelerate waste package degradation. Less permeable shale host rock delays buffer swelling, consequently retarding DRZ permeability reduction as well as chemical transport within the barrier system.

Experimental and Numerical Investigation on Hydraulic Fracture Propagation Law of Composite Rock Materials considering the Disturbing Stress Effect

The stress disturbance effect will significantly affect the propagation path of hydraulic fractures in the composite rock reservoir. To reveal the influence mechanism of stress disturbance effect on the hydraulic fracture propagation, several groups of laboratory tests and simulation tests were carried out. The test results showed that the hydraulic fracture tip formed a disturbing stress field because of the pore water pressure. Before the hydraulic fracture was extended to the bedding plane, the bedding plane had been damaged under stress disturbance, and the disturbed fracture zone was formed. The propagation mode of hydraulic fracture at the bedding plane was highly sensitive to the formation of the disturbed fracture zone. The sensitivity is mainly reflected from two aspects. (1) Under the action of the hydraulic fracture tip disturbance stress, many microfractures are generated and penetrated into the disturbance fracture zone on the bedding plane. This behavior is accompanied by energy dissipation causing the bedding plane material to be significantly softened, and the energy required for hydraulic fracture propagation is reduced dramatically. (2) The formation of the disturbed fracture zone improves the degree of fragmentation of the bedding plane, and the permeability of the local area increases significantly, forming the dominant circulation path. The higher the development of the disturbed fracture zone, the greater the hydraulic fracture propagation tendency along the bedding plane. According to the formation characteristics of the bedding plane disturbed fracture zone, the author proposed a nonlinear fracture model of the bedding plane disturbed fracture zone and established the hydraulic fracture propagation path criterion. This paper further analyzed the influencing factors of the disturbed fracture zone’s formation conditions and found that the bedding plane’s cementation strength was the main factor affecting the development degree of the disturbed fracture zone.

Study on the excavation disturbed zone during tunneling in sandy cobble stratum considering the material meso-structure

The excavation disturbed zone plays an important role in the evaluation of tunnel stability. The identification of the excavation disturbed zone is perceived as a main concern. Taking the material meso-structure into account, this paper investigates the construction mechanical behavior in heterogeneous sand cobble stratum and aims to precisely predict the excavation disturbed zone. Firstly, the meso-scale numerical models were used to simulate tunnel excavation in sandy cobble strata, in which the large-sized rock blocks and fine-grained soil matrix were treated as separate constituents. Then, the stress redistribution and deformation performance in the ground during tunneling were explored in detail. Subsequently, combined with the deformation performance characteristics, a method for identifying the excavation disturbed zone was proposed. The boundary of the excavation disturbed zone can be identified by the displacement mutation point of the monitoring paths. Finally, a parametric study was performed to understand the influence of key factors on the excavation disturbed zone, including the rock meso-structure parameters, the soil matrix properties, and the tunnel geometry characteristics. The simulation results indicate that both the rock content and rock size have a significant impact on the excavation disturbed zone, the strength parameters and lateral pressure coefficient have a marked effect, and the tunnel radius and tunnel burial depth have a negligible influence on the excavation disturbed zone under the given conditions when normalized.

Impact of Weed Managements and Anthropogenic Stress on Quantitative Attributes of Plant Community Composition in Gopegarh Ecopark, Paschim Medinipur, West Bengal, India

Eco-parks are generally set up worldwide for serving both recreational and conservation purposes of local biodiversity through limited maintenance. Gopegarh Eco Park was set by the Forest Department, Government of West Bengal in highlands bank of Kangsabati Kansai) river with a heritage ‘Garh’ area with remnants of Khan Raja’s establishment in Midnapore, West Bengal. This park was a place to study for its rich resources of indigenous vegetation, insects and birds for students and researchers. Increased development for amusements including picnic shades and human accessibility, intense weeding and mud ovens are set up. This study to measure quantitative characteristics of plant communities by quardrat method in low, moderate and severely disturbed zones revealed gradual decrease in indigenous flora with time; specially, herbaceous vegetation. The vegetation is gradually turning towards a monodominant tree community of Acacia auriculiformis, in low and moderate disturbed sites and Anacardium occidentale in severely disturbed sites; both planted earlier. Species frequency, diversity and density are decreasing with stress. The frequent cutting and weeding is affecting intensely on the ecosystem; decreasing soil moisture, organic carbon and changes in pH. This practice may affect propagule formation, dispersal and establishment of herbs, shrub and tree species. The park may gradually lose the indigenous flora and the flora dependant fauna and its utility as in situ sustainable maintenance of biodiversity and a resource place for practical study by students and researchers.

