Kelly M Dorgan

Kelly M Dorgan
Dauphin Island Sea Lab | DISL

PhD

About

69
Publications
16,876
Reads
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1,432
Citations
Additional affiliations
January 2011 - October 2013
University of California, San Diego
Position
  • PostDoc Position
November 2007 - December 2010
University of California, Berkeley
Position
  • PostDoc Position
Education
June 2002 - November 2007
University of Maine
Field of study
  • Oceanography

Publications

Publications (69)
Article
Full-text available
Infaunal sedimentary communities underpin marine ecosystems worldwide. Understanding how disturbances such as oil spills influence infauna is therefore important, especially given that oil can be trapped in sediments for years or even decades. The 2010 Deepwater Horizon (DWH) event was the largest marine oil spill in United States history, impactin...
Article
Full-text available
Infaunal organisms are susceptible to disturbances such as hypoxia and sediment contamination; changes in infaunal community structure are therefore often used as indicators of anthropogenic disturbance. Susceptibility to disturbance varies across taxa, either due to physiological factors or to behaviors or functional roles that increase exposure....
Article
Depth-dependent variability in seabed acoustic and geophysical properties can be introduced by both physical and biogenic processes. An experiment was conducted near the mouth of Mobile Bay, Alabama to investigate spatial variability over a mud-sand gradient, where sediment properties showed lateral changes on the scales of tens of meters. Addition...
Article
Interstitial organic matter (OM) is a ubiquitous constituent of marine sediment, particularly prevalent in sediments with significant silt/clay fractions, and is often quantified across a wide range of disciplines. OM suspends silt and clay particles in the sediment matrix, adsorbs onto mineral surfaces, and resides primarily between mineral contac...
Article
No PDF available ABSTRACT Seabed variability introduced by physical or biogenic processes contributes to multi-scale horizontal and vertical variability in seabed acoustic and geotechnical properties. An experiment was conducted near the mouth of Mobile Bay to investigate such spatial variability over a mud-sand gradient. A normal-incidence bottom...
Article
No PDF available ABSTRACT Storm disturbance of shallow coastal sediments can resuspend subtidal sediment and transport and deposit sand from beach erosion, creating sorted layers of differing grain sizes. These sediments provide habitat for diverse and abundant infaunal organisms that mix these layers (bioturbation), but how the reestablishment of...
Article
No PDF available ABSTRACT Whether deposited from the water column or generated by benthic infauna, interstitial organic matter is a ubiquitous constituent of marine sediment and is particularly prevalent in sediments with significant silt/clay fractions. Interstitial organic matter suspends silt and clay particles in the sediment matrix, adsorbs on...
Article
No PDF available ABSTRACT Nearshore and estuarine sediments experience varying sediment inputs that create sharp gradients in sediment properties over fairly small vertical and horizontal distances. In this study, we explored the sand-mud transition in sediment cores collected from Mobile Bay, AL, with acoustic and geotechnical approaches. A custom...
Article
Full-text available
The benthic impact of aquaculture waste depends on the area and extent of waste accumulation on the sediment surface below and around the farm. In this study we investigated the effect of flow on biodeposit transport and initial deposition by calculating a rough aquaculture “footprint” around an oyster aquaculture farm in the Damariscotta River, ME...
Article
Synopsis The connection between structure and function is one of the fundamental tenets of biology: a biological unit’s structure determines its function, and, conversely, its function depends upon its structure. Historically, important advances have been made either when understanding of structure leads to questions about function or when understa...
Article
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A broad diversity of biological organisms and systems interact with soil in ways that facilitate their growth and survival. These interactions are made possible by strategies that enable organisms to accomplish functions that can be analogous to those required in geotechnical engineering systems. Examples include anchorage in soft and weak ground,...
Article
Mud blister worms bore into oyster shells; and oysters respond to shell penetration by secreting new layers of shell, resulting in mud blisters on inner surfaces of oyster shells. We conducted two experiments in off-bottom oyster farms along Alabama's coast in summer 2017 to explore the dynamics of worm infestation, blister formation, and shell rep...
Article
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Mudblister worms Polydora websteri bore holes into oyster shells, and oysters respond by secreting extra layers of shell, creating a mudblister. When shucked, mudblisters can burst and release anoxic mud. Thus, infestation devalues oysters, particularly on the half-shell market. This study quantified oyster condition index and worm abundances over...
Article
