Distribution and ecology of freshwater sponges in Connecticut

A survey of Connecticut lakes and rivers revealed the presence of 7 species of freshwater sponge: Spongilla lacustris, Ephydatia muelleri, Eunapius fragilis, Anheteromeyenia ryderi, A. argyrosperma, Corvomeyenia carolinensis, and Corvospongilla novaeterrae in order of decreasing frequency of occurrence. Corvomeyenia carolinensis has not been reported previously beyond its type locality in South Carolina. In addition, microscleres of Spongilla lacustris, Anheteromeyenia-like megascleres, Ephydatia muelleri-like megascleres, and smooth megascleres (amphioxeas), which could not be assigned to a particular species, were found in surface sediments from lake cores. Spongilla lacustris inhabiting small rivers produced brown, thick-capsuled gemmules during the summer and yellow, thin-capsuled gemmules during the fall. The thick-capsuled gemmules, but not the thin-capsuled gemmules, are tolerant of desiccation; and populations of Spongilla lacustris and Ephydatia muelleri survived severe drying of their habitats during the summer.     

Pione lampa,a bioeroding sponge in a worm reef

A bioeroding sponge was found in a sabellariid worm reef in Florida, USA. The sponge was investigated with standard techniques for species identification (tissue digestion, microscopy techniques, examination of spicules) and was identified as the clionid Pione lampa (De Laubenfels, 1950). This species is extremely similar to Pione vastifica (Hancock, 1849). Morphological and ecological similarities and possible dissimilarities are discussed. Arguments for conspecifity were found to be weaker than evidence of P. lampa and P. vastifica being separate species. The sampled sponge contained asexual reproductive elements: superficial buds and internal gemmules. Buds were very delicate, consisting mainly of a radially-oriented mesh of collageneous threads. They further comprised abundant granular material and acanthose microrhabds. Numerous choanosomal gemmules were found in the sponge body attached to erosion chamber walls. They were subspherical to lenticular and had an aspicular, unstructured, smooth and rigid coat. It enclosed dense cell material and various spicule types. Whereas buds are interpreted to function as dispersal elements, gemmules will primarily ensure survival under adverse conditions such as smothering, exposure to air and high temperatures. Gemmules from this site might occasionally be freed and scattered, since the Florida reef can suffer heavy damage during periods of increased wave activity such as that created during hurricane season. Bioerosion activity of the sponge increases the chance to free gemmules, as the sponge not only etches into calcareous particles cemented into the matrix produced by the worms, but also into the matrix itself. This ability enables the sponge to utilise the reef as substrate. Within the Clionidae, Cliona annulifera and three species of the genus Pione are the only species known to produce typical gemmules. Possible reasons are: (1) reproduction of bioeroding sponges is understudied and asexual bodies may have been overlooked in other species, and (2) clionid gemmules are an adaptation to survive life in risky environments. Sponges of the genus Pioneare comparatively successful in environments in which they are close to their physical limits or in potentially unstable or mobile substrates.     

High diversity of tropical intertidal zone sponges in temperature, salinity and current extremes

The wide intertidal zone of the Quirimba Archipelago (Mozambique, East Africa) encompasses many different habitats, which all experience wide environmental variation. Large daily fluctuations in temperature occur when standing water is heated up at low tide to >10°C above ambient. Salinity may be high in the dry season and periodically almost fresh in the wet season. Very high current velocities (≈3 ms⁻¹) may occur and the direction of water flow is often complex. Sponges were a major component of the fauna (and dominate the sessile forms) in most of the eight habitats studied: exposed reef, sheltered reef, sand-rock, cave, reef boulders, boulders on sand, mangrove swamp and seagrass meadows. The highest number of sponge species occurred in the two reef habitats: from mean values of between ≈2.5 and ≈0.5 species/m² (upper and lower shore, respectively). The diversity of species present yielded a high Shannon index value of H=2.95 for the total of 33 species. A rank-abundance plot of the data showed a high level of equitability (J=0.84). Community similarity measurement using Bray–Curtis index showed two clusters; the exposed habitats of the reefs and sand-rock and the refugia of cave, reef and sand boulders.     

