Nathan Ruhl

Rowan University · Department of Biological & Biomedical Sciences

Zebrafish are an established model organism in developmental and behavioral neuroscience, also recently emerging as an excellent model to study social behavior. Zebrafish are highly social, forming groups (shoals) with structured social relationships, dominance hierarchies and overt territoriality. Moreover, social behavior in zebrafish exhibits co...

Cyanobacterial Harmful Algal Blooms (CHABs) in lentic waterbodies are becoming increasingly common because of climate change, changes in water usage and eutrophication. This study provides observational evidence that CHAB formation in a small Ohio reservoir (Lake Hope) is associated with metalimnetic disturbance during the summer months. Disturbanc...

Background Categorization of topographical features into landform type is a long-standing method for understanding physiographic patterns in the environment. Differences in forest composition between landform types are driven primarily by concurrent differences in soil composition and moisture, but also disturbance regime. Many studies have focused...

Zooplankton exported from lentic systems provision lotic systems with easily captured, consumed, and assimilated prey items. Previous studies have demonstrated that the community composition of zooplankton exports (CCZE) vary over time, which introduces temporal differences in lotic resource availability (zooplankton prey) in downstream habitats. I...

Aggression is a psychological construct that is commonly used to classify zebrafish behavior. Aggression is a complex trait that can be difficult to accurately measure. The literature on fish behavior describes many different methodologies to examine aggression, which, we believe, have not been compared in a formal manner. In this study we observed...

Damming a stream inserts a lentic system (an impoundment or reservoir) into a lotic system, changing downstream hydrological, biogeochemical, and ecological processes. One such ecological effect of damming is to create a resource subsidy of easily captured and consumed zooplankton, which are preyed upon by filter-feeders and visual predators. In th...

The discovery of frog abnormalities by students on a school field trip in 1995 sparked hundreds of scientific studies in search of the cause of abnormality. This Socio-Scientific Issue has been used as an inquiry-based learning exercise for training in the practice of science, but it is also well-suited to teaching the nature of science. Our goal h...

As higher education undergoes rapid and fundamental change, eco‐educators need to be prepared to promote the inclusion of the ecological sciences in the biological sciences curriculum of the future. Here, we present an instructional alignment for an introductory ecology course, which is informed by and integrated with the Four‐Dimensional Ecology E...

The frog abnormalities phenomenon was first discovered by students on a field trip in 1995 and their discovery sparked hundreds of scientific studies. This discovery has been integrated into the curriculum of thousands of students as a way to learn the scientific method, but the frog abnormality phenomenon is also well suited as a socio-scientific...

Introduction: A bag valve mask (BVM) is a life saving device used by all levels of health care professionals during resuscitative care. We focus most of our time optimizing the patient's position, firmly securing the mask, and frequency of ventilations. However, despite our best efforts to control these factors, we may still be precipitating harm...

Zooplankton exported from reservoirs are an understudied food resource for downstream communities, especially when the watershed contains multiple connected reservoirs. Previous work has linked atmospheric conditions to the Community Composition of Zooplankton Exports (CCZE) from a polymictic reservoir. In this study we investigate how the Density...

Non-scholarly sources of information (e.g., non-peer reviewed popular press and mass-media articles) have been shown to shape individual opinions about global climate change (GCC) and subsequently reinforce those opinions by isolating individuals from dissenting viewpoints. The diversity of non-scholarly material surrounding the public GCC debate p...

A behavioral syndrome is considered present when individuals consistently express correlated behaviors across two or more axes of behavior. These axes of behavior are shy-bold, exploration-avoidance, activity, aggression, and sociability. In this study we examined aggression, boldness and sociability (shoaling) within a juvenile convict cichlid bro...

Reservoirs possess gradients in conditions and resources along their long (deep-shallow) axis, but the response of littoral vertebrates (fish and turtles) to these gradients is poorly understood. We have quantified the littoral vertebrate communities throughout a small reservoir in Southeastern Ohio during July and August using traps, and related c...

Reservoirs exhibit gradients in conditions and resources along the transition from lotic to lentic habitat that may be important to bluegill ecology. The lotic-lentic gradient can be partitioned into three functional zones: the riverine, transitional, and lacustrine zones. We measured catch frequency and length of bluegills (Lepomis macrochirus) ca...

My perspective of the lentic-lotic gradient is based primarily on the concept that estuaries and reservoirs possess a variety of strong environmental gradients as a result of the confluence of lotic water with more lentic water. Furthering the understanding of how aquatic organisms respond to fluctuating resources and conditions along the lotic-len...

While many behavioural syndrome studies focus on individual-level correlations of behaviors across various contexts, it is also possible to examine these syndromes on a population level, comparing various species or groups. In this study we tested wild type zebrafish (Danio rerio), longfin zebrafish (Danio rerio lof mutants) and the closely related...

Fish typically choose shoalmates with similar phenotypic characteristics to themselves, thus creating shoals for which predators have difficulty identifying and attacking one specific individual. And while shoaling should provide similar anti-predator benefits to both males and females, the two sexes do not always make the same shoaling decisions....

Owing to a lack of basic information on the biology of zebrafish (Danio rerio), lab managers must often base decisions regarding the care and use of this species on anecdotal information. In an effort to provide researchers with context-specific behavioral information, the authors evaluated shoaling and spawning behaviors in small groups of zebrafi...

Heterospecific grouping behavior of mummichogs (Fundulus heteroclitus) and banded killifish (Fundulus diaphanus) was analyzed in the laboratory and in a freshwater tidal marsh in Cremona, Maryland. Several parameters of wild, intact shoals were measured, including species composition, body length, parasite load, gender, and any physical abnormaliti...

The Linesville spillway of Pymatuning State Park is one of the most visited tourist attractions in Pennsylvania, USA, averaging more than 450,000 visitors . year(-1). Carp (Cyprinus carpio Linnaeus) and waterfowl congregate at the spillway where they are fed bread and other foods by park visitors. We hypothesized that the "breadthrowers" constitute...

Male and female zebra fish Danio rerio were given choices of shoals that differed in sex and size. Male zebra fish preferred to associate with female shoals over male shoals, but had no preference when given a choice between a mixed-sex shoal and either a male or female shoal. Female zebra fish showed no significant preference when given a choice b...

Thesis (M.S.)--Saint Joseph's University, 2005. Includes bibliographical references.