Breakdown of fresh and dried Rhizophora mucronata leaves in a mangrove of Southwest India

Abstract

Patterns of fungal colonization, mass loss and biochemical changes during the decomposition of predried and fresh (naturally fallen) leaves of Rhizophora mucronata were studied in a southwest mangrove of India. Dried and fresh leaves in litter bags were introduced at the mid-tide zone and retrieved after 1, 2, 4, 8, 10, 12 and 14 weeks. On incubation in the laboratory, a total of 5 ascomycetes and 18 anamorphic fungi were recorded. The majority of anamorphic taxa were natural inhabitants of the phyllosphere of senescent leaves. Following two weeks of exposure, they were largely replaced by marine fungi (ascomycetes and anamorphic fungi). More taxa were recovered from dried than from fresh leaves, and predrying accelerated the initial rate of mass loss. Ergosterol levels were much lower than those reported from vascular plant detritus exposed in other aquatic habitats. Both ergosterol and nitrogen levels peaked after between 4 weeks and 8 weeks of exposure; ergosterol levels subsequently declined, while nitrogen remained stable in predried leaves and fell in fresh leaves. The dynamics of remaining mass for the first 8 weeks of exposure were best described by a double-exponential decay model. The decay rate then appeared to accelerate, and the second phase was best described by a single exponential decay model. The apparent breakpoint coincided with an increase in the salinity of the mangrove swamp.

Diversity, role in decomposition, and succession of zoosporic fungi and straminipiles on submerged decaying leaves in a woodland stream

“…were observed during the early and latest stages of the decomposition. These results were in agreement with the findings of Kaushik & Hynes (1971), Bärlocher & Kendrick (1974), and Ananda et al (2008) who observed that some terrestrial Hyphomycetes, such as Alternaria and Cladosporium (in our case also Pestalotiopsis guepinii) were common in senescent and recently submerged leaves. After the immersion of leaves, the number of terrestrial taxa decreased (Bärlocher & Kendrick, 1974;Suberkropp & Klug, 1980) and persisted up to 5-14 days, when they were replaced by aquatic Hyphomycetes.…”

Leaf-litter decomposition of the mangrove speciesAvicennia schaueriana,Laguncularia racemosaandRhizophora mangle

“…This rapid weight loss, which results from the high decomposition rate in the beginning of the experiment, is usually attributed to leaching of soluble compounds such as sugars, organic acids, proteins and phenols (Mfilinge et al, 2002;Davis et al, 2003Davis et al, , 2007Kristensen et al, 2008). This phase is normally marked by a more gradual decomposition (Ananda et al, 2008;Galeano et al, 2010) and is well recognized in the literature as a period of intense microbial action, when the N content increases (Robertson et al, 1988Wafar et al, 1997;Davis et al, 2007). This phase is normally marked by a more gradual decomposition (Ananda et al, 2008;Galeano et al, 2010) and is well recognized in the literature as a period of intense microbial action, when the N content increases (Robertson et al, 1988Wafar et al, 1997;Davis et al, 2007).…”

“…According to the classification of Ananda et al (2008), all three species had rapid decomposition rates (k . 0.01).…”

Short Communication: The relationship between content of particular metabolites of fallen mangrove leaves and the rate at which the leaves decompose over time

“…The value for k of R. stylosa (0.079) was higher than the k value for S. alba (0.028). In general, the k values in our study can be regarded as high, since according to the classification of Ananda et al (2008), values of k>0.01 reflect fast decaying leaves, values of k between 0.005 and 0.01 are obtained from leaves that decay at medium rates, and slow decaying leaves have values of k <0.005.…”