Anthropogenic disturbances such as oil spills can cause mortality in benthic infaunal communities, reducing diversity and abundance and impeding sediment ecosystem functions. Sublethal effects of oil exposure have received less attention, however. We conducted a mesocosm experiment exposing 2 infaunal taxa, the polychaete Owenia fusiformis and the...
Article
The activities of infaunal organisms, including feeding, locomotion, and home building, alter sediment physical properties including grain size and sorting, porosity, bulk density, permeability, packing, tortuosity, and consolidation behavior. These activities are also known to affect the acoustic properties of marine sediments, although previous s...
Article
No PDF available ABSTRACT Infauna influence sediment physical parameters, such as porosity, grain size, and pore fluid properties, through bioturbation and other biological processes. To investigate the effects of the resulting sediment inhomogeneity, in situ measurements of compressional and shear wave propagation were acquired in Petit Bois Pass,...
Article
Benthic macrofauna play important roles in coastal ecosystems through their impact on nutrient cycling and by serving as an mportant trophic link. This study investigated the influence of environmental stressors on macrofaunal community abundance, biomass and diversity and evaluated impacts of those benthic organisms on nutrient fluxes and denitrif...
Conference Paper
Biological organisms are prevalent on and near the seabed; however, most predictive theoretical models do not explicitly address the acoustic behavior of biologically active marine sediments. Sediment-acoustics models, such as those based on Biot theory or grain-shearing theory, allow for parameterization of various physical properties including bu...
Article
Infauna, animals living in marine sediments, modify sediment structure by burrowing, constructing burrows and tubes, and irrigating burrows. These activities can change the bulk porosity and density as well as create heterogeneity in sediment structure. We test the hypothesis that these activities alter sound speed and attenuation in sediments by m...
Article
This paper presents in situ measurements of sediment sound speed and attenuation collected in the New England Mud Patch using the Acoustic Coring System (ACS) with comparisons to sound speed measurements from a multi-sensor core logger (MSCL). The ACS uses rod-mounted piezoelectric cylinders mounted below the penetrating tip of a gravity corer to o...
Article
Infauna dwell in the benthic zone and have the capacity to modify the physical and acoustic properties of the seabed through bioturbation. To investigate such effects, in situ measurements of compressional and shear wave speed and attenuation were conducted in Petit Bois Pass, near the mouth of Mobile Bay, Alabama, USA. The measurement system was d...
Article
Peristaltic burrowing in muds applies normal forces to burrow walls, which extend by fracture, but the kinematics and mechanics of peristaltic burrowing in sands has not been explored. The opheliid polychaete, Thoracophelia mucronata, uses direct peristalsis to burrow in beach sands, using kinematics consistent with the "dual anchor system" of burr...
Article
Polychaetes exhibit diverse feeding strategies and diets, with some species possessing hardened teeth or jaws of varying complexity. Species in the order Eunicida have complex, rigid, articulated jaws consisting of multiple pairs of maxillae and a pair of mandibles. While all Eunicida possess this general jaw structure, several characteristics of t...
Article
Marine sediments cover most of the seafloor and vary in physical structure from unconsolidated gravel or sand grains to cohesive, gel-like muds. Sediments also provide a habitat to diverse and abundant animals (infauna). Infauna are impacted by but can also affect the sediment’s physical and biogeochemical properties and fluid flow through and acro...
Article
To investigate the effects of infauna on seabed geoacoustic properties, a field experiment was conducted during May 2017 in Petit Bois Pass, near the mouth of Mobile Bay, Alabama. In situ measurements of seabed geoacoustic properties were collected using hydrophones to generate and receive compressional waves from 5 kHz to 100 kHz and bimorph trans...
Article
Benthic infauna perform important ecological functions such as water filtration, the recycling of organic matter, and forage for larger predators. However, how infauna affect bulk acoustical properties of the sediment is less studied and warrants further investigation. During a field experiment conducted in Petit Bois Pass, AL, multiple cores of fi...
Article
Marine infauna alter the surrounding habitat in many ways. Compact mud burrows, tubes built from shell hash, and large subsurface galleries are a few examples of these alterations. Structural changes such as these can have varying effects on the geoacoustic properties of sediment. Here, we investigate how infauna may affect the sound speed and atte...
Conference Paper
Full-text available
Benthic infauna perform important ecological functions such as water filtration, the recycling of organic matter, and forage for larger predators. However, how infauna affect bulk acoustical properties of the sediment is less studied and warrants further investigation. During a field experiment conducted in Petit Bois Pass, AL, multiple cores of fi...
Conference Paper
