Phosphorus enrichment effects on interactions among the ecosystem components in a long-hydroperiod oligotrophic marsh in Everglades National Park

Hydrology and a history of oligotrophy unite the massive landscape comprising freshwater marsh in Everglades National Park. With restoration of water flow to the Everglades, phosphorus (P) enrichment, both from agricultural and domestic sources, may increase nutrient load to the marsh ecosystem. Previous research of P enrichment of Everglades soil, periphyton, and macrophytes revealed each of these ecosystem components responds to increased P loads with increased production and nutrient content. Interactions among these ecosystem components and how P affects the magnitude and direction of interaction are poorly understood and are the focus of my research. Here I present results of a two-year, two-factor experiment of P enrichment and manipulation in Everglades National Park. I quantified biomass, nutrient content, and production for periphyton and macrophyes and found macrophyte removal drives change in nutrient content, biomass, and production of periphyton. Periphyton removal did not appear to control macrophyte dynamics. Soil chemical and physical characteristics were explained primarily by site differences but there was an enrichment effect of soil porewater nitrite + nitrate, nitrite, and soluble reactive phosphorus. Flocculent materials production and depth were significantly affected by macrophyte removal where depth and production were significantly greater with the no macrophyte treatment. The dominant macrophyte of the marsh, Eleocharis cellulosa, increased more in the unenriched marsh than in the enriched marsh. The combination of these findings suggests that dynamics in floc and periphyton are controlled primarily by the presence of periphyton and that this relationship is significantly affected by low-level P enrichment. These results may be valuable in their application to both managers and policy makers who are involved in the Everglades restoration process. ^

Academic achievement orientation of West Indian American parents and adolescents

Literature addressing academic achievement orientation of Black adolescents in the United States often depicts poor school related attitudes and adaptation patterns, low academic achievement, and deficient family backgrounds. However, some researchers maintained that certain Black immigrant groups possessed positive academic achievement orientations and exemplary academic achievements (Ogbu, 1991; Gibson, 1991; Vernez, & Abrahamse, 1996). In this study, I attempted to combine qualitative data from multiple sources (surveys, interviews, observations, literature, and document analysis), using standard case study methodology and the constant comparative method of analysis to understand the relationship that existed between the academic achievement orientation of a select group of West Indian American parents and adolescents in Broward County, Florida. The sub-sample of 11 families, comprising 15 adolescents and 13 parents, was selected through maximum variation sampling from a pool of 23 families. The findings were presented as a single composite case study. The participants possessed specific, longstanding educational and career goals for the children. The parents were deeply involved and were knowledgeable of their children's schools and academic progress. While mothers were the parents most actively involved in the schools, fathers were strong authoritative figures. Families evidenced a strong moral religious base with set rules of behavior, firm parenting practices, and established chains of authority. Family members emphasized education over material things; reading over audiovisual or social activities; family cohesion over individual wishes; and academics over extracurricular activities. The parents' strong positive academic achievement orientation was communicated to the children and reinforced by relatives, family friends, and others. In turn, the adolescents possessed positive school-related attitudes and attributional styles. While they admitted their parents were somewhat strict, they voluntarily complied with the rules and were highly motivated to succeed because they believed their parents deeply cared for them and that education leads to success and upward mobility. Each adolescent was pursuing an academic track and planning for college and specific profession. The findings support Ogbu's cultural ecological model (1991). I recommend these findings to teachers, counselors, administrators, parents, and others working with West Indian American families. ^

Patterns of acculturative stress: Continuity, discontinuity, and adjustment among Latino youth

This study evaluated inter- and intra-individual changes in acculturation, acculturative stress, and adaptation experiences, as well as their associations with adjustment outcomes among a group of Latino adolescents in South Florida. Specifically, the current study investigated the incidence, changes, and effects of stressors that arise from acculturation experiences (e.g., related to culture, discrimination, language difficulties) among Latino youth by employing a person-centered approach and a longitudinal research design. Four separate groups of analyses were conducted to investigate (a) within-group differences in levels of reported acculturative stress, (b) patterns of continuity and discontinuity in levels of acculturative stress across time, (c) adjustment outcomes associated with distinct patterns of acculturative stress within each measurement occasion, and (d) predictive relations between longitudinal acculturative stress trajectories in early adolescence and psychosocial adjustment outcomes in young adulthood. ^ Results from the multivariate analyses indicated great within group heterogeneity in acculturative stress among Latino youth during early adolescence, as well as significant continuity and discontinuity in the patterns of shifts among acculturative stress profiles between contiguous measurement occasions. Within each developmental period, membership in acculturative stress clusters was significantly and differentially associated with multiple adjustment outcomes, suggesting that maladaptive outcomes are more likely to occur among Latino adolescents experiencing high levels of psychological distress across multiple acculturative domains. In general, Latino youth acculturation is best understood as multi-dimensional, to be variable across time, and to be fluid and responsive to multiple factors and influences. Implications for preventive strategies are discussed with regard to acculturation and developmental psychology research literatures. ^