Marine primary production is the chemical synthesis in the ocean of
organic compounds from atmospheric or dissolved
carbon dioxide. It principally occurs through the process of
photosynthesis, which uses light as its source of energy, but it also occurs through
chemosynthesis, which uses the oxidation or reduction of inorganic chemical compounds as its source of energy. Almost all
life on Earth relies directly or indirectly on
primary production. The organisms responsible for primary production are called
primary producers or
autotrophs.
Most marine primary production is generated by a diverse collection of
marine microorganisms called
algae and
cyanobacteria. Together these form the principal primary producers at the base of the
ocean food chain and produce half of the world's oxygen. Marine primary producers underpin almost all marine animal life by generating nearly all of the oxygen and food marine animals need to exist. Some marine primary producers are also
ecosystem engineers which change the environment and provide
habitats for other marine life.
Primary production in the ocean can be contrasted with primary production on land. Globally the ocean and the land each produce about the same amount of primary production, but in the ocean primary production comes mainly from cyanobacteria and algae, while on land it comes mainly from
vascular plants.
Marine algae includes the largely invisible and often
unicellularmicroalgae, which together with
cyanobacteria form the ocean
phytoplankton, as well as the larger, more visible and complex
multicellularmacroalgae commonly called
seaweed. Seaweeds are found along coastal areas, living on the floor of
continental shelves and washed up in
intertidal zones. Some seaweeds drift with plankton in the sunlit surface waters (
epipelagic zone) of the open ocean. Back in the
Silurian, some phytoplankton evolved into
red,
brown and
green algae. These algae then invaded the land and started evolving into the
land plants we know today. Later in the
Cretaceous some of these land plants returned to the sea as
mangroves and
seagrasses. These are found along coasts in
intertidal regions and in the brackish water of
estuaries. In addition, some seagrasses, like seaweeds, can be found at depths up to 50 metres on both soft and hard bottoms of the continental shelf.
Primary producers are the
autotroph organisms that make their own food instead of eating other organisms. This means primary producers become the starting point in the
food chain for
heterotroph organisms that do eat other organisms. Some marine primary producers are specialised bacteria and archaea which are
chemotrophs, making their own food by gathering around
hydrothermal vents and
cold seeps and using
chemosynthesis. However, most marine
primary production comes from organisms which use
photosynthesis on the carbon dioxide dissolved in the water. This process uses energy from sunlight to convert water and
carbon dioxide[4]: 186–187 into sugars that can be used both as a source of chemical energy and of organic molecules that are used in the structural components of cells.[4]: 1242 Marine primary producers are important because they underpin almost all marine animal life by generating most of the
oxygen and food that provide other organisms with the chemical energy they need to exist.
The principal marine primary producers are
cyanobacteria,
algae and marine plants. The
oxygen released as a by-product of photosynthesis is needed by
nearly all living things to carry out
cellular respiration. In addition, primary producers are influential in the global
carbon and
water cycles. They stabilize coastal areas and can provide habitats for marine animals. The term
division has been traditionally used instead of
phylum when discussing primary producers, although the
International Code of Nomenclature for algae, fungi, and plants now accepts the terms as equivalent.[5]
In a reversal of the pattern on land, in the oceans, almost all photosynthesis is performed by algae and
cyanobacteria, with a small fraction contributed by
vascular plants and other groups. Algae encompass a diverse range of organisms, ranging from single floating cells to attached
seaweeds. They include photoautotrophs from a variety of groups.
Eubacteria are important photosynthetizers in both oceanic and terrestrial ecosystems, and while some
archaea are
phototrophic, none are known to utilise oxygen-evolving
photosynthesis.[6] A number of
eukaryotes are significant contributors to primary production in the ocean, including
green algae,
brown algae and
red algae, and a diverse group of unicellular groups. Vascular plants are also represented in the ocean by groups such as the
seagrasses.
