Part A | 2.3
16 Part A Marine Flora and Fauna
ized hyphae called conidiophores. Conidial ontogeny
forms the basis for identification and segregation of
Fungi imperfecti. It comprises 1700 genera of Hyphomycetes, and 700 genera of Coelomycetes that cover
some 20 000 known species. They colonize, survive,
and multiply in air, litter, soil, and other substrates
and contribute extensively towards bio-degradation and
recycling of organic matter, enzyme production, and
industrial production including antibiotics, immunoregulators, and bio-control agents, in addition to causing
profound mycoses, allergies, and plant diseases. About
8000 Fungi imperfecti are reported from India. Very
few thermophilic fungi are reported from India with
growth optima of around 45
ı C.
2.3 Habitats of Fungi in the Marine Ecosystem
Different marine habitats support very different fungal communities. Fungi can be found in niches ranging from ocean depths and coastal waters to mangrove swamps and estuaries with low salinity levels. It
is more than five decades since the marine mycology
has evolved and it evidently states that marine fungi
show a great variance not only in their taxonomy but
also in their morphological, physiological and ecological adaptation capabilities from both terrestrial and
freshwater fungi. Although marine fungi is a common
term used to refer all fungi that are present in the sea,
they are distinctly referred as marine, oceanic, manglicolous, arenicolous, or estuarine, based on their habitat.
2.3.1 Marine Fungi
Marine fungi form an ecological and not a taxonomic
group. According to their origin marine fungi are categorized into two types i. e., obligate marine fungi and
facultative marine fungi. Obligate marine fungi grow
and sporulate exclusively in seawater, and their spores
are capable of germinating in seawater. However, facultative marine fungi are those from fresh water or
a terrestrial source that have undergone physiological
adaptations that allow them to grow and also sporulate
in the marine environment [2.4].
Marine fungi comprise an estimated 1500 species,
excluding those that form lichens [2.20]. This number is
much smaller when compared to the number of named
and undescribed terrestrial fungi, which has been estimated to be 250 000 or more [2.4]. So far less than 500
filamentous higher marine fungi have been described
and only 79 are associated with algae as parasites or
symbionts, and 18 with animal hosts [2.21].
2.3.2 Fungi in Mangroves
Among the tropical marine ecosystems, mangroves
and coral reefs are the major habitats in gross productivity [2.22]. Mangrove forests are spread over
181 000 km
2 in 112 countries in the tropics and subtropics [2.23, 24]. Through detritus production and
decomposition mangroves support a variety of planktonic, benthic, and fish communities [2.25–27]. Up to
41% of mangroves exist in South East Asia [2.24].
The Indian subcontinent ranks fourth (6700 km
2 ) after
Indonesia, Bangladesh, and Malaysia in mangrove vegetation cover [2.28]. Mangroves are intertidal forested
wetland confined to tropical and subtropical regions,
and mangrove vegetation is considered to be a dynamic
ecotone (or transition zone) between terrestrial and marine habitats [2.29].
Mangrove ecosystems command intensive attention
among coastal ecosystems, not only due to their peculiar habitat characteristics but also due to their rich
biodiversity. Mangrove forests are biodiversity hotspots
for marine fungi because the bases of mangrove trunks
and aerating roots are permanently or intermittently
submerged. Because the upper parts of roots and trunks
are rarely or never reached by salt water, terrestrial
fungi and lichens occupy the upper part of the trees
and marine species occupy the lower part. At the interface, there is an overlap between marine and terrestrial
fungi [2.30]. Mangrove fungi constitute the second
largest ecological group of marine fungi. The latest estimate of marine fungi is 1500 species, in which 339 are
found in mangrove ecosystems [2.31].
The fungi in mangroves play a significant role in
litter decomposition and nutrient cycling, thereby contributing to the fertility of the environment. Fungal
biomass along with detritus contributes significantly to
the food chain of the detritus-feeding organisms found
in mangroves. Aspergillus and Penicillium are dominant
fungi involved in litter decomposition of mangroves.
Since 1944, marine fungi have been extensively studied,
particularly wood-inhabiting fungi [2.3]. About 150
species are found exclusively on decaying mangrove
wood, aerial roots, and seedlings, and are categorized
as Manglicolous fungi; most of the species belong to
the class of Ascomycetes.
