In general, different aquaculture systems have been used to improve water quality and reduce the stress of shrimp in intensive systems, with the consequent increase in the growth rate, among which are the recirculating aquaculture system (RAS), artificial substrates, biofloc technology (BFT) and photoheterotrophic system.
It was found in this study that production of 2.83 g [m.sup.-3] or stocking density of 500 ind [m.sup.-3] (T500) could be acceptable for juvenile shrimp reared in a photoheterotrophic intensive system in circular grow-out lined ponds, with minimal water replacement.
The latter added an insight to the exotic marine photoheterotrophic
lifestyle first described by Beja and colleagues only a few years before .
Four methods are: phototrophic (light as the only source of energy), heterotrophic (organic matter as the energy source), mixotrophic (organic and C[O.sub.2] required for photosynthesis), and photoheterotrophic
(use light to extract energy from organic matter) .
Hristova, "Mathematical model of Chlorella minutissima UTEX2341 growth and lipid production under photoheterotrophic
fermentation conditions," Bioresource Technology, vol.
(1987) proposed that, because light levels and DO vary during the day, this bacterium alternates between photoheterotrophic
growth (at high light levels; using organic matter excreted by the cyanobacteria) and sulfide co-metabolism with cyanobacteria (at relatively low light levels, where [O.sub.2] production is minimal).
(1981, 1984b) noted that the main growth phase is the planktonic form which is photoautotrophic while the benthic form is photoheterotrophic
and serves as the <<inoculum>> for the plankton.
Although diatoms known to contain nitrogen-fixing cyanobacteria (Rhizosolenia and Hemiaulus) appear to be well represented in the waters near Easter and Salas y Gomez islands, a diverse group of heterotrophic, nitrogen-fixing bacteria or photoheterotrophic
cyanobacteria may dominate nitrogen fixation in the south Pacific subtropical gyre (Von Dassow & Collado-Fabbri, 2014).
Alternatively, researchers are looking into the potential of mixotrophic (photoheterotrophic
) mode upon realization of enhanced growth and unrepressed light-dependent bioproducts formation from the combined effects of photosynthesis and the cells' own ability to ingest either prey or dissolved organic materials .
Heterotrophic and photoheterotrophic
utilization of lactate by the diatom Cylindrotheca fusiformis.
Nevertheless, a recent study found that heterotrophic [N.sub.2]-fixing bacteria and possibly photoheterotrophic
unicellular cyanobacteria appeared to dominate [N.sub.2] fixation in the SPSG (Halm et al., 2012), which is very different from the [N.sub.2]-fixing communities dominated by phototrophs seen in other gyre systems (see above) and in the western SPSG (Hashihama et al., 2010).