First record of red macroalgae bloom in Southern Atlantic Brazil

Abstract

Blooms of macroalgae have grown over the planet in recent decades as a possible result of eutrophication of coastal waters. Visually, a bloom forming can be identified by dominant presence of an organism at the expense of others. In mid-January 2014, a forming bloom of red algae was detected on the beach of Garopaba, Santa Catarina State, Brazil. This aroused the interest of tourists and locals as well as the scientific community. Thus, the objective of this study was to characterize and quantify the photosynthetic floating organisms contributing to this phenomenon. In addition, we qualitatively compared algal composition of the bloom to those deposited in the post-beach area and the adjacent rocky shore community. Five sampling points in random patches of floating material were defined. At each point, five replicates were taken with a cube of 32,768 cm 3 , resulting in a total of 25 samples. Samples were collected in the inner area enclosed by a PVC quadrate of about 900 cm² from the shore and the specimens found in post-beach zone (wrack). Twenty-four taxa of macroalgae were found in the bloom, with Aglaothamnion uruguayense as the dominance one. Ten taxa were found on shore. Only four taxa were found in the post-beach area. The biomass estimated for A. uruguayense in the floating material was 8.35 tons with an estimated area of 52,770 m 2 . It is possible that this huge biomass value of the bloom is related to the local nutrient intake, and our results reinforce the necessity of coastal integrative management initiatives.

Human Health and Ocean Pollution

“…In these blooms, the great masses of algae that have accumulated in an area of the sea exhaust inorganic nutrients in the water column allowing bacteria move in and decompose the senescing organic material. The consequences are reduced dissolved oxygen in the ocean, dead zones, fish kills, and a broad range of adverse ecological impacts [ 321 322 323 ] (Figure 9 ).…”

The oceans are changing: impact of ocean warming and acidification on biofouling communities

“…Similarly, in January-February 2014 extremely high ocean temperatures on the Atlantic coast of Brazil stimulated the largest algal bloom in the country's history. The bloom was composed of several species with the red alga Aglaothamnion uruguayense being the most abundant (Martins et al 2016 in the Persian Gulf, an algal bloom of the dinoflagellate Margalefidinium (Cochlodinium) polycricoides probably brought by ballast waters caused high mortality among benthic animals and fishes (Richlen et al 2010) and dramatically decreased biomass of biofouling communities (Dobretsov 2015). These examples suggest that algal bloom conditions are becoming the norm for most populated coastal regions and their impact on benthic and fouling community ecosystems will intensify in the warming oceans.…”