Algal bloom: A fast accumulation of cells in an algal population in aquatic systems.

Catalyse: To increase the speed at which a chemical reaction takes place.

Enzyme: A protein that quickens chemical reactions.

Endogenous: Naturally occurring or produced in that organism.

Eukaryotes: Organisms that have cells with a nucleus. They include animals, plants and fungi.

Genome: The total of genetic genetic information of an organism.

Genus: A taxonomic rank in biological classification. The hierarchy of the classification from general to specific is: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

Homology: Evolutionary trait derived from a common ancestor

Krill: A small group of animals that feed primarily on phytoplankton. They are near the bottom of the food chain and make up a large part of the diet of larger animals.

Mutualism: A symbiotic relationship between two organisms in which both organisms benefit from each other.

Natural selection: Darwin's theory that characteristics of an organism become more or less frequent in a population because they are either advantageous for an organisms or they are not.

Organelle: Structure inside a cell that carries out certain specific functions.

Oxidative stress: The accumulation of ROS levels that causes significant damage to cell structures.

Photon emission: Molecules consist of atoms. Atoms, in turn, are built up by three different types of particles. The first are protons, positive particles that form, in part, the nucleus of the atom. The second are neutrons, which are also located in the nucleus and have no charge. The third type are electrons, negative particles which are mostly present in orbits around the nucleus. These orbits determine the energy of an electron. An electron in an orbit far from the nucleus has more energy than an electron closer to the nucleus. An electron in an atom can get kicked out of its low-energy orbit close to the nucleus. This is due to absorption of energy by the electron. Now the electron is located in one of the outer orbits of the atom, this is called an electron in its excited state. An atom in this state is not stable and the electron will fall back into a low-energy orbit. When it does so, energy in the form of a photon is produced. A photons colour depends on the amount of energy that is released. The difference in energy is determined by the falling back-distance of the electron. The further it falls, the more energy is released.

Phylogeny: The grouping of organisms into evolutionary related groups.

Phylum: A taxonomic rank in biological classification. The hierarchy of the classification from general to specific is: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species. Can also be seen as a group of clades with the same characteristics.

Plastids: Cell organelles that have their own DNA.

Promoter: The switch of a gene, which determines if a gene will be transcribed or not. In a way, a gene can be put on and off, by using the switch. There is an array of different promoters that are sensitive to specific internal and external stimuli, which makes the transcription of a gene dependent on the environment.

Protein: A generic term for molecules produced in cells, which can carry out an array of different functions. They consist of a sequence of molecules called 'amino acids'. This sequence is unique for every single protein and is determined by the DNA.

Sequence: In biology, a sequence is the order of the building blocks of DNA, called nucleotides. It might also refer to the sequence of protein building blocks, called amino acids. The order of these building blocks are very important for the function of DNA and proteins.

Symbiosis: A close cooperation between organisms.

Symbiosis: A close cooperation between different species that have become dependant on each other and live together.

Mutualism: A symbiotic relationship between two species in which both species benefit from each other.

Cyanobacteria: A phylum of bacteria well known for its ability to photosynthesise. Named after the colour that organisms within the phylum generally have.

Commensal: A symbiotic relationship between two species in which one of the species benefits and the other experiences neither a positive nor a negative effect.

Primary metabolites: All metabolic compounds that are directly involved with growth, maintenance, development and reproduction. Everything that living cells need to survive.

Genes: Stretches of DNA coding for proteins or RNAs as final products. Basic hereditary units of life.

Ribosomal RNA: Important part of ribosomes, the cellular machines that translate the primary products of genes, RNA, into protein. The genes encoding this type of RNA have largely remained the same throughout evolutionary history because of their importance in the synthesis of proteins, the basic workhorses of the cell. Because of this, it offers a good estimation of relatedness between organisms.

Sequence: In biology, a DNA sequence is the order of the building blocks of DNA, called nucleotides, i.e. a string of A, G, T and C. It might also refer to the amino acid sequence of proteins. The order of these building blocks is very important for the function of DNA and proteins and comparison can yield insights into relatedness or function.

Phylum: A taxonomic rank in biological classification. The hierarchy of the classification from general to specific is: Domain,Kingdom, Phylum, Class, Order,Family, Genus, Species.

