The Lagoon Region and Estuary Ecosystem of Cananeia, Brazil
125
waters has its origin in the mixing processes of coastal waters with nutrient-enriched waters of the lagoon region. Rainfall, solar radiation, and
high summer temperatures are the main forcing functions.
Copepods, like the dominant Oithona hebes, Acartia lilljeborghi, Pseudodiaptomus acutus, Euterpina acutifrons, Paracalamus crassirostris,
Oithona oswaldocruzi, Acartia tonsa, and Temora turbinata, are principal
component (68-97 %) of the zooplankton community (Tundisi 1972;
Fonseca and Bjornberg 1976; Fonseca and Almeida Prado 1979; Almeida
Prado and Lansac Toha 1984; Almeida Prado et al. 1989; Ara 1998). The
distribution of several zooplankton species and larvae is strongly effected
by salinity. The vertical migration of the salinity-tolerant copepod Pseudodiaptomus acutus towards the bottom, followed by tidal transport to
upper reaches of the estuary where reproductive populations thrive under
optimal conditions in backwaters of mangrove channels (Tundisi and
Matsumura-Tundisi 1968), proved to be a paradigm for the behavior and
distribution of estuarine zooplankton in temperate and tropical regions
(Rodriguez 1975). As for phytoplankton, standing stock values of zooplankton, with a minimum in the winter (July-August), tend to be higher
in the lagoon region than in coastal waters. Daily production of copepods
ranges from 2.08 to 44.76mg C m- 3 day- 1 •
9.3.3 Benthic Community
Among the 73 taxa, mainly Annelida, Crustacea, and Mollusca (Jorcin 1997),
polychaetes dominate in number of species and individuals, Loadalia
americana, Laonice japonica, Clymene sp., and Clymenella sp. being the
most common species (Tommasi 1970). The distribution and abundance
of macro benthic fauna is related to the nature of the substrate and physicochemical variables, with highest density and richness occurring in the
upper 5 em of Trapande Bay. The almost permanent influence of coastal
water and elevated nutrient and organic matter concentrations are likely to
favor elevated standing stock and diversity of benthic fauna (Jorcin 1997).
Inside the estuarine-lagoon complex, muddy bottoms display a poorer epifauna and only on infralittoral stone bottoms a rich epifauna of hydroids
(i.e., Eudendrium carneum, Ophiotrix angulata) and amp hi pods occurs.
Freshwater components, such as Insecta and Naididae (Oligochaeta), are
found in the upper reaches of the estuary. The seasonal changes in macrobenthic abundance and diversity are attributed to changes in salinity, redox
potential, sediment granulometry, and organic matter concentrations.
125
waters has its origin in the mixing processes of coastal waters with nutrient-enriched waters of the lagoon region. Rainfall, solar radiation, and
high summer temperatures are the main forcing functions.
Copepods, like the dominant Oithona hebes, Acartia lilljeborghi, Pseudodiaptomus acutus, Euterpina acutifrons, Paracalamus crassirostris,
Oithona oswaldocruzi, Acartia tonsa, and Temora turbinata, are principal
component (68-97 %) of the zooplankton community (Tundisi 1972;
Fonseca and Bjornberg 1976; Fonseca and Almeida Prado 1979; Almeida
Prado and Lansac Toha 1984; Almeida Prado et al. 1989; Ara 1998). The
distribution of several zooplankton species and larvae is strongly effected
by salinity. The vertical migration of the salinity-tolerant copepod Pseudodiaptomus acutus towards the bottom, followed by tidal transport to
upper reaches of the estuary where reproductive populations thrive under
optimal conditions in backwaters of mangrove channels (Tundisi and
Matsumura-Tundisi 1968), proved to be a paradigm for the behavior and
distribution of estuarine zooplankton in temperate and tropical regions
(Rodriguez 1975). As for phytoplankton, standing stock values of zooplankton, with a minimum in the winter (July-August), tend to be higher
in the lagoon region than in coastal waters. Daily production of copepods
ranges from 2.08 to 44.76mg C m- 3 day- 1 •
9.3.3 Benthic Community
Among the 73 taxa, mainly Annelida, Crustacea, and Mollusca (Jorcin 1997),
polychaetes dominate in number of species and individuals, Loadalia
americana, Laonice japonica, Clymene sp., and Clymenella sp. being the
most common species (Tommasi 1970). The distribution and abundance
of macro benthic fauna is related to the nature of the substrate and physicochemical variables, with highest density and richness occurring in the
upper 5 em of Trapande Bay. The almost permanent influence of coastal
water and elevated nutrient and organic matter concentrations are likely to
favor elevated standing stock and diversity of benthic fauna (Jorcin 1997).
Inside the estuarine-lagoon complex, muddy bottoms display a poorer epifauna and only on infralittoral stone bottoms a rich epifauna of hydroids
(i.e., Eudendrium carneum, Ophiotrix angulata) and amp hi pods occurs.
Freshwater components, such as Insecta and Naididae (Oligochaeta), are
found in the upper reaches of the estuary. The seasonal changes in macrobenthic abundance and diversity are attributed to changes in salinity, redox
potential, sediment granulometry, and organic matter concentrations.