To investigate the effects of infauna on seabed geoacoustic properties, a field experiment was conducted during May 2017 in Petit Bois Pass, near the mouth of Mobile Bay, Alabama. In situ measurements of seabed geoacoustic properties were collected using hydrophones to generate and receive compressional waves from 5 kHz to 100 kHz and bimorph trans...
Article
The acoustic effects of biological activity within shallow water ocean environments are not well understood, yet are of increasing importance in some sonar applications. These environments remain insufficiently characterized in part due to the presence of benthic organisms within and near the sediment and water-sediment interface. Among the most pr...
Article
Muddy sediments are elastic solids through which morphologically diverse animals extend burrows by fracture. Muddy sediments inhabited by burrowing infauna vary considerably in mechanical properties, however, and at high enough porosities, muds can be fluidized. In this study, we examined burrowing behaviors and mechanisms of burrow extension for t...
Article
Biology is prevalent on and within many ocean bottom sediments. Organisms can include animals dwelling at or near the water-sediment interface or infauna living within surficial sediments. Bioturbation from burrowing, tube building, or other activities can have physical effects on the sediment acoustic properties. As part of the Sediment Characteri...
Conference Paper
Biology is prevalent on and within many ocean bottom sediments. Organisms can include animals dwelling at or near the water-sediment interface or infauna living within surficial sediments. Bioturbation from burrowing, tube building, or other activities can have physical effects on the sediment acoustic properties. As part of the Sediment Characteri...
Article
Full-text available
Worms of different sizes extend burrows through muddy sediments by fracture, applying dorso-ventral forces that are amplified at the crack tip. Smaller worms displace sediments less than larger worms, and therefore are limited in how much force they can apply to burrow walls. We hypothesized that small worms would exhibit a transition in burrowing...
Article
Full-text available
Burrowers and borers are ecosystem engineers that alter their physical environments through bioturbation, bioirrigation and bioerosion. The mechanisms of moving through solid substrata by burrowing or boring depend on the mechanical properties of the medium and the size and morphology of the organism. For burrowing animals, mud differs mechanically...
Article
Full-text available
Polychaetes are common in most marine habitats and dominate many infaunal communities. Functional guild classification based on taxonomic identity and morphology has linked community structure to ecological function. The functional guilds now include osmotrophic siboglinids as well as sipunculans, echiurans, and myzostomes, which molecular genetic...
Article
Full-text available
Divergent morphologies among related species are often correlated with distinct behaviors and habitat uses. Considerable morphological and behavioral differences are found between two major clades within the polychaete family Opheliidae. For instance, Thoracophelia mucronata burrows by peristalsis, whereas Armandia brevis exhibits undulatory burrow...
Article
Muddy and sandy sediments have different physical properties. Muds are cohesive elastic solids, whereas granular beach sands are non-cohesive porous media. Infaunal organisms such as worms that burrow through sediments therefore face different mechanical challenges that potentially lead to a variety of burrowing strategies and morphologies. In this...
Article
Full-text available
Recent work has shown that muddy sediments are elastic solids through which animals extend burrows by fracture, whereas non-cohesive granular sands fluidize around some burrowers. These different mechanical responses are reflected in the morphologies and behaviours of their respective inhabitants. However, Armandia brevis, a mud-burrowing opheliid...
Article
Full-text available
Thoracophelia (Annelida, Opheliidae) are burrowing deposit feeders generally found in the mid- to upper intertidal areas of sandy beaches. Thoracophelia mucronata (Treadwell, 1914) is found along the west coast of North America, including at Dillon Beach, CA. Two additional species, Thoracophelia dillonensis (Hartman, 1938) and T. williamsi (Hartma...
Article
Full-text available
This study reports the first in situ measurements of tensile fracture toughness, K IC, of soft, surficial, cohesive marine sediments. A newly developed probe continuously measures the stress required to cause tensile failure in sediments to depths of up to 1 m. Probe measurements are in agreement with standard laboratory methods of K IC measurement...
Article
Full-text available
Sea ice typically forms at the ocean’s surface, but given a source of supercooled water, an unusual form of ice—anchor ice—can grow on objects in the water column or at the seafloor. For several decades, ecologists have considered anchor ice to be an important agent of disturbance in the shallow-water benthic communities of McMurdo Sound, Antarctic...
Article
Full-text available
Sea ice typically forms at the ocean's surface, but given a source of supercooled water, an unusual form of ice--anchor ice--can grow on objects in the water column or at the seafloor. For several decades, ecologists have considered anchor ice to be an important agent of disturbance in the shallow-water benthic communities of McMurdo Sound, Antarct...
