Light Environment Research Articles

Automatic Method for Extracting Tree Branching Structures from a Single RGB Image

Creating automated methods for detecting branches in images is crucial for applications like harvesting robots and forest monitoring. However, the tree images encountered in real-world scenarios present significant challenges for branch detection techniques due to issues such as background interference, occlusion, and varying environmental lighting. While there has been notable progress in extracting tree trunks for specific species, research on identifying lateral branches remains limited. The primary challenges include establishing a unified mathematical representation for multi-level branch structures, conducting quantitative analyses, and the absence of suitable datasets to facilitate the development of effective models. This study addresses these challenges by creating a dataset encompassing various tree species, developing annotation tools for multi-level branch structure labeling, designing branch vector representations and quantitative metrics. Building on this foundation, the study introduces an automatic extraction model for multi-level branch structures that utilizes ResNet and a self-attention mechanism, along with a tailored loss function for branch extraction tasks. The study evaluated several model variants through both qualitative and quantitative experiments. Results from different tree images demonstrate that the final model can accurately identify the trunk structure and effectively extract detailed lateral branch structures, offering a valuable tool for applications in this area.

Research on the health lighting scheme of university library reading room

The quality of the indoor lighting environment in the reading space of the university library is essential for students' visual perception, emotional evaluation, and cognitive efficiency. The design of the lighting environment considering the change of natural light is one of the important development directions to improve the light environment quality of the reading room and meet the health requirements of students. This paper from the perspective of reading vision, emotion, and cognitive probes into the natural light environment lighting design, builds a reading lighting environment laboratory, using subjective evaluation, task performance, and physiological indicators of the measurement method, first analyses the weight of different indicators under different time, establish lighting environment comprehensive evaluation index I and artificial illumination and desktop illumination prediction model. The experimental results show that experimental results show that visual discomfort and clarity are the key factors in the early and later stages. In the transition phase, emotional indicators become particularly important. The model of dynamic lighting design scheme during 17:30–20:30 is: y = 227753.1746–900120.63492x+ 1179428.57142x2-512000x3, R2 = 0.99702; the fitting formula of desktop illumination in 17:30–20:30 period is: y = 566.666667–197.08995x + 158.73016x2-37.03704x3, R2 = 0.95238. The results aim to provide a theoretical basis for the design and optimization of dynamic lighting under natural light in the library reading room.

Fast stomatal kinetics in sorghum enables tight coordination with photosynthetic responses to dynamic light intensity and safeguards high water use efficiency.

In this study, we assessed 43 accessions of Sorghum from 16 countries across three continents. Our objective was to identify stomatal and photosynthetic traits that could be exploited in breeding programs to increase photosynthesis without increasing water use under dynamic light environments. Under field conditions, Sorghum crops often have limited water availability and are exposed to rapidly fluctuating light intensity, which influences both photosynthesis and stomatal behaviour. Our results highlight a tight coupling between photosynthetic rate (A) and stomatal conductance (gs) even under dynamic light conditions that results in steady Wi. This was due mainly to rapid stomatal responses, with the majority of Sorghum accessions responding within 5min or less. The maintenance of Ci:Ca over a large range of accessions suggests high stomatal sensitivity to changes in Ci, that could underlie the rapid gs responses and extremely close relationship between A and gs under both dynamic and steady-state conditions. Therefore, Sorghum represents a prime candidate for uncovering the elusive mechanisms that coordinate A and gs, and such information could be used to design crops with high A without incurring significant water losses and eroding Wi.

The impact of light adjustment versus tuneable white mode on ICU staff’s circadian rhythms

ABSTRACT The significance of lighting design in intensive care units (ICUs) for healthcare professionals’ demanding work and its profound impact on health, visual comfort and overall well-being cannot be overstated. This study investigates the potential of controlling luminous flux and spectral characteristics to enhance ICU lighting environments. It aims to determine whether modifying the lighting spectrum positively affects health without compromising visual comfort and colour discrimination. Two distinct LED lighting configurations were tested. The first adjusted only light levels, providing insights into staff responses. The second used tuneable white lighting, allowing changes in spectral content and colour temperature throughout shifts, resembling natural light variations. Effects were assessed via subjective perception surveys and objective colour rendering tests. Physiological impacts were evaluated through urine and blood samples, analysing melatonin suppression and cortisol levels, crucial for regulating rhythms and stress. Results offer valuable insights into lighting’s impact on ICU occupants’ well-being, highlighting the potential benefits of spectral adjustments while maintaining visual comfort and colour discrimination. This holistic approach to lighting design in critical care settings emphasizes the importance of balancing health benefits with lighting quality.