Phylogenetic: To do with phylogeny: the study concerned with grouping organisms into evolutionarily related groups, often based upon genome sequences.

Monophyletic group: Group or taxon that includes all the named descendants of a particular most recent common ancestor. That is to say, if five finches all evolved from one primal finch, the five finches are in a monophyletic group.

Fixate: In the context of living organisms this means: 'Incorporate into organic compounds'.

Taxon: Term used to refer to a particular group of organisms. Can be used to refer to: Domain, Kingdom, Phylum, Class, Order, Family, Genus or anything in between.

Reactive oxygen species (ROS): Chemically reactive molecules that contain oxygen. ROS are a natural by-product of oxygen reactions. ROS levels can increase during times of environmental stress, which can cause significant damage to cells.

Denature: In the case of proteins this means: 'lose natural form', and therefore the loss of normal functionality.

Turgid: Inflated by the power of osmosis, a force that strives to balance out the concentrations of solutions divided by a barrier that only allows water to pass, such as a cellular membrane. A cell with strong cell walls, however, is limited in the amount of water it can take up and as a result becomes strongly inflated only up to the point that the wall allows, which gives plants and fungi their rigidness.

Eukaryotic: Concerning eukaryotes: organisms with a nucleus in their cell(s), which sets them apart from prokaryotes, organisms with no nucleus in their cell, i.e. bacteria and the less well known Archaea.

Apoptosis: Controlled cell death, i.e. an orderly recycling of a cell that has outlived its use or is not viable anymore.

Genus: A taxonomic rank in biological classification. The hierarchy of the classification from general to specific is: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

Epithelial: Concerning epithelium: tissue that lines the cavities and surfaces of structures throughout the body.

Hepatocytes: Cells that make up most of the liver, from Greek 'ἡπατος' or hepatos, meaning liver.

Homogenised: Blended, mixed until a mixture is equally divided

Promoter: The switch of a gene, encoded in the DNA, which determines if a gene will be transcribed or not. One could say that a gene can be turned on or off by using the switch. There is an array of different promoters that are sensitive to specific internal and external signals, which makes the transcription of a gene dependant on the environment.

Plasmid: Self-replicating, circular piece of DNA.

Genome: An organism's total genetic information.

Alkaliphilic: Organisms (mostly microorganisms) that are able to survive in alkalic environments, with a pH of 8.5-10. They grow optimally in a pH of around 10.

Hydrophilic: Having a strong affinity for water.

Hydrophobic: Repelling, tending not to combine with, or incapable of dissolving in water.

Acute radiation syndrome: A collection of acute health effects occurring within 24 h of 1 Sv (a unit of) radiation.

Adsorbent: A material capable of binding other substances to its surface.

Bioaccumulation: The process of accumulating a substance in the tissue of a living organism.

Detoxification: The process that changes toxins to less toxic substances.

Differentiation: The process of development in which a cell specialises to perform a specific function.

Genetic: Of, relating to, or produced by the basic hereditary units of life (genes).

Hydrolysis: Chemical reaction between a substance and water where chemical bonds are broken.

Oxidative damage: Damage caused by reactive oxygen species.

Pathogenic: Being able to cause disease.

Phosphatase: A group of enzymes that remove a phosphate group by hydrolysing the substance.

Promoter: The switch of a gene, which determines if a gene will be transcribed or not. In a way, a gene can be put on and off, by using the switch. There is an array of different promoters that are sensitive to specific internal and external stimuli, which makes the transcription of a gene dependent on the environment.

Protein: A generic term for molecules produced in cells, which can carry out an array of different functions. They consist of a sequence of molecules called 'amino acids'. This sequence is unique for every single protein and is determined by the DNA.

Reactive oxygen species (ROS): Chemically reactive molecules that contain oxygen. ROS are a natural by-product of oxygen reactions. ROS levels can increase during times of environmental stress, which can cause significant damage inside cells.

Anaerobic: Without air, i.e. without oxygen. While we need oxygen to live, it is toxic to many organisms. Hence, these organisms thrive in anaerobic environments, such as the intestines.

Cytokines: Small proteins which are important in cell signalling. Especially important in modulating immune responses.

