Terrestrial Plant Life Research Articles

Development of natural sporopollenin microcapsules: from bee pollen to versatile biomaterials

Abstract The outer layer of the pollen grain, which plays a crucial role in the continuity of terrestrial plant life, has received significant attention due to its robustness, chemical inertness, and biocompatible structure made of sporopollenin. Herein, we present a straightforward method for producing high-purity (up to 97%) polymeric sporopollenin biocapsules (S-BioCaps) from bee pollen, exploring new plant sources for S-BioCaps, and diversifying the available morphologies to broaden the applications of pollen-based microcapsules. Following a purification process involving defatting, acidolysis, and several washing steps, we removed the inner components of the pollen grains and reduced the protein content to 2%. Confocal laser scanning and scanning electron microscopy images showed that the hollow and 3D S-BioCaps microstructure were preserved, while laser diffraction particle size analysis validated their monodisperse distribution across each pollen type within the size range of 15 to 24 μm. S-BioCaps tended to exhibit hydrophobic behavior when assessed through water dispersion and water marble analysis. Moreover, we sought to figure out the chemical changes occurring in specimens through Fourier-transform infrared analysis, and findings were consistent with simultaneous thermal analysis, where the thermal decomposition of sporopollenin biopolymer reached up to 457 °C. Overall, this work demonstrates a straightforward approach for utilizing pollen grains from Echium sp., Jasione sp., Papaver sp., Amaranthaceae, and Helianthemum sp., collected with the assistance of honeybees, to produce stable S-BioCaps with diverse morphologies, thereby broadening their potential applications as drug delivery microcarriers. Graphical abstract

Ocean Plastics: Extraction, Characterization and Utilization of Macroalgae Biopolymers for Packaging Applications

This review details the extraction, characterization and utilization of seaweed-derived biopolymers for future packaging applications. The review is contextualized within the broader scope of the challenge of plastic pollution and the current urgent need for more sustainable packaging materials. Macroalgae (or seaweed) has been highlighted as a promising source of biopolymers, most commonly sodium alginate, agar and carrageenan, for reasons such as a rapid growth rate and decreased environmental impact when compared with terrestrial plant life. Extraction methods detailed include traditional solvent-based extraction and more sustainable developments such as ultrasound-assisted extraction, microwave-assisted extraction and bead milling. This review additionally presents the characterization techniques most pertinent in determining the applicability of these biopolymers in packaging applications. Properties of key importance to the development of sustainable packaging materials such as thermal properties, mechanical strength, barrier properties and biodegradability are highlighted in comparison to conventional petroleum-based plastics. This review concludes by realistically identifying the challenges faced by implementing seaweed-based biopolymers into packaging structures, such as cost-effectiveness, scalability and performance while suggesting future directions to mitigate these issues and improve the commercial viability of these materials for the packaging industry.

The Soil is Alive: Cultivating Human Presence Towards the Ground Below Our Feet

Abstract This article invites readers to rethink the presence and role of soil by creating a soliumpoietics, without which terrestrial plant life itself struggles to occur. It utilizes both materialism/material agency and hyperobject lenses to analyze soil. In so doing it argues that these lenses may provide a more holistic understanding to better theorize soil as an agential and interobjective other, without which civilization would most likely rapidly collapse. It undertakes this exploration within the context of rapid climate change and global heating, which threatens the survival of many soils (and thus plants), too. These alarming scenarios have severe implications for the academy, broadly, which the article argues scholars must attend to within their teaching and researching, including new research regimes on plant-based caloric lifeways, especially where such lifeways are regenerative to soil, plants, and thus, the human.

Preparation of Nanocellulose-Based Aerogel and Its Research Progress in Wastewater Treatment.

Nowadays, the fast expansion of the economy and industry results in a considerable volume of wastewater being released, severely affecting water quality and the environment. It has a significant influence on the biological environment, both terrestrial and aquatic plant and animal life, and human health. Therefore, wastewater treatment is a global issue of great concern. Nanocellulose's hydrophilicity, easy surface modification, rich functional groups, and biocompatibility make it a candidate material for the preparation of aerogels. The third generation of aerogel is a nanocellulose-based aerogel. It has unique advantages such as a high specific surface area, a three-dimensional structure, is biodegradable, has a low density, has high porosity, and is renewable. It has the opportunity to replace traditional adsorbents (activated carbon, activated zeolite, etc.). This paper reviews the fabrication of nanocellulose-based aerogels. The preparation process is divided into four main steps: the preparation of nanocellulose, gelation of nanocellulose, solvent replacement of nanocellulose wet gel, and drying of nanocellulose wet aerogel. Furthermore, the research progress of the application of nanocellulose-based aerogels in the adsorption of dyes, heavy metal ions, antibiotics, organic solvents, and oil-water separation is reviewed. Finally, the development prospects and future challenges of nanocellulose-based aerogels are discussed.