Light sampling behaviour regulates circadian entrainment in mice

BackgroundThe natural light environment is far more complex than that experienced by animals under laboratory conditions. As a burrowing species, wild mice are able to self-modulate their light exposure, a concept known as light environment sampling behaviour. By contrast, under laboratory conditions mice have little opportunity to exhibit this behaviour. To address this issue, here we introduce a simple nestbox paradigm to allow mice to self-modulate their light environment. Dark nestboxes fitted with passive infrared sensors were used to monitor locomotor activity, circadian entrainment, decision making and light environment sampling behaviour.ResultsUnder these conditions, mice significantly reduce their light exposure to an average of just 0.8 h across a 24 h period. In addition, mice show a distinct pattern of light environment sampling behaviour, with peaks at dawn and dusk under a ramped light dark cycle. Furthermore, we show that the timing of light environment sampling behaviour depends upon endogenous circadian rhythms and is abolished in mice lacking a circadian clock, indicating a feedback loop between light, the circadian clock and behaviour.ConclusionsOur results highlight the important role of behaviour in modifying the light signals available for circadian entrainment under natural conditions.

New color channel driven physical lighting model for low-light image enhancement

Outdoor imaging systems, affected by low-light conditions, generally produce low-quality images with poor visibility. Low-quality images can directly influence high-level tasks such as surveillance and autonomous navigation systems. Enhancing the images captured under inadequate lighting conditions aims to generate higher visual quality in these images. However, current low-light enhancement methods may result in color unnaturalness, information loss, and strange artifacts. We propose a new color channel-driven physical lighting model (NCC-PLM) to respond to these issues to improve image quality. More concretely, we first apply a gamma correction to the input image according to its darkness degree, which is determined by its average intensity value. Then, we introduce a new color channel prior to estimate the environmental light (EL) and light scattering attenuation rate (LSAR). Finally, the enhanced image is obtained through the estimations and physical lighting model. Experimental results on various datasets demonstrate the proposed method's effectiveness and superiority over the compared methods both visually and qualitatively. Specifically, we enhance the visual quality of low-light images by revealing intricate details and maintaining color consistency, leading to a natural appearance.

Characterizing the structural complexity of the Earth’s forests with spaceborne lidar

Forest structural complexity is a key element of ecosystem functioning, impacting light environments, nutrient cycling, biodiversity, and habitat quality. Addressing the need for a comprehensive global assessment of actual forest structural complexity, we derive a near-global map of 3D canopy complexity using data from the GEDI spaceborne lidar mission. These data show that tropical forests harbor most of the high complexity observations, while less than 20% of temperate forests reached median levels of tropical complexity. Structural complexity in tropical forests is more strongly related to canopy attributes from lower and middle waveform layers, whereas in temperate forests upper and middle layers are more influential. Globally, forests exhibit robust scaling relationships between complexity and canopy height, but these vary geographically and by biome. Our results offer insights into the spatial distribution of forest structural complexity and emphasize the importance of considering biome-specific and fine-scale variations for ecological research and management applications. The GEDI Waveform Structural Complexity Index data product, derived from our analyses, provides researchers and conservationists with a single, easily interpretable metric by combining various aspects of canopy structure.

A Cross-Sectional Study of Circadian Stimulus in Swedish Radiographers' Light Environment.

Background: Timely light exposure is a vital aspect to achieve better sleep and well-being. As there are risks with a disturbed circadian rhythm and benefits with light settings that stimulate the rhythm, the circadian effective light, circadian stimulus (CS), for radiographers was examined. Aim: The aim of the study was to compare radiographers' light environment on the workstations, at a university hospital in Southern Sweden in the form of CS and relate that to recommendations published by the Swedish Environmental Protection Agency. Method: A cross-sectional method has been applied. The measurements for CS were collected in all labs in the radiology department in the middle of January. Result: A total of 804 measures were evenly collected resulting in a median for the 19 labs, where the observed median for all labs was 0.091 CS which is significantly lower than the recommended value of 0.3 CS (p < .001). Comparing work light settings with maximum light levels in the brightest and darkest labs showed a significant difference (p < .001). Conclusion: The CS values in the labs, at the radiology department at a university hospital in Southern Sweden, do not reach the recommended values of circadian stimulus published by the Swedish Environmental Protection Agency when the radiographers themselves set the light. There is a potential for improvement as a significant difference could be seen between the chosen level of light and the maximum possible level of light.

