Effects Of Organic Enrichment Research Articles

Chronic Toxicity of Ammonia to New Zealand Freshwater Invertebrates: A Mesocosm Study.

Freshwater macroinvertebrate communities were established within 12 artificial streams or "toroidal" mesocosms and exposed to three replicated concentrations of ammonia for 29 days at constant temperature (16 degrees C) and pH (median 8.4). The criterion units (CU = measured [ammonia]/US EPA 1985 chronic criterion value) of total ammonia in the LOW, MED, and HIGH treatments were 2.0, 4.8, and 13 CUs respectively, and 1.9, 5.8, and 12 CUs for the unionized ammonia. Macroinvertebrates were tolerant of the ammonia exposures with no significant (p > 0.1) effect on taxa richness; number of taxa in the orders Ephemeroptera, Plecoptera, and Trichoptera (EPT); or the quantitative macroinvertebrate community index (QMCI), a biotic index proposed for assessing effects of organic enrichment in New Zealand streams. Significant differences (p < 0.05) occurred for the mean abundance and the numbers of EPT individuals (QEPT), with the HIGH treatment significantly lower (-41%) than the control for both abundance and QEPT. Of the major species, only the mayflies Deleatidium sp. (Ephemeroptera: Leptophlebiidae) and Coloburiscus humeralis (Ephemeroptera: Oligoneuriidae) showed significant reductions in abundance, with only the caddisflies Beraeoptera roria (Trichoptera: Conoesucidae) and Confluens sp. (Trichoptera: Conoesucidae) showing significant increases in abundance. The abundance of juvenile Deleatidium sp. had a negative concentration-response relationship that resulted in an 82% decrease in abundance in the HIGH treatment. Drift of invertebrates showed no response to ammonia treatments. The 29-day EC(50) values for Deleatidium sp. for total and unionized ammonia were 2.15 mg (N)/L (pH 8.4) and 0.145 mg (NH(3)-N)/L. No observed effect concentration (NOEC) values were 0.95 mg (N)/L and 0.066 mg (NH(3)-N)/L, and the threshold effect concentration (TEC) was 1.49 mg (N)/L and 0.102 mg (NH(3)-N)/L. Comparison of the Deleatidium sp. chronic ammonia sensitivity data with the US EPA 1985 chronic criterion value (CCC = 0.45 mg [N]/L, pH 8.4, 16 degrees C) showed the TEC value for total ammonia was 3.3x CCC, and 2.2x higher than the updated US EPA 1998 criteria. The findings suggest that use of the US EPA criteria would provide minimal protection for Deleatidium for chronic ammonia exposure, and that development of site-specific criteria, covering a wide range of environmental conditions, may be required to adequately protect this species.http://link.springer-ny.com/link/service/journals/00244/bibs/37n3p338.html

Effects of organic enrichment and burrowing activity of the polychaete Neries diversicolor on the fate of tetrachlorobiphenyl in marine sediments

AbstractThe effects of organic enrichment and burrowing activity of the infaunal polychaete Nereis (Hediste) diversicolor on the distribution of 14C‐3,3′,4,4′‐tetrachlorobiphenyl (TCB) were studied in an experimental benthic system. Organic enrichment of the sediment was provided by a mixture of the diatom Skeletonema costatum and the sea lettuce Ulva lactuca. Organic matter and TCB were both initially added to a surface sediment layer of the microcosms. A factorial design with organic enrichment (control vs enriched) and bioturbation (presence or absence of N. diversicolor) as fixed factors and concentration of TCB in sediment, water, and biota as dependent variables allowed us to test the four combinations. Release of TCB from the sediment to the water column was measured in the outflowing water of the aquaria. After 28 d of exposure, TCB concentrations were measured in animals, feces, sediment cores, burrows, sediment surface, and in sulfur bacteria mats. Both bioturbation and organic enrichment enhanced the release of TCB from the sediment to the water column. The greatest effect was caused by the combination of the two factors, which increased release rates by 280% compared with controls. No general downward transport and vertical redistribution of TCB in the sediment were observed. However, TCB concentrations were significantly higher in the burrow linings of the worms than in the bulk sediment. Increased TCB accumulation by the animals was observed following organic enrichment, which was considered to be the result of selective feeding on TOC‐rich contaminated food particles. The organic enrichment also stimulated the production of sulfur bacteria mats, which were found to accumulate high TCB concentrations. Our results contradict those of several other studies that have reported a reduced bioavailability of organic contaminants with increasing sedimentary organic carbon content. Our study suggests that the quality of the organic matter should be considered in the evaluation of exposure in benthic organisms.

