Structure and temporal dynamic of tropical turf-forming macroalgal assemblages of the western coast of Mexico

The study of the structure and dynamics of assemblages of benthic organisms has gained interest in recent decades because it can account for the influence of anthropogenic activities in the coastal zone and be incorporated into management and conservation plans. The region of Zihuatanejo, Mexico, has had an accelerated and unplanned urban development, negatively affecting coastal communities. However, studies on the structure and dynamics of algal assemblages, as well as some of the predominant physical factors in this region are scarce. The objective of this research was to carry out a preliminary study on the structure of macroalgal assemblages and their spatio-temporal variation in a depositional environment. The work was realized from June 2006 to December 2008 collecting randomly macroalgal samples and placing sediment traps on the bottom to characterize the deposition environment. The subtidal algal assemblages of the studied localities were predominantly turfs. The Detendred Correspondence Analysis showed that each locality had a particular species composition. The highest biomass was 37.82 +/- 12.90 g dw m(-2) and the lowest of 0-7.86 g dw m(-2). The highest total sedimentation rate was 1818.10 +/- 82.11 g dw m(-2) day(-1) and the lowest was 58.82 +/- 8.75 g dw m(-2) day(-1). Significant differences were found in calcareous and articulated biomass, as well as in fine, coarse and total sedimentation rates among localities. The results obtained provide a basis for further research on the effects of sedimentation on the subtidal macroalgae assemblages of the study region.