Unlike terrestrial ecosystems, the majority of primary production in the ocean is performed by free-living
microscopic organisms called
phytoplankton. It has been estimated that half of the world's oxygen is produced by phytoplankton.[7][8] Larger autotrophs, such as the seagrasses and macroalgae (
seaweeds) are generally confined to the
littoral zone and adjacent shallow waters, where they can
attach to the underlying substrate but still be within the
photic zone. There are exceptions, such as Sargassum, but the vast majority of free-floating production takes place within microscopic organisms.
The factors limiting primary production in the ocean are also very different from those on land. The availability of water, obviously, is not an issue (though its
salinity can be). Similarly, temperature, while affecting
metabolic rates (see
Q10), ranges less widely in the ocean than on land because the
heat capacity of seawater buffers temperature changes, and the formation of
sea iceinsulates it at lower temperatures. However, the availability of light, the source of energy for photosynthesis, and mineral
nutrients, the building blocks for new growth, play crucial roles in regulating primary production in the ocean.[9] Available Earth System Models suggest that ongoing ocean bio-geochemical changes could trigger reductions in ocean NPP between 3% and 10% of current values depending on the emissions scenario.[10]
In 2020 researchers reported that measurements over the last two decades of primary production in the
Arctic Ocean show an increase of nearly 60% due to higher concentrations of
phytoplankton. They hypothesize new nutrients are flowing in from other oceans and suggest this means the Arctic Ocean may be able to support
higher trophic level production and additional
carbon fixation in the future.[11][12]
Cyanobacteria
Evolution of photosynthesis from cyanobacteria
The origin and evolutionary tree of life that is based on small-subunit RNA. The branches that perform oxygenic photosynthesis are labeled with 'O2'. The black arrow indicates the plastid endosymbiotic event that resulted in the origin of eukaryotic photosynthesis from cyanobacteria-like organisms, which ultimately became chloroplasts in algae and later in plants. However, while chloroplasts of the higher plants, glaucophytes, green and red algae are thought to be the result of the plastid (primary) endosymbiosis, all other groups of algae are assumed to have arisen due to the algal (secondary and tertiary) endosymbiosis (not shown), in which one eukaryotic alga was incorporated into another eukaryote.[13][14][15][16][17] Only some branches of bacteria, eukarya, and archaea are displayed.[18]
Cyanobacteria are a phylum (division) of bacteria, ranging from unicellular to
filamentous and including
colonial species, which
fix inorganic carbon into organic carbon compounds. They are found almost everywhere on earth: in damp soil, in both freshwater and marine environments, and even on Antarctic rocks.[19] In particular, some species occur as drifting cells floating in the ocean, and as such were amongst the first of the
phytoplankton. These bacteria function like algae in that they can process nitrogen from the atmosphere when none is in the ocean.
The first primary producers that used photosynthesis were oceanic
cyanobacteria about 2.3 billion years ago.[20][21] The release of molecular
oxygen by
cyanobacteria as a by-product of photosynthesis induced global changes in the Earth's environment. Because oxygen was toxic to most life on Earth at the time, this led to the near-extinction of
oxygen-intolerant organisms, a
dramatic change which redirected the evolution of the major animal and plant species.[22]
The tiny marine cyanobacterium Prochlorococcus, discovered in 1986, forms today part of the base of the ocean
food chain and accounts for more than half the photosynthesis of the open ocean[23] and an estimated 20% of the oxygen in the Earth's atmosphere.[24] It is possibly the most plentiful genus on Earth: a single millilitre of surface seawater may contain 100,000 cells or more.[25]
Originally, biologists thought
cyanobacteria was algae, and referred to it as "blue-green algae". The more recent view is that cyanobacteria are bacteria, and hence are not even in the same
Kingdom as algae. Most authorities exclude all
prokaryotes, and hence cyanobacteria from the definition of algae.[26][27]
Biological pigments
Biological pigments are any coloured material in plant or animal cells. All biological pigments selectively
absorb certain wavelengths of light while
reflecting others.[28][29] The primary function of pigments in plants is
photosynthesis, which uses the green pigment
chlorophyll and several colourful pigments that absorb as much light energy as possible.
