Intra-annual variability of phytoplankton biomass and nutrients in a tropical estuary during a severe drought

Seagrass and rhodolith beds are important seascapes for the development of fish eggs and larvae in tropical coastal areas

“…Seagrass beds may also act as important areas of ecological and genetic connectivity between mangroves, rhodolith beds, and marginal coral reefs (Soares et al, 2017;Soares, 2020), influencing the survival of juvenile fish and increasing the abundance of reef species (Unsworth et al, 2008;Eggertsen et al, 2017;Mota et al, 2017). The number of families common to both seascapes suggests physical and ecological connectivity between the seagrass and rhodolith beds, which is an important finding for these seascapes, given their proximity to key areas, such as shallow and hypersaline estuaries with mangrove forests (Barroso et al, 2018) (Fig. 1).…”

Non-indigenous upside-down jellyfish Cassiopea andromeda in shrimp farms (Brazil)

“…The study area is located in the Brazilian Equatorial Margin (Figure 1), western equatorial Atlantic Ocean, under oligotrophic conditions and a semiarid climate. In this area, the rainfall pattern is defined by two seasons: rainy (January to May) and dry (June to December) (Barroso et al, 2018), with low intra-annual and interannual variation in sea temperature (26-30° C) (Soares et al, 2019).…”

“…Moreover, the study area is of special interest owing to the occurrence of an easterly flowing equatorial current that links the western equatorial Atlantic and the Amazon coast at this tropical latitude (Soares et al, 2017). The shrimp farms are generally found in coastal areas (Queiroz et al, 2013), where there are shallow and hypersaline estuaries characterized by freshwater-deprived conditions (e.g., multiple dams and severe droughts) and mangrove forests (Barroso et al, 2018).…”

“…The estuarine environments have a wide range of salinity profiles due to the influx of freshwater and tidal action (Azhikodan and Yokoyama, 2016). However, the studied shallow-water estuary is located on the equatorial coast and has thermal stability (ranging from 26-30°C) (Soares et al, 2019) and sometimes, the higher salinities of the hypersaline estuaries (Barroso et al, 2018), which favor the occurrence of Cassiopea andromeda. In addition, there is a large amount of food available for both the pelagic and benthic fauna in this estuarine area due to the high levels of organic matter and phytoplankton productivity (Barroso et al, 2018).…”

Analysis of a hypersaline drought-prone estuary reveals low density and diversity of fish eggs and larvae

“…Hypersaline conditions expose aquatic biota, such as fish eggs and larvae, to osmotic stress and metabolic changes that affect their temporal and spatial distribution as well as survival rates (Tweedley et al, 2019;Whitfield et al, 2006). Furthermore, increased salinity is an important factor that can simplify the estuarine communities, select stress-tolerant species (Barroso et al, 2018), and reduce the overall abundance and diversity of organisms (Cyrus et al, 2010;Carrasco and Perissinotto, 2012;Rosa et al, 2016;Sloterdijk et al, 2017).…”