Marine Biology Commons^™

Bottom-Up Control Of Parasites, David S. Johnson, Richard W. Heard

Faculty Publications

Parasitism is a fundamental ecological interaction. Yet we understand relatively little about the ecological role of parasites compared to the role of free-living organisms. Bottom-up theory predicts that resource enhancement will increase the abundance and biomass of free-living organisms. Similarly, parasite abundance and biomass should increase in an ecosystem with resource enhancement. We tested this hypothesis in a landscape-level experiment in which salt marshes (60,000 m2 each) received elevated nutrient concentrations via flooding tidal waters for 11 yr to mimic eutrophication. Nutrient enrichment elevated the densities of the talitrid amphipod, Orchestia grillus, and the density and biomass of its trematode …

Prey Naïveté And Predator-Prey Interactions Between Pterois Volitans, Pomacentridae, And Tetraodontidae In Two Reefs In The Guna Yala Archipelago, Panama, Jesse Garrett-Larsen

Independent Study Project (ISP) Collection

The invasion of Pterois volitans along the Atlantic coast of the Americas is one of the top marine conservation issues of the century. Prey naïveté has been suggested as a mechanism for the success of P. volitans, but conclusive field observations have not been completed. This study tested for prey naïveté in situ by comparing time spent by Pomacentridae and Tetraodontidae in close proximity to P. volitans and a native predator, Cephalopholis cruentata. Difference in time spent by Pomacentridae and Tetraodontidae in the presence of the two predators was observed. The predators P. volitans and C. cruentata were sequentially observed …

Inventory Of Gulf Of Mexico Oceanic Fauna Data Including Species, Weight, And Measurements From R/V Point Sur (Cruises Dp03 And Dp04) May-August, 2016, April Cook, Tracey Sutton

DEEPEND Datasets

This data set includes the biological and environmental data for all of the species collected during the DP03 (May 2016) and DP04 cruises (August 2016). The main gear type used was a 10-m2 Multiple Opening Closing Net and Environmental Sensing System (MOCNESS). The MOCNESS was fitted with 6 nets which were opened according to the following depth scheme: net 0 from the surface to 1500m, net 1 from 1500-1200m, net 2 from 200-1000m, net 3 from 1000-600m, net 4 from 600-200m, and net 5 from 200m to the surface. Two trawls were conducted at each station sampled to capture diel …

Understanding The Transition From Benthic Egg To Dispersive Larvae: Observations On The Intra-Capsular Growth And Development Of A Marine Snail (Kelletia Kelletii), Megan N. Wilson

Biological Sciences

It has long been understood that the larval life stage is responsible for the dispersion of many marine organisms across their biogeographic range. Such organisms have a bipartite life cycle, existing in the water column and subject to oceanographic processes as planktonic larvae before settling to suitable habitat along the benthos where they grow and mature. Previous studies have demonstrated that larval growth rate and behavior in the water column can alter larval position in relation to ocean currents and affects their dispersal pathway. However, there is a paucity of information regarding the growth rate of the earliest larval stage …

New Genera And Species Of Fossil Marine Amioid Fishes (Actinopterygii, Holostei) From The Late Cretaceous Agoult Locality In Southeastern Morocco, Mark V. Wilson, Alison M. Murray, Terry C. Grande

Biology: Faculty Publications and Other Works

The document is Terry C. Grande's (et al.) abstract in the Society of Vertebrate Paleontology 77th Annual Meeting Program and Abstracts.

Synergistic Use Of Remote Sensing And Modeling To Assess An Anomalously High Chlorophyll-A Event During Summer 2015 In The South Central Red Sea, Wenzhao Li, Hesham El-Askary, K. P. Manikandan, Mohamed A. Qurban, Michael J. Garay, Olga V. Kalishnikova