Sperm ultrastructure of a member of the black coral family Aphanipathidae: Rhipidipathes reticulata (Anthozoa, Antipatharia)

Fertile male polyps of three colonies of the black coral Rhipidipathes reticulata (Aphanipathidae) from Togian Islands (Indonesia) have been the source of the sperm investigated at ultrastructural level, in order to compare their organization with that of other members belonging to the family Antipathidae and Myriopathidae. The extension of the studies to a representative of the family Aphanipathidae stresses once more the structural similarity of the male gametes in antipatharians. A sketch of the sperm model reports the similarity and differences in the examined taxa. Among the micro-characters, the cup-like body linked to the pericentriolar apparatus, is exclusive of the antipatharians. Other inclusions concern the more common pro-acrosomal vesicles or the acrosomelike structure observed only in Antipathella subpinnata and Myriopathes japonica. Lipid vesicles are occasionally present. A typical inclusion, the electron-dense content of which has a C-shaped configuration, is restricted to Rhipidipathes reticulata and is associated to the cup-like body or to the mitochondrion.     

Upstream processes in antibody production: evaluation of critical parameters

The demand for monoclonal antibody for therapeutic and diagnostic applications is rising constantly which puts up a need to bring down the cost of its production. In this context it becomes a prerequisite to improve the efficiency of the existing processes used for monoclonal antibody production. This review describes various upstream processes used for monoclonal antibody production and evaluates critical parameters and efforts which are being made to enhance the efficiency of the process. The upstream technology has tremendously been upgraded from host cells used for manufacturing to bioreactors type and capacity. The host cells used range from microbial, mammalian to plant cells with mammalian cells dominating the scenario. Disposable bioreactors are being promoted for small scale production due to easy adaptation to process validation and flexibility, though they are limited by the scale of production. In this respect Wave bioreactors for suspension culture have been introduced recently. A novel bioreactor for immobilized cells is described which permits an economical and easy alternative to hollow fiber bioreactor at lab scale production. Modification of the cellular machinery to alter their metabolic characteristics has further added to robustness of cells and perks up cell specific productivity. The process parameters including feeding strategies and environmental parameters are being improved and efforts to validate them to get reproducible results are becoming a trend. Online monitoring of the process and product characterization is increasingly gaining importance. In total the advancement of upstream processes have led to the increase in volumetric productivity by 100-fold over last decade and make the monoclonal antibody production more economical and realistic option for therapeutic applications.     

Reproductive performance in grey seals: age-related improvement and senescence in a capital breeder

1. Three hypotheses have been advanced to account for age-related improvement in performance: the selection hypothesis predicts improved due to the loss of lower quality phenotypes, the constraint hypothesis predicts individuals improve function, and the restraint hypothesis predicts younger individuals forego or reduce effort because of mortality risks. A decline in age-related performance (i.e. senescence) is predicted by mutation accumulation, antagonistic pleiotropy and disposable soma (wear and tear) hypotheses. 2. Using five measures of performance - birth rate, maternal and pup birth mass, pup weaning mass, weaning success and lactation length - we tested these hypotheses concerning age-related change in reproduction in 279 female grey seals (Halichoerus grypus), ages 4-42 years, over a 23-year period between 1983 and 2005 on Sable Island, Nova Scotia. These females produced 2071 pups. 3. Although body mass of primiparous females increased with age (4-7 years) birth mass of their pups did not, but pup weaning mass did. Second- and third-parity females of the same age as primiparous females gave birth to and weaned heavier pups. However, parity and age were dropped from models when maternal body mass was included. 4. The proportion of females giving birth varied significantly with maternal age, increasing in young females and then declining late in life. Weaning success rate also increased rapidly to about 8 years and subsequently declined in females > 32 years. 5. Generalized additive models indicated nonlinear changes in 3 day body mass (i.e. approximately birth mass) and weaning mass of pups as a function of maternal age, after accounting statistically for the effects of maternal body mass. Mixed-effects, repeated-measures models fitted to longitudinal data further supported the conclusion that pup birth mass and weaning mass vary nonlinearly with maternal age and indicated nonlinear changes in lactation duration. 6. We found some support for the constraint hypothesis, but our findings were not consistent with the selection hypothesis or the restraint hypothesis as the basis for improvement in reproductive performance. 7. Senescence was evident in multiple female and offspring traits, indicating the degeneration in function of several physiological systems as predicted by the disposable soma hypothesis.     

