Phytoplankton taxonomy, identification and enumeration

Phytoplankton are microscopic, free floating organisms and is the principal primary producers of the oceans. Their size range from 0.2 μm to 2 mm. Phytoplankton contains primary pigments and accessory pigments such as chlorophyll (Chl), carotenoids etc. which strongly absorbs the blue and red light of the visible spectra. Phytoplankton also influences the total scattering properties of sea water

Phytoplankton functional types

The term “functional types” emerged from biogeochemical studies. It represents the group of organisms that share common characteristic role in biogeochemical functions. In ecology, a functional type or group represents an aggregation of organisms according to some well-defined property that sets a role or “function” for them in a system. Phytoplankton Functional types (PFT) are defined as a group of organisms (irrespective of taxonomic affiliation) that carry out a particular chemical process such as calcification, silicification, nitrogen fixation, or dimethyl sulfide production; they are also referred to as “biogeochemical guilds”. For example, in Nitrogen-Phytoplankton-Zooplankton (NPZ) models, P and Z are representatives of functional types, i.e., producers and consumers. This aggregation is acceptable for some applications, but may be too coarse or even inappropriate for others

Regional and seasonal variations in phytoplankton

One of the main goals of remote-sensing observations is the study of seasonal cycles of phytoplankton biomass in different regions of the World Ocean. In many regions these cycles repeat every year including minor details. This pattern is a result of seasonal oscillations of physical environment. In high latitudes these oscillations are more pronounced, and the response of phytoplankton is more evident

Satellite ocean colour sensors

The 70% of the earth’s surface is covered by the ocean and the life inhabiting the oceans play an important role in shaping the earth’s climate. Phytoplankton, also known as microalgae, are the single celled, autotrophic components of the plankton community and a key part of oceans, seas and freshwater basin ecosystems. They are significant factor in the ocean carbon cycle and, hence, important in all pathways of carbon in the ocean. Phytoplankton contain chlorophyll pigments for photosynthesis, similar to terrestrial plants and require sunlight in order to live and grow. Most of them are buoyant and float in the upper part of the ocean, where plenty of sunlight is available. They also require inorganic nutrients such as nitrates, phosphates, and sulphur which they convert into proteins, fats, and carbohydrates. In a balanced ecosystem, phytoplankton are the base of the food web and provide food for a wide range of sea creatures (NOAA). The measurement of phytoplankton can be indexed as chlorophyll concentration and is important as they are fundamental to understanding how the marine ecosystem responds to climate variability and climate change

Fundamentals of ocean colour remote sensing

Remote sensing refers to collection of information about an object without being in direct contact with the object. Remote sensing aids in measuring remote areas which are inaccessible by any other means and offer less expense than in-situ measurements. Remote sensing facilitates creation of long time series and extended measurement. This has the advantage that several parameters can be measured at same time and satellite-based remote sensing measurements allow global observations. Remote sensing has its own advantages and disadvantages. The limitation includes indirect measurements of large areas which are not of interest to the user. The automated instrument degradation creates retrieval errors and are affected by several factors/processes, and not only by the object of interest. Additional assumptions and models are needed for the interpretation of the measurements and before using these models in oceanographic studies, it is extremely important to validate the performance of the various ocean colour algorithms with in-situ observations (Swirgon et al., 2015)

Gravitational wave production after inflation for a hybrid inflationary model

We discuss a cosmological scenario with a stochastic background of gravitational waves sourced by the tensor perturbation due to a hybrid inflationary model with cubic potential. The tensor-to-scalar ratio for the present hybrid inflationary model is obtained as $r \approx 0.0006$. Gravitational wave spectrum of this stochastic background, for large-scale CMB modes, $10^{-4}Mpc^{-1}$ to $1Mpc^{-1}$ is studied. The present-day energy spectrum of gravitational waves $\Omega_0^{gw}(f)$ is sensitively related to the tensor power spectrum and r which is, in turn, dependent on the unknown physics of the early cosmos. This uncertainty is characterized by two parameters: $\hat{n_t}(f)$ logarithmic average over the primordial tensor spectral index and $\hat{w}(f)$ logarithmic average over the effective equation of state parameter. Thus, exact constraints in the $\hat{w}(f)$, $\hat{n_t}(f)$ plane can be obtained by comparing theoretical constraints of our model on r and $\Omega_0^{gw}(f)$. We obtain a limit on $\hat{w}(10^{-15}Hz)$<$0.33$ around the modes probed by CMB scales

Upwelling over the eastern Arabian Sea

Upwelling is a vital oceanographic phenomena determining the biological productivity of the coastal oceanic provinces in a greater extent. The annual pelagic fisheries of coastal rim countries, adjacent to the eastern boundary of the Ocean, over the trade wind zone are greatly dependent on upwelling. Over the North India Ocean (NIO), west coast of India, adjacent to the eastern Arabian Sea is well known for its seasonal occurrence of upwelling and downwelling annually. Over the past, several authors have studied upwelling along the west coast of India (Banse 1959, 1968; Sharma 1978; Johannessen et al., 1987