16 Part A Marine Flora and Fauna
ized hyphae called conidiophores. Conidial ontogeny
forms the basis for identification and segregation of
Fungi imperfecti. It comprises 1700 genera of Hyphomycetes, and 700 genera of Coelomycetes that cover
some 20 000 known species. They colonize, survive,
and multiply in air, litter, soil, and other substrates
and contribute extensively towards bio-degradation and
recycling of organic matter, enzyme production, and
industrial production including antibiotics, immunoregulators, and bio-control agents, in addition to causing
profound mycoses, allergies, and plant diseases. About
8000 Fungi imperfecti are reported from India. Very
few thermophilic fungi are reported from India with
growth optima of around 45
ı C.
2.3 Habitats of Fungi in the Marine Ecosystem
Different marine habitats support very different fungal communities. Fungi can be found in niches ranging from ocean depths and coastal waters to mangrove swamps and estuaries with low salinity levels. It
is more than five decades since the marine mycology
has evolved and it evidently states that marine fungi
show a great variance not only in their taxonomy but
also in their morphological, physiological and ecological adaptation capabilities from both terrestrial and
freshwater fungi. Although marine fungi is a common
term used to refer all fungi that are present in the sea,
they are distinctly referred as marine, oceanic, manglicolous, arenicolous, or estuarine, based on their habitat.
2.3.1 Marine Fungi
Marine fungi form an ecological and not a taxonomic
group. According to their origin marine fungi are categorized into two types i. e., obligate marine fungi and
facultative marine fungi. Obligate marine fungi grow
and sporulate exclusively in seawater, and their spores
are capable of germinating in seawater. However, facultative marine fungi are those from fresh water or
a terrestrial source that have undergone physiological
adaptations that allow them to grow and also sporulate
in the marine environment [2.4].
Marine fungi comprise an estimated 1500 species,
excluding those that form lichens [2.20]. This number is
much smaller when compared to the number of named
and undescribed terrestrial fungi, which has been estimated to be 250 000 or more [2.4]. So far less than 500
filamentous higher marine fungi have been described
and only 79 are associated with algae as parasites or
symbionts, and 18 with animal hosts [2.21].
2.3.2 Fungi in Mangroves
Among the tropical marine ecosystems, mangroves
and coral reefs are the major habitats in gross productivity [2.22]. Mangrove forests are spread over
181 000 km
2 in 112 countries in the tropics and subtropics [2.23, 24]. Through detritus production and
decomposition mangroves support a variety of planktonic, benthic, and fish communities [2.25–27]. Up to
41% of mangroves exist in South East Asia [2.24].
The Indian subcontinent ranks fourth (6700 km
2 ) after
Indonesia, Bangladesh, and Malaysia in mangrove vegetation cover [2.28]. Mangroves are intertidal forested
wetland confined to tropical and subtropical regions,
and mangrove vegetation is considered to be a dynamic
ecotone (or transition zone) between terrestrial and marine habitats [2.29].
Mangrove ecosystems command intensive attention
among coastal ecosystems, not only due to their peculiar habitat characteristics but also due to their rich
biodiversity. Mangrove forests are biodiversity hotspots
for marine fungi because the bases of mangrove trunks
and aerating roots are permanently or intermittently
submerged. Because the upper parts of roots and trunks
are rarely or never reached by salt water, terrestrial
fungi and lichens occupy the upper part of the trees
and marine species occupy the lower part. At the interface, there is an overlap between marine and terrestrial
fungi [2.30]. Mangrove fungi constitute the second
largest ecological group of marine fungi. The latest estimate of marine fungi is 1500 species, in which 339 are
found in mangrove ecosystems [2.31].
The fungi in mangroves play a significant role in
litter decomposition and nutrient cycling, thereby contributing to the fertility of the environment. Fungal
biomass along with detritus contributes significantly to
the food chain of the detritus-feeding organisms found
in mangroves. Aspergillus and Penicillium are dominant
fungi involved in litter decomposition of mangroves.
Since 1944, marine fungi have been extensively studied,
particularly wood-inhabiting fungi [2.3]. About 150
species are found exclusively on decaying mangrove
wood, aerial roots, and seedlings, and are categorized
as Manglicolous fungi; most of the species belong to
the class of Ascomycetes.