Reproductive strategies and early development of three freshwater gobies

Three species of gobiid fish inhabit the freshwater Lake Trichonis of western Greece. Two of these species, Economidichthys pygmaeus and E. trichonis are endemic, and the third is the widespread Knipowitschia caucasica . There are habitat separations between the three species, E. pygmaeus and E. trichonis prefer vegetated areas, the first being fully demersal at all stages of development and the second being semi-demersal. Knipowitschia caucasica prefers sandy bottoms and is distributed in shallower waters. Female E. pygmaeus and E. trichonis spawn in nests prepared by the males in the cavities of broken reeds. The males subsequently guard the eggs until they hatch, with females playing no role in parental care. Economidichthys trichonis is probably the smallest freshwater European species. Its eggs are ovoid, measuring about 0.64 × 0.58 mm, from which tiny, unpigmented and incompletely developed pelagic larvae hatch out after an incubation period lasting less than 1 day at a water temperature of 19.5° C. The eggs of E. pygmaeus are cylindrical and larger, measuring about 2.38 × 0.89 mm, from which relatively large, strongly pigmented and ontogenetically more advanced larvae hatch out after a longer incubation period. Both species reproduce only once in their lifetime, at the age of 1 year, and die shortly after spawning, but the breeding season involves several spawnings by each individual fish. These biological, developmental and reproductive characteristics are discussed in relation to current theories on evolution of life-historics.     

Reproductive competence: a recurrent logic module in eukaryotic development

Developmental competence is the ability to differentiate in response to an appropriate stimulus, as first elaborated by Waddington in relation to organs and tissues. Competence thresholds operate at all levels of biological systems from the molecular (e.g. the cell cycle) to the ontological (e.g. metamorphosis and reproduction). Reproductive competence, an organismal process, is well studied in mammals (sexual maturity) and plants (vegetative phase change), though far less than later stages of terminal differentiation. The phenomenon has also been documented in multiple species of multicellular fungi, mostly in early, disparate literature, providing a clear example of physiological differentiation in the absence of morphological change. This review brings together data on reproductive competence in Ascomycete fungi, particularly the model filamentous fungus Aspergillus nidulans, contrasting mechanisms within Unikonts and plants. We posit reproductive competence is an elementary logic module necessary for coordinated development of multicellular organisms or functional units. This includes unitary multicellular life as well as colonial species both unicellular and multicellular (e.g. social insects such as ants). We discuss adaptive hypotheses for developmental and reproductive competence systems and suggest experimental work to address the evolutionary origins, generality and genetic basis of competence in the fungal kingdom.     

Reproductive allocation and the long-term costs of reproduction in Siparuna grandiflora, a dioecious neo-tropical shrub

1 Using a combination of observational and experimental approaches, both allocation of resources to reproduction (often called the direct cost of reproduction) and the subsequent long-term costs (the indirect, delayed or demographic cost) associated with reproductive allocation to male and female function in Siparuna grandiflora (Siparunaceae), a tropical dioecious shrub, were examined.
2 The objectives were to determine whether females allocate more biomass or nitrogen per reproductive episode than males, and whether there is a long-term cost of reproduction in terms of subsequent growth or reproduction for either sex. If there is no long-term cost of reproduction, then reproduction may be viewed as free in an evolutionary sense.
3 As is generally the case in dioecious species, females allocated more biomass and nitrogen to reproduction than males. Females also showed delayed costs of reproduction in terms of decreased growth and subsequent reproduction, whereas males did not.
4 The lack of measurable delayed costs in males suggests that with the evolution of dioecy, selection has reduced delayed costs of reproduction in S. grandiflora males. In contrast, females that were prevented from reproducing were able to re-allocate resources to growth, and produced more stem length on average than males. This re-allocation response may have evolved to reduce delayed costs of reproduction in females over time frames longer than that considered in the present study.     

Reproductive physiology studies in zoological species: Concerns and strategies

A sophisticated understanding of reproductive physiology of domestic animals has evolved over only the past several decades. Related technical advances in this field have permitted propagation through artificial insemination and/or embryo transfer using fresh or frozen-thawed gametic or embryonic material. More recent studies in genetic engineering and embryo micromanipulation have generated additional potential for improved reproductive efficiency in the farm-animal industry. Although these procedures provide incentive for solving management problems and improving the endangered status of many zoological species, achieving these objectives will be neither simple nor immediate. Major obstacles to confront include the poor image of research, unavailability of research stocks, lack of financial support, scarcity of trained personnel, and the idea that new reproductive techniques offer a “quick fix” to the problem of inadequate reproduction in an endangered species. Zoological researchers should now concentrate on establishing basic reproductive relationships in species of interest. Comparative studies in domesticated animals will accelerate progress. The immediate goal should be the production of sound scientific data of publishable quality. Only then can artificial propagation be considered as a viable alternative to preserving wildlife species.     

