Multiple Evidence for Climate Patterns Influencing Ecosystem Productivity across Spatial Gradients in the Venice Lagoon

Abstract

Effects of climatic changes in transitional ecosystems are often not linear, with some areas likely experiencing faster or more intense responses, which something important to consider in the perspective of climate forecasting. In this study of the Venice lagoon, time series of the past decade were used, and primary productivity was estimated from hourly oxygen data using a published model. Temporal and spatial patterns of water temperature, salinity and productivity time series were identified by applying clustering analysis. Phytoplankton and nutrient data from long-term surveys were correlated to primary productivity model outputs. pmax, the maximum oxygen production rate in a given day, was found to positively correlate with plankton variables measured in surveys. Clustering analysis showed the occurrence of summer heatwaves in 2008, 2013, 2015 and 2018 and three warm prolonged summers (2012, 2017, 2019) coincided with lower summer pmax values. Spatial effects in terms of temperature were found with segregation between confined and open areas, although the patterns varied from year to year. Production and respiration differences showed that the lagoon, despite seasonality, was overall heterotrophic, with internal water bodies having greater values of heterotrophy. Warm, dry years with high salinity had lower degrees of summer autotrophy.

Reproduction of the invasive largemouth bass Micropterus salmoides (Lacepède, 1802) in a Neotropical reservoir with suggestions to management and control

“…Warmer seasons (spring and summer) can increase the reproductive success of the species, by increasing the chances of survival and ensuring higher growth rates for young individuals, where food resources are most abundant (Parkos & Wahl, 2002;Beamish et al, 2005). This could be due to a direct metabolic effect, or through indirect factors (e.g., greater resource in warmer seasons due to increased productivity) (Bertolini et al, 2021). Environmental factors are described as capable of controlling the beginning and duration of reproduction in fish.…”

Overfishing and recent risk for collapse of fishery in coastal Mediterranean lagoon ecosystem (Karavasta lagoon, southeastern Adriatic sea)

“…5) shows that productivity is also related to water temperature and salinity, beside that they do not show rapid changes over long time periods. This is a need of further long-term survey, while recent studies and projections for the similar ecosystems shows that climate change together with the peculiarities of mixing water will undoubtedly alter hydrological regime of this lagoons and biota components including primary productivity and sequencing food chain within ecosystem (Bertolini et al, 2021;Jakimavičius et al, 2018). This study shows that in the Karavasta lagoon in the latest decade, there have been years where high water temperatures were recorded for long periods over the summer while winters had colder values than other years (1990,2000,2004) as well as a cluster of years when extremely high summer water temperatures were observed (2017,2019,2021).…”

Spatio-temporal Variation of Shallow Microhabitats and Associated Juvenile Fish Assemblages in a Mediterranean Lagoon

“…Therefore, even if water temperature probably affects the global list of species found in the lagoon, it was not the primary direct driver for the observed temporal changes in juvenile fish abundance. Nonetheless, in estuarine and lagoon systems, the primary productivity cycle coincides with that of temperature, usually peaking in the summer (Murrel and Lores 2004;Bertolini et al 2021), and fish abundances, notably at the larval and juvenile stages, usually follow this annual cycle (Pérez-Ruzafa et al 2004;Kristiansen et al 2011).…”