Effects of heavy metals on benthic macroinvertebrate communities in New Zealand streams

AbstractWe performed chemical analyses of heavy metals in water and periphyton, toxicity tests with Daphnia magna and an indigenous mayfly (Deleatidium sp.), and field surveys of benthic macroinvertebrates to estimate the degree of metal pollution in three catchments in the Coromandel Peninsula of New Zealand. Good agreement was found between toxicity tests and measures of benthic community structure, particularly at stations with the highest metal levels. Responses of benthic communities at stations with low or moderate levels of metal contamination were variable and were probably confounded by factors other than heavy metals. Effects of heavy metals on benthic communities in New Zealand streams were similar to those reported for metal‐polluted streams in North America and Europe, suggesting that responses to metal contamination are predictable. Abundance and species richness of mayflies, number of taxa in the orders Ephemeroptera, Plecoptera, and Trichoptera, and total taxonomic richness were the best indicators of heavy metals in New Zealand streams. In contrast, the quantitative macroinvertebrate community index (QMCI), a biotic index proposed for assessing effects of organic enrichment in New Zealand streams, could not distinguish between reference and metal‐polluted streams. The poor performance of the QMCI was primarily due to incorrect tolerance scores for some taxa to heavy metals. Because of concerns regarding the subjective assignment of tolerance values to species, we recommend that tolerance values for dominant species in New Zealand streams should be verified experimentally in stream microcosms.

Earthworm activity and soil structure changes due to organic enrichments in vineyard systems

The effect of organic enrichment on earthworm activity and soil structure was studied in two French vineyards, by comparing control and test plots. In each vineyard the organic matter quantitatively increased the abundance and biomass of the earthworm community. These increases were associated with a higher level of species diversity and a higher evenness corresponding to the development of endogeic community. These earthworm community changes were associated with an increase in granular bioturbated areas and in macroporosity in the top soil layer. The micromorphological approach incorporated an original process of image analysis which appeared to be an appropriate method for characterizing pore morphology in this study. The pores when characterized by their size and shape could be related to ecological groups and growth stages of earthworms.

Interactions between eutrophication and contaminants. IV. Effects on sediment-dwelling organisms

Effects of organic enrichment, oxygen availability and the presence of contaminants on three sediment-dwelling invertebrates, the polychaete Nereis (Hediste) diversicolor, the bivalve Abra alba and the brittle star Amphiura filiformis, were assessed using growth, arm regeneration and biomarkers (metallothionein-like proteins, glutathione reductase, glutathione S-transferase) in a 93-day microcosm experiment. Moderate organic enrichment (approx. 40 g C m −2) increased growth and hypoxia (2.4–3.5 mg l −1) decreased growth in all three species. Effects of organic enrichment and low oxygen availability were additive for growth in N. diversicolor and A. filiformis, whereas there was an interaction between hypoxia and organic enrichment in their effects on growth in A. alba, reflecting a decreased ability of this species to utilize the available organic material under hypoxic conditions. Sediment-bound contaminants (4.8 mg kg −1 Cd and 1.32 mg kg −1 benzo[ a]pyrene) had minor effects on growth and arm regeneration. Some biomarkers in N. diversicolor and A. filiformis reflected tissue contaminant concentrations, whereas there was no response of biomarkers in A. alba to any treatment or contaminant.

Eutrophication and Zoobenthos dynamics

Abstract The possible effects of eutrophication on benthic dynamics are discussed based on the Pearson-Rosenberg Model that describes the effects of organic enrichment on qualitative characteristics of benthic communities. Depending on the amount of organic matter reaching the sediments, the model describes three successive states: a) slight increases in biomass and few or no changes in species composition over the “normal” situation; b) strong increases of biomass and replacement of “normal” species by opportunistic species; c) disappearance of benthic animal species and azoic sediments. In the field, increase of benthic biomass and changes in species composition on decadal scales which are attributed to eutrophication have been documented in a few cases. Mesocosm studies tend to show much more rapid (weeks to months) but often incoherent responses after experimental nutrient and organic matter additions. The few studies of the “opportunistic” species that appear adapted to become the first recolonizers ...

