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1.
- 1 This paper summarises the most important contributions on trophic relationships of lotic meiofauna. In contrast to marine research, the few quantitative studies of the freshwater meiobenthos have shown that these invertebrates not only take up particulate/fine organic matter, but also dissolved organic substances attached to organic particles. In lotic ecosystems, further estimates of grazing rate and bacterial/algal ingestion rate are needed, particularly in situ measurements.
- 2 The effects of macroinvertebrate predators upon meiofauna are still under debate. Depending on the type of experiments (laboratory vs. field) it seems that macrofauna may or may not affect meiofauna. Field samples and analyses of gut contents of larval tanypod chironomids have shown that the impact upon meiofauna was low and larvae were nonselective predators. Predation amounted to 2.2% of the combined prey density and prey consumption averaged 1.3 individuals per predator individual per year.
- 3 Adding taxonomic resolution by including the meiofaunal component within lotic food webs distinctly increases the number of total species and, as a consequence, changes food web statistics. Webs that included meiofauna revealed that these metazoans contributed substantially to the percentage of intermediate species (species with predators and prey). The resolution of dietary analyses of major consumers of macro‐ and meiobenthos showed that many stream invertebrates feed on meiofauna.
2.
The importance of meiofauna to lotic ecosystem functioning 总被引:2,自引:0,他引:2
- 1 Although meiofauna occur in large numbers in many streams, almost nothing is known about their functional role.
- 2 In other systems, meiofauna influence microbial and organic matter dynamics through consumption and bioturbation. Given that these are important processes in streams, meiofauna have the potential to influence lotic function by changing the quality and availability of organic matter as well as the number and biotic activity of benthic microbes. Selective feeding by meiofauna has the potential to alter the availability of nutrients and organic carbon.
- 3 Meiofauna generally contribute only a small amount to metazoan production and biomass in streams, although exceptions occur. Within a stream, the relative importance of meiofauna may reflect whether the temporary or permanent meiofauna dominate the meiobenthos as well as the season when samples are collected.
- 4 We suggest stream conditions (small sediment grain size, restricted interstitial flow) under which meiofauna have the greatest likelihood of influencing stream ecosystem function.
- 5 Important areas for future research include addressing whether meiofauna feed selectively, whether meiofauna are links or sinks for carbon in streams, and whether bioturbation by meiofauna influences stream ecosystem processes in a predictable manner.
3.
4.
- 1 Lotic meiofaunal communities demonstrate extremely variable dynamics, especially when viewed at small spatial scales (≤ metres). Given the limited amount of research on lotic meiofauna, we chose to organise our discussion of their small‐scale spatial patterns around the dominant factors we believe drive their spatial distributions in streams. We separate scale‐dependent effects that structure lotic meiofauna into biotic factors (e.g. predation, food quantity/quality, dispersal) and abiotic factors (e.g. local flow dynamics and substratum characteristics).
- 2 The impact of predation on the distribution of meiofauna varies with the scale over which predators forage (e.g. fish predation influences meiofauna in different ways and at broader spatial scales than do invertebrate predators), the type of streambed substrata in which the predator‐prey interactions occur, and the dispersal ability of different meiofauna. The latter is greatly influenced by predator and prey (meiofauna) interactions with the flow environment.
- 3 Organic matter influences the small‐scale distribution of meiofauna in streams. Both its quality as food (as indicated by C:N content, ATP content, or microbial biomass) and its spatial distribution on the streambed, influence meiofauna patchiness, community structure and life history characteristics. As a habitat, the structure that organic matter provides (e.g. wood or leaves) can influence predator‐prey interactions, offer materials for case‐building and offer refugia during disturbance events ‐ all of which influence the small‐scale spatial distribution of meiofauna.
- 4 Stream flow influences the distribution of meiofauna at broad scales (10s–100s of metres), primarily because of the high susceptibility of meiofauna to passive drift; small‐scale interactions between flow and substrata are also important, however, particularly at more localised (≤ metre) scales. At both scales, substratum particle size is important to interstitial‐dwelling fauna, influencing the probability of passive drift by meiofauna as well as local microhabitat conditions (e.g. dissolved oxygen; upwelling/downwelling in the hyporheic zone) and, thus, the small‐scale distribution among microhabitats.
- 5 In general, the processes governing the distribution of meiofauna at small scales cannot be separated entirely from those processes working at larger scales. A conceptual diagram is presented illustrating the relative importance of various factors in influencing the spatial patterns of meiofauna and over what scales these factors act.