Electrolyte: A substance which dissolves into ions when introduced to a suitable solvent. Electrolyte balance is important to cells for all sorts of chemical processes. An example of an electrolyte is salt, which dissolves into Na⁺ and Cl^-.

Endospore: A dormant, tough, non-reproductive structure formed by some bacteria to survive periods of environmental stress.

Epithelial cells: Cells which cover those surfaces of the body where it comes into contact with the outside world. The skin is covered in epithelial cells, and so is the lining of the colon. The food that passes through you is essentially the external environment, from which the colon extracts nutrients.

Eukaryotic: Concerning eukaryotes: organisms with a nucleus in their cell(s), which sets them apart from prokaryotes. The latter are organisms without a nucleus in their cell, i.e. bacteria and the less well known Archaea.

Genus: A taxonomic rank in biological classification. The hierarchy of the classification from general to specific is: Domain -> Kingdom -> Phylum -> Class -> Order -> Family -> Genus -> Species.

Gram positive: Bacteria that have a thick outer layer of peptidoglycan are gram positive. They are so-called because of the Gram staining procedure in which these bacteria are coloured purple.

Lyses: Lysis, to lyse: The process whereby a cell's plasma membrane breaks and it dies abruptly, as opposed to the controlled cell death that is apoptosis.

Macrophages: Immune cells that can infiltrate tissues, ingest and destroy pathogens, and activate other components of the immune system by presenting parts of pathogens on their cell membrane.

Mutagenic: Inducing the appearance of mutations in the DNA.

Peptidoglycan: A polymer which consists of sugars and amino acids and forms the cell wall of many bacteria.

Tight junctions: Tight junctions make cells adhere so strongly to each other that leakage between them is nigh impossible. This is achieved by proteins across the cell surface that interact very strongly.

Villi: The finger-like protrusions in the epithelium lining the intestines which increase the surface area for uptake of nutrients immensely.

Competitive exclusion: The principle that when two species compete for the same resources one of the species in time will dominate and can cause extinction of the other species.

Cretaceous: A geological period that lasted from approximately 145 to 66 million years ago.

Ecological niche: The role of an organism in a community in terms of the habitat it occupies, its interactions with other organisms and its effect on the environment. A given niche, e.g. the small herbivore niche, may be occupied by different species in different ecosystems and different parts of the world.

Exoskeleton: A cuticle that stabilises the shape of their body.

Extant: Still in existence.

Family: A taxonomic rank in biological classification. The hierarchy of the classification from general to specific is: Domain -> Kingdom -> Phylum -> Class -> Order -> Family -> Genus -> Species.

Mandibles: The lower part of the jaw in vertebrates.

Meiosis: A type of nuclear division which results in daughter nuclei each containing half the number of chromosomes of the parent, i.e. chromosome number is reduced from diploid to haploid.

Order: A taxonomic rank in biological classification. The hierarchy of the classification from general to specific is: Domain -> Kingdom -> Phylum -> Class -> Order -> Family -> Genus -> Species.

Pheromone: A chemical released in minute amounts by one organism which is detected and acts as a signal to another member of the same species.

Phylum: A taxonomic rank in biological classification. The hierarchy of the classification from general to specific is: Domain -> Kingdom -> Phylum -> Class -> Order -> Family -> Genus -> Species.

Primary production: The synthesis of organic compounds from CO2 mostly by photosynthesis with sunlight as energy source, but can also be done by chemosynthesis which uses the oxidation of inorganic molecules as energy source. Primary producers are at the base of the food chain and almost all life is dependent on them.

Taxonomy: The science of classifying organisms or groups of organisms into an hierarchical structure.

Albedo: Ratio of the amount of light reflected by a surface to the amount of incident light. A surface with a higher albedo has a higher reflectivity.

Ecological niche: The role of an organism in a community in terms of the habitat it occupies, its interactions with other organisms and its effect on the environment.

Ecological succession: The natural process whereby communities of plant and animal species are replaced by others, usually more complex, over time as a mature ecosystem develops.

Ecosystem services: The benefits people obtain from ecosystems.

Evapotranspiration: Loss of water from the soil by transpiration of the plants growing thereon.

