Inter-annual cascade effect on marine food web: A benthic pathway lagging nutrient supply to pelagic fish stock

Abstract

Currently, spatial and temporal changes in nutrients availability, marine planktonic, and fish communities are best described on a shorter than inter-annual (seasonal) scale, primarily because the simultaneous year-to-year variations in physical, chemical, and biological parameters are very complex. The limited availability of time series datasets furnishing simultaneous evaluations of temperature, nutrients, plankton, and fish have limited our ability to describe and to predict variability related to short-term process, as species-specific phenology and environmental seasonality. In the present study, we combine a computational time series analysis on a 15-year (1995–2009) weekly-sampled time series (high-resolution long-term time series, 780 weeks) with an Autoregressive Distributed Lag Model to track non-seasonal changes in 10 potentially related parameters: sea surface temperature, nutrient concentrations (NO2, NO3, NH4 and PO4), phytoplankton biomass (as in situ chlorophyll a biomass), meroplankton (barnacle and mussel larvae), and fish abundance (Mugil liza and Caranx latus). Our data demonstrate for the first time that highly intense and frequent upwelling years initiate a huge energy flux that is not fully transmitted through classical size-structured food web by bottom-up stimulus but through additional ontogenetic steps. A delayed inter-annual sequential effect from phytoplankton up to top predators as carnivorous fishes is expected if most of energy is trapped into benthic filter feeding organisms and their larval forms. These sequential events can explain major changes in ecosystem food web that were not predicted in previous short-term models.

Evaluation of wood degradation rates by Teredinidae (Mollusca: Bivalvia) in two ecologically distinct areas, and temperature and salinity influences on the cellulolytic activity of associated bacteria

“…Barreto et al (1993) found a different Bankia species as dominant close to Forno cove, although at a much lower density. Those variations in species dominance in the study region may be explained by the extreme variations in oceanographic features there, mainly related to sea water temperature, salinity, and water mass changes (Fernandes et al 2017, Valentin 2001. Additionally, our data represents the first information concerning the Teredinidae family in an area under the direct influence of upwelling.…”

“…The upwelling Southeast Atlantic Central Water (SACW) is characterized by temperatures below 20°C and a rich nutrient content (Valentin 2001). The surface emergence of those waters increases primary productivity, favouring mainly benthic life (Fernandes et al 2017). Average annual rainfall is ca.…”

Multi-scale temporal variation of marine femtoplankton and picophytoplankton: the role of size and environment

“…Our study area is the Cabo Frio upwelling region, one of the most active planktivorous fishing areas (mainly sardines) along the Brazilian coast (Freire et al, 2021) due to the seasonal upwelling that boosts the energy transfer throughout the trophic chain (Fernandes et al, 2012(Fernandes et al, , 2017. Upwelling events in Cabo Frio usually last a few days , further highlighting the importance of high-frequency monitoring of planktonic organisms.…”

The Biophysical Controls of Macroalgal Growth on Subtropical Reefs

“…High nitrogen concentration is a characteristic effect of upwelling events in the north of Rio de Janeiro state (>2 µMdissolved inorganic nitrogen, Valentin, 1984;Gonçalves, 1999;Fernandes et al, 2017), which enhances local productivity (Fernandes et al, 2017). Thus, the total nitrogen (NH 4 + , NO 2 − and NO 3 − ) concentration (subsequently "nutrients") in the water was measured in the laboratory (following the methods of Strickland and Parsons, 1972) from samples taken weekly in triplicates from superficial water from 20 days prior to the experiment starting and throughout the experimental period to evaluate the effect of natural eutrophication on benthic cover.…”