Reproductive habitat selection in alien and native populations of the genus Discoglossus

The existence of suitable breeding habitats is an important factor explaining the regional presence of an anuran species. This study examined patterns of habitat selection in populations of three species of the genus Discoglossus: Discoglossus galganoi (south-western Iberian Peninsula), Discoglossus scovazzi (Morocco) and Discoglossus pictus (three different areas were included in the study: Sicily, Tunisia and north-eastern Iberian Peninsula). The populations of D. pictus on the Iberian Peninsula are allochthonous, and analysis of these patterns may provide insights into the processes that regulate the invasion phase. The hypotheses tested were: (i) congeneric species show the same patterns of habitat selection, and alien species have been established following these patterns; (ii) there are differences in species associations between assemblages structured deterministically and by chance, i.e. native versus invaded assemblages. The larval habitats of three species of this genus were characterized by measuring physical and chemical parameters of the water bodies. We examined the covariation between the presence of Discoglossus species and the species richness of sympatric anurans, and investigated a possible relationship between morphological similarity (as a proxy of functional group) and overlap in habitat use. The results showed that congeneric species are morphologically conservative and also select very similar types of aquatic habitat. The alien population and other sympatric species showed a high degree of overlap in habitat use, which was greater than that observed in the native assemblage with a similar functional richness. Species associations were not structured on the basis of morphological similarity in any of the assemblages. Among native populations, the presence of Discoglossus was either negatively correlated or not significantly correlated with species richness. Only the alien population showed a positive correlation between its presence and species richness, which suggests a loss of assemblage structure.     

ADP-ribosyl cyclase and abscisic acid are involved in the seasonal growth and in post-traumatic tissue regeneration of Mediterranean sponges

In previous papers it has been demonstrated that the plant hormone abscisic acid (ABA) is responsible for the stimulation of water filtration and oxygen consumption elicited by a temperature increase in the Mediterranean demosponge Axinella polypoides. The signal transduction pathway triggered by ABA involves activation of ADP-ribosyl cyclase (ADPRC), leading to an increase of the intracellular concentration of cyclic ADP-ribose (cADPR), a universal and potent intracellular calcium mobilizer. These data prompted us to investigate the possible involvement of the ABA/ADPRC/cADPR system in the sponge life cycle and in post-traumatic tissue regeneration of Mediterranean sponges. ADPRC activity was detected in the cell lysate from several common Mediterranean sponge species, including Calcarea and Demospongiae. Specimens were collected monthly over a 2-year period, from January 2002 to April 2004. All species studied showed a peak of ADPRC activity during July and August 2003, concomitant with an anomalous heat wave that struck the whole Mediterranean basin during these months. In the aquarium, during spontaneous tissue regeneration, an increase of the [ABA]_i and of the ADPRC activity over time zero values was consistently observed. In conclusion, these results indicate that an increase of ABA content and of ADPRC activity correlates with the growth and with post-traumatic tissue regeneration in several Mediterranean sponge species, indicating that the ABA/ADPRC/cADPR system is involved in the response to environmental stress in sponges. Determination of ADPRC activity/ABA content may provide a means to assess metabolic activation of sponge populations under conditions of environmental stress.     

Causes of decreased photosynthetic rate and metabolic capacity in water-deficient leaf cells: a critical evaluation of mechanisms and integration of processes

Background

Water deficit (WD) decreases photosynthetic rate (A) via decreased stomatal conductance to CO₂ (g_s) and photosynthetic metabolic potential (A_pot). The relative importance of g_s and A_pot, and how they are affected by WD, are reviewed with respect to light intensity and to experimental approaches.