Effects of Light and Water Agitation on Hatching Processes in False Clownfish Amphiprion ocellaris.

False clownfish (Amphiprion ocellaris) employ a hatching strategy regulated by environmental cues, wherein parents provide water flow to encourage embryos to hatch after sunset on the hatching day. Despite previous studies demonstrating the necessity of complete darkness and water agitation for hatching, the regulatory mechanisms underlying these environmental cues remain elusive. This study aimed to investigate how darkness and water agitation affect the secretion of hatching enzymes and the hatching movements of embryos in false clownfish. Assessment of chorion digestion and live imaging of Ca2+ in hatching glands using GCaMP6s, a Ca2+ indicator, revealed that darkness stimulation triggers the secretion of hatching enzymes by increasing Ca2+ levels in hatching gland cells. On the other hand, water agitation primarily stimulated hatching movements in embryos, which led to the rupture of their egg envelopes. These results suggest that changes in light environments following sunset induce embryos to secrete hatching enzymes and that water agitation provided by parents stimulates hatching movements. These responses to environmental cues, light and water agitation, contribute to the rapid and synchronous hatching in false clownfish.

Environmental Light Controls the Daily Organization of Breathing by Activating Brn3b-expressing Intrinsically Photosensitive Retinal Ganglion Cells in Mice.

Rhythmic, daily fluctuations in minute ventilation are controlled by the endogenous circadian clock located in the suprachiasmatic nucleus (SCN). While light serves as a potent synchronizer for the SCN, it also influences physiology and behavior by activating Brn3b-expressing, intrinsically photosensitive retinal ganglion cells (ipRGCs). It is currently unclear the extent to which the external light environment shapes daily ventilatory patterns independent of the SCN. To determine the relative influence of environmental light versus circadian timing on the organization of daily rhythms in minute ventilation, we used whole-body plethysmography to measure the breathing of mice housed on a non-entraining T28 cycle (14 h light:14 h dark). Using this protocol, we found that minute ventilation exhibits a ~28-h rhythm with a peak at dark onset that coincides with the light:dark cycle and the animals' locomotor activity. To determine if this 28-h rhythm in minute ventilation was mediated by Brn3b-expressing ipRGCs, we measured the breathing of Brn3bDTA mice housed under the T28 cycle. Brn3bDTA mice lack the Brn3b-expressing ipRGCs that project to many non-SCN brain regions. We found that despite rhythmic light cues occurring on a 28-h basis, Brn3bDTA mice exhibited 24-h rhythms in minute ventilation, locomotor activity, and core body temperature consistent with organization by the SCN. The 24-h minute ventilation rhythm of Brn3bDTA mice was found to be driven predominantly by tidal volume rather than respiratory rate. These data indicate that the external light:dark cycle can directly drive daily patterns in minute ventilation by way of Brn3b-expressing ipRGCs. In addition, these data strongly suggest that the activation of Brn3b-expressing ipRGCs principally organizes daily patterns in breathing and locomotor activity when light:dark cues are presented in opposition to endogenous clock timing.

Prolonged Post-Harvest Preservation in Lettuce (Lactuca sativa L.) by Reducing Water Loss Rate and Chlorophyll Degradation Regulated through Lighting Direction-Induced Morphophysiological Improvements.