Mathematics, Physics, and Computer Science Faculty Articles and Research

An anomalously high chlorophyll-a (Chl-a) event (>2 mg/m3) during June 2015 in the South Central Red Sea (17.5° to 22°N, 37° to 42°E) was observed using Moderate Resolution Imaging Spectroradiometer (MODIS) data from the Terra and Aqua satellite platforms. This differs from the low Chl-a values (<0.5 mg/m3) usually encountered over the same region during summertime. To assess this anomaly and possible causes, we used a wide range of oceanographical and meteorological datasets, including Chl-a concentrations, sea surface temperature (SST), sea surface height (SSH), mixed layer depth (MLD), ocean current velocity and aerosol optical depth (AOD) obtained from different sensors and models. Findings confirmed this anomalous behavior in the spatial domain using Hovmöller data analysis techniques, while a time series analysis addressed monthly and daily variability. Our analysis suggests that a combination of factors controlling nutrient supply contributed to the anomalous phytoplankton growth. These factors include horizontal transfer of upwelling water through eddy circulation and possible mineral fertilization from atmospheric dust deposition. Coral reefs might have provided extra nutrient supply, yet this is out of the scope of our analysis. We thought that dust deposition from a coastal dust jet event in late June, coinciding with the phytoplankton blooms in the area under investigation, might have also contributed as shown by our AOD findings. However, a lag cross correlation showed a two- month lag between strong dust outbreak and the high Chl-a anomaly. The high Chl-a concentration at the edge of the eddy emphasizes the importance of horizontal advection in fertilizing oligotrophic (nutrient poor) Red Sea waters.

Determining Critical Internesting And Foraging Habitats For The Conservation Of Sea Turtles In Gabon, Africa Using Satellite Tracking And Stable Isotope Analysis, Tiffany M. Dawson

Biological Sciences Theses & Dissertations

Understanding the horizontal and vertical habitat of olive ridley sea turtles (Lepidochelys olivacea), a threatened species, is critical for determining regions of protection that may effectively reduce bycatch, the largest threat to this species. Satellite transmitters were used to determine the movement and dive behavior of 21 female olive ridley turtles tagged in Pongara National Park, Gabon during the 2012, 2013, and 2015 nesting seasons. A switching state space model was used to filter the tracking data and categorize the internesting and post-nesting movements. Gridded utilization distribution (UD) home range analysis of tracking data revealed that the entire core habitat …

Multiple Opening Closing Net Environmental Sensing System (Mocness) Instrument Data For Cruise Dp05 R/V Point Sur In-Situ Deep Seawater And Associated Fauna, May 1-11, 2017, Viosca Knoll Gom, Gray Lawson, Travis Richards

DEEPEND Datasets

The Multiple Opening Closing Net and Environmental Sensing System(s) (MOCNESS) deployed during the DEEPEND field program collects data (e.g., pressure, temperature, conductivity, volume filtered, horizontal and vertical velocity, latitude, and longitude) from several sensors while the instrument is in use. These data help characterize the environment and assess the orientation and speed of the MOCNESS. The flow and net angle can be used to calculate the volume of water filtered for each net. The biological data and ship data collected during this cruise are available in GRIIDC datasets R4.x257.226:0005 and R4.x257.226:0014 respectively.

Molecular Assisted Identification Reveals Hidden Red Algae Diversity From The Burica Peninsula, Pacific Panama, David Wilson Freshwater, Jennifer N. Idol, Seth L. Parham, Cindy Fernández-García, Noemi León, Paul W. Gabrielson, Brian Wysor

Arts & Sciences Faculty Publications

The marine flora of Panama harbors a rich diversity of green, red and brown algae, and despite chronic understudy, it is reported as the second most diverse marine flora along the Pacific Central American coast, with 174 macroalgal species. Extensive new collections and molecular assisted identification (MAI) by an international team of researchers has revealed an even greater diversity for this country. Here, the intertidal and shallow subtidal marine flora of the remote Burica Peninsula is introduced. This area is characterized by an uplifted extensive intertidal flat composed of firm, sedimentary benthos known as mudrock, on which abundant algal communities …

The Population Genetics Of Morro Bay Eelgrass (Zostera Marina), Julia Gardner Harencar

Master's Theses

Seagrass populations are in decline worldwide. Zostera marina (eelgrass), one of California’s native seagrasses, is no exception to this trend. In the last 8 years, Morro Bay, California has lost 95% of its eelgrass. Eelgrass is an ecosystem engineer, providing important ecosystem services such as sediment stabilization, nutrient cycling, and nursery habitats for fish. The failure of recent restoration efforts necessitates a better understanding of the causes of eelgrass decline in this estuary. Previous research on eelgrass in California has demonstrated a link between population genetic diversity and eelgrass bed health, ecosystem functioning, and resilience to disturbance and extreme climatic …