Article
Full-text available
Burrowing through marine sediments has been considered to be much more energetically expensive than other forms of locomotion, but previous studies were based solely on external work calculations and lacked an understanding of the mechanical responses of sediments to forces applied by burrowers. Muddy sediments are elastic solids through which worm...
Article
Full-text available
Burrowing marine infauna are morphologically diverse and ecologically important as ecosystem engineers. The polychaetes Nereis virens and Cirriformia moorei extend their burrows by crack propagation. Nereis virens does so by everting its pharynx and C. moorei, lacking an eversible pharynx or proboscis, uses its hydrostatic skeleton to expand its an...
Article
Full-text available
The polychaete Cirriformia moorei burrows in muddy sediments by fracture, using its hydrostatic skeleton to expand its anterior region and exert force against its burrow wall to extend a crack. Burrowing occurs in four phases: stretching forward into the burrow, extending the crack anteriorly, thickening the burrowing end to amplify stress at the t...
Article
Full-text available
Mechanics, kinematics, and energetics of crawling and burrowing by limbless organisms using hydrostatic skeletons depend on the medium and mode in which the organism is moving. Whether the animal is moving over or through a solid has long been considered important enough to distinguish crawling and burrowing as different terms, and in fact the mech...
Article
Full-text available
Burrowing marine infauna are morphologically diverse and range in size over several orders of magnitude. Whilst effects of ontogenetic and morphological differences on running, flying and swimming are relatively well understood, similar analyses of burrowing mechanics and kinematics are lacking. The polychaete Nereis virens Sars extends its burrow...
Article
Full-text available
Recent studies document linear elastic response of muddy marine sediments to load and deformation on temporal and spatial scales relevant to animal movement, with burrowers making openings for movement in such sediments by fracture. Cracks propagate through linear elastic solids in mode I (opening-mode crack growth) when the stress intensity factor...
Article
Full-text available
The polychaete Nereis virens burrows through muddy sediments by exerting dorsoventral forces against the walls of its tongue-depressor-shaped burrow to extend an oblate hemispheroidal crack. Stress is concentrated at the crack tip, which extends when the stress intensity factor (KI) exceeds the critical stress intensity factor (KIc). Relevant force...
Chapter
Full-text available
Physics, materials sciences and mechanical engineering provide constraints that can be used to understand what infaunal animals do and did in the contexts of both making and destroying traces. As a primary example, on the temporal and spatial scales of burrow extension, many muds behave as linearly elastic solids that fail by cracking. These cracks...
Article
Marine muds are elastic solids through which animals move by propagating a crack-shaped burrow. Dilations previously considered anchors serve to exert dorsoventral compressive stresses on the burrow walls that, through elastic behavior of the medium, focus strongly at the tip of the burrow. This focused stress breaks adhesive or cohesive bonds, pro...
Chapter
Full-text available
Burrowing by benthic infauna mixes both sediment grains and interstitial fluids, affecting sedimentary redox conditions and determining fates of organic matter and pollutants. Explicit, quantitative analyses of material properties of sediments, however, have been applied only recently to understand mechanisms of burrowing. Muds are elastic solids t...
Article
Full-text available
Burrowing by benthic infauna mixes both sediment grains and interstitial fluids, affect-ing sedimentary redox conditions and determining fates of organic matter and pollutants. Explicit, quantitative analyses of material properties of sediments, however, have been applied only recently to understand mechanisms of burrowing. Muds are elastic solids...
Article
Full-text available
The mechanics of uncemented soft sediments during bubble growth are not widely understood and no rheological model has found wide acceptance. We offer definitive evidence on the mode of bubble formation in the form of X-ray computed tomographic images and comparison with theory. Natural and injected bubbles in muddy cohesive sediments are shown to...
Article
Full-text available
Until now, the analysis of burrowing mechanics has neglected the mechanical properties of impeding, muddy, cohesive sediments, which behave like elastic solids. Here we show that burrowers can progress through such sediments by using a mechanically efficient, previously unsuspected mechanism--crack propagation--in which an alternating 'anchor' syst...
Article
Full-text available
The genus Platydoris Bergh, 1877 is characterized by a at body, wide mantle margin, and elevated branchial and rhinophoral sheaths. Examination of a number of specimens and a review of the literature have shown that there are at least 20 valid species of the genus Platydoris world-wide. Some of them have previously been described by other authors a...

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