To investigate the relationship between the lighting direction-induced morphophysiological traits and post-harvest storage of lettuce, the effects of different lighting directions (top, T; top + side, TS; top + bottom, TB; side + bottom, SB; and top + side + bottom, TSB; the light from different directions for a sum of light intensity of 600 μmol·m-2·s-1 photosynthetic photon flux density (PPFD)) on the growth morphology, root development, leaf thickness, stomatal density, chlorophyll concentration, photosynthesis, and chlorophyll fluorescence, as well as the content of nutrition such as carbohydrates and soluble proteins in lettuce were analyzed. Subsequently, the changes in water loss rate, membrane permeability (measured as relative conductivity and malondialdehyde (MDA) content), brittleness (assessed by both brittleness index and β-galactosidase (β-GAL) activity), and yellowing degree (evaluated based on chlorophyll content, and activities of chlorophyllase (CLH) and pheophytinase (PPH)) were investigated during the storage after harvest. The findings indicate that the TS treatment can effectively reduce shoot height, increase crown width, enhance leaves' length, width, number, and thickness, and improve chlorophyll fluorescence characteristics, photosynthetic capacity, and nutrient content in lettuce before harvest. Specifically, lettuce's leaf thickness and stomatal density showed a significant increase. Reasonable regulation of water loss in post-harvested lettuce is essential for delaying chlorophyll degradation. It was utilized to mitigate the increase in conductivity and hinder the accumulation of MDA in lettuce. The softening speed of leafy vegetables was delayed by effectively regulating the activity of the β-GAL. Chlorophyll degradation was alleviated by affecting CLH and PPH activities. This provides a theoretical basis for investigating the relationship between creating a favorable light environment and enhancing the post-harvest preservation of leafy vegetables, thus prolonging their post-harvest storage period through optimization of their morphophysiological phenotypes.

Isolation, purification, characterization and stability analysis of melanin pigment from Mesona chinensis

In this study, the isolation and purification of melanin pigment from Mesona chinensis (MCM) were conducted, and the structural characterization and stability evaluation of MCM were performed. The results indicate that MCM is consistent with the spectral features of catechins and polyphenols, identified the stretching vibrations of functional groups such as OH, CH, CO, and CO. It is inferred that the structure of MCM is consistent with that of theophylline and it is mainly composed of phenolic acids, terpenoids, and organic acids. Stability evaluations indicate that MCM exhibits stability under white light, ultraviolet (UV) light, neutral, and alkaline environments, and it shows low sensitivity to reducing agents.

Differences in anterior segment structure and pupillary diastolic characteristics of eyes with primary angle closure suspects under light and shade environments

Objective: To investigate the anatomical structure changes of the anterior segment and dynamic pupil changes in eyes with suspected primary angle-closure (PACS) under light and dark conditions, and their correlation with the occurrence of acute primary angle-closure (APAC). Methods: This cross-sectional study collected data from 37 PACS patients (66 eyes) who visited the ophthalmology clinic of the Second Affiliated Hospital of Harbin Medical University between September 2019 and March 2021. The patients included 12 males and 25 females, with an average age of (61.27±7.35) years. Of the 66 eyes, 58 had no history of APAC in the contralateral eye, while 8 had a history of APAC in the contralateral eye. Patients without a history of APAC in both eyes underwent the dark room prone provocative test (DRPPT), and the eyes were divided into three groups: DRPPT- (44 eyes), DRPPT+ (14 eyes), and APAC (8 eyes). The DRPPT+ and APAC groups were combined into the APAC+ group. All patients underwent ultrasound biomicroscopy (UBM) to measure the changes in various parameters under light and dark conditions, including anterior chamber angle 500 (ACA500Δ) and 1000 (ACA1000Δ), angle opening distance 500 (AOD500Δ) and 1000 (AOD1000Δ), and iris thickness 500 (IT500Δ) and 1000 (IT1000Δ). Anterior segment analysis was performed to capture the pupil changes under light and dark conditions, recording pupil diameter, maximum dilation speed (Vmax), maximum constriction speed (Vmin), and average speed (Vm). Results: There was no significant difference in the parameters between DRPPT+ group and APAC group (P>0.05). In the difference analysis, it was found that the Vm value of DRPPT- group [(0.17±0.07) mm/s] was higher than that of APAC+ group [(0.13±0.06)mm/s], and the difference was statistically significant (P<0.05). There was no significant difference in other parameters (P>0.05). Vmax was positively correlated with temporal ACA1000Δ and temporal AOD1000Δ in all patients with PACS (r=0.302, 0.260; P<0.05), Vmin was negatively correlated with temporal ACA1000Δ and temporal AOD1000Δ (r=-0.338, -0.330; P<0.05). Conclusions: The dynamic changes in the anterior segment and pupil under different lighting conditions provide insights into the risk factors and potential predictive indicators for the occurrence of APAC in PACS patients.