Marine Tardigrades From South Carolina, Usa, Paul J. Bartels, Lilvia J. Bradbury, Diane R. Nelson

Journal of the South Carolina Academy of Science

Until now, there have been only three studies of marine tardigrades from South Carolina, USA. The Fall 2015 invertebrate zoology class from Warren Wilson College collected four sediment samples from Huntington Beach State Park: shallow beach sand, deep beach sand, shallow salt marsh sediment, and deep salt marsh sediment. No tardigrades were found in the salt marsh, but two species were found in the beach samples. Batillipes pennaki Marcus, 1946 was found in shallow and deep beach sand, and three specimens of a potentially new species of Stygarctus Schulz, 1951 were found in the deep beach sand at groundwater level. …

Dna Sequences Of The Mitochondrial Cytochrome C Oxidase I (Coi) Genes From Deep Sea Fishes. Cruises Dp01 And Dp02 From May 2015 - August 2015, Andrea Bernard, Max Weber, Kimberly A. Finnegan, Mahmood S. Shivji, Ron Eytan

DEEPEND Datasets

The deep sea ecosystem is believed to contain the highest biomass of fish in the oceans. However, the taxonomic diversity in this ecosystem is incompletely described and likely to be vastly underestimated. DNA sequence data (barcodes) have become a key tool to discover hidden biodiversity. We generated mitochondrial DNA barcode datasets based on the Cytochrome c oxidase I (COI) gene from deep sea fishes. These data were analyzed using phylogenetic and statistical methods to reveal cryptic species and make taxonomic linkages between adult fishes and their early life stages. These datasets were generated from fishes collected in the Northern Gulf …

Growth Of Orbicella Faveolata In La Parguera, Puerto Rico, Darren B. Marshall

HCNSO Student Theses and Dissertations

Reef-building corals are subject to high amounts of stress, including pollution and rising sea surface temperatures due to climate change. These factors can affect the ability of corals to produce their calcium carbonate skeletons. Evaluation of the effects of climate change may be facilitated by evaluation of records of coral skeletal growth over a long period of time. The aim of this study was to evaluate skeletal growth of the coral Orbicella faveolata in La Parguera, Puerto Rico over a 32-year period. For this, 14 Orbicella faveolata core samples were collected from corals at two reefs (1.2 km apart) in …

Dna Barcoding Reveals A New Morphotype Of The Sugar Kelp, Saccharina Latissima, Dallin Brimley, Zakery Ford, Travis Gould, Brandon Guerra, Emily Haggett, Ian Jones, Elyse Johnson, Ken Peterson, Matthew Prout

Thinking Matters Symposium Archive

Phytoplankton blooms follow predictable annual cycles in the Gulf of Maine, characterized by a large spring bloom and a smaller bloom in the fall. Marine phytoplankton form the foundation of primary production in Gulf of Maine waters, and thus community changes in composition, and abundance could have cascading effects on our coastal ecosystems.

We set out to monitor the community composition, diversity, and abundance of the spring micro-phytoplankton bloom, at a Friends of Casco Bay water quality monitoring site, in South Portland, Maine. The Gulf of Maine is experiencing accelerated warming rates, and this type of monitoring can aid in …

Aggressive Displays In Male Betta Splendens Based On Color Patterns, Julian Bones, Thomas Johnson

Thinking Matters Symposium Archive

The traits of an opponent can influence how an individual uses aggressive displays to dissuade the opponent from physical conflict. Whereas one previous study found that conspecific aggression was less intense between differently-colored Siamese fighting fish (Betta splendens), we felt that more evidence was needed to corroborate or dispute their findings. We hypothesized that B. splendens act less aggressively towards similarly- colored fish than to differently-colored fish, based on the notion that males would avoid conflict with a phenotypically similar opponent due to the costs of displaying. To test for differences in aggression due to coloration, we paired …

Differential Response Of Coral Symbiotic Dinoflagellates To Bacterial Toxins That Produce Bleaching In Stony Corals, Diego L. Gil-Agudelo, Yael Ban-Haim, Eugene Rosenberg, Garriet W. Smith

