Botanical Survey of India

Abstract

Bhitarkanika Wildlife Sanctuary, situated in the north-eastern part of Kendrapada district of Odisha, India, spreads over an area of about 672 sq. km. Within the sanctuary, an area of approximately 145 sq.km. is designated as Bhitarkanika National Park and obtained the status of a Ramsar site on 19th August 2002. It is the second largest mangrove ecosystem of India consisting of huge mangrove forests, river deltas, estuaries, backwaters and mud flats etc. They serve as the base of an elaborate and productive food web in this extraordinarily diverse estuarine ecosystem. The present investigation aims at enumeration and ultrastructural examination of certain diatom taxa collected as a part of our ongoing studies on diatom diversity of major areas of Bhitarkanika national park viz. Dangmal, Kalibhanjdian, Khola, Bhitarkanika and Ragarapatia. The present paper reports the occurrence of three diatom species namely, Navicula subrostellata Hustedt, Navicula torneensis Cleve and Caloneis oregonica (Ehrenberg) R.M. Patrick belonging to order Naviculales under the family Naviculaceae from Bhitarkanika National Park as the new distributional records from India based on examination of morphological features and ultrastructure through scanning electron
microscopy (SEM). Occurrence of these 3 diatom species in Bhitarkanika Wildlife Sanctuary is of considerable phytogeographical significance and important addition to the checklist of least-explored diatom flora of this important mangrove habitat.

Full text

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New distributional records of three Naviculales (Naviculaceae) from the
Bhitarakanika National Park of Odisha, India
S. Mishra1, S. Bhakta2Ψ and A.K. Bastia1
1. P.G. Department of Botany, MSCB University, Takatpur, Baripada-757003, Mayurbhanj, Odisha.
2. Botanical Survey of India, Western Regional Circle. 7-Koregaon Road, Pune-411001, Maharashtra.
Plant Science Research 44 (1&2) : 66-70, 2022
Plant Science Research
ISSN 0972-8546
ABSTRACT
Article history:
Received : 1 November, 2022
Revised : 24 November, 2022
Accepted : 2 December, 2022
Bhitarkanika Wildlife Sanctuary, situated in the north-eastern part of Kendrapada district of
Odisha, India, spreads over an area of about 672 sq. km. Within the sanctuary, an area of
approximately 145 sq.km. is designated as Bhitarkanika National Park and obtained the
status of a Ramsar site on 19th August 2002. It is the second largest mangrove ecosystem
of India consisting of huge mangrove forests, river deltas, estuaries, backwaters and mud
flats etc. They serve as the base of an elaborate and productive food web in this extraordinarily
diverse estuarine ecosystem. The present investigation aims at enumeration and ultrastructural
examination of certain diatom taxa collected as a part of our ongoing studies on diatom
diversity of major areas of Bhitarkanika national park viz. Dangmal, Kalibhanjdian, Khola,
Bhitarkanika and Ragarapatia. The present paper reports the occurrence of three diatom
species namely, Navicula subrostellata Hustedt, Navicula torneensis Cleve and Caloneis
oregonica (Ehrenberg) R.M. Patrick belonging to order Naviculales under the family
Naviculaceae from Bhitarkanika National Park as the new distributional records from India
based on examination of morphological features and ultrastructure through scanning electron
microscopy (SEM). Occurrence of these 3 diatom species in Bhitarkanika Wildlife Sanctuary
is of considerable phytogeographical significance and important addition to the checklist of
least-explored diatom flora of this important mangrove habitat.
ARTICLE INFO
1. Introduction
Mangroves are one of the most extraordinarily diverse
evergreen estuarine open ecosystems, formed by a variety
of salt tolerant species growing in the inter-tidal areas and
estuary mouth, can provide critical habitat for a diverse
marine, brackish and terrestrial flora and fauna. They act as
nutrient sinks and protect offshore ecosystems and often
referred to as bio-shields or natural sea defence (Roy et al.,
2009). Nearly 60-70% of the world’s tropical and subtropical
coastlines are covered with mangroves, which are known to
be world’s most productive ecosystems of remarkable
ecological value (Thatoi et al., 2013). The dynamic mangrove
ecosystem supports the growth of many phosphate
solubilizing, nitrogen fixing, sulphate reducing and
methanogenic bacteria, wood degrading fungi as well as
photosynthetic algae like diatoms, cyanobacteria, green-
algae and other microalgae, which play significant role in
maintaining nutrient cycling and ecological balance in this
unique ecosystem. One of the major groups of microalgae
in mangroves is diatoms, which is a very valuable
environment indicator. About one-fifth of the photosynthesis
on earth is carried out by these fabulous photosynthetic
workhouses. Therefore, exploration of these bioresources
from different ecosystems will definitely help us to
understand their role in ecosystem functioning and show
the path for bioprospecting for commercial applications.
Bhitarkanika, the second largest mangrove ecosystem
of India, consists of mangrove forests, river deltas, creeks,
estuaries, backwater, accreted land and mud flats. Most of
the published literature on this sanctuary pertains to
documentation of flora and fauna. Due to inaccessible forest
cover and vast expanse of water, the microbes of thisnational
park have remained poorly studied. Though scanty reports
are available on phytoplankton and other microalgal diversity
(Rath & Adhikary, 2006; Chakraborty et al., 2012; Thatoi et
al., 2012; Dash et al., 2019), not much work has been done
© 2022 Orissa Botanical Society
Keywords:
Bhitarakanika,
Naviculales,
Diatom,
Mangrove ecosystem
Corresponding author; Email: skmrbhakta@gmail.com