Evaluating the impact of road lighting on pedestrian reassurance through the day-dark approach

A field study in the urban area of Ljubljana, Slovenia, explored the impact of variations in lighting parameters on pedestrian perceptions of safety, visual comfort and risk. Utilising the day-dark approach with 35 participants, this research evaluates differences in perception under daytime and after dark (but with road lighting) environments to determine the optimal lighting conditions. The results suggested that a minimum horizontal illuminance of 1.8 lx, corresponding to a day-dark differential of 0.5 on a 5-point scale, and a minimum luminance of about 0.15 cd m−2 were optimal for perceived safety and comfort. The results suggest that minimum illuminance provided a more effective predictor of pedestrian reassurance than did the other lighting parameters considered.

Light quality and spatial variability influences on seedling regeneration in Hawaiian lowland wet forests

Abstract Tropical forest understories tend to be light‐limited. The red‐to‐far‐red ratio (R:FR) is a useful and reliable index of light quality and its spatial variability can influence competition between native and non‐native seedlings. While per cent light transmittance has been quantified in some Hawaiian lowland wet forests (HLWF), no information exists on how the spatial distribution of understorey light varies in relation to species invasion, or if patterns of seedling regeneration and light are linked. We measured the R:FR of light in the understorey to assess light quality in three HLWF forest types: native‐dominated, partially invaded and Psidium cattleyanum‐ (strawberry guava) dominated to quantify light quality in the understorey (0–50 cm height). We also identified relationships between light quality and native and non‐native seedling presence, diversity and abundance. Together, these data can help to determine the restoration potential of HLWF. Linear mixed‐effect modelling showed that native‐dominated forests had significantly greater R:FR than P. cattleyanum‐dominated forests, demonstrating a transformation in the light environment with increased invasion. Heterogeneity in R:FR varied more across sites than among forest types. In both native‐dominated and partially invaded forests, there were more native seedlings in the low‐quality R:FR (0.0–0.40) category and fewer in the medium‐ (0.41–0.70), and high‐quality (≥0.71) light categories than would be expected by chance, and there were no native seedlings in the P. cattleyanum‐dominated forests. Native‐dominated forests had greater species richness and abundance of native seedlings than the partially invaded forests, likely due to propagule availability. However, the spatial clustering of seedlings, the mismatch of native seedlings in light environments less suitable, and a considerable proportion of open high‐quality microsites, highlights that conditions are not optimal for native species in HLWF in the long term. Synthesis and applications. The native‐dominated and partially invaded forests still hold conservation value, despite variation among sites. Seedling additions could be targeted to different R:FR environments and at different spatial scales, but the lack of a strong relationship between R:FR and seedling number suggests that other factors besides light quality should be considered in seedling enrichment or other management activities.

Efficacy of agomelatine on sleep disorders and lateral habenula neuronal activity in chronic restraint stress depression model mice.

Sleep disorders (SD) are one of the common manifestations of depression patients. This article aimed to explore the effect of Agomelatine (Ago) on SD in chronic restraint stress (CRS) depression model mice and its effect on the activity of neurons in the lateral habenula (LHb). 30 C57BL/6J mice were divided into normal (C57BL/6J) group, CRS group, and Ago group. CRS experiment was used to establish the depression model, and Ago was used to treat CRS mice. Based on behavioral tests in mice and electrophysiology record, SD and LHb neuron activity were assessed. The expression levels of brain-derived neurotrophic factor (BDNF) and nuclear phosphoprotein (c-Fos) in LHb were detected by Western blot (WB). As against the CRS group, the Ago group had a reduction in the immobility time during forced swimming training and an increase in the preference for sucrose in the sucrose preference test; The expression levels of c-Fos and BDNF proteins in the LHb neurons of the Ago group mice were lower than those in the CRS group (P < 0.05), and the values approached the levels of the normal control group. In both dark and light environments, the rapid eye movement (REM) sleep duration of the CRS group mice was significantly longer than that of the normal control group (P < 0.05). It was concluded that Ago may intervene in the depressive-like behavior and overall sleep patterns of CRS depression model mice by regulating the activity of LHb neurons and inhibiting the neuroinflammatory process. This provides a potential drug target for the development of new treatment strategies for depression.

How many surfaces can you distinguish by color? Real environmental lighting increases discriminability of surface colors.