Chlorophyll is the primary pigment in plants; it is a
chlorin that absorbs yellow and blue wavelengths of light while reflecting
green. It is the presence and relative abundance of chlorophyll that gives plants their green colour.
Green algae and plants possess two forms of this pigment: chlorophyll a and chlorophyll b.
Kelps,
diatoms, and other photosynthetic
heterokonts contain chlorophyll c instead of b, while red algae possess only chlorophyll a. All chlorophylls serve as the primary means plants use to intercept light in order to fuel photosynthesis.
Chloroplasts (from the Greek chloros for green, and plastes for "the one who forms"[31]) are
organelles that conduct
photosynthesis, where the photosynthetic pigment
chlorophyll captures the
energy from
sunlight, converts it, and stores it in the energy-storage molecules while freeing
oxygen from water in
plant and
algal cells. They then use the stored energy to make organic molecules from
carbon dioxide in a process known as the
Calvin cycle.
A chloroplast is a type of organelle known as a
plastid, characterized by
its two membranes and a high concentration of
chlorophyll. They are highly dynamic—they circulate and are moved around within plant cells, and occasionally
pinch in two to reproduce. Their behavior is strongly influenced by environmental factors like light colour and intensity. Chloroplasts, like
mitochondria, contain their own
DNA, which is thought to be inherited from their ancestor—a photosynthetic
cyanobacterium that was
engulfed by an early
eukaryotic cell.[32] Chloroplasts cannot be made by the plant cell and must be inherited by each daughter cell during cell division.
Most chloroplasts can probably be traced back to a single
endosymbiotic event, when a cyanobacterium was engulfed by the eukaryote. Despite this, chloroplasts can be found in an extremely wide set of organisms, some not even directly related to each other—a consequence of many
secondary and even
tertiary endosymbiotic events.
Phototrophic metabolism relies on one of three energy-converting pigments:
chlorophyll,
bacteriochlorophyll, and
retinal. Retinal is the
chromophore found in
rhodopsins. The significance of chlorophyll in converting light energy has been written about for decades, but phototrophy based on retinal pigments is just beginning to be studied.[35]
In 2000 a team of microbiologists led by
Edward DeLong made a crucial discovery in the understanding of the marine carbon and energy cycles. They discovered a gene in several species of bacteria[37][38] responsible for production of the protein
rhodopsin, previously unheard of in bacteria. These proteins found in the cell membranes are capable of converting light energy to biochemical energy due to a change in configuration of the rhodopsin molecule as sunlight strikes it, causing the pumping of a
proton from inside out and a subsequent inflow that generates the energy.[39] The archaeal-like rhodopsins have subsequently been found among different taxa, protists as well as in bacteria and archaea, though they are rare in complex
multicellular organisms.[40][41][42]
Research in 2019 shows these "sun-snatching bacteria" are more widespread than previously thought and could change how oceans are affected by global warming. "The findings break from the traditional interpretation of marine ecology found in textbooks, which states that nearly all sunlight in the ocean is captured by chlorophyll in algae. Instead, rhodopsin-equipped bacteria function like hybrid cars, powered by organic matter when available — as most bacteria are — and by sunlight when nutrients are scarce."[43][35]
There is an
astrobiological conjecture called the
Purple Earth hypothesis which surmises that original life forms on Earth were retinal-based rather than chlorophyll-based, which would have made the Earth appear purple instead of green.[44][45]
Algae is an informal term for a widespread and diverse collection of photosynthetic
eukaryotic organisms which are not necessarily closely related and are thus
polyphyletic. Unlike higher plants, algae lack roots, stems, or leaves.