Journal of the South Carolina Academy of Science

Bleaching of corals and other organisms with symbiotic zooxanthellae is a worldwide phenomenon with increasing importance due to global warming scenarios. Bleaching has been historically related to changes in the environment, especially water temperature increase, that stress corals and provoke the release of zooxanthellae. The discovery of Vibrio shilonii, a bacterium causing bleaching under thermal stress in corals of the Mediterranean Sea has changed our thinking about the cause (or explanation) for bleaching of corals worldwide. During this study, we evaluated the effect of a proline rich toxin, extracted from Vibrio shilonii, on zooxanthellae obtained from: Oculina patagonica from the …

Exploring The Potential For Artificial Reefs In Coral Reef Restoration: Responses And Interactions Of Associated Biota To Varying Experimental Treatments In The Mexican Caribbean, Audie Kirk Kilfoyle

HCNSO Student Theses and Dissertations

Coral reefs are being negatively impacted by various causes worldwide, and direct intervention is often warranted following disturbance to restore or replace lost ecosystem structure and function. An experimental coral reef restoration study involving standardized artificial reef modules (Reefballs^TM) was conducted in Mexico’s Yucatan Peninsula in the towns of Puerto Morelos and Akumal. The purpose was to explore the use of artificial structure for restoration and mitigation applications in a highly diverse and dynamic Caribbean coral reef environment by applying and evaluating the performance of select experimental treatments hypothesized to accelerate development of the associated biota. The first …

Presence/Absence And Density Data For Epipelagic Tows From 48 Stations In The Northern Gulf Of Mexico From R/V Blazing Seven Cruises Lf2015a And Lf2015b June 2015 And July 2015, Jay R. Rooker, R.J. David Wells

DEEPEND Datasets

Larval catch data after the oil spill is being used to improve our understanding of the causes of temporal variability as it relates to the Deep Water Horizon oil spill (DWHOS). Bongo and neuston net tows were conducted at 48 stations in both June and July, 2015 in the northern Gulf of Mexico. Cruise data collected at each site included latitude/longitude, date, time and environmental data (temperature, salinity, dissolved oxygen). The occurrence and density of selected epipelagic (e.g., billfishes, tunas, dolphinfishes, flyingfishes) and deep pelagic (e.g., lanternfishes, bristlemouths, marine hatchetfishes) fish larvae were quantified and are being used to extend …

The Phenology Of Sand Crabs, Lepidopa Benedicti (Decapoda: Albuneidae), Zen Faulkes

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Albuneid sand crabs are widespread on sandy beaches around the world, but because they conceal themselves by digging in sand and are often found at low densities, little is known about their basic biology. Lepidopa species were collected from the beaches of South Padre Island, Texas, on the western coast of Gulf of Mexico, a location that had previously been suggested to act as a population sink. The site contained Lepidopa benedicti and L. websteri, although the latter was extremely rare (collected three times in 5 years). There was significant variation in abundance across the year, with higher densities …

Nematocyst Distribution Corresponds To Prey Capture Location In Hydromedusae With Different Predation Modes, Marco Corrales-Ugalde, Sean Colin, Kelly R. Sutherland

Arts & Sciences Faculty Publications

Understanding the factors that control predation in pelagic communities can inform predictions of community structure in marine ecosystems. Ubiquitous and selective predators such as cnidarian hydromedusae rely on their nematocysts to capture and retain prey but it is not clear how the density and spatial distribution of these cells relate to predation mode. We examined the relationship between prey capture and nematocyst distribution in the tentacles of Aglantha digitale and Proboscidactyla flavicirrata, which are considered ambush predators, and Clytia gregaria and Mitrocoma cellularia, which are considered feeding-current predators. First, we analyzed video of predator-prey interactions to compare capture locations of …

Marine Aquarium Trade In India: Challenges And Opportunities For Conservation And Policy, Sanjeevi Prakash, Thipramalai Thangappan Ajith Kumar, Rajeev Raghavan, Andrew L. Rhyne, Michael F. Tlusty, Thanumalaya Subramoniam

Arts & Sciences Faculty Publications

The collection of marine taxa for the aquarium trade continues to demand live animals be extracted from reefs, but in doing so, offers economic benefits for local communities. To improve our understanding of the status of marine aquariumtrade in India, information on harvested species and their volume was gathered at the major collection hubs (Tuticorin, Kilakarai and Mandapam) in the Gulf of Mannar region, and compared to the export data. During one year, 87 species of fish (51% belonging to the family Pomacentridae) and 21 species of invertebrates were harvested for the trade. The conservation status of exploited species revealed …