67
on the taxonomy and diversity of diatoms of Bhitarkanika.
In the present investigation, attempt has been made, for the
first time, to examine the ultrastructure of three brackish
water diatoms through scanning electron microscopy (SEM).
2. Materials and methods
Bhitarkanika, a mangrove wetland in Odisha is
surrounded by Bay of Bengal on east, the villages of
Kendrapara district on west, Dhamra estuary on north and
the Mahanadi estuary on south. Field visits were made to
Bhitarkanika and diatom samples were collected randomly
from different niches of mangrove sediments, mud surfaces,
attached to pneumatophores of some selected mangrove
species. Sample collections were made from sites such as
Khola, Dangmal, Kalibhanjdian, Bhitarkanika and Ragarapatia
of Bhitarkanika Wildlife Sanctuary and National Park during
November-December, 2018. Samples were collected in sterile
specimen tubes (Tarson) of 25 × 50 mm size in duplicate of
which one set was stored in ethanol. Ethanol was added to
reach final concentration of 20% by volume (Kolbe, 1948;
Krammer & Lange-Bertalot, 2000; Krammer, 2002; Karthic et
al., 2010). Diatoms were cleaned by acid wash method using
HCL and pre-oxidant potassium permanganate (Hasle, 1978;
Round et al., 1990; Karthic et al., 2010) and hot hydrogen
peroxide method (Van Der Werff, 1955; Karthic et al., 2010).
After that, cleaned diatoms were stored in 70% of ethanol
for further study. For identification, the permanent slides of
cleaned diatoms were prepared and observed under the
microscope (Hund Wetzlar Trinocular Compound Microscope
with Canon-EOS 550D Camera attachment), followed by
photomicrography. The processed diatoms were diagnosed
under a Scanning Electron Microscope (Zeiss EVO 18 special
edition). The diatom species were identified through
morphometrical analysis following standard monographs and
literature (Cleve, 1894; Hustedt, 1930; Cleve-Euler, 1953;
Desikachary, 1988). Taxonomy of each species and the
protologues were verified as cited in algaebase.org (https:/
/www.google.com) (Guiry & Guiry, 2019) and diatombase.org
(https://www.diatombase.org).
3. Enumeration of species
3.1. Navicula subrostellata Hustedt 1955: 27 (Plate 1, Fig.
1-2)
Lanceolate to linear-lanceolate valves with protracted
apices, length of valve (AA) 29-31.5 µm, width of valve
(TA) 6.5 -7 µm. The axial area is narrow and straight. The
central area is round to elliptical. External proximal raphe
ends are straight and very close to each other. Striae are
radiated around the centre, parallel then gently convergent
at the apices, transapically elongated areolae, number of
striae 14 in 10 µm.
Place of collection: Bhitarkanika.
Mode of occurrence: Benthic and epiphytic.
3.2. Navicula torneensis Cleve 1891: 33 (Plate 1, Fig. 3)
Synonym: Schizonema torneense (Cleve) Kuntze
Valve wide lanceolate with cuneate to slightly rostrate
ends, length of the valve 35-36.9 µm, width of the valve 16-
17 µm. Striae slightly curved around central area, radiate
throughout the valve, no of striae 12-13 in 10µm, some short
striae are found around the central area. The first group of
areolae is slightly more elongated, slits like areolae are present
surrounding the central area. Axial area narrow and linear.
Small central area, circular to transversely elliptical due to
position of striae. Raphe straight, thin with simple drop like
central endings, apical endings are simple and slightly
deflected to opposite side of the valve.
Place of collection: Bhitarkanika.
Mode of occurrence: Benthic.
3.3. Caloneis oregonica (Ehrenberg) R.M. Patrick 1966:
581 (Plate 2, Fig. 1-7)
Basionym: Pinnularia oregonica Ehrenberg
Synonyms: Navicula oregonica (Ehrenberg) Kützing;
Navicula liburnica Grunow; Caloneis liburnica Grunow;
Navicula amphisbaena var. liburnica (Grunow) M. Peragallo
Valve elliptic to linear-elliptic, flat valve external surface
with rounded apices, length of valve (AA) 40-75 µm, width
of valve (TA) 13-17 µm. Axial area slightly irregular,
lanceolate, comparatively wider at centre, tapering towards
the valve apices and situated more closely to the raphe on
one side than the other. Central area distinctly separated
from axial area and almost circular to transversally elliptical
to slightly rhombic due to the position of striae. Central
nodule slightly depressed externally. External raphe branches
thin, straight, central raphe fissures end in pore-like
expansions; large, hooked, sickle-shaped terminal raphe
endings extending up to the end mantle area, both deflected
to same side of the valve. A single longitudinal line runs
parallel with the valve margin at about two-third of the
distance from the raphe to the valve rim which is quite
distinct (Fig.1). Internally the axial area quite distinct, at the
centre a slightly siliceous thickening occurs on one side of
the central raphe ends. Internally raphe straight with simple
central raphe endings, slightly bent towards siliceous
thickening and terminal endings with simple coaxial pore,
small compressed and horseshoe-shaped helictoglossa
(Fig.6). Striae slightly radiate to parallel, number of stria
density: 15-16.
Place of collection: Bhitarkanika.
Mode of occurrence: Benthic.
S. Mishra, S. Bhakta and A.K. Bastia
V. No. NOU 928
V.No. NOU938
V.No. NOU931

