Analysis of the energy balance and CO2 flow under the influence of the seasonality of climatic elements in a mangrove ecosystem in Eastern Amazon

Antonio Sérgio C Freire,Maria Isabel Vitorino,Adriano Marlisson L De Souza,Michell Fontenelle Germano

doi:10.1007/s00484-021-02224-8

Abstract

An unprecedented study was carried out in a mangrove ecosystem in the northeastern coast of the Brazilian Amazon to understand the behavior of climatic elements in a year with the occurrence of El Niño (2015), associated with the seasonal function source/sink of CO2 by the ecosystem. Global radiation (Rg), net radiation (Rn), temperature, relative humidity, precipitation, horizontal wind speed and direction, as well as turbulent flows of sensible heat (H), latent heat (LE), and carbon (f_CO2) were recorded using eddy covariance, a system for studying turbulent flows of heat and gases in the atmosphere. We observed a drastic reduction in rainfall volumes, which accounts for 63.7% of the expected total according to the region’s climatology. Regarding f_ CO2, the highest values of photosynthesis, autotrophic, and heterotrophic respiration of the ecosystem occurred in the wet season due to precipitation, ideal photosynthetically active radiation, lower soil salinity, and higher NDVI of the ecosystem. In the 2nd semester of the year, we observed that the decrease in cloudiness, causing a higher radiation supply in the forest canopy, accompanied by a reduction in precipitation and an increase in the value of H and soil salinity, favored the increase of foliar abscission by the dominant genus Rhizophora and Avicennia, thus influencing the reduction of magnitudes of carbon source/sink functions in the ecosystem during this season, even on high tide days.

Highlights

Mangroves are coastal ecological systems typical of estuarine transition areas between terrestrial and marine environments, subject to tidal regimes
The daily analysis of the air temperature in the mangrove ecosystem showed that March had inverse values for the relative humidity throughout the year, which we can highlight the biggest temperature occurring on December 11 with 31.2 °C at midnight, while the lowest temperature occurred on March 7 with 23.9 °C at 5:30 am
For 2015, under El Niño Southern Oscillation (ENSO) in the mangrove ecosystem of the experimental site of Cuiarana, on the northeastern coast of the state of Pará, we verified that the precipitation had volumes below the climatological normal, evidencing the strong influence of the sea surface temperature anomalies in the Pacific Ocean over the Amazon

Summary

Introduction

Mangroves are coastal ecological systems typical of estuarine transition areas between terrestrial and marine environments, subject to tidal regimes They represent a considerable flow of mass and energy, where the balance of this energy and the carbon involved in the biosphere-atmosphere exchange is transformed into organic matter, from simple. Brazil is the third biggest country in mangrove extension, with an area of 9,623.83 km, extending from the State of Amapá to its Southern limit in Santa Catarina We observe in these ecosystems a significant variation of biological communities, where it operates at certain times of the year as a nursery for a considered variety of invertebrate and vertebrate species (Giri et al 2011; Lee et al 2014; Schaeffer-Novelli et al 2000; Spalding et al, 1997).

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