Nutrient recycling by fish can be an important part of nutrient cycles in both freshwater and marine ecosystems. As a result, understanding the mechanisms that influence excretion elemental ratios of fish is of great importance to a complete understanding of aquatic nutrient cycles. As fish consume a wide range of diets that differ in elemental composition, stoichiometric theory can inform predictions about dietary effects on excretion ratios.
We conducted a meta-analysis to test the effects of diet elemental composition on consumption and nutrient excretion by fish. We examined the relationship between consumption rate and diet N : P across all laboratory studies and calculated effect sizes for each excretion metric to test for significant effects.
Consumption rate of N, but not P, was significantly negatively affected by diet N : P. Effect sizes of diet elemental composition on consumption-specific excretion N, P and N : P in laboratory studies were all significantly different from 0, but effect size for raw excretion N : P was not significantly different from zero in laboratory or field surveys.
Our results highlight the importance of having a mechanistic understanding of the drivers of consumer excretion rates and ratios. We suggest that more research is needed on how consumption and assimilation efficiency vary with N : P and in natural ecosystems in order to further understand mechanistic processes in consumer-driven nutrient recycling.
Grasshoppers Regulate N: P Stoichiometric Homeostasis by Changing Phosphorus Contents in Their Frass
According to the National Institute on Deafness and other Communication Disorders (NIDCD), approximately 37 million Americans suffer from some degree of hearing loss, which impacts their ability to communicate fluently with the hearing world. This number includes up to 17% of the adult population, many who have experienced post-lingual or late-deafness. While hearing loss is known to be one of the most prevalent chronically disabling sensory conditions, little is known about the impact it has on individuals’ cultural identity and sense of well-being. There is somewhat of a deficit in the research literature addressing these issues of cultural identity, especially as it relates to post-lingually deaf adults. Improved knowledge of these dimensions of hearing loss is needed—a knowledge which could lead to more effective resources for late-deafened people. Though hearing loss can be disabling, access to American Sign Language and the Deaf culture may compensate for social and cultural loss and potentially improve well-being within late-deafened individuals. Using the framework of Social Identity Theory and Neil Glickman’s Deaf Identity Development model, this study sought to identify late-deafened adults who fall into the marginal category, placing them at greater risk of becoming socially marginalized and experiencing diminished well-being. Subjective well-being was then measured by the Flourishing Scale to determine how being socially marginal may impact one’s sense of self, personal prosperity, social efficacy, and sense of social competency. Results showed that marginal individuals do experience diminished subjective well-being, a fact which should be further explored by researchers, especially in the context of developing more effective interventions and services for late-deafened individuals.