68 New distributional records of diatoms from Bhitarkanika
Plate 1 (Figs. 1-3): Fig. 1-2 Navicula subrostellata; Fig. 3 Navicula torneensis

69
Plate 2 (Figs. 1-7): Coloneis oregonica, LM = 10X
S. Mishra, S. Bhakta and A.K. Bastia
4. Discussion
The present investigation discloses the occurrence of
three Naviculales, namely, Navicula subrostellata Hustedt,
Navicula torneensis Cleve, Caloneis oregonica (Ehrenberg)
R.M. Patrick belonging to family Naviculaceae from
Bhitarkanika, this being the first report from India. According
to earlier distributional records, Caloneis oregonica was
reported to be mostly confined to brackish water habitat
worldwide (Kociolek, 2005; Maulood et al., 2013), but
Navicula subrostellata was a marine form (Hafner et al.,
2018). Navicula torneensis Cleve was the most common
species of different estuaries of Korea (Joh, 2013) and mostly
found as epipssamic forms. Exploring diatom diversity from
this unexplored area will not only provide an opportunity
for exploring of different endemic taxa and new distributional
records from those unique habitats but also unlatch the
opportunity for obtaining different novel organisms for
various commercial purposes.
Acknowledgement
Authors are privileged to convey their heartfelt
gratitude to the Head, P.G. Dept. of Botany, MSCB
University, Baripada and the authorities of Botanical Survey
of India for providing necessary facility to carry out the
present work.

70
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