The light requirements for growth and photosynthesis in seagrasses with emphasis on Texas estuaries : a literature survey

During the last 20 years, seagrass communities throughout the world have experienced decreased productivity and distribution. These declines have often been attributed to decreased water transparency as a result of turbidity or shading by epiphytic algae. Epiphytic shading is often an indication of nutrient enrichment caused by anthropogenic inputs. Although both epiphytes and turbidity occur as natural phenomena, human activities can exacerbate existing natural conditions with adverse effects on seagrass communities. The objectives of this study were (a) to review the existing literature and data available on the effect of natural and anthropogenic factors on the underwater light environment; (b) to examine the relationship between light and seagrass distribution and productivity; and (c) to make recommendations on how to protect seagrass habitats in Texas bays and estuaries. To meet these goals, we have examined the available literature, emphasizing the physiological response of seagrasses to light and temperature. By using data and observations collected on a variety of species from around the world we may be better able to define the light requirements of Texas seagrasses. A knowledge of the minimum annual light requirements for seagrass growth is necessary to maintain the current distribution of Texas species. This information will also be required in the development of a management plan that permits the expansion and establishment of new seagrass habitat.Submitted to United States Environmental Protection Agency, Region 6 ... Dallas, Tx31 July 1993Marine Scienc