Green algae live most of their lives as single cells or are filamentous, while others form
colonies made up from long chains of cells, or are highly differentiated macroscopic seaweeds. They form an informal group containing about 8,000 recognized species.[47]
Red algae
Modern
red algae are mostly
multicellular with differentiated cells and include many notable
seaweeds.[48][49] As
coralline algae, they play an important role in the ecology of coral reefs. They form a (disputed) phylum containing about 7,000 recognized species.[48]
Coccolithophores are almost exclusively marine and are found in large numbers throughout the
sunlight zone of the
ocean. They have
calcium carbonate plates (or scales) of uncertain function called coccoliths, which are important
microfossils. Coccolithophores are of interest to those studying global
climate change because as
ocean acidity increases, their coccoliths may become even more important as a
carbon sink.[55] The most abundant species of coccolithophore, Emiliania huxleyi is an ubiquitous component of the plankton base in
marine food webs.[56] Management strategies are being employed to prevent eutrophication-related coccolithophore blooms, as these blooms lead to a decrease in nutrient flow to lower levels of the ocean.[57]
Traditionally the
phylogeny of microorganisms, such as the algal groups discussed above, was inferred and their
taxonomy established based on studies of
morphology. However developments in
molecular phylogenetics have allowed the evolutionary relationship of species to be established by analyzing their
DNA and
protein sequences.[59] Many taxa, including the algal groups discussed above, are in the process of being reclassified or redefined using molecular phylogenetics. Recent developments in
molecular sequencing have allowed for the recovery of
genomes directly from environmental samples and avoiding the need for culturing. This has led for example, to a rapid expansion in knowledge of the abundance and diversity of
marine microorganisms. Molecular techniques such as genome-resolved
metagenomics and
single cell genomics are being used in combination with
high throughput techniques.
Between 2009 and 2013, the
Tara Oceans expedition traversed the world oceans collecting plankton and analysing them with contemporary molecular techniques. They found a huge range of previously unknown photosynthetic and mixotrophic algae.[60] Among their findings were the
diplonemids. These organisms are generally colourless and oblong in shape, typically about 20 µm long and with two flagella.[61] Evidence from
DNA barcoding suggests diplonemids may be among the most abundant and most species-rich of all marine eukaryote groups.[62][63]
By size
Algae can be classified by size as microalgae or macroalgae.
Microalgae
Microalgae are the microscopic types of algae, not visible to the naked eye. They are mostly
unicellular species which exist as individuals or in chains or groups, though some are
multicellular. Microalgae are important components of the
marine protists, as well as the
marine phytoplankton. They are very
diverse. It has been estimated there are 200,000-800,000 species of which about 50,000 species have been described.[64] Depending on the species, their sizes range from a few micrometers (µm) to a few hundred micrometers. They are specially adapted to an environment dominated by viscous forces.
Microalgae
Zooxanthellae is a photosynthetic algae that lives inside hosts like
coral
Macroalgae are the larger,
multicellular and more visible types of algae, commonly called
seaweeds. Seaweeds usually grow in shallow coastal waters where they are anchored to the seafloor by a
holdfast. Seaweed that becomes adrift can wash up on beaches.
Kelp is a large brown seaweed that forms large underwater
forests covering about 25% of the world coastlines.[65] They are among the most productive and dynamic ecosystems on Earth.[66] Some Sargassum seaweeds are planktonic (free-floating) and form floating drifts.[67]: 246–255 Like microalgae, macroalgae (seaweeds) are technically
marine protists since they are not true plants.