Color supports object identification. However, two objects that differ in color under one light can appear indiscriminable under a second light, a phenomenon known as illuminant metamerism. Past studies evaluated the frequency of illuminant metamerism only under single, uniform illuminants. Here we used computer-graphics techniques to simulate a pair of planar surfaces placed under newly measured hyperspectral illumination maps that quantify the directional variability of real-world lighting environments. We counted the instances of illuminant metamerism that can be solved simply by viewing surfaces tilted to a different direction. Results show that most instances of illuminant metamerism can in theory be resolved for both trichromatic and dichromatic observers, suggesting that the physical directional variability available in natural lighting environments substantially mitigates the biological limitations of trichromacy or dichromacy.

Advanced understanding of the natural forces accelerating aging and release of black microplastics (tire wear particles) based on mechanism and toxicity analysis

Currently, tire wear particles (TWPs), a typical type of black microplastics (MPs), are frequently overlooked as the major source of MPs in aquatic environments. TWPs are widely distributed and exhibit complex environmental behaviors. However, how natural forces affect the aging and release behavior of TWPs at the nano(micro)scale remains inadequately explored. This study systematically investigated the aging behavior and mechanism of TWPs under the action of simulated natural light and high-temperature in both dry and wet environments, as well as the effect of aging treatment on the released leachate. The findings demonstrated that aging treatment significantly altered the physicochemical properties of TWPs, including chain scission and surface oxidation, and facilitated the release of heavy metals and organic additives in the meantime. In particular, the leaching concentration of Zn exhibited a positive linear relationship with exposure time. In the thermal-aging process, the oxidation of TWPs was primarily caused by superoxide anion (O2•−). During the photo-aging exposure, TWPs exhibited heightened electron-donating capacity, resulting in the formation of more O2•− and singlet oxygen (1O2) to attack TWPs. Moreover, the analysis of leachate produced under light and high-temperature conditions suggested that heavy metals exerted low ecological risks in water. Nonetheless, the photo-aging process enhanced the toxicity of released leachate to L929 cells, which could be attributed to highly toxic additive transformation products (such as HMMM-411 and 6PPD-Q) and more heavy metals. These findings shed light on the fate of TWPs and the ecological risks posed by aged TWPs in aquatic environments.

A framework of insole blanking robot based on adaptive edge detection and FSPS-BIT* path planning

Insole blanking production technology plays a vital role in contemporary machining and manufacturing industries. Existing insole blanking production models have limitations because most robots are required to accurately position the workpiece to a predetermined location, and special auxiliary equipment is usually required to ensure the precise positioning of the robot. In this paper, we present an adaptive blanking robotic system for different lighting environments, which consists of an industrial robot arm, an RGB-D camera configuration, and a customized insole blanking table and mold. We introduce an innovative edge detection framework that utilizes color features and morphological parameters optimized through particle swarm optimization (PSO) techniques to Adaptive recognition of insole edge contours. A path planning framework based on FSPS-BIT* is also introduced, which integrates the BIT* algorithm with the FSPS algorithm for efficient path planning of the robotic arm.

Chromatic acclimation in cyanobacteria renders robust photosynthesis and fitness in dynamic light environment: Recent advances and future perspectives.

Cyanobacteria are photoautotrophic organisms that use light and water as a source of energy and electrons, respectively, to fix atmospheric carbon dioxide and release oxygen as a by-product during photosynthesis. However, photosynthesis and fitness of organisms are challenged by seasonal and diurnal fluctuations in light environments. Also, the distribution of cyanobacteria in a water column is subject to changes in the light regime. The quality and quantity of light change significantly in low and bright light environments that either limit photochemistry or result in photoinhibition due to an excess amount of light reaching reaction centers. Therefore, cyanobacteria have to adjust their light-harvesting machinery and cell morphology for the optimal harvesting of light. This adjustment of light-harvesting involves remodeling of the light-harvesting complex called phycobilisome or incorporation of chlorophyll molecules such as chlorophyll d and f into their light-harvesting machinery. Thus, photoacclimation responses of cyanobacteria at the level of pigment composition and cell morphology maximize their photosynthetic ability and fitness under a dynamic light environment. Cyanobacteria exhibit different types of photoacclimation responses that are commonly known as chromatic acclimation (CA). In this work, we discuss different types of CA reported in cyanobacteria and present a molecular mechanism of well-known type 3 CA where phycoerythrin and phycocyanin of phycobilisome changes according to light signals. We also include other aspects of type 3 CA that have been recently studied at a molecular level and highlight the importance of morphogenes, cytoskeleton, and carboxysome proteins. In summary, CA gives a unique competitive benefit to cyanobacteria by increasing their resource utilization ability and fitness.