Scope and Conclusions

With progressive WD, A decreases as g_s falls. Under low light during growth and WD, A is stimulated by elevated CO₂, showing that metabolism (A_pot) is not impaired, but at high light A is not stimulated, showing inhibition. At a given intercellular CO₂ concentration (C_i) A decreases, showing impaired metabolism (A_pot). The C_i and probably chloroplast CO₂ concentration (C_c), decreases and then increases, together with the equilibrium CO₂ concentration, with greater WD. Estimation of C_c and internal (mesophyll) conductance (g_i) is considered uncertain. Photosystem activity is unaffected until very severe WD, maintaining electron (e⁻) transport (ET) and reductant content. Low A, together with photorespiration (PR), which is maintained or decreased, provides a smaller sink for e⁻_, causing over-energization of energy transduction. Despite increased non-photochemical quenching (NPQ), excess energy and e⁻ result in generation of reactive oxygen species (ROS). Evidence is considered that ROS damages ATP synthase so that ATP content decreases progressively with WD. Decreased ATP limits RuBP production by the Calvin cycle and thus A_pot. Rubisco activity is unlikely to determine A_pot. Sucrose synthesis is limited by lack of substrate and impaired enzyme regulation. With WD, PR decreases relative to light respiration (R_L), and mitochondria consume reductant and synthesise ATP. With progressing WD at low A, R_L increases C_i and C_c. This review emphasises the effects of light intensity, considers techniques, and develops a qualitative model of photosynthetic metabolism under WD that explains many observations: testable hypotheses are suggested.Key words: Water stress, photosynthesis, photorespiration, stomata, ATP synthase, ATP, photoinhibition, electron transport, Rubisco, fluorescence, sucrose, mesophyll conductance     

Single-cell genomics reveals the lifestyle of Poribacteria,a candidate phylum symbiotically associated with marine sponges

In this study, we present a single-cell genomics approach for the functional characterization of the candidate phylum Poribacteria, members of which are nearly exclusively found in marine sponges. The microbial consortia of the Mediterranean sponge Aplysina aerophoba were singularized by fluorescence-activated cell sorting, and individual microbial cells were subjected to phi29 polymerase-mediated ‘whole-genome amplification''. Pyrosequencing of a single amplified genome (SAG) derived from a member of the Poribacteria resulted in nearly 1.6 Mb of genomic information distributed among 554 contigs analyzed in this study. Approximately two-third of the poribacterial genome was sequenced. Our findings shed light on the functional properties and lifestyle of a possibly ancient bacterial symbiont of marine sponges. The Poribacteria are mixotrophic bacteria with autotrophic CO₂-fixation capacities through the Wood–Ljungdahl pathway. The cell wall is of Gram-negative origin. The Poribacteria produce at least two polyketide synthases (PKSs), one of which is the sponge-specific Sup-type PKS. Several putative symbiosis factors such as adhesins (bacterial Ig-like domains, lamininin G domain proteins), adhesin-related proteins (ankyrin, fibronectin type III) and tetratrico peptide repeat domain-encoding proteins were identified, which might be involved in mediating sponge–microbe interactions. The discovery of genes coding for 24-isopropyl steroids implies that certain fossil biomarkers used to date the origins of metazoan life on earth may possibly be of poribacterial origin. Single-cell genomic approaches, such as those shown herein, contribute to a better understanding of beneficial microbial consortia, of which most members are, because of the lack of cultivation, inaccessible by conventional techniques.     

Theorizing transnational immigration: a critical review of current efforts

During the past decade, transnationalism has entered the lexicon of migration scholars. As with other terms used in the study of immigration and ethnicity, this concept suffers from ambiguity as a result of competing definitions that fail to specify the temporal and spatial parameters of the term and to adequately locate it vis-à-vis older concepts such as assimilation and cultural pluralism. This article offers a review and critique of the ways the term has come to be employed at the hands of key spokespersons that have articulated the most sustained theoretical rationales to date for transnationalism as a conceptual construct to account for new immigrant identities and communities. The conclusion of the essay offers in schematic form an alternative assessment of transnationalism that locates it as one potential subset of assimilation theory, rather than as an alternative to it.     