Macroalgae
Giant kelp is technically a protist since it is not a true plant, yet it is multicellular and can grow to 50 m
Sargassum seaweed is a brown alga with air bladders that help it float
Sargassum fish are camouflaged to live among drifting Sargassum seaweed
The diagram on the right shows an evolutionary scenario for the conquest of land by streptophytes.[69]Streptophyte algae include all
green algae, and are the only photosynthetic
eukaryotes from which the macroscopic land flora evolved (red lines). That said, throughout the course of evolution, algae from various other lineages have colonized land (yellow lines) — but also streptophyte algae have continuously and independently made the wet to dry transition (convergence of red and yellow). Throughout history, numerous lineages have become extinct (X labels). Terrestrial algae of various taxonomic affiliations dwell on rock surfaces and form biological
soil crusts. From the diversity of the
paraphyletic streptophyte algae, however, did an organism whose descendants eventually conquered land on a global scale emerge: a likely branched filamentous — or even
parenchymatous — organism that formed
rhizoidal structures and experienced desiccation from time to time. From this "hypothetical hydro-terrestrial alga", the lineages of
Zygnematophyceae and
embryophytes (land plants) arose.[69] In its infancy, the trajectory leading to the embryophytes was represented by the — now extinct — earliest land plants.[71]
The earliest land plants probably interacted with beneficial
substratemicrobiota that aided them in obtaining nutrients from their substrate. Furthermore, the earliest land plants had to successfully overcome a barrage of terrestrial stressors (including ultraviolet light and photosynthetically active
irradiance, drought, drastic temperature shifts, etc.). They succeeded because they had the right set of traits — a mix of adaptations that were selected for in their hydro-terrestrial algal ancestors, exaptations, and the potential for co-option of a fortuitous set of genes and pathways.[69] During the course of evolution, some members of the populations of the earliest land plants gained traits that are adaptive in terrestrial environments (such as some form of water conductance,
stomata-like structures, embryos, etc.); eventually, the "hypothetical
last common ancestor of land plants" emerged. From this ancestor, the extant
bryophytes and
tracheophytes evolved. While the exact trait repertoire of the hypothetical last common ancestor of land plants is uncertain, it will certainly have entailed properties of
vascular and
non-vascular plants. What is also certain is that the last common ancestor of land plants had traits of algal ancestry.[69]
Light is only able to penetrate the top 200 metres (660 ft) so this is the only part of the sea where plants can grow.[77] The surface layers are often deficient in biologically active nitrogen compounds. The marine
nitrogen cycle consists of complex microbial transformations which include the
fixation of nitrogen, its assimilation,
nitrification,
anammox and denitrification.[78] Some of these processes take place in deep water so that where there is an upwelling of cold waters, and also near estuaries where land-sourced nutrients are present, plant growth is higher. This means that the most productive areas, rich in plankton and therefore also in fish, are mainly coastal.[79]: 160–163
Mangroves
Mangroves provide important nursery habitats for marine life, acting as hiding and foraging places for larval and juvenile forms of larger fish and invertebrates. Based on satellite data, the total world area of mangrove forests was estimated in 2010 as 134,257 square kilometres (51,837 sq mi).[80][81]
Like mangroves, seagrasses provide important nursery habitats for larval and juvenile forms of larger fish and invertebrates. The total world area of seagrass meadows is more difficult to determine than mangrove forests, but was conservatively estimated in 2003 as 177,000 square kilometres (68,000 sq mi).[82]
The
stoichiometry (measurement of chemical
reactants and
products) of primary production in the surface ocean plays a crucial role in the
cycling of elements in the global ocean. The ratio between the elements
carbon (C),
nitrogen (N), and
phosphorus (P) in exported organic matter expressed in terms of the C:N:P ratio helps determine how much
atmospheric carbon is
sequestered in the deep ocean with respect to the availability of
limiting nutrients.[84] On geologic timescales, the N:P ratio reflects the relative availability of
nitrate with respect to
phosphate, both of which are externally supplied from the atmosphere via
nitrogen fixation and/or continents via river supply and lost by
denitrification and burial.[85][86][87][88] On shorter timescales, the average stoichiometry of exported bulk
particulate organic matter reflects the elemental stoichiometry of
phytoplankton,[89][90][91] with additional influences from biological diversity and secondary processing of organic matter by
zooplankton and
heterotrophic bacteria. In the face of global change, understanding and quantifying the mechanisms that lead to variability in C:N:P ratios are crucial in order to have an accurate projection of future climate change.[84]