Genus: A taxonomic rank in biological classification. The hierarchy of the classification from general to specific is: Domain -> Kingdom -> Phylum -> Class -> Order -> Family -> Genus -> Species.

Habitat fragmentation: A process wherein habitat is destroyed, resulting in a smaller and more isolated remaining habitat.

Invasive species: An organism that is introduced into a new environment, where it is not native (also known as an exotic or nuisance species).

Monoculture:Large area covered by a single species (or for crops, a single variety) of plants, especially if grown year after year.

Pioneer species: First species that colonize a bare site at the first stage in ecological succession.

Refuge: An area that has remained unaffected by environmental changes to the surrounding area, such as a mountain area that was not covered with ice during the Pleistocene, and in which, therefore, the previous flora and fauna has survived.

Wildlife corridor: In urban and suburban areas, narrow continuous areas of favourable habitat which connect built-up areas with the country and allow the movement of animals, birds and plants along them.

Alleles: Alternative forms of the same gene.

Biological species concept: Species are groups of actually or potentially interbreeding populations, which are reproductively isolated from other such groups. This means that biological differences between species greatly reduce gene exchange among them, even without geographical isolation

Biome: The world's major communities, classified according to the predominant vegetation and characterised by adaptations of organisms to that particular environment

Bryophytes: Land plants that do not have vascular tissue, such as mosses, hornworts and liverworts.

Family: A taxonomic rank in biological classification. The hierarchy of the classification from general to specific is: Domain -> Kingdom -> Phylum -> Class -> Order -> Family -> Genus -> Species.

Gene flow: Exchange of genes between individuals from different populations through mating or otherwise

Genes: Stretches of DNA coding for proteins or RNAs as final products. Basic hereditary units of life.

Phenotypic: Concerning an organism's observable characteristics or traits

Reactive oxygen species (ROS): Chemically reactive molecules that contain oxygen. ROS are a natural by-product of oxygen reactions. ROS levels can increase during times of environmental stress, which can cause significant damage inside cells.

Recombination: The mixing of parental genes during meiosis in gametes that creates novel genetic combinations in offspring.

Semi-natural habitat: A habitat where human-induced changes can be detected or that is human-managed, but which still exhibits biodiversity comparable to a natural habitat

Taxon: Term used to refer to a particular group of organisms. Can be used to refer to: Domain, Kingdom, Phylum, Class, Order, Family, Genus or anything in between.

Xenobiotic: Substance found within an organism that is not naturally produced by or expected to be present within that organism

Aerobic: In conditions with air, i.e. with oxygen. While we need oxygen to breathe, it is toxic to many other organisms. An important distinction is therefore whether an organism is aerobic or anaerobic.

Anaerobic: In conditions without air, i.e. without oxygen. While we need oxygen to breathe, it is toxic to many other organisms. An important distinction is therefore whether an organism is aerobic or anaerobic.

Carbonyl: A type of molecular bond in which a carbon atom is attached to an oxygen atom with a double bond, i.e. C=O

DA (Dalton) A unit of molecular weight. 1 Da = 1g/mol

Extracellular matrix: A collection of extracellular molecules secreted by cells that provide them with structural support or cohesion and/or biochemical support. In this specific instance, one can think of a sort of slime that keeps the bacteria together and traps nutrients, making them continuously available to the bacteria.

Hetereotrophic: Concerning organisms that acquire carbon for growth from organic carbon, i.e. that eat plants or other animals to build their bodies.

Functional group: A group of atoms on an organic molecule that possesses its own chemical properties.

Metabolic activity: the breakdown of macromolecules into smaller parts, whereby energy is released.

Ecosystem services: The benefits a certain ecosystem provides. Think about water storage, cleaning air, hosting species diversity, providing raw materials etc.

No glossary needed to understand this article!

Anthropogenic forcing: The change in earth's climate due to human activities.

Plasticisers: A substance that can be added to materials to increase the flexibility and plasticity and to reduce brittleness.

D- and L-conformation: The D- and L-conformation of a structure are mirror images of each other. They both consist of the same molecules and differ only in position of particular molecules.

PET: Polyethylene terephthalate, a commonly used plastic for water botles based on petroleum.

Torpor: An animal becomes in a state of decreased physiological activity, usually by a reduced metabolic rate and body temperature.