Temporal coherence among tropical coastal lagoons: a search for patterns and mechanisms

Abstract

Temporal coherence (i.e., the degree of synchronicity of a given variable among ecological units within a predefined space) has been shown for several limnological features among temperate lakes, allowing predictions about the structure and function of ecosystems. However, there is little evidence of temporal coherence among tropical aquatic systems, where the climatic variability among seasons is less pronounced. Here, we used data from long-term monitoring of physical, chemical and biological variables to test the degree of temporal coherence among 18 tropical coastal lagoons. The water temperature and chlorophyll-a concentration had the highest and lowest temporal coherence among the lagoons, respectively, whereas the salinity and water colour had intermediate temporal coherence. The regional climactic factors were the main factors responsible for the coherence patterns in the water temperature and water colour, whereas the landscape position and morphometric characteristics explained much of the variation of the salinity and water colour among the lagoons. These results indicate that both local (lagoon morphometry) and regional (precipitation, air temperature) factors regulate the physical and chemical conditions of coastal lagoons by adjusting the terrestrial and marine subsidies at a landscape-scale. On the other hand, the chlorophyll-a concentration appears to be primarily regulated by specific local conditions resulting in a weak temporal coherence among the ecosystems. We concluded that temporal coherence in tropical ecosystems is possible, at least for some environmental features, and should be evaluated for other tropical ecosystems. Our results also reinforce that aquatic ecosystems should be studied more broadly to accomplish a full understanding of their structure and function.Keywords: synchrony, temporal coherence, local factors, regional factors, shallow lakes, coastal lagoons. Coerência temporal entre lagoas costeiras tropicais: uma busca por padrões e mecanismos ResumoA coerência temporal (i.e., o nível de sincronismo de uma dada variável ecológica entre unidades ecológicas) tem sido demonstrada para uma vasta gama de variáveis limnológicas em lagos de clima temperado, permitindo que predições sobre a estrutura e o funcionamento destes ecossistemas sejam realizadas. Entretanto, há pouca evidência da coerência temporal de variáveis limnológicas entre ecossistemas aquáticos tropicais, onde a variação climática é menos pronunciada entre as estações do ano. Neste estudo, utilizamos dados de longa duração do monitoramento de variáveis físicas, químicas e biológicas para testar a ocorrência de coerência temporal entre 18 lagoas costeiras tropicais. A temperatura da água e a concentração de clorofila-a apresentaram, respectivamente, a maior e a menor coerência temporal entre as lagoas, enquanto que a salinidade e a coloração da água apresentaram padrões intermediários. Fatores climáticos regionais foram os principais fatores responsáveis pelos padrões de coerência da temperatura e coloração d...

The role played by aquatic macrophytes regarding CO2 balance in a tropical coastal lagoon (Cabiúnas Lagoon, Macaé, RJ)

“…Cabiúnas is a pristine freshwater coastal lagoon surrounded by a natural restinga ecosystem featuring coarse sandy soil. The highly permeable watershed and dendritic morphometry (Figure 1) of the Cabiúnas favors a large input of colored terrestrial dissolved organic matter into the lagoon (Caliman et al, 2010), contributing to its waters' classification as humic. Cabiúnas' shallow water column and dendritic morphometry support the establishment and the growth of aquatic macrophytes on its margins (Panosso et al, 1998).…”

An update on the fish composition (Teleostei) of the coastal lagoons of the Restinga de Jurubatiba National Park and the Imboassica Lagoon, northern Rio de Janeiro State

“…Variations in the rainfall regime among different years and the orientation of the longest axis of those lagoons in relation to the coastline also affect their depth and salinity (Caliman et al, 2010). The deepest lagoons are typically those whose main axis is oriented perpendicularly to the coastline, and are herein referred to as Orthogonal lagoons: the Imboassica, Cabiúnas, Comprida, Carapebus, Paulista and Preta lagoons ( Figure 1, lagoons 1-5 and 14).…”

“…The deepest lagoons are typically those whose main axis is oriented perpendicularly to the coastline, and are herein referred to as Orthogonal lagoons: the Imboassica, Cabiúnas, Comprida, Carapebus, Paulista and Preta lagoons ( Figure 1, lagoons 1-5 and 14). Orthogonal lagoons are less influenced by the sea in terms of salinity, because they receive freshwater inputs from their catchment area and have a short extent of their perimeter close to the sea (Caliman et al, 2010). Aquatic macrophytes typically abound in the lateral and distal (opposite to the sea) portions of Orthogonal lagoons, and they are more prone to events of sandbar breaching in years of intense rainfall.…”

“…Aquatic macrophytes typically abound in the lateral and distal (opposite to the sea) portions of Orthogonal lagoons, and they are more prone to events of sandbar breaching in years of intense rainfall. The longest axes of the remaining lagoons of the Restinga de Jurubatiba National Park are parallel to the coastline (Caliman et al, 2010), and they are therefore referred to as Parallel lagoons. Those lagoons are the Encantada, Amarra Boi, Bezerra, Garças, Piripiri, Maria Menina, Robalo, Visgueiro, Catingosa, Pires, Barrinha, Casa Velha, and Ubatuba ( Figure 1, lagoons 6-14 and 16-17).…”

Effects of water-soluble fraction of petroleum on growth and prey consumption of juvenile Hoplias aff. malabaricus (Osteichthyes: Erythrinidae)

“…Although coastal lagoons in this region are mostly maintained by small streams, sporadic saltwater intrusion may occur via sandbar breaching events or during extreme high tides events (Caliman et al, 2010). In addition, diffuse pollutant inputs may originate from road runoff, domestic usage and licensed discharges of oil derivatives used as energy sources in urban areas (Marchand et al, 2002).…”