Steel for Pipes of Strength Class K60 (X70) with Ferrite, Martensite and M/A-Component Microstructure for Sections of Main Pipelines Crossing Active Tectonic Disturbance Zones

Steel for Pipes of Strength Class K60 (X70) with Ferrite, Martensite and M/A-Component Microstructure for Sections of Main Pipelines Crossing Active Tectonic Disturbance Zones

Laboratory Measurement of Excavation Disturbance Effect Due to Trenchless Construction Using Distributed Fiber Optics Strain Sensing

Abstract Excavation disturbance induced by trenchless construction may lead to underground movement and deformation, which can be a potential hazard to the safety of overlying pavement structure. However, the development of a fiber optic–distributed sensing approach in recent years has provide an effective way for continuous measurement of soil strain. In this study, the mechanism of the excavation disturbance effect that is due to trenchless construction was investigated based on laboratory experiments. The sensing fibers were embedded within the overburden layer above the excavation surface to measure the distributed soil strain using Brillouin optical time-domain analysis. The relationships between ground settlements and soil strains were analyzed. The partition theory of excavation disturbance zone was verified based on test results. The influence of excavation on mechanical responses of overlying model pavement, including bending deformation and soil pressure, was measured and discussed. Laboratory test results indicated that soil strains were nearly symmetrically distributed around the excavation area, which was compressive close to the centerline and then became tensile on both sides of the excavation area. The width of the excavation disturbance zone derived from the soil strain measurements was found close to the calculation results based on the partition theory. Because of the uneven distribution of the support force that was caused by foundation settlement, the model pavement showed notable bending deformation after excavation. Therefore, the combined effects of traffic loading and excavation disturbance should be considered in the safety evaluation of trenchless construction.

Effect of disturbed zone thickness on rock slope stability

Cut slope surfaces are affected by excavation activities and weathering agents. Disturbances on the surface can penetrate down to a certain depth. Slope stability analyses made on the cut slopes can reveal unsatisfactory results unless the disturbance depth is determined. Moreover, false designs ignoring the shear strength parameter differences of inner and surface sections of the slopes can affect the safety of the highways. Disturbance thickness due to blasting effect is already presented in the literature; however, the mechanical excavation is still unknown. In this study the effect of mechanical excavation on disturbance thickness is investigated by using 54 cut slopes selected from Western Black Sea Region of Turkey. According to UCS results, the strength values of the undisturbed zones are found to be two times higher than the disturbed zones. The disturbance depths formed by excavation and weathering are found to be changing between 0.05 and 0.50 m on the cut slopes. Regarding the height (H) of the slopes, disturbance thickness is found to be affecting the slope up to 0.06 H which is lower than the blasting effect. It is recommended that this thickness should be taken into consideration when assigning the disturbance factor (D) and used to prevent stability problems of the cut slopes.

Response of benthic invertebrate assemblages to seasonal and habitat condition in the Wewe River, Ashanti region (Ghana).

Aquatic macro-invertebrates play a vital role in the food chain of river ecosystem at several trophic guilds and consumer levels, and are used as biomonitoring tools for aquatic ecosystem health. However, hydrologic conditions of these ecosystems have been severely altered because of the increase in urban development and agricultural expansion. This study examined benthic invertebrate response to processes that structure their community in the Wewe River, segmented into intact, medium, and severe condition zones. We sampled in 100 stations in a period of 4 months in the wet (June–September, 2019) and 3 months in the dry (January–March, 2020) seasons. Geometric series, rarefaction, and Hill numbers models were used to quantify invertebrate assemblages, while ordination technique, canonical correspondence analysis, was used to evaluate the influence of predictive factors on their assemblages. A total of 2,075 individuals belonging to 20 family taxa were registered. There was no significant difference in benthic assemblages between the dry and wet seasons. Predictive factors accounted for 47.04 and 50.84% variances, respectively. Taxa distribution patterns differed significantly only in the severely disturbed zone during the wet season. Neptidae, Libellulidae, and Chironomidae were the most abundant taxa, indicating their broad range habitat preference and their ability to adapt to seasonal changes. Asellidae and Perlidae were the least detected, suggesting their sensitivity to elevated levels of some water quality parameters. The findings highlight the threats to the benthic community and overall functional state of the Wewe River, with the need to consider the proposed conservation interventions indicated in this study.

An Ethology of Adaptation: Dolphins Stop Feeding but Continue Socializing in Construction-Degraded Habitat

Adaptation is a biological mechanism by which organisms adjust physically or behaviorally to changes in their environment to become more suited to it. This is a report of free-ranging bottlenose dolphins’ behavioral adaptations to environmental changes from coastal construction in prime habitat. Construction was a 5-year bridge removal and replacement project in a tidal inlet along west central Florida’s Gulf of Mexico coastline. It occurred in two consecutive 2.5-year phases to replace the west and east lanes, respectively. Lane phases involved demolition/removal of above-water cement structures, below-water cement structures, and reinstallation of below + above water cement structures (N= 2,098 photos). Data were longitudinal (11 years: 2005–2016,N= 1,219 surveys 2–4 times/week/11 years,N= 4,753 dolphins, 591.95 h of observation in the construction zone, 126 before-construction surveys, 568 during-construction surveys, 525 after-construction surveys). The dependent variable was numbers of dolphins (count) in the immediate construction zone. Three analyses examined presence/absence, total numbers of dolphins, and numbers of dolphins engaged in five behavior states (forage-feeding, socializing, direct travel, meandering travel, and mixed states) across construction. Analyses were GLIMMIX generalized linear models for logistic and negative binomial regressions to account for observation time differences as an exposure (offset) variable. Results showed a higher probability of dolphin presence than absence before construction began, more total dolphins before construction, and significant decreases in the numbers of feeding but not socializing dolphins. Significant changes in temporal rhythms also revealed finer-grained adaptations. Conclusions were that the dolphins adapted to construction in two ways, by establishing feeding locations beyond the disturbed construction zone and shifting temporal rhythms of behaviors that they continued to exhibit in the construction zone to later in the day when construction activities were minimized. This is the first study to suggest that the dolphins learned to cope with coastal construction with variable adjustments.