A key unresolved question is what determines C:N:P of individual phytoplankton. Phytoplankton grows in the
upper light-lit layer of the ocean, where the amount of inorganic nutrients, light, and temperature vary spatially and temporally.[84] Laboratory studies show that these fluctuations trigger responses at the cellular level, whereby cells modify resource allocation in order to adapt optimally to their ambient environment.[92] For example, phytoplankton may alter resource allocation between the P-rich biosynthetic apparatus, N-rich light-harvesting apparatus, and C-rich energy storage reserves.[93] Under a typical future warming scenario, the global ocean is expected to undergo changes in nutrient availability, temperature, and
irradiance.[94] These changes are likely to have profound effects on the physiology of phytoplankton,[95][96] and observations show that competitive phytoplankton species can acclimate and adapt to changes in temperature, irradiance, and nutrients on decadal timescales.[97] Numerous laboratory and field experiments have been conducted that study the relationship between the C:N:P ratio of phytoplankton and environmental drivers. It is, however, challenging to synthesize those studies and generalize the response of phytoplankton C:N:P to changes in environmental drivers.[84] Individual studies employ different sets of
statistical analyses to characterize the effects of the environmental driver(s) on elemental ratios, ranging from a simple
t test to more complex mixed models, which makes interstudy comparisons challenging. In addition, since environmentally induced trait changes are driven by a combination of
plasticity (
acclimation), adaptation, and life history,[98][99] stoichiometric responses of phytoplankton can be variable even amongst closely related species.[84]
Meta-analysis/
systematic review is a powerful statistical framework for synthesizing and integrating research results obtained from independent studies and for uncovering general trends.[100] The seminal synthesis by Geider and La Roche in 2002,[101] as well as the more recent work by Persson et al. in 2010,[102] has shown that C:P and N:P could vary by up to a factor of 20 between nutrient-replete and nutrient-limited cells. These studies have also shown that the C:N ratio can be modestly plastic due to nutrient limitation. A meta-analysis study by Hillebrand et al. in 2013 highlighted the importance of growth rate in determining elemental stoichiometry and showed that both C:P and N:P ratios decrease with the increasing growth rate.[103] In 2015, Yvon-Durocher et al. investigated the role of temperature in modulating C:N:P.[104] Although their dataset was limited to studies conducted prior to 1996, they have shown a statistically significant relationship between C:P and temperature increase. MacIntyre et al. (2002)[105] and Thrane et al. (2016)[106] have shown that irradiance plays an important role in controlling optimal cellular C:N and N:P ratios. Most recently, Moreno and Martiny (2018) provided a comprehensive summary of how environmental conditions regulate cellular stoichiometry from a physiological perspective.[93][84]
The elemental stoichiometry of marine phytoplankton plays a critical role in global biogeochemical cycles through its impact on nutrient cycling, secondary production, and carbon export. Although extensive laboratory experiments have been carried out over the years to assess the influence of different environmental drivers on the elemental composition of phytoplankton, a comprehensive quantitative assessment of the processes is still lacking. Here, the responses of P:C and N:C ratios of marine phytoplankton have been synthesized to five major drivers (inorganic phosphorus, inorganic nitrogen, inorganic iron, irradiance, and temperature) by a meta-analysis of experimental data across 366 experiments from 104 journal articles. These results show that the response of these ratios to changes in macronutrients is consistent across all the studies, where the increase in nutrient availability is positively related to changes in P:C and N:C ratios. The results show that eukaryotic phytoplankton are more sensitive to the changes in macronutrients compared to prokaryotes, possibly due to their larger cell size and their abilities to regulate their gene expression patterns quickly. The effect of irradiance was significant and constant across all studies, where an increase in irradiance decreased both P:C and N:C. The P:C ratio decreased significantly with warming, but the response to temperature changes was mixed depending on the culture growth mode and the growth phase at the time of harvest. Along with other oceanographic conditions of the subtropical gyres (e.g., low macronutrient availability), the elevated temperature may explain why P:C is consistently low in subtropical oceans. Iron addition did not systematically change either P:C or N:C.[84]
^
abCampbell, Neil A.; Reece, Jane B.; Urry, Lisa Andrea; Cain, Michael L.; Wasserman, Steven Alexander; Minorsky, Peter V.; Jackson, Robert Bradley (2008). Biology (8 ed.). San Francisco: Pearson – Benjamin Cummings.