5.
Bruce C. Coull 《Austral ecology》1999,24(4):327-343
Meiofauna are ubiquitous in estuaries worldwide averaging 106 m?2. Abundance and species composition are controlled primarily by three physical factors: sediment particle size, temperature and salinity. While meiofauna are integral parts of estuarine food webs, the evidence that they are biologically controlled is equivocal. Top down (predation) control clearly does not regulate meiofaunal assemblages. Meiofauna reproduce so rapidly and are so abundant that predators cannot significantly reduce population size. Food quantity (bottom up control) also does not appear to limit meiofaunal abundance; there is little data on the effect of food quality. In estuarine sediments meiofauna: (i) facilitate biomineralization of organic matter and enhance nutrient regeneration; (ii) serve as food for a variety of higher trophic levels; and (iii) exhibit high sensitivity to anthropogenic inputs, making them excellent sentinels of estuarine pollution. Generally mineralization of organic matter is enhanced and bacterial production stimulated in the presence of meiofauna. Tannins from mangrove detritus in northern Queensland appear to inhibit meiofaunal abundance and therefore the role of meiofauna in breakdown of the leaves. Meiofauna, particularly copepods, are known foods for a variety of predators especially juvenile fish and the meiofaunal copepods are high in the essential fatty acids required by fish. The copepod’s fatty acid composition is like that of the microphytobenthos they eat; bacterial eaters (nematodes?) do not have the essential fatty acids necessary for fish. Most contaminants in estuaries reside in sediments, and meiofauna are intimately associated with sediments over their entire life-cycle, thus they are increasingly being used as pollution sentinels. Australian estuarine meiofauna research has been concentrated in Queensland, the Hunter River estuarine system in New South Wales, and Victoria’s coastal lagoons. Studies in northern Queensland have primarily concentrated on the role of nematodes in mineralization of organic matter, whereas those from southern Queensland have concentrated on the role of meiofauna as food for fish and as bacterial grazers. The New South Wales studies have concentrated on the Hunter River estuary and on the structure and function of marine nematode communities. In Victoria, several fish have been shown to eat meiofauna. The Australian world of meiofaunal research has hardly been touched; there are innumerable opportunities for meiofaunal studies. In contaminated estuarine sediments reduced trophic coupling between meiofauna and juvenile fish is a basic ecological question of habitat suitability, but also a question with relevance to management of estuarine resources. Because meiofauna have short lifecycles, the effects of a contaminant on the entire life-history can be assessed within a relatively short time. The use of modern molecular biology techniques to assess genetic diversity of meiofauna in contaminated vs uncontaminated sediments is a promising avenue for future research. Much of the important meiofaunal functions take place in very muddy substrata; thus, it is imperative to retain mudflats in estuaries. 相似文献
6.
Global and regional patterns in lotic meiofauna 总被引:4,自引:0,他引:4
- 1 Parsimony analysis of endemicity (PAE) was used to assess patterns in the distribution of harpacticoid copepods (all freshwater species and stream species only) at global and regional scales. These analyses provided a focus for reviewing large scale patterns and processes in freshwater meiofauna.
- 2 On a global scale, PAE suggested that large‐scale biogeographical events have been most important in shaping present‐day distributions in the Canthocamptidae. A small proportion (4%) of canthocamptid species were widespread (i.e. occurred in more than one biogegraphical region), suggesting that dispersal may also play a role in determining distribution at the species level. Global distribution patterns for other meiofauna suggest varying roles for dispersal and vicariant events. No consistent latitudinal trends in species diversity were evident, although a lack of distributional data for many regions, and uncertainty over the status of many cosmopolitan species, precludes more robust analyses. Molecular techniques should prove useful in identifying truly cosmopolitan taxa.
- 3 On a regional scale, a PAE within Western Europe demonstrated a clear link between the distribution of canthocamptid species and the extent of the Last (Wiechselian) glaciation. Northern and southern areas of Europe contain distinctive harpacticoid faunas and the recolonisation of northern Europe appears to have been from the Balkans rather than other Mediterranean peninsulae. The high harpacticoid diversity in southern Europe, may reflect a lack of glacial disruption of groundwater habitats.