Microbiome And Bacterioplankton Rrna Gene Sequence Data Collected From Gulf Of Mexico Seawater Samples, Cruises Dp01 And Dp02 From May 2015 - August 2015, Cole Easson, Jose V. Lopez

DEEPEND Datasets

Seawater was collected and filtered for microbiome and bacterioplankton sequencing and analyses at various depths during two planned DEEPEND cruise expeditions to the GOM. Filters were stored and then processed for total environmental genomic DNA according to standard methods (see earthmicrobiome.org). 16S rRNA amplicon libraries covering the V4 hypervariable region was generated with universal PCR primers and then sequenced on an Illumina MiSeq DNA sequencing platform. Bioinformatics analyses in QIIME and R was used to quality filter and assess microbial community diversity and taxonomic composition. These baseline characterizations track alpha and beta diversity at different depths ranging from 0 – …

Blubber Transciptome Response To Acute Stress Axis Activation Involves Transient Charges In Adipogenesis And Lipolysis In Fast-Adapted Marine Mammal, J. I. Khudyakov, C. D. Champagne, L. M. Meneghetti, D. E. Crocker

Biological Sciences Faculty Publications

Stress can compromise an animal's ability to conserve metabolic stores and participate in energy-demanding activities that are critical for fitness. Understanding how wild animals, especially those already experiencing physiological extremes (e.g. fasting), regulate stress responses is critical for evaluating the impacts of anthropogenic disturbance on physiology and fitness, key challenges for conservation. However, studies of stress in wildlife are often limited to baseline endocrine measurements and few have investigated stress effects in fasting-adapted species. We examined downstream molecular consequences of hypothalamic-pituitary-adrenal (HPA) axis activation by exogenous adrenocorticotropic hormone (ACTH) in blubber of northern elephant seals due to the ease of …

Cruise Data For Neuston Net And Paired Bongo Net Tows From 48 Stations In The Northern Gulf Of Mexico From R/V Blazing Seven Cruises Lf2015a And Lf2015b June 2015 And July 2015, Jay R. Rooker, R.J. David Wells

DEEPEND Datasets

Shelf and slope waters in the Deep Water Horizon oil spill (DWHOS) area are known to serve as critical spawning, nursery, and foraging habitat of several important oceanic species including billfishes (e.g. blue marlin, white marlin, sailfish), tunas (bluefin tuna, yellowfin tuna), and other pelagic taxa (swordfish, dolphinfishes). The aim of this component was to further investigate potential ecological effects of the DWHOS on pelagic fishes during the early life period. Larval fishes were sampled from 48 stations in the northern Gulf of Mexico and cruise data was collected at each site including latitude/longitude, date, time and environmental data (sea …

The Lower Actinopterygian Fauna From The Lower Carboniferous Albert Shale Formation Of New Brunswick, Canada – A Review Of Previously Described Taxa And A Description Of A New Genus And Species, Kathryn E. Mickle

College of Humanities and Sciences Faculty Papers

The Lower Carboniferous Albert shale formation of New Brunswick, Canada, is well-known for the preservation of countless articulated lower actinopterygian palaeoniscoid fishes. This site is at the boundary between the Devonian and the Lower Carboniferous, making the lower actinopterygians preserved at this site important. The taxonomic history of previously described Albert shale formation actinopterygians is reviewed here. Many of the earliest described actinopterygian taxa from the Albert Formation are represented by poorly preserved type specimens and have the distinction of being moved from one paraphyletic genus to another paraphyletic genus. While these taxa are in need of major redescriptions, such …

Comparative Transcriptomics Of Elasmobranchs And Teleosts Highlight Important Processes In Adaptive Immunity And Regional Endothermy, Nicholas J. Marra, Vincent P. Richards, Angela Early, Steve M. Bogdanowicz, Paulina D. Pavinski Bitar, Michael J. Stanhope, Mahmood S. Shivji

Biology Faculty Articles

Background: Comparative genomic and/or transcriptomic analyses involving elasmobranchs remain limited, with genome level comparisons of the elasmobranch immune system to that of higher vertebrates, non-existent. This paper reports a comparative RNA-seq analysis of heart tissue from seven species, including four elasmobranchs and three teleosts, focusing on immunity, but concomitantly seeking to identify genetic similarities shared by the two lamnid sharks and the single billfish in our study, which could be linked to convergent evolution of regional endothermy.