ISBN978-0-321-54325-7.
^Sigman, D.M.; Hain, M.P. (2012).
"The Biological Productivity of the Ocean"(PDF). Nature Education Knowledge. 3 (6): 1–16. Retrieved 1 June 2015. The deep chlorophyll maximum (DCM) occurs at the contact where there is adequate light for photosynthesis and yet significant nutrient supply from below.
^Blankenship, R. E., Sadekar, S., and Raymond, J. (2007) "The evolutionary transition from anoxygenic to oxygenic photosynthesis". In: Evolution of Aquatic Photoautotrophs, eds P. G. Falkowski and A. N. Knoll, New York: Academic Press, pages 21–35.
doi:
10.1016/B978-012370518-1/50004-7.
^Hohmann-Marriott, M.F. and Blankenship, R.E. (2011) "Evolution of photosynthesis". Annual review of plant biology, 62: 515–548.
doi:
10.1146/annurev-arplant-042110-103811.
^Kim, E., Harrison, J.W., Sudek, S., Jones, M.D., Wilcox, H.M., Richards, T.A., Worden, A.Z. and Archibald, J.M.(2011) "Newly identified and diverse plastid-bearing branch on the eukaryotic tree of life". Proceedings of the National Academy of Sciences, 108(4): 1496–1500.
doi:
10.1073/pnas.1013337108.
^Garcia-Mendoza, E. and Ocampo-Alvarez, H. (2011) "Photoprotection in the brown alga Macrocystis pyrifera: evolutionary implications". Journal of Photochemistry and Photobiology B: Biology, 104(1-2): 377–385.
doi:
10.1016/j.jphotobiol.2011.04.004.
^Shevela, D. (2011) "Adventures with cyanobacteria: a personal perspective". Frontiers in plant science, 2: 28.
doi:
10.3389/fpls.2011.00028.
^"The Rise of Oxygen". Astrobiology Magazine. 30 July 2003. Archived from the original on 3 April 2015. Retrieved 6 April 2016.{{
cite web}}: CS1 maint: unfit URL (
link)
^Sparks, William B.; DasSarma, S.; Reid, I. N. (December 2006). "Evolutionary Competition Between Primitive Photosynthetic Systems: Existence of an early purple Earth?". American Astronomical Society Meeting Abstracts. 38: 901.
Bibcode:
2006AAS...209.0605S.
^"Biogeography and dispersal of micro-organisms: a review emphasizing protists", Acta Protozoologica, 45 (2): 111–136, 2005
^Yunev, O.A.; et al. (2007), "Nutrient and phytoplankton trends on the western Black Sea shelf in response to cultural eutrophication and climate changes", Estuarine, Coastal and Shelf Science, 74 (1–2): 63–67,
Bibcode:
2007ECSS...74...63Y,
doi:
10.1016/j.ecss.2007.03.030
^Bork, P., Bowler, C., De Vargas, C., Gorsky, G., Karsenti, E. and Wincker, P. (2015) "Tara Oceans studies plankton at planetary scale".
doi:
10.1126/science.aac5605.
