Climate forcing on estuarine zooplanktonic production.

Estuaries are among the most valuable aquatic systems in the world and resolving how there are impacted by climate change is fundamental to their management under global change scenarios. In this study, a ten-year time series (2003-2013) of zooplankton in an estuarine area (Mondego estuary, Portugal) is used to determine the impact of climate variability on estuarine zooplanktonic secondary production. For that, a trend analysis of seasonal zooplankton production was applied and their link with large-scale, regional, and local environment was tested by Distance-based multivariate multiple regression (DistLM). The annual integrated production of zooplankton varied between 34.27 mg C m-3 (2003) and 179.804 mg C m-3 (2013). Results showed that estuarine and marine zooplanktonic production increased in the estuary, mostly during summer/autumn and spring/summer, respectively. Local and regional environmental forcing drove copepod production in the estuary, with large-scale regime shifts affecting both directly and indirectly.

Function of estuaries and coastal areas as nursery grounds for marine fish early life stages.

The present study describes the larval and juvenile fish fauna of an estuary and its adjacent coastal area (Mondego estuary, Northwest coast of Portugal) and evaluates their function as nurseries for marine fish. For this, larvae and juveniles were sampled in both systems. The temporal and spatial patterns of the ichthyoplankton community were described for each system and related to the influence of environmental factors. Additionally, the recruitment pattern was evaluated based on the composition of juveniles. Results show a seasonal variation of larval density and community structure between and within systems, indicating a degree of segregation according to their ecological functional classification. Temperature was the most important environmental factor structuring the communities. The juvenile recruitment patterns observed show a different nursery function of the estuary and coastal area for early life stages of different species, reinforcing the need to integrate larval and juvenile stages to better understand fish life cycles and the connectivity between systems.