Course Manual Winter School on Structure and Functions of Marine Ecosystem: Fisheries

Marine ecosystems comprises of diverse organisms and their ambient abiotic components in varied relationships leading to an ecosystem functioning. These relationships provides the services that are essential for marine organisms to sustain in the nature. The studies examining the structure and functioning of these relationships remains unclear and hence understanding and modelling of the ecological functioning is imperative in the context of the threats different ecosystem components are facing. The relationship between marine population and their environment is complex and is subjected to fluctuations which affects the bottom level of an ecosystem pyramid to higher trophic levels. Understanding the energy flow within the marine ecosystems with the help of primary to secondary producers and secondary consumers are potentially important when assessing such states and changes in these environments. Many of the physiological changes are known to affect the key functional group, ie. the species or group of organisms, which play an important role in the health of the ecosystem. In marine environment, phytoplankton are the main functional forms which serves as the base of marine food web. Any change in the phytoplankton community structure may lead to alteration in the composition, size and structure of the entire ecosystem. Hence, it is critical to understand how these effects may scale up to population, communities, and entire marine ecosystem. Such changes are difficult to predict, particularly when more than one trophic level is affected. The identification and quantification of indicators of changes in ecosystem functioning and the knowledge base generated will provide a suitable way of bridging issues related to a specific ecosystem. New and meaningful indicators, derived from our current understanding of marine ecosystem functioning, can be used for assessing the impact of these changes and can be used as an aid in promoting responsible fisheries in marine ecosystems. Phytoplantkon is an indicator determining the colour of open Ocean. In recent years, new technologies have emerged which involves multidisciplinary activities including biogeochemistry and its dynamics affecting higher trophic levels including fishery. The winter school proposed will provide the insights into background required for such an approach involving teaching the theory, practical, analysis and interpretation techniques in understanding the structure and functioning of marine ecosystems from ground truth measurements as well as from satellite remote sensing data. This is organized with the full funding support from Indian council of Agricultural Research (ICAR) New Delhi and the 25 participants who are attending this programme has been selected after scrutiny of their applications based on their bio-data. The participants are from different States across Indian subcontinent covering north, east, west and south. They are serving as academicians such as Professors/ scientists and in similar posts. The training will be a feather in their career and will enable them to do their academic programmes in a better manner. Selected participants will be scrutinized initially to understand their knowledge level and classes will be oriented based on this. In addition, all of them will be provided with an e-manual based on the classes. All selected participants are provided with their travel and accommodation grants. The faculty include the scientists who developed this technology, those who are practicing it and few user groups who do their research in related areas. The programme is coordinated by the Fishery Resources Assessment Division of CMFRI. This programme will generate a team of elite academicians who can contribute to sustainable management of marine ecosystem and they will further contribute to capacity building in the sector by training many more interested researchers in the years to come

Linocin and OmpW Are Involved In Attachment Of The Cystic Fibrosis-Associated Pathogen Burkholderia Cepacia Complex To Lung Epithelial Cells and Protect Mice Against Infection

Burkholderia cepacia complex (Bcc) causes chronic opportunistic lung infections in people with cystic fibrosis (CF) resulting in a gradual lung function decline and, ultimately, patient death. Bcc is a complex of eighteen species and is rarely eradicated once a patient is colonised, therefore vaccination may represent a better therapeutic option. We developed a new proteomics approach to identify bacterial proteins that are involved in attachment of Bcc to lung epithelial cells. Fourteen proteins were reproducibly identified by 2-DE from four Bcc strains, representative of two Bcc species: B. cenocepacia, the most virulent and B. multivorans, the most frequently acquired. Seven proteins were identified in both species, but only two were common to all four strains, Linocin and OmpW. Both proteins were selected based previously published data on these proteins in other species. The E. coli strains expressing recombinant Linocin and OmpW showed enhanced attachment (4.2- and 3.9-fold) to lung cells, compared to control, confirming that both proteins are involved in host cell attachment. Immunoproteomic analysis using serum from Bcc colonised CF patients confirmed that both proteins elicit potent humoral responses in vivo. Mice immunised with either recombinant Linocin or OmpW were protected from B. cenocepacia and B. multivorans challenge. Both antigens induced potent antigen-specific antibody responses and stimulated strong cytokine responses. In conclusion, our approach identified adhesins that induced excellent protection against two Bcc species and are promising vaccine candidates for a multi-subunit vaccine. Furthermore, it highlights the potential of our proteomics approach to identify potent antigens against other difficult pathogens