Abstract. Mangrove forests are extremely productive ecosystems, are
sources and sinks of organic carbon, and provide essential services both to
the marine environment and people. We have studied the composition and
species richness of modern benthic foraminiferal assemblages from mangrove
swamps along the Mamanguape River in Paraíba, northern Brazil. Sampling
points for foraminifera were selected to acquire information on the
composition of foraminiferal assemblages from dense mangrove stands
collected along a river transect. Almost 100 species of benthic foraminifera
were identified within the shallow mangrove habitats. The large number of
identified mangrove taxa is the highest recorded so far for true mangrove
habitats. The high species richness rivals shallow-water assemblages
recorded from nearby offshore and reef environments and indicates that a
particularly large number of species is capable of growing and flourishing under
multiple stressor conditions. Numerical analysis of the faunal
assemblages shows that specific taxa, which were previously known to be
uncommon in mangrove environments, are abundant in the Mamanguape River
estuary. The atypical foraminiferal fauna found in the Mamanguape River
estuary resembles shallow-water offshore assemblages, is characterized by
high percent abundances of perforate and miliolid taxa, and contains only
very few of the otherwise typical and numerically abundant agglutinated
mangrove taxa. The unusual structure of the assemblages recorded provides
insight into what combination of environmental variables controls their
composition and novel perspectives to reconstruct past mangrove
environments. Distribution, diversity, and species-specific analysis will
provide guidance on the use of Brazilian mangrove foraminifera as indicators
for the strength of tidal activity, pollution, and anoxia in coastal waters
and sea-level reconstructions.
INTERACTIONS OF DIURNAL AND TIDAL RHYTHMS IN THE FIDDLER CRAB, UCA PUGNAX
