Final technical report for NSF grant #OCE 75-20241, entitled Identification and role of the ultraplankton of the lower Chesapeake Bay region

Numbers and species identities of the most dominant small (\u3c15μm) photosynthetic Plankton were determined from samples of lower Chesapeake Bay water. The data is being compared to physical and chemical measurements of the Bay waters in an effort to determine conditions which encourage or inhibit growth of the organisms. Pure cultures of some of the more common species have been established and are being used to evaluate the roles of the organisms in terms of photosynthetic rates and utilization and excretion of nitrogen compounds

Biomass and nutrient flux measurements on Holothuria atra populations on windward reef flats at Enewetak, Marshall Islands

A population survey of the holothurian, Holothuria atra, on the interisland coral reefs of Enewetak revealed average animal densities of about 3 animals m-2 in the zone of small coral heads, Median fresh weighy was 60 g, The size distribution of these animals was negatively correlated with water velocity along the reef. Ammonia release rates for three species of holothurians, H. atra, H. difficilus and Actinopyga mauritina were weight specific, The release of annnonia by H. atra on Transect II was equivalent to 9% of the total amnnonia exported from the reef proper. The release of phosphorus followed the general rules set for size - metabolism relationships. Nitrogen/phosphorus release ratios are 25:1 for 1 gram fresh weight animals and 42:1 for 60 gram animals, Urea is also releasedhttps://scholarworks.wm.edu/vimsbooks/1138/thumbnail.jp

Household-level factors associated with relapse following discharge from treatment for moderate acute malnutrition

AbstractFactors associated with relapse among children who are discharged after reaching a threshold denoted ‘recovered’ from moderate acute malnutrition (MAM) are not well understood. The aim of this study was to identify factors associated with sustained recovery, defined as maintaining a mid-upper-arm circumference≥12·5 cm for 1 year after release from treatment. On the basis of an observational study design, we analysed data from an in-depth household (HH) survey on a sub-sample of participants within a larger cluster randomised controlled trial (cRCT) that followed up children for 1 year after recovery from MAM. Out of 1497 children participating in the cRCT, a subset of 315 children participated in this sub-study. Accounting for other factors, HH with fitted lids on water storage containers (P=0·004) was a significant predictor of sustained recovery. In addition, sustained recovery was better among children whose caregivers were observed to have clean hands (P=0·053) and in HH using an improved sanitation facility (P=0·083). By contrast, socio-economic status and infant and young child feeding practices at the time of discharge and HH food security throughout the follow-up period were not significant. Given these results, we hypothesise that improved water, sanitation and hygiene conditions in tandem with management of MAM through supplemental feeding programmes have the possibility to decrease relapse following recovery from MAM. Furthermore, the absence of associations between relapse and nearly all HH-level factors indicates that the causal factors of relapse may be related mostly to the child’s individual, underlying health and nutrition status.</jats:p

Impacts of human hunting on spatial behavior of white-tailed deer (Odocoileus virginianus)

This study was funded by The Samuel Roberts Noble Foundation, Inc., and the Department of Wildlife, Fisheries and Aquaculture at Mississippi State University.Predators can influence populations through top-down effects, but most large predators have been extirpated from the white-tailed deer’s (Odocoileus virginianus) range. Hunters have filled this predatory role, but also can indirectly influence prey species. Indirect behavioral responses can include altered resource selection, space use, or movement patterns. Herein, we developed a controlled study that contained both temporal and spatial risk levels to assess how deer behavior changes in space relative to temporal periods of risk. Total distance travelled (m) and micro-range area (m²) were calculated over two-day periods to determine the general effects of hunting season on deer spatial behavior. Generally, distance travelled, micro-range area, and exploratory behavior decreased during the course of the study, with the greatest decrease occurring during the active 16-day hunting period. Despite potential risk and disturbance from hunters, deer maintained site fidelity to previously established ranges and did not expand micro-range areas. These data indicate that deer recognize threats from humans on the landscape and adapt behavioral strategies by minimizing movement and exhibiting high residency times in well-established ranges, factors known to influence harvest susceptibility. This information can be used to assess potential impacts from hunting for management purposes, but also to test the adaptive ability of animals to risk.Publisher PDFPeer reviewe

The Functional ecology of submerged aquatic vegetation in the lower Chesapeake Bay

The research program, The Functional Ecology of Submerged Aquatic Vegetation in the Lower Chesapeake Bay (EPA/CBP Grant No. R805974), is an integrative effort composed of seven principal investigators. The research team has worked since July 1978 at one study site, the Vaucluse Shores area, to develop and institute a coherent research program on SAV ecological relationships. The principal studies have focused on plant productivity, metabolism and nutrient cycling, the role of resident consumers in SAV community dynamics, the role of migratory species and efforts to develop a realistic, ecosystem simulation model of SAV communities. The preliminary results of the first years study in these research areas are contained in the following report. Many interpretations remain preliminary at this time. We welcome comments and criticisms and in particular ideas concerning data interpretation. Questions concerning specific aspects of the various sections should be addressed to the following: 1. Productivity, Metabolism and Nutrient Cycling; R. L. Wetzel 2. Resident Consumers; R. J. Orth 3. Migratory Consumers; J. V. Merriner 4. Ecosystem Modelling; R. L. Wetze

Does Human Predation Risk Affect Harvest Susceptibility of White-Tailed Deer During Hunting Season?