Results: Across seven species, we identified an average of 10,877 Swiss-Prot annotated genes from an average of 32,474 open reading frames within each …

Feeding Habits And Dietary Overlap Of Age-0 Winter Flounder (Pseudopleuronectes Americanus) And Summer Flounder (Paralichthys Dentatus) In Southern New England Tidal Rivers, David L. Taylor, Carissa L. Gervasi

Arts & Sciences Faculty Publications

Age-0 winter flounder (Pseudopleuronectes americanus; 20-90 mm in total length [TL]) and summer flounder (Paralichthys dentatus; 19-172 mm TL) were collected from the Seekonk and Taunton Rivers (in Rhode Island and Massachusetts, respectively) from May through September during 2009-2015, and stomach content analysis was used to assess diet composition and resource overlap for these species. Winter and summer flounder underwent ontogenetic dietary shifts. Winter flounder < 40 mm TL predominantly fed on copepods, transitioning to amphipods, isopods, and bivalves with increasing size. Polychaetes also were consumed frequently by winter flounder, irrespective of size. The principal prey of summer flounder < 60 mm TL were mysid shrimp and copepods, whereas sand shrimp (Crangon septemspinosa), amphipods, and fish were the dominant prey of larger conspecifics. There was minimal dietary overlap for the flounder species when comparisons were made independent of body size, indicating food niche segregation. For winter and summer flounder of equivalent sizes, however, dietary overlap was inversely related to TL. Moderate to high resource overlap occurred for small winter and summer flounder (< 40 mm TL) and was attributed to their mutual reliance on copepods and amphipods. Despite evidence of dietary overlap, it is unlikely that shared prey resources were diminished enough to negatively affect either flounder species.

Comparative Postembryonic Skeletal Ontogeny In Two Sister Lineages Of Old World Tree Frogs (Rhacophoridae: Taruga, Polypedates), Gayani Senevirathne, Ryan R. Kerney, Madhava Meegaskumbura

Biology Faculty Publications

Rhacophoridae, a family of morphologically cryptic frogs, with many genetically distinct evolutionary lineages, is understudied with respect to skeletal morphology, life history traits and skeletal ontogeny. Here we analyze two species each from two sister lineages, Taruga and Polypedates, and compare their postembryonic skeletal ontogeny, larval chondrocrania and adult osteology in the context of a well-resolved phylogeny. We further compare these ontogenetic traits with the direct-developing Pseudophilautus silus. For each species, we differentially stained a nearly complete developmental series of tadpoles from early postembryonic stages through metamorphosis to determine the intraspecific and interspecific differences of cranial and postcranial …

Fisheries Management Paper No.283 - Abalone Resource Of Western Australia Harvest Strategy 2106 - 2021, Department Of Fisheries Western Australia

Fisheries Management Papers

Harvest strategies for aquatic resources managed by the Western Australian Department of Fisheries (the Department) are formal documents prepared to support the decision-making processes required to ensure the management of these resources are consistent with the principles of Ecologically Sustainable Development (ESD). The objectives of ESD are reflected in the objects of the Fish Resources Management Act 1994 (FRMA) and Section 9 of the Aquatic Resources Management Act, which will replace the FRMA once proclaimed.

The publication of these strategies is intended to make the decision-making considerations and processes for the management of specified aquatic resources publicly transparent and provide …

Mechanical Properties Of Sediment Determine Burrowing Success And Influence Distribution Of Two Lugworm Species, R. L. Crane, Rachel Merz

Biology Faculty Works

We apply new perspectives on how organisms burrow by examining the association of in situ variation in sediment mechanical properties with burrowing ability and species distribution of two sympatric lugworms, Abarenicola pacifica and Abarenicola claparedi. We quantified the sediment's resistance to penetration and its grain size distribution at sites inhabited by each species. Abarenicola pacifica individuals were found in significantly harder to penetrate, more heterogeneous sediments. We compared worm burrowing ability using reciprocal transplant experiments. Worms from firmer sediments, A. pacifica, were able to make successful steep burrows in sediments characteristic of either species. In contrast, A. claparedi individuals often …