^De Vargas, C., Audic, S., Henry, N., Decelle, J., Mahé, F., Logares, R., Lara, E., Berney, C., Le Bescot, N., Probert, I., Carmichael, M. and 44 others (2015) "Eukaryotic plankton diversity in the sunlit ocean. Science", 348(6237): 1261605.
doi:
10.1126/science.1261605.
^Wernberg, T., Krumhansl, K., Filbee-Dexter, K. and Pedersen, M.F. (2019) "Status and trends for the world’s kelp forests". In: World seas: an environmental evaluation, pages 57–78). Academic Press.
doi:
10.1016/B978-0-12-805052-1.00003-6.
^Mann, K.H. 1973. Seaweeds: their productivity and strategy for growth. Science 182: 975-981.
^Kindersley, Dorling (2011). Illustrated Encyclopedia of the Ocean. Dorling Kindersley.
ISBN978-1-4053-3308-5.
^Stow, Dorrik (2004). Encyclopedia of the Oceans. Oxford University Press.
ISBN978-0-19-860687-1.
^Giri C, Ochieng E, Tieszen LL, Zhu Z, Singh A, Loveland T, et al. (2011) "Status and distribution of mangrove forests of the world using earth observation satellite data". Global Ecology and Biogeography, 20(1):154–159.
doi:
10.1111/j.1466-8238.2010.00584.x
^Thomas, N., Lucas, R., Bunting, P., Hardy, A., Rosenqvist, A. and Simard, M. (2017) "Distribution and drivers of global mangrove forest change, 1996–2010". PLOS ONE, 12(6): e0179302.
doi:
10.1371/journal.pone.0179302
^Boyd, Philip W.; Strzepek, Robert; Fu, Feixue; Hutchins, David A. (2010). "Environmental control of open-ocean phytoplankton groups: Now and in the future". Limnology and Oceanography. 55 (3): 1353–1376.
Bibcode:
2010LimOc..55.1353B.
doi:
10.4319/lo.2010.55.3.1353.
S2CID15511444.
^Finkel, Z. V.; Beardall, J.; Flynn, K. J.; Quigg, A.; Rees, T. A. V.; Raven, J. A. (2010). "Phytoplankton in a changing world: Cell size and elemental stoichiometry". Journal of Plankton Research. 32: 119–137.
doi:
10.1093/plankt/fbp098.
^Persson, Jonas; Fink, Patrick; Goto, Akira; Hood, James M.; Jonas, Jayne; Kato, Satoshi (2010). "To be or not to be what you eat: Regulation of stoichiometric homeostasis among autotrophs and heterotrophs". Oikos. 119 (5): 741–751.
doi:
10.1111/j.1600-0706.2009.18545.x.
^Yvon-Durocher, Gabriel; Dossena, Matteo; Trimmer, Mark; Woodward, Guy; Allen, Andrew P. (2015). "Temperature and the biogeography of algal stoichiometry". Global Ecology and Biogeography. 24 (5): 562–570.
doi:
10.1111/geb.12280.
^MacIntyre, Hugh L.; Kana, Todd M.; Anning, Tracy; Geider, Richard J. (2002). "Photoacclimation of Photosynthesis Irradiance Response Curves and Photosynthetic Pigments in Microalgae and Cyanobacteria1". Journal of Phycology. 38: 17–38.
doi:
10.1046/j.1529-8817.2002.00094.x.
S2CID29301640.
^Lucking, R., Huhndorf, S., Pfister, D.H., Plata, E.R. and Lumbsch, H.T. (2009) "Fungi evolved right on track". Mycologia, 101(6): 810–822.
doi:
10.3852/09-016.
^Heckman, D.S., Geiser, D.M., Eidell, B.R., Stauffer, R.L., Kardos, N.L. and Hedges, S.B. (2001) "Molecular evidence for the early colonization of land by fungi and plants". Science, 293(5532): 1129–1133.
doi:
10.1126/science.1061457.