Large carnivores are considered a primary source of mortality for many ungulate populations, but harvest by hunters is the primary means of population management. However, research is needed to evaluate how human predation risk influences observability (a surrogate to harvest susceptibility) of ungulates. We determined how hunting intensity and duration influence observation rates of white-tailed deer (Odocoileus virginianus) and how deer behavior (i.e., movement rate and resource selection) affects observation rates. We sampled 37 adult (≥2 yr) male deer at 2 levels of risk (i.e., low-risk = 1 hunter/101 ha; and high-risk = 1 hunter/30 ha) during 3 exposure periods (i.e., first, second, and third weekend of hunting) on a 1,861-ha property in Oklahoma, USA, during the 2008 and 2009 rifle deer-seasons. Observation rates (collared deer/hunter-hr/day) were greatest during the first weekend in both the low- and high-risk treatments, but declined each weekend thereafter in both treatments. Immediately prior to hunter observation, movement rate of observed collared deer was greater than that of unobserved collared deer, but only when hunting risk was high. Greater movement rates of deer in the high-risk treatment also led to a greater probability of observation. Hunters also had a greater probability of observing collared deer at higher elevations. Overall, deer modified their behavior to avoid detection by hunters. These results can be used to explain decreased observation rates to hunters and to modify harvest rates by altering timing and intensity of human predation risk during the recreational hunting season to help achieve population management goals through harvest

Classic flea-borne transmission does not drive plague epizootics in prairie dogs

We lack a clear understanding of the enzootic maintenance of the bacterium (Yersinia pestis) that causes plague and the sporadic epizootics that occur in its natural rodent hosts. A key to elucidating these epidemiological dynamics is determining the dominant transmission routes of plague. Plague can be acquired from the bites of infectious fleas (which is generally considered to occur via a blocked flea vector), inhalation of infectious respiratory droplets, or contact with a short-term infectious reservoir. We present results from a plague modeling approach that includes transmission from all three sources of infection simultaneously and uses sensitivity analysis to determine their relative importance. Our model is completely parameterized by using data from the literature and our own field studies of plague in the black-tailed prairie dog (Cynomys ludovicianus). Results of the model are qualitatively and quantitatively consistent with independent data from our field sites. Although infectious fleas might be an important source of infection and transmission via blocked fleas is a dominant paradigm in the literature, our model clearly predicts that this form of transmission cannot drive epizootics in prairie dogs. Rather, a short-term reservoir is required for epizootic dynamics. Several short-term reservoirs have the potential to affect the prairie dog system. Our model predictions of the residence time of the shortterm reservoir suggest that other small mammals, infectious prairie dog carcasses, fleas that transmit plague without blockage of the digestive tract, or some combination of these three are the most likely of the candidate infectious reservoirs. disease modeling ͉ disease reservoir ͉ Yersinia pestis ͉ Cynomys ludovicianu

Acute White Matter Integrity Post-trauma and Prospective Posttraumatic Stress Disorder Symptoms

Background: Little is known about what distinguishes those who are resilient after trauma from those at risk for developing posttraumatic stress disorder (PTSD). Previous work indicates white matter integrity may be a useful biomarker in predicting PTSD. Research has shown changes in the integrity of three white matter tracts—the cingulum bundle, corpus callosum (CC), and uncinate fasciculus (UNC)—in the aftermath of trauma relate to PTSD symptoms. However, few have examined the predictive utility of white matter integrity in the acute aftermath of trauma to predict prospective PTSD symptom severity in a mixed traumatic injury sample. Method: Thus, the current study investigated acute brain structural integrity in 148 individuals being treated for traumatic injuries in the Emergency Department of a Level 1 trauma center. Participants underwent diffusion-weighted magnetic resonance imaging 2 weeks post-trauma and completed several self-report measures at 2-weeks (T1) and 6 months (T2), including the Clinician Administered PTSD Scale for DSM-V (CAPS-5), post-injury. Results: Consistent with previous work, T1 lesser anterior cingulum fractional anisotropy (FA) was marginally related to greater T2 total PTSD symptoms. No other white matter tracts were related to PTSD symptoms. Conclusions: Results demonstrate that in a traumatically injured sample with predominantly subclinical PTSD symptoms at T2, acute white matter integrity after trauma is not robustly related to the development of chronic PTSD symptoms. These findings suggest the timing of evaluating white matter integrity and PTSD is important as white matter differences may not be apparent in the acute period after injury

Acute posterior cingulum integrity post-trauma prospectively predicts depression but not PTSD symptoms

Background: Little is known about what distinguishes those who are resilient after trauma from those at risk for developing posttraumatic stress disorder (PTSD). Previous work indicates white matter integrity may be a useful biomarker in predicting PTSD. Research has shown changes in the integrity of three white matter tracts—the cingulum bundle, corpus callosum (CC), and uncinate fasciculus (UNC)—in the aftermath of trauma relate to PTSD symptoms. However, few have examined the predictive utility of white matter integrity in the acute aftermath of trauma to predict prospective PTSD symptom severity in a mixed traumatic injury sample. Method: Thus, the current study investigated acute brain structural integrity in 148 individuals being treated for traumatic injuries in the Emergency Department of a Level 1 trauma center. Participants underwent diffusion-weighted magnetic resonance imaging 2 weeks post-trauma and completed several self-report measures at 2-weeks (T1) and 6 months (T2), including the Clinician Administered PTSD Scale for DSM-V (CAPS-5), post-injury. Results: Consistent with previous work, T1 lesser anterior cingulum fractional anisotropy (FA) was marginally related to greater T2 total PTSD symptoms. No other white matter tracts were related to PTSD symptoms. Conclusions: Results demonstrate that in a traumatically injured sample with predominantly subclinical PTSD symptoms at T2, acute white matter integrity after trauma is not robustly related to the development of chronic PTSD symptoms. These findings suggest the timing of evaluating white matter integrity and PTSD is important as white matter differences may not be apparent in the acute period after injury