Dinoflagellate blooms and physical systems in the Gulf of Maine

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution May 1990Numerous studies have shown dinoflagellate blooms to be closely related to density discontinuities and fronts in the ocean. The spatial and temporal patterns of the dinoflagellate population depend on the predominant mode of physical forcing, and its scales of variability. The present study combined field sampling of hydrographic and biological variables to examine the relationship of dinoflagellate population distributions to physical factors along the southwestern cost of the Gulf of Maine. A bloom of Ceratium longipes occurred along this coast during the month of June, 1987. A simple model which coupled along-isopycnal diffusion with the logistic growth equation suggested that the cells had a growth rate of about 0.1 d-1 , and had reached a steady horizontal across-shelf distribution within about 10 d. Fur~her variations in population density appeared to be related to fluctuations of light with periods of -10 d. To our knowledge, this was the first use of this simple diffusion model as a diagnostic tool for quantifying parameters describing the growth and movement of a specific phytoplankton population. Blooms of the toxic dinoflagellate, Alexandrium tamarense have been nearly annual features along the coasts of southern Maine, New Hampshire and Massachusetts since 1972; however the mechanisms controlling the distribution of cells and concomitant shellfish toxicity are relatively poorly understood. Analysis of field data gathered from April to September, 1987-1989, showed that in two years when toxicity was detected in the southern part of this region, A. tamarense cells were apparently transported into the study area between Portsmouth and Cape Ann, Massachusetts, in a coastally trapped buoyant plume. This plume appears to have been formed off Maine by the outflow from the Androscoggin and Kennebec Rivers. Flow rates of these rivers, hydrographic sections, and satellite images suggest that the plume had a duration of about a month, and extended alongshore for several hundred kilometers. The distribution of cells followed the position of the plume as it was influenced by wind and topography. Thus when winds were downwelling-favourable, cells were moved alongshore to the south, and were held to the coast; when winds were upwelling-favourable, the plume sometimes separated from the coast, advecting the cells offshore. The alongshore advection of toxic cells within a coastally trapped buoyant plume can explain the temporal and spatial patterns of shellfish toxicity along the coast. The general observation of a north-to-south temporal trend of toxicity is consistent with the southward advection of the plume. In 1987 when no plume was present, Alexandrium tamarense cells were scarce, and no toxicity was recorded at the southern stations. A hypothesis was formulated explaining the development and spread of toxic dinoflagellate blooms in this region. This plume-advection hypothesis included: source A. tamarense populations in the north, possibly associated with the Androscoggin and Kennebec estuaries; a relationship between toxicity patterns and river flow volume and timing of flow peaks; and a relationship between wind stresses and the distribution of low salinity water and cells. Predictions of the plume-advection hypothesis were tested with historical records of shellfish toxicity, wind speed and direction, and river flow. The predictions tested included the north-south progression of toxic outbreaks, the occurrence of a peak in river flow prior to the PSP events, the relationship of transit time of PSP toxicity along the coast with river flow volume, and the influence of surface wind stress on the timing and location of shellfish toxicity. All the predictions tested were supported by the historical records. In addition it was found that the plume-advection hypothesis explains many details of the timing and spread of shellfish toxicity, including the sporadic nature of toxic outbreaks south of Massachusetts Bay, and the apparently rare occurrence of toxicity well offshore on Nantucket Shoals and Georges Bank.This research was supported by ONR contract N00014-87-K-0007 and ONR grant N00014-89-J-111 to Donald M. Anderson, and NOAA Office of Sea Grant contract NA86AA-D-SG090

Comparison of pain, cortisol levels, and psychological distress in women undergoing surgical termination of pregnancy under local anaesthesia versus intravenous sedation

<p>Abstract</p> <p>Background</p> <p>The weight of evidence suggests that women who freely choose to terminate a pregnancy are unlikely to experience significant mental health risks, however some studies have documented psychological distress in the form of posttraumatic stress disorder and depression in the aftermath of termination. Choice of anaesthetic has been suggested as a determinant of outcome. This study compared the effects of local anaesthesia and intravenous sedation, administered for elective surgical termination, on outcomes of pain, cortisol, and psychological distress.</p> <p>Methods</p> <p>155 women were recruited from a private abortion clinic and state hospital (mean age: 25.4 ± 6.1 years) and assessed on various symptom domains, using both clinician-administered interviews and self-report measures just prior to termination, immediately post-procedure, and at 1 month and 3 months post-procedure. Morning salivary cortisol assays were collected prior to anaesthesia and termination.</p> <p>Results</p> <p>The group who received local anaesthetic demonstrated higher baseline cortisol levels (mean = 4.7 vs 0.2), more dissociative symptoms immediately post-termination (mean = 14.7 vs 7.3), and higher levels of pain before (mean = 4.9 vs 3.0) and during the procedure (mean = 8.0 vs 4.4). However, in the longer-term (1 and 3 months), there were no significant differences in pain, psychological outcomes (PTSD, depression, self-esteem, state anxiety), or disability between the groups. More than 65% of the variance in PTSD symptoms at 3 months could be explained by baseline PTSD symptom severity and disability, and post-termination dissociative symptoms. Of interest was the finding that pre-procedural cortisol levels were positively correlated with PTSD symptoms at both 1 and 3 months.</p> <p>Conclusion</p> <p>High rates of PTSD characterise women who have undergone surgical abortions (almost one fifth of the sample meet criteria for PTSD), with women who receive local anaesthetic experiencing more severe acute reactions. The choice of anesthetic, however, does not appear to impact on longer-term psychiatric outcomes or functional status.</p

Recommendations for Enhancing Psychosocial Support of NICU Parents through Staff Education and Support

Providing psychosocial support to parents whose infants are hospitalized in the neonatal intensive care unit (NICU) can improve parents’ functioning as well as their relationships with their babies. Yet, few NICUs offer staff education that teaches optimal methods of communication with parents in distress. Limited staff education in how to best provide psychosocial support to families is one factor that may render those who work in the NICU at risk for burnout, compassion fatigue and secondary traumatic stress syndrome. Staff who develop burnout may have further reduced ability to provide effective support to parents and babies. Recommendations for providing NICU staff with education and support are discussed. The goal is to deliver care that exemplifies the belief that providing psychosocial care and support to the family is equal in importance to providing medical care and developmental support to the baby