Adult neurogenesis and pattern separation in rodents: A critical evaluation of data,tasks and interpretation

The ability to discriminate and store similar inputs as distinct representations in memory is thought to rely on a process called pattern separation in the dentate gyrus of the hippocampus. Recent computational and empirical findings support a role for adult-born granule neurons in spatial pattern separation. We reviewed rodent studies that have manipulated both hippocampal adult neurogenesis and assessed pattern separation. The majority of studies report a supporting role of adult born neurons in pattern separation as measured at the behavioral level. However, closer evaluation of the published findings reveals variation in both pattern separation tasks and in the interpretation of behavioral performance that, taken together, suggests that the role of hippocampal adult neurogenesis in pattern separation may be less established than is currently assumed. Assessment of pattern separation at the network level through the use of immediate early gene expression, optogenetic, pharmacogenetic and/or in vivo electrophysiology studies could be instrumental in further confirming a role of adult born neurons in pattern separation further. Finally, hippocampal adult neurogenesis and pattern separation are not an exclusive pair, as evidence for hippocampal adult neurogenesis contributing to the temporal separation of events in memory, forgetting and cognitive flexibility has also been found. We conclude that whereas current empirical evidence for the involvement of hippocampal adult neurogenesis in pattern separation seems supportive, there is a need for careful interpretation of behavioral findings and an integration of the various proposed functions of adult born neurons.     

Environmentally Contingent Reproductive Strategies in Mayan and Ache Males

This research explores male reproductive parameters, particularly the timing of first reproduction, in two traditional populations. Predictions are drawn from theoretical arguments that have their roots in evolutionary psychology and behavioral ecology, and that interpret variation in reproductive outcomes as environmentally contingent adaptations. In both Ache and Mayan samples, father absence, predicted to act as a stressor that causes precocious sexuality and reproduction as well as unstable pair bonds, did not affect the timing of first reproduction in male offspring in the expected way. Father absence in Mayan men, however, was found to be associated with responses to questionnaire items indicating lack of willingness to pay time and energy costs to maintain existing sexual unions. The results suggest that father absence affects male mating strategy, but that strategic differences did not translate into reproductive outcomes in the sample. In the Mayan population, education was associated with early reproduction, more lifetime sex partners, and higher fertility, which was also contrary to the predicted pattern based on a life-history tradeoff approach. Parental resources were associated with earlier reproduction in the Mayan sample, confirming the prediction that restricted resources should delay reproduction.     

Reproductive allometry in Malaysian rain forest trees: Biomechanics versus optimal allocation

Summary Quantitative predictions of reproductive allometry in iteroparous plants may be derived from two bodies of theory: biomechanics and optimal allocation theory. Biomechanical theory predicts allometric scaling exponents between reproductive (R) and vegetative (V) biomass in the range of 0.44–1.33, while very general models of life history evolution predictR–V exponents > 1 in all cases. These predictions are examined in light of allometric patterns of flower and fruit production in 32 species of Malaysian rain forest trees. Among these species the mean estimatedR–V exponents are in the range 1.8–2.0 for staminate flower, pistillate flower and fruit production. This range of exponent values provides unambiguous support for some of the general predictions of optimal allocation models, but not for biomechanical theory. Optimal allocation models also predict a positive relationship between species size andR–V slope and a positive relationship between species size andR–V intercept parameters. The latter, but not the former prediction is supported by the data.R–V allometries in sexes of dioecious species were also found to differ in intercept, though not slope, reflecting smaller sizes at reproductive onset in staminate trees. Further critical examinations of reproductive allometry are encouraged as a relatively unexplored avenue for increasing the contact of theory and data in studies of life history evolution in long-lived organisms such as tropical trees.     

Winery wastewater treatment: a critical overview of advanced biological processes

Wine production is one of the leading sectors of the food processing industry. The wine industry produces a large amount of wastewater characterized by a high strength in terms of organic pollution and large variability throughout the year. Most of the organic matter is soluble and easily biodegradable. On the other hand, nitrogen and phosphorous are lacking. The aerobic and anaerobic processes are largely applied for winery wastewater treatment because they can quickly react to changes in the organic loading. This review analyzes e applied biological systems, considering both aerobic and anaerobic processes, and different reactor configurations. The performances of different biological processes are evaluated in terms of operational conditions (organic loading rate and hydraulic retention time). Aerobic processes can guarantee chemical oxygen demand removal up to 98% for organic loading rates of some 1-2?kg of chemical oxygen demand m^?3d^?1 but requires good aeration systems to supply the required process oxygen. The management cost of these processes could be high considering the power density in the range 60-70?W m^?3_reactor and that nutrients should be added to support biomass growth. On the other hand, anaerobic processes are able to face high organic loads with low running costs, but COD removal is generally limited to 90%. Combination of the two treatment systems (anaerobic followed by aerobic) could reduce management costs and meet high discharge standards.