Changes in the Diet of Demersal Fish due to Eutrophication-Induced Hypoxia in the Kattegat, Sweden

The diets of five dominant bottom-feeding fish species, Atlantic cod (Gadus morhua), whiting (Merlangius merlangus), plaice (Pleuronectes platessa), dab (Limanda limanda), and American plaice (Hippoglossoides platessoides), were analysed during spring and autumn between May 1984 and April 1988 in the southeast Kattegat. A general long-term change in the diet of bottom-feeding fish in the Kattegat has taken place since the beginning of the century and, for some of the species, the feeding pattern was different from that in adjacent areas. The observed dietary shift appeared to be due to changes in species composition of benthic macrofauna. Prey species favored by increased organic enrichment were dominant in the diet. Several infaunal species increased in dietary importance during recent hypoxia. In contrast, during hypoxia, a reduction of epibenthic crustaceans was observed in the fish diet. This study emphasizes the potential effects of organic enrichment and hypoxia (due to eutrophication) on trophic interactions in marine benthic communities. Repeated stress from hypoxia might favor small-sized prey species with a short life cycle, which would in turn favor small-sized fishes. Thus, altered food resources and the direct effects of hypoxia might result in shift in dominance among demersal fish species.

Effects of Organic Enrichment on Zooplankton Abundance and Walleye Fry Growth and Survival in Artificial Rearing Ponds

ABSTRACT Cylindrical aluminum enclosures in an artificial rearing pond were used to examine the effect of organic enrichment with alfalfa pellets and fish predation on the abundance and size structure of cladocerans and the growth and survivorship of walleye (Stizostedion vitreum vitreum) fry. Organic enrichment had a stronger effect than walleye fry predation on cladoceran abundance. Increased cladoceran abundance was due to increased abundance of smaller individuals, suggesting organic enrichment stimulated cladoceran reproduction. Although fish predation did not influence total cladoceran abundance, it did appear to reduce the abundance of larger size classes of cladocerans (> 1.25 mm total length). Organic enrichment did not increase survival of walleye fry but did increase their average weight and condition, especially among larger fry.

Effects of organic enrichment on estuarine macrofaunal benthos: a comparison of sediment profile imaging and traditional methods

Sediment profile imaging (SPI) is a technique that involves collecting data In the field on sedimentary conditions, particularly vertical variations at and below the sed imen tha te r interface SPI approaches were developed nearly 20 yr ago, but have not been widely used in routine pollution monitoring efforts, although their potential for saving time and money is great. The present report is a comparison of SPI and 'traditional' (which involves excising a sediment sample, removing the organisms, and identifying and further processing them in the laboratory) benthic sampling techniques used along an organic enrichment gradient in a temperate coastal lagoon. Twenty-four core samples were taken in summer 1985 along an enrichment gradient mainly resulting from the discharge of sewage effluents, and processed by traditional rnacrofaunal benthic methods. Coincidental with these cores, sediment samples were taken for various physicochemical analyses, and optically clear acrylic box core samples were taken and analyzed in the field for changes in redox potential, dominant benthic taxa and their relative abundances, and sedimentary features. Various univariate and multivariate analyses of the benthic and sedimentary data showed substantial, and expected, changes along the pollution gradient. The changes were similar to those reported from other coastal waters affected by organic wastes: an area nearest the pollution source with lowest taxa numbers (S), abundances (A) and biomass (B); and increased S, A and B with increasing distance from the pollution source. Small near-surface polychaetes (capitellids and Streblospio benedicti) and the amphipod Ampelisca sp , were numerical dominants at all sites, and large, deep-burrowing species (e.g. Asychis elongata) were only found at the least-enriched sites SPI allowed identification of the dominant benthic taxa to useful levels ( e g . 'small near-surface dwelling annelids', 'large deep-burrowing polychaetes'), and location of the apparent color redox potential discontinuity (RPD) layer depth. The RPD ranged from about 1 cm at the site nearest the pollution source to 2 4 cm at the 2 sites farthest away. The SPI data were a s useful a s the traditional data in delimiting the spatial extent of the pollution-impacted benthos. It is suggested that a variety of coring devices presently exist for quickly and efficiently obtaining SPI data, especially in shallow waters.

