Mississippi River water levels typically rise in the early spring after snow melt in the extensive watershed. However, in 2016, warm air temperatures coupled with high precipitation led to a historically early river flood pulse, resulting in the opening of a flood release valve (Bonnet Carré Spillway) in early January to protect the city of New Orleans, Louisiana. The goal of this research was to determine the ecosystem response of this wintertime nutrient flood pulse on the receiving estuarine system and compare it to historical opening responses, which are generally several months later. Nutrients, TSS, and Chl a were measured along a 30 km transect in the Lake Pontchartrain estuary, before, during, and after the river diversion event. In the past, NO concentrations were quickly reduced to below detection in the estuary in <4 weeks post-event accompanied by a moderate phytoplankton bloom. However, due to seasonal limitations (cold water temperatures and light limitation) during the 2016 event, NO remained elevated for >2 months post-closure and Chl a values were low, indicating limited assimilation of nutrients into phytoplankton biomass. Consequently, much of the bioavailable nitrogen was denitrified by sediments and dispersed to the coastal ocean over time, limiting the transfer of nutrients into the food web by means of a spring phytoplankton bloom. An increasing warming trend in temperate and polar river watersheds is leading to earlier spring flood pulses, altering the timing of coastal nutrient transport, decoupled from conditions supporting primary production, which could significantly affect coastal food webs.
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http://dx.doi.org/10.1016/j.scitotenv.2023.162623 | DOI Listing |
Sci Rep
January 2025
Institute of Environment, Florida International University, Miami, FL, 33199, USA.
Variability in space use among conspecifics can emerge from foraging strategies that track available resources, especially in riverscapes that promote high synchrony between prey pulses and consumers. Projected changes in riverscape hydrological regimes due to water management and climate change accentuate the need to understand the natural variability in animal space use and its implications for population dynamics and ecosystem function. Here, we used long-term tracking of Common Snook (Centropomus undecimalis) movement and trophic dynamics in the Shark River, Everglades National Park from 2012 to 2023 to test how specialization in the space use of individuals (i.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Centre de Recherche sur la Biodiversité et l'Environnement, Université de Toulouse, Institut de Recherche pour le Développement, Institut National Polytechnique de Toulouse, Université Toulouse 3 - Paul Sabatier, Toulouse F-31062, France.
Unlike most rivers globally, nearly all lowland Amazonian rivers have unregulated flow, supporting seasonally flooded floodplain forests. Floodplain forests harbor a unique tree species assemblage adapted to flooding and specialized fauna, including fruit-eating fish that migrate seasonally into floodplains, favoring expansive floodplain areas. Frugivorous fish are forest-dependent fauna critical to forest regeneration via seed dispersal and support commercial and artisanal fisheries.
View Article and Find Full Text PDFEcol Evol
January 2025
CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences Yantai China.
Estuaries are ecologically sensitive areas influenced by river regulation. Knowledge of how marine megabenthos responds to river regulation and artificial flooding events remains limited. The study aims to provide a comprehensive understanding of the impacts of river regulation on marine megabenthic fauna.
View Article and Find Full Text PDFHeliyon
November 2024
Entomology Division, Pulses Research Centre, Bangladesh Agricultural Research Institute, Ishurdi, 6620, Pabna, Bangladesh.
Sci Total Environ
December 2024
The Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China. Electronic address:
Disentangling the mechanisms underlying community assembly is a central topic in community ecology and an important prerequisite for bioassessment. The relative importance of deterministic and stochastic processes is expected to change among organisms relying on different dispersal modes and may vary considerably through time. However, how seasonal change and dispersal modes will interplay to influence community assembly remains to be demonstrated.
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