Differentiating siliceous particulate matter in the diets of mammalian herbivores

AbstractSilica is crucial to terrestrial plant life and geochemical cycling on Earth. It is also implicated in the evolution of mammalian teeth, but there is debate over which type of siliceous particle has exerted the strongest selective pressure on tooth morphology.Debate revolves around the amorphous silica bodies (phytoliths) present in plants and the various forms of siliceous grit—that is, crystalline quartz (sand, soil, dust)—on plant surfaces. The problem is that conventional measures of silica often quantify both particle types simultaneously.Here we describe a protocol that relies on heavy‐liquid flotation to separate and quantify siliceous particulate matter in the diets of herbivores. The method is reproducible and well suited to detecting species‐ or population‐level differences in silica ingestion. In addition, we detected meaningful variation within the digestive tracts of cows, an outcome that supports the premise of ruminal fluid ‘washing’ of siliceous grit.We used bootstrap resampling to estimate the sample sizes needed to compare species, populations or individuals in space and time. We found that a minimum sample of 12 individuals is necessary if the species is a browser or as many as 55 if the species is a grazer, which are more variable. But a sample size of 20 is adequate for detecting statistical differences. We conclude by suggesting that our protocol for differentiating and quantifying silica holds promise for testing competing hypotheses on the evolution of dental traits.

A biological nanofoam: The wall of coniferous bisaccate pollen.

The outer layer of the pollen grain, the exine, plays a key role in the survival of terrestrial plant life. However, the exine structure in different groups of plants remains enigmatic. Here, modern and fossil coniferous bisaccate pollen were examined to investigate the detailed three-dimensional structure and properties of the pollen wall. X-ray nanotomography and volume electron microscopy are used to provide high-resolution imagery, revealing a solid nanofoam structure. Atomic force microscopy measurements were used to compare the pollen wall with other natural and synthetic foams and to demonstrate that the mechanical properties of the wall in this type of pollen are retained for millions of years in fossil specimens. The microscopic structure of this robust biological material has potential applications in materials sciences and also contributes to our understanding of the evolutionary success of conifers and other plants over geological time.

The Widened Pipe Model of plant hydraulic evolution

Shaping global water and carbon cycles, plants lift water from roots to leaves through xylem conduits. The importance of xylem water conduction makes it crucial to understand how natural selection deploys conduit diameters within and across plants. Wider conduits transport more water but are likely more vulnerable to conduction-blocking gas embolisms and cost more for a plant to build, a tension necessarily shaping xylem conduit diameters along plant stems. We build on this expectation to present the Widened Pipe Model (WPM) of plant hydraulic evolution, testing it against a global dataset. The WPM predicts that xylem conduits should be narrowest at the stem tips, widening quickly before plateauing toward the stem base. This universal profile emerges from Pareto modeling of a trade-off between just two competing vectors of natural selection: one favoring rapid widening of conduits tip to base, minimizing hydraulic resistance, and another favoring slow widening of conduits, minimizing carbon cost and embolism risk. Our data spanning terrestrial plant orders, life forms, habitats, and sizes conform closely to WPM predictions. The WPM highlights carbon economy as a powerful vector of natural selection shaping plant function. It further implies that factors that cause resistance in plant conductive systems, such as conduit pit membrane resistance, should scale in exact harmony with tip-to-base conduit widening. Furthermore, the WPM implies that alterations in the environments of individual plants should lead to changes in plant height, for example, shedding terminal branches and resprouting at lower height under drier climates, thus achieving narrower and potentially more embolism-resistant conduits.

Toxic mercury pulses into late Permian terrestrial and marine environments

Abstract Large spikes in mercury (Hg) concentration are observed globally at the latest Permian extinction (LPE) horizon that are thought to be related to enhanced volcanic emissions of the Siberian Traps large igneous province (LIP). While forming an effective chemostratigraphic marker, it remains unclear whether such enhanced volcanic Hg emissions could have generated toxic conditions that contributed to extinction processes. To address this, we examined the nature of enhanced Hg emissions from the Siberian Traps LIP and the potential impact it may have had on global ecosystems during the LPE. Model results for a LIP eruption predict that pulses of Hg emissions to the atmosphere would have been orders of magnitude greater than normal background conditions. When deposited into world environments, this would have generated a series of toxic shocks, each lasting >1000 yr. Such repeated Hg loading events would have had severe impact across marine trophic levels, as well as been toxic to terrestrial plant and animal life. Such high Hg loading rates may help explain the co-occurrence of marine and terrestrial extinctions.

The preceding root system drives the composition and function of the rhizosphere microbiome

BackgroundThe soil environment is responsible for sustaining most terrestrial plant life, yet we know surprisingly little about the important functions carried out by diverse microbial communities in soil. Soil microbes that inhabit the channels of decaying root systems, the detritusphere, are likely to be essential for plant growth and health, as these channels are the preferred locations of new root growth. Understanding the microbial metagenome of the detritusphere, and how it responds to agricultural management such as crop rotations and soil tillage, is vital for improving global food production.ResultsThis study establishes an in-depth soil microbial gene catalogue based on the living-decaying rhizosphere niches in a cropping soil. The detritusphere microbiome regulates the composition and function of the rhizosphere microbiome to a greater extent than plant type: rhizosphere microbiomes of wheat and chickpea were homogenous (65–87% similarity) in the presence of decaying root (DR) systems but were heterogeneous (3–24% similarity) where DR was disrupted by tillage. When the microbiomes of the rhizosphere and the detritusphere interact in the presence of DR, there is significant degradation of plant root exudates by the rhizosphere microbiome, and genes associated with membrane transporters, carbohydrate and amino acid metabolism are enriched.ConclusionsThe study describes the diversity and functional capacity of a high-quality soil microbial metagenome. The results demonstrate the contribution of the detritusphere microbiome in determining the metagenome of developing root systems. Modifications in root microbial function through soil management can ultimately govern plant health, productivity and food security.

Tabula rasa in the Patagonian Channels II: The cushion peat bog species Astelia pumila (Asteliaceae) and Donatia fascicularis (Stylidiaceae) survived the last glacial in south‐central Chile

AbstractAimPlant phylogeographic data from the Patagonian Channels are scant and it is largely unknown how the extensive Quaternary glaciations affected the population dynamics of the region's major vegetation component, that is cushion peat bogs (Magellanic moorland). Whether ice‐age glaciers wiped out all terrestrial plant life or whether some populations persisted in situ remains unclear. We reconstructed the phylogeography of two dominant Patagonian cushion peat bog species, Astelia pumila (G.Forst.) Gaudich. (Asteliaceae) and Donatia fascicularis J.R.Forst. & G.Forst. (Stylidiaceae), to test (a) the hypothesis of a glacial refugium for moorland plants in south‐central Chile and (b) the tabula rasa scenario for the Patagonian Channels. The retrieved phylogeographic patterns were compared with those reported previously for a further cushion peat bog species (Pfanzelt et al., Molecular Ecology 26, 4027–4044), with the objective to provide a broader picture of how West Patagonian moorland plants responded to the Quaternary ice‐ages.LocationWest and Fuegian Patagonia, and the Falkland Islands (Islas Malvinas), southern South America.MethodsDNA sequence data from seven and fourteen, respectively, nuclear loci containing Simple Sequence Repeats of 371 and 328 individuals of the two study species were analysed using population genetic summary statistics, phylogenetic networks and Bayesian and multivariate methods to determine genetic structure. Ecological niche modelling was used to reconstruct the spatial distribution of suitable habitat at the Last Glacial Maximum.ResultsAll A. pumila populations belong to a single population genetic cluster. In the case of D. fascicularis, only the northernmost sampled population from Nahuelbuta (Chile) is genetically distinct, whereas the remainder forms a cluster without much further substructure. According to palaeodistribution models, south‐central Chile offered suitable habitat during the last glacial.Main conclusionBoth ecological niche modelling and the very low genetic subdifferentiation are congruent with a tabula rasa scenario for the Patagonian Channels. Populations survived the last glacial in south‐central Chile, in an area to the northwest of the ice sheet. From there, southern regions were recolonized through highly bottlenecked source populations. Other, non‐mutually exclusive factors may have further shaped the population genetic patterns, among them high gene flow mediated by the strong westerly winds.

Control of root meristem establishment in conifers.

The evolution of terrestrial plant life was made possible by the establishment of a root system, which enabled plants to migrate from aquatic to terrestrial habitats. During evolution, root organization has gradually progressed from a very simple to a highly hierarchical architecture. Roots are initiated during embryogenesis and branch afterward through lateral root formation. Additionally, adventitious roots can be formed post-embryonically from aerial organs. Induction of adventitious roots (ARs) forms the basis of the vegetative propagation via cuttings in horticulture, agriculture and forestry. This method, together with somatic embryogenesis, is routinely used to clonally multiply conifers. In addition to being utilized as propagation techniques, adventitious rooting and somatic embryogenesis have emerged as versatile models to study cellular and molecular mechanisms of embryo formation and organogenesis of coniferous species. Both formation of the embryonic root and the AR primordia require the establishment of auxin gradients within cells that coordinate the developmental response. These processes also share key elements of the genetic regulatory networks that, e.g. are triggering cell fate. This minireview gives an overview of the molecular control mechanisms associated with root development in conifers, from initiation in the embryo to post-embryonic formation in cuttings.

May the Fittest Protein Evolve: Favoring the Plant‐Specific Origin and Expansion of NAC Transcription Factors

Plant-specific NAC transcription factors (TFs) evolve during the transition from aquatic to terrestrial plant life and are amplified to become one of the biggest TF families. This is because they regulate genes involved in water conductance and cell support. They also control flower and fruit formation. The review presented here focuses on various properties, regulatory intricacies, and developmental roles of NAC family members. Processes controlled by NACs depend majorly on their transcriptional properties. NACs can function as both activators and/or repressors. Additionally, their homo/hetero dimerization abilities can also affect DNA binding and activation properties. The active protein levels are dependent on the regulatory cascades. Because NACs regulate both development and stress responses in plants, in-depth knowledge about them has the potential to help guide future crop improvement studies.

TALEN-mediated genome-editing approaches in the liverwort Marchantia polymorpha yield high efficiencies for targeted mutagenesis

BackgroundThe liverwort Marchantia polymorpha occupies a crucial position in land plant evolution and provides the opportunity to investigate adaptations to a terrestrial plant life style. Marchantia reverse genetic analyses have thus far been conducted by employing a homologous recombination approach, which yields an efficiency of around 3%. Availability of the characterized and suitable endogenous MpEF1α promoter prompted us to establish the TALEN gene targeting technique for Marchantia.ResultsHere, two different TALEN techniques, using custom and self-assembled TALEN constructs, were applied and compared. The MpNOP1 gene was selected as a candidate gene, as the respective knockout mutant has been shown to lack air chamber formation, representing an easily traceable phenotype. We demonstrate that both TALEN approaches are successful in Marchantia yielding high gene targeting efficiencies of over 20%. Investigation of selected G1 up to G4 generations proved the stability of the knockout mutants. In 392 analyzed T1 plants, no additional phenotypes were observed and only one chimeric knockout plant was detected after an extended cultivation period. Interestingly, two out of the 24 sequenced mutants harbored indels causing in-frame mutations and revealed novel Mpnop1-related phenotypes. This demonstrates the potential to detect crucial amino acids and motives of targeted proteins, which is of special interest for essential genes where full knockouts are lethal. The FastTALE™ TALEN assembly kit enables the rapid assembly and ligation of the TALEN arms within half a day. For transformations, custom and assembled constructs were subcloned into Marchantia binary vectors possessing the MpEF1α promoter.ConclusionConsidering time, costs and practicability, the assembly TALEN approach represents a rapid and highly efficient gene targeting system to generate Marchantia knockout mutants, which can be further adapted for future advanced genome-editing applications.

Cloning and functional characterization of a 4-coumarate CoA ligase from liverwort Plagiochasma appendiculatum

Plant phenylpropanoids represent a large group of secondary metabolites which have played an important role in terrestrial plant life, beginning with the evolution of land plants from primitive green algae. 4-Coumarate: coenzyme A ligase (4CL) is a provider of activated thioester substrates within the phenylpropanoid synthesis pathway. Although 4CLs have been extensively characterized in angiosperm, gymnosperm and moss species, little is known of their functions in liverworts. Here, a 4CL homolog (designated as Pa4CL1) was isolated from the liverwort species Plagiochasma appendiculatum. The full-length cDNA sequence of Pa4CL1 contains 1644bp and is predicted to encode a protein with 547amino acids. The gene products were 40–50% identical with 4CL sequences reported in public databases. The recombinant protein was heterologously expressed in Escherichia coli and exhibited a high level of 4CL activity, catalyzing formation of hydroxycinnamate-CoA thioesters by a two-step reaction mechanism from corresponding hydroxycinnamic acids. Kinetic analysis indicated that the most favorable substrate for Pa4CL1 is p-coumaric acid. The transcription of Pa4CL1 was induced when P. appendiculatum thallus was treated with either salicylic acid or methyl jasmonate.

Drosophila Embryos as Model to Assess Cellular and Developmental Toxicity of Multi-Walled Carbon Nanotubes (MWCNT) in Living Organisms

Different toxicity tests for carbon nanotubes (CNT) have been developed to assess their impact on human health and on aquatic and terrestrial animal and plant life. We present a new model, the fruit fly Drosophila embryo offering the opportunity for rapid, inexpensive and detailed analysis of CNTs toxicity during embryonic development. We show that injected DiI labelled multi-walled carbon nanotubes (MWCNTs) become incorporated into cells in early Drosophila embryos, allowing the study of the consequences of cellular uptake of CNTs on cell communication, tissue and organ formation in living embryos. Fluorescently labelled subcellular structures showed that MWCNTs remained cytoplasmic and were excluded from the nucleus. Analysis of developing ectodermal and neural stem cells in MWCNTs injected embryos revealed normal division patterns and differentiation capacity. However, an increase in cell death of ectodermal but not of neural stem cells was observed, indicating stem cell-specific vulnerability to MWCNT exposure. The ease of CNT embryo injections, the possibility of detailed morphological and genomic analysis and the low costs make Drosophila embryos a system of choice to assess potential developmental and cellular effects of CNTs and test their use in future CNT based new therapies including drug delivery.

Carsten Egeberg Borchgrevink (1864-1934): The Man Who Claimed to be the First to Set Foot on Antarctica

Carsten Borchgrevink continues to be one of the most enigmatic Antarctic explorers. He made two visits to Antarctica, briefly in 1895, and much longer in 1898-1900. Today it is acknowledged that he made significant contributions to Antarctic exploration. He made a claimed first discovery of terrestrial plant life in 1895. He led the first party to winter on Antarctica in 1899 in very difficult weather conditions. His expedition made a year-long continuous record of weather conditions, and glacier movement was briefly measured. Useful zoological data were obtained, but the death of Hanson, the zoologist and loss of some of his records, lessened their possible value. New plants, some insects, and shallow sea-water fauna were discovered. Extensive photographic records were obtained. The 1898-1900 expedition noted the reduction in the seaward extent of the Ross Ice Sheet. It discovered what later became known as the Bay of Whales, and there made the first ascent onto the Ross Sea Barrier, showing that travel inland was feasible in that region, ‘opening the way to the South’. A reasonable estimate of the then position of the South Magnetic Pole was made. In addition Borchgrevink showed the effectiveness of kayaks for local water transport, and dogs with trained dog-handlers for land travel (and companionship). His expedition was underpinned by good planning for housing, equipment (including use of the recently invented Primus Stove), clothing (notably shoes lined with sennegrass) and food. His scientific party was well-chosen for their abilities, but national and social differences played a part in periods of tension with the leader, who was inclined to overestimate his own scientific ability. The achievements of the expedition were given little recognition for most of his life, particularly in Britain, in part because of his initial success, over a period of some years, in gaining financial support for his expedition in the face of strong opposition from ‘official’ British scientific bodies. In addition his rather brash and abrasive personality, some public quarrels and perhaps a rather quirky sense of humour did not make him popular. His achievements have been obscured to some extent by inaccurate and exaggerated criticisms of his activities.

Lignin--Designed Randomness

0 0 1 282 1608 Biologic Institute 13 3 1887 14.0 Normal 0 false false false EN-US ZH-CN X-NONE Humans have long used wood as a structural material for some of the same reasons that trees use it—it combines great strength, flexibility and durability with a relatively low density. These desirable properties depend partly on lignin , a major chemical constituent of many plants, including trees. Lignin is the most abundant aromatic polymer on earth and the second most abundant organic polymer of any kind, exceeded only by cellulose. It is estimated that 30% of the earth’s non-fossil organic carbon is in the form of lignin. Considering its massive abundance and its high energy content (40% higher than cellulose, gram for gram), it is striking that no organism seems to have tapped it as an energy source. After posing this as an evolutionary enigma, we prepare to address it by reviewing what is known about the structure, biosynthesis and biodegradation of wood in general and of lignin in particular. Then, returning to the enigma, we ask whether it is more readily explained within a Darwinian framework or a design framework. The Darwinian account must somehow reconcile 400 million years of failure to evolve a relatively modest innovation—growth on lignin—with a long list of spectacular innovations thought to have evolved in a fraction of that time. How can one mechanism have been at the same time so effective and so ineffective? That tension vanishes completely when the design perspective is adopted. Terrestrial animal life is crucially dependent on terrestrial plant life, which is crucially dependent on soil, which is crucially dependent on the gradual photo- and biodegradation of lignin. Fungi accomplish th e bio degradation, and the surprising fact that it costs them energy to do so keeps the process gradual. The peculiar properties of lignin therefore make perfect sense when seen as part of a coherent design for the entire ecosystem of our planet.

Why do some small islands lack vegetation? Evidence from long-term introduction experiments

Classic island biogeography theory predicts that very small islands, near the extreme lower end of the speciesarea relationship, should support very few species. At times no species may be present, however, due to randomness in the immigrationextinction dynamics. Alternatively, a lack of vegetation on very small islands may indicate that such islands do not contain the appropriate habitat for the establishment or long-term survival of plants, or that disturbances are too frequent or intense. These potential mechanisms were evaluated in the central Exumas, Bahamas, where surveys of 117 small islands revealed that over a third of the islands supported no terrestrial plant life. Area and exposure were significant predictors of whether a small island was vegetated or not in multiple logistic regressions. No islands naturally devoid of vegetation were colonized over a 17-yr period, and only two naturally vegetated islands lost all vegetation. Experimental introductions of two speciesSesuvium portulacastrum and Borrichia arborescensrevealed that a number of islands naturally lacking vegetation were able to sustain introduced populations over the long term (up to 15 yr). Drought and hurricanes appeared to have reduced the establishment success and possibly long-term survival of the introductions, although some populations survived four major hurricanes. Turnover rates of both introduced species were often an order of magnitude higher on the experimental introduction islands than on other islands in the archipelago. It appears many of the islands in this system that naturally lack vegetation may be physically capable of supporting terrestrial plant life, yet have no plants primarily due to barriers to colonization.

Structure of Isoprene Synthase Illuminates the Chemical Mechanism of Teragram Atmospheric Carbon Emission

The X-ray crystal structure of recombinant PcISPS (isoprene synthase from gray poplar hybrid Populus × canescens) has been determined at 2.7 Å resolution, and the structure of its complex with three Mg 2+ and the unreactive substrate analogue dimethylallyl- S-thiolodiphosphate has been determined at 2.8 Å resolution. Analysis of these structures suggests that the generation of isoprene from substrate dimethylallyl diphosphate occurs via a syn-periplanar elimination mechanism in which the diphosphate-leaving group serves as a general base. This chemical mechanism is responsible for the annual atmospheric emission of 100 Tg of isoprene by terrestrial plant life. Importantly, the PcISPS structure promises to guide future protein engineering studies, potentially leading to hydrocarbon fuels and products that do not rely on traditional petrochemical sources.

Monitoring mangrove forest dynamics of the Sundarbans in Bangladesh and India using multi-temporal satellite data from 1973 to 2000

Mangrove forests in many parts of the world are declining at an alarming rate—possibly even more rapidly than inland tropical forests. The rate and causes of such changes are not known. The forests themselves are dynamic in nature and are undergoing constant changes due to both natural and anthropogenic forces. Our research objective was to monitor deforestation and degradation arising from both natural and anthropogenic forces. We analyzed multi-temporal satellite data from 1970s, 1990s, and 2000s using supervised classification approach. Our spatio-temporal analysis shows that despite having the highest population density in the world in its periphery, areal extent of the mangrove forest of the Sundarbans has not changed significantly (approximately 1.2%) in the last ∼25 years. The forest is however constantly changing due to erosion, aggradation, deforestation and mangrove rehabilitation programs. The net forest area increased by 1.4% from the 1970s to 1990 and decreased by 2.5% from 1990 to 2000. The change is insignificant in the context of classification errors and the dynamic nature of mangrove forests. This is an excellent example of the co-existence of humans with terrestrial and aquatic plant and animal life. The strong commitment of governments under various protection measures such as forest reserves, wildlife sanctuaries, national parks, and international designations, is believed to be responsible for keeping this forest relatively intact (at least in terms of area). While the measured net loss of mangrove forest is not that high, the change matrix shows that turnover due to erosion, aggradation, reforestation and deforestation was much greater than net change. The forest is under threat from natural and anthropogenic forces leading to forest degradation, primarily due to top-dying disease and over-exploitation of forest resources.