Effects of organic enrichment on estuarine macrofaunal benthos: a comparison of sediment profile imaging and traditional methods

Sediment profile imaging (SPI) is a technique that involves collecting data In the field on sedimentary conditions, particularly vertical variations at and below the sed imen tha te r interface SPI approaches were developed nearly 20 yr ago, but have not been widely used in routine pollution monitoring efforts, although their potential for saving time and money is great. The present report is a comparison of SPI and 'traditional' (which involves excising a sediment sample, removing the organisms, and identifying and further processing them in the laboratory) benthic sampling techniques used along an organic enrichment gradient in a temperate coastal lagoon. Twenty-four core samples were taken in summer 1985 along an enrichment gradient mainly resulting from the discharge of sewage effluents, and processed by traditional rnacrofaunal benthic methods. Coincidental with these cores, sediment samples were taken for various physicochemical analyses, and optically clear acrylic box core samples were taken and analyzed in the field for changes in redox potential, dominant benthic taxa and their relative abundances, and sedimentary features. Various univariate and multivariate analyses of the benthic and sedimentary data showed substantial, and expected, changes along the pollution gradient. The changes were similar to those reported from other coastal waters affected by organic wastes: an area nearest the pollution source with lowest taxa numbers (S), abundances (A) and biomass (B); and increased S, A and B with increasing distance from the pollution source. Small near-surface polychaetes (capitellids and Streblospio benedicti) and the amphipod Ampelisca sp , were numerical dominants at all sites, and large, deep-burrowing species (e.g. Asychis elongata) were only found at the least-enriched sites SPI allowed identification of the dominant benthic taxa to useful levels ( e g . 'small near-surface dwelling annelids', 'large deep-burrowing polychaetes'), and location of the apparent color redox potential discontinuity (RPD) layer depth. The RPD ranged from about 1 cm at the site nearest the pollution source to 2 4 cm at the 2 sites farthest away. The SPI data were a s useful a s the traditional data in delimiting the spatial extent of the pollution-impacted benthos. It is suggested that a variety of coring devices presently exist for quickly and efficiently obtaining SPI data, especially in shallow waters.

Increase of benthic biomass in the Skagerrak-Kattegat during the 1970s and 1980s - effects of organic enrichment?

Biomass and abundance of macrobenthos was monitored from 1972 to 1988 at 14 softsediment stations below the h a l o c h e in the Skagerrak-Kattegat area. Year-to-year variations in fauna were analysed. Clear general trends were demonstrated over the study area, w h c h is > 170 km long. Total biomasses showed linear increases by a median factor of 1.8, primanly from 1981 to 1988. and biornasses excluding some large species, notably echinoids, increased by a median factor of l . ? from 1972 to 1988. The changes were primarily due to echinoderms, notably the amphiurold Amphiura filiformis, and polychaetes. Polychaetes contributed more to the increase at the deepest stations, and the absolute increase of this group was positively related with water depth. The relative increases in 'biomass without large species' as well as biornass of arnphiuroids and polychaetes were positively related to water depth. Parallel to the biornass change, land freshwater run-off from western Sweden and to Danish inner waters have increased, and this has influenced the input of nutrients to the sea. Although rellable data on primary production and sedimentation of organic material are largely lacking. the present results are in accordance with hypotheses that soft-sediment infauna in the area is food limited, and that the area is being affected by organic enrichment. P MARINE ECOLOGY PROGRESS SERIES Mar. Ecol. Prog. Ser.

Effects of organic enrichment on meiofauna: a laboratory study

An 84 day laboratory experiment indicates the decline of intertidal meiofauna abundance may be directly related to treatment level and time of exposure to sewage sludges. The observed changes revealed a marked decrease of nematodes and total disappearance of mesobenthic harpacticoids while the non-interstitial copepod species were little affected. The possibility of a new interpretation of the Nematode/Copepod ratio as an index of organic pollution in sediments is discussed.

Effects of organic enrichment on meiofaunal abundance and community structure in sublittoral soft sediments

In experimental mesocosms established at Solbergstrand, Oslofjord, Norway, organic enrichment was effected by the addition of powdered Ascophyllum nodosum (L.) Le Jol., in quantities equivalent to 50gC·m −2 and 200gC·m −2, to boxes of sublittoral soft sediment. After 56 days, the structure of the meiofaunal communities in these treatments was compared with that of the control boxes. At this time the meiofaunal communites at each level of organic enrichment were markedly different from each other and from that in the control sediment. The responses of the two major components of the meiofauna, however, were different. Although the abundance of nematodes was slightly reduced in the high dose treatment this was not accompanied by detectable changes in community structure. Harpacticoid copepods, on the other hand, increased significantly in abundance in the treatment boxes and showed a general trend towards increased dominance and decreased diversity with increasing levels of organic enrichment, although in the low dose treatment there was also an increase in the number of species present. It is also shown that the nematode/copepod ratio is unreliable as a biomonitoring tool and it is suggested that the differential responses in community structure between the nematode and copepod components of the meiofauna might be a better indication of stress at the community level.

Use of the nematode-copepod ratio as an index of organic pollution

Controversy exists on the utility of the nematode-copepod ratio as a method for assessing the effects of pollution on benthic communities. In a test of this ratio along a known gradient of organic enrichment in Oslofjord, the index showed the same trends as a previously undertaken macrofaunal survey. Copepod numbers decreased and nematode numbers increased along the gradient of increasing organic enrichment giving rise to changes in the ratio. Grain-size parameters showed no correlation with the ratio. Copepod numbers, however, showed a significant negative correlation with oxygen concentration 1 m above the sediment. The nematode-copepod ratio is suggested as being an acceptable addition to a suite of techniques for the assessment of organic enrichment effects on benthic communities, but does require special expertise. A decrease in the numbers of meiofaunal taxa along the organic enrichment gradent was found and is similar to the gradient in the nematode-copepod ratio. The fact that all indices show responses in Oslofjord may merely reflect the strong organic enrichment gradient that exists; it should not necessarily be construed that such results will be found everywhere.

The effects of organic enrichment upon a community of meiobenthic harpacticoid copepods

A nutrient enrichment experiment was conducted on an estuarine intertidal beach. A nutrient suitable for marine heterotrophic bacteria, derived from acid-hydrolysed casein, was applied to areas of sediment at low tide, at two frequencies. At the greater frequency of application the numbers of species of harpacticoid copepod comprising the community increased, as did the logarithmic series index of diversity. Displacement, presumably competitive, of the numerically dominant species by two confamilial species, formerly of less abundance, occurred and resulted in a decrease in the Berger-Parker dominance diversity. As the community converged to an equilibrium, due to the rapid growth rates of two species, it was predicted that the species richness and ecological diversity of the community would decrease, as some species underwent competitive exclusion, and in so doing would raise the dominance diversity. Before harpacticoid copepod communities can be used satisfactorily in biological monitoring programmes more basic research is needed to assess the response of a variety of meiobenthic communities to various loads of organic pollution.

Environmental and biochemical investigation of some effects of organic pollution in Inner Oslofjord, Norway

Coordinated environmental monitoring and biochemical studies of the polychaete Glycera alba (Muller) have been applied to the assessment of the impact of inputs of organically rich waste material into Inner Oslofjord. Six sampling stations at intervals of 5 km on a transect extending from Lysakerfjord, 5 km from Oslo harbour, to Vollengropen, a few kilometres from the Drobak sill were used in the investigation. Samples of water, sediment and biological material were collected from these sampling stations on one occasion, in September 1980. On the basis of dissolved oxygen content of the water column near the sediment surface, carbon and nitrogen contents and redox potential (Eh) in the sediments, the greatest impact of organic enrichment was found at Lysakerfjord. Localised variations in sediment condition were, however, pronounced in the transect. Maximal activities of 4 enzymes associated with energy-yielding metabolism were estimated in 7 to 11 individual G. alba from each sampling station. Relatively low activities of the glycolytic enzyme phosphofructokinase in the group of G. alba from Lysakerfjord may constitute a biochemical response to the effects of organic enrichment in this area. In G. alba from the sampling station at Slemmestad, it is suggested that low phosphofructokinase and malate dehydrogenase activities may reflect a biochemical response to effects of prelominantly inorganic waste material from a nearby cement factory. In groups of G. alba from 5 sampling stations, i.e., excluding Slemmestad, mean phosphofructokinase activity is correlated with redox potential at 4 to 5 cm depth in the sediments. The results are discussed with reference to earlier biological studies and it is shown that low phosphofructokinase activities are found in the groups of G. alba from those areas where low diversity of macrobenthic fauna have been reported. It is concluded that the changes in phosphofructokinase activity may consistently reflect effects of environmental changes that are characteristically associated with inputs of waste material.