- 4 A PAE of lotic data for harpacticoid copepods within the Holarctic reflected the global PAE for freshwater harpacticoids as a whole, but not the regional PAE. A high proportion of stream‐dwelling harpacticoids are widespread species, but only one (Bryocamptus zschokkei) was found in streams across the Holarctic. Other cosmopolites were restricted to streams in Europe or North America, suggesting that species‘ niche requirements might differ among regions. There appeared to be some convergence in the composition of lotic copepod communities in terms of the number of species within genera.
- 5 We conclude that large‐scale processes inevitably have a major influence on the local composition of lotic meiofaunal communities, but that the relative importance of small scale vs. large scale processes is unclear at present, largely due to a paucity of suitable data.
7.
Horizontal and vertical distribution of meiofauna on sandy beaches of the North Sea (The Netherlands, Belgium, France) 总被引:3,自引:0,他引:3
Lech Kotwicki Marleen De Troch Barbara Urban-Malinga Tom Gheskiere Jan Marcin Węslawski 《Helgoland Marine Research》2005,59(4):255-264
Sandy intertidal zones were analysed for the presence of meiofauna. The material was collected on six macro-tidal sandy beaches
along the North Sea (The Netherlands, France, Belgium), in order to analyse the vertical and horizontal meiofaunal distribution
patterns. Eleven higher meiofauna taxa (one represented by larval stage—Copepoda nauplii) were recorded. The maximum total
meiofauna abundance was observed on the Dutch beach (4,295±911 ind. 10 cm−2) in the Westerschelde estuary, while the lowest values (361±128 ind. 10 cm−2) were recorded in France at the Audresselles beach. Meiofauna of the different localities consisted mainly of nematodes,
harpacticoids and turbellarians. Nematodes numerically dominated all sampled stations, comprising more than 45% of the total
meiofauna density. Meiofauna was mainly concentrated at the sand surface with about 70% present in the uppermost 5 cm. Meiofauna
occurred across the entire intertidal zone. A clear zonation pattern in the distribution of meiofauna taxa across the beaches
was observed. The present work suggests that designation of exposed sandy beaches as physically controlled (McLachlan 1988) does not explain their biological variability. 相似文献
8.
Top-down control of prey assemblages by fish predation has been clearly demonstrated for zooplankton and macroinvertebrates. However, in the benthic communities of freshwater ecosystems, the impact of fish predation on meiofaunal assemblages is nearly unknown. In this study, the predation effects of juvenile carp (Cyprinus carpio) and gudgeon (Gobio gobio) on meiofaunal abundance, biomass, community structure, and the diversity of nematodes were examined using microcosms that were sampled repeatedly over 64 days. Significant differences in abundance and biomass were found between the two fish treatments (carp and gudgeon) and their respective controls for nematodes, oligochaetes, and crustaceans (copepods, harpacticoids, ostracods, and cladocerans), but not for rotifers. These changes were consistent with top-down control of the freshwater meiofaunal assemblages in the microcosms over time. By contrast, small-bodied meiofauna was more abundant, suggesting indirect facilitation. Neither the species richness nor the diversity of the nematode community was affected by fish predation. The results indicate that predation by juvenile freshwater fish depresses the overall abundance and biomass of meiofaunal assemblages, except for rotifers, and alters the size structure of the meiofaunal community. Therefore, the meiofaunal assemblages of freshwater ecosystems may be influenced by bottom-feeding juvenile fish, e.g., carp and gudgeon, through top-down control of meiofaunal populations. 相似文献
9.
An introduction to a special issue on lotic meiofauna 总被引:1,自引:0,他引:1
- 1 This special issue focuses on the meiofauna of lotic freshwater systems, providing a review of the biology and ecology of this relatively poorly studied constituent of the benthos in running waters.
- 2 Six papers review the biology and ecology of the major groups of lotic meiofauna: microturbellarians; rotifers and gastrotrichs; nematodes; water mites; microcrustaceans and tardigrades.
- 3 Current knowledge of the ecology of lotic meiofauna is presented further in six papers that also highlight important future directions for research.
10.
11.
Meiofauna distribution and mesoscale variability in two sites of the Ross Sea (Antarctica) with contrasting food supply 总被引:5,自引:0,他引:5
Meiofauna abundance, biomass and community structure were investigated in two comparable deep sites of the Ross Sea (Antarctica)
characterized by different trophic and sediment characteristics. Site B (567 m depth, dominated by muddy sediments) and site
C (439 m depth, characterized by the presence of calcareous debris and coarse sand) were located at increasing distance from
the polynyas and were subject to different inputs of organic material to the seabed. Total meiofauna abundance ranged from
192.0 to 1191.2 ind. 10 cm−2, and total biomass varied between 9.5 and 50.3 μgC 10 cm−2. Meiofauna densities from the Ross Sea are, on average, 2–7 times lower than those reported from other similar deep polar
regions and displayed significant differences between the sites. Nematodes dominated the samples at both sites, but their
relative significance changed between the sites (80% at site B and 56% at site C), followed by copepods (1.6% and 35% at sites
B and C, respectively). Meiofauna composition at site B appeared similar to that reported for deep-sea antarctic or temperate
sediments, whereas the composition at site C was similar to that of coastal areas. On a macroscale, the different inputs of
utilizable organic material at the two sites were reflected in meiofaunal distribution patterns, indicating that meiofaunal
communities from the Ross Sea are dependent on particulate organic matter fluxes from the photic layer and are coupled to
pelagic phenomena. Very low microscale variations (i.e. between replicates) in meiofauna density contrasted with large mesoscale
variability, which was related to the concentration of the main food indicators (phytopigments, proteins, carbohydrates and
lipids).
Accepted: 18 February 1999 相似文献
12.
Nabil Majdi Miriam Colls Linette Weiss Vicenç Acuña Sergi Sabater Walter Traunspurger 《Freshwater Biology》2020,65(11):1906-1922
- Intermittent streams (IS) comprise a large proportion of the drainage network in many parts of the world. The non-flow period of IS are known to impact stream biota because aquatic habitats dry out. However, less well understood are the relative effects of the temporal component of these drying events including their duration and frequency.
- Here, we characterised effects of temporal component of drying events on abundant and species-rich meiofauna. The effects were assessed in 22 streams in the north-eastern Iberian Peninsula. The duration and frequency of non-flow events was characterized over a period of 250 days prior to sampling the sediment-dwelling meiofauna in riffle zones that completely dried out.
- Overall, meiofauna abundances were amongst the highest ever reported for streambeds. Most meiofaunal taxa correlated positively with the frequency of drying events and correlated positively with the length of dry periods recorded shortly before sampling, suggesting that the community was able to recover quickly. Tardigrades were the only group to correlate positively with the longest dry periods, suggesting that they had the best resilience capabilities in streams that had experienced the longest droughts.
- On average, nematodes made up half of the meiofauna. We identified a total of 113 different nematode species. The nematode community was more taxonomically diverse in IS, with a smaller proportion of bacterivores and a higher proportion of fungivore species such as Filenchus vulgaris. Thereby resembling the trophic structure commonly observed in soil ecosystems.
- Our results show that most meiofauna were positively influenced by drying disturbance, that is being able to quickly recover after them. This suggests outstanding resilience capabilities, and points out meiofaunal organisms as key players for kick-starting stream food webs and functions once flow returns.
13.
Composition,distribution and biomass of meiobenthos in the Oosterschelde estuary (SW Netherlands) 总被引:2,自引:2,他引:0
Meiofauna composition, abundance, biomass, distribution and diversity were investigated for 31 stations in summer. The sampling covered the whole Oosterschelde and comparisons between the subtidal — intertidal and between the western-central — eastern compartment were made.Meiofauna had a community density ranging between 200 and 17 500 ind 10 cm–2, corresponding to a dry weight of 0.2 and 8.4 gm–2. Abundance ranged between 130 and 17 200 ind 10 cm–2 for nematodes and between 10 and 1600 ind 10 cm–2 for copepods. Dry weight biomass of these taxa was between 0.5–7.0 gm–2 and 0.008–0.3 gm–2 for nematodes and copepods respectively.The meiofauna was strongly dominated by the nematodes (36–99%), who's abundance, biomass and diversity were significantly higher intertidally than subtidally and significantly higher in the eastern part than in the western part. High numbers were positively correlated with the percentage silt and negatively with the median grain size of the sand fraction. The abundance and diversity of the copepods were highest in the subtidal, but their biomass showed an inverse trend being highest on the tidal flats.The taxa diversity of the meiofauna community and species diversity of both the nematodes and the copepods were higher in subtidal stations than on tidal flats. In the subtidal, the meiofauna and copepod diversity decreased from west to east, whereas nematode diversity increased.The vertical profile clearly reflected the sediment characteristics and could be explained by local hydrodynamic conditions.Seasonal variation was pronounced for the different taxa with peak abundance in spring, summer or autumn and minimum abundance in winter.Changes in tidal amplitude and current velocity enhanced by the storm-surge barrier will alter the meiofauna community structure. As a result meiofauna will become more important in terms of density and biomass, mainly due to increasing numbers of nematodes, increasing bioturbation, nutrient mineralisation and sustaining bacterial growth. A general decrease in meiofauna diversity is predicted. The number of copepods is expected to decrease and interstitial species will be replaced by epibenthic species, the latter being more important in terms of biomass and as food for the epibenthic macrofauna and fishes. 相似文献
14.
Anne L. Robertson 《Freshwater Biology》2000,44(1):135-147
1. The spatial and temporal dynamics of lotic meiofaunal communities were examined with a focus on colonisation, maintenance of populations in lotic environments and persistence of meiofaunal communities.
2. Lotic meiofaunal colonisation of new habitats may take place via a number of mechanisms and is rapid at both the patch scale (within hours–days) and the drainage basin scale (within 20 years). Successional patterns in lotic meiofaunal communities are evident although data are extremely limited.
3. Lotic meiofaunal communities appear to be resilient to high flow disturbances. Resilience is moderated by the availability of in-stream refugia and habitat hydrology. Lotic meiofauna may also adopt a 'refuge as habitat' approach to such disturbances.
4. Lotic cyclopoid copepods possess a common suite of life history characteristics that confers resilience to disturbances. Compared to pelagic planktonic species they have short generation times, many descendants per reproductive cycle and long lifespans. Females in 'source' populations are likely to survive disturbances and so could continuously reproduce over a long period of time producing large numbers of offspring which develop rapidly and recolonise 'sink' areas of the stream.
5. Persistence of lotic meiofaunal communities is highly variable. Meiofaunal persistence does not increase with increasing proportions of in-stream flow refugia. 相似文献
2. Lotic meiofaunal colonisation of new habitats may take place via a number of mechanisms and is rapid at both the patch scale (within hours–days) and the drainage basin scale (within 20 years). Successional patterns in lotic meiofaunal communities are evident although data are extremely limited.
3. Lotic meiofaunal communities appear to be resilient to high flow disturbances. Resilience is moderated by the availability of in-stream refugia and habitat hydrology. Lotic meiofauna may also adopt a 'refuge as habitat' approach to such disturbances.
4. Lotic cyclopoid copepods possess a common suite of life history characteristics that confers resilience to disturbances. Compared to pelagic planktonic species they have short generation times, many descendants per reproductive cycle and long lifespans. Females in 'source' populations are likely to survive disturbances and so could continuously reproduce over a long period of time producing large numbers of offspring which develop rapidly and recolonise 'sink' areas of the stream.
5. Persistence of lotic meiofaunal communities is highly variable. Meiofaunal persistence does not increase with increasing proportions of in-stream flow refugia. 相似文献
15.
Meiofauna distribution in Martel Inlet, King George Island (Antarctica): sediment features versus food availability 总被引:4,自引:4,他引:0
The meiofauna density in Martel Inlet, Admiralty Bay, King George Island (Antarctica) was studied in order to better understand the spatial patterns of meiofauna distribution in shallow polar seas. Sampling was undertaken by scuba-diving at 15 m depth at 7 stations during the summers of 1996/1997 and 1997/1998. The meiofauna was dominated by nematodes (>60%), followed by copepods, nauplii and polychaetes. The mean densities found during the 2 years studied (4.09 and 3.5᎒6 ind. m-2) suggest that the shallow area of Martel Inlet is characterized by higher numbers of meiofaunal organisms than are found in other ecosystems, which is in agreement with other meiofaunal studies carried out in polar areas. It may be concluded that it is mainly the sedimentary features that influence the meiofauna distribution. However, food availability must contribute to the support of the higher meiofauna densities found in the inlet. 相似文献
16.
Transitional Environments (TEs) have been deeply modified to meet human requirements, and for this reason are currently ranked among the most endangered aquatic ecosystems. The Adriatic basin hosts a large number of TEs of which the Lagoon of Venice is the largest one, but information on its meiofauna are very dated or focused to localized areas. The present study is the first to document the spatial distribution of meiofauna in the whole Venice lagoon. Furthermore, the health status of the TE of Venice has been assessed by means of several faunal parameters (richness, diversity indices, structure of the entire meiofaunal assemblage and only rare taxa). All the univariate meiofaunal parameters (i.e. richness, diversity indices, Ne:Co ratio) were consistent in highlighting the worst ecological quality of the Porto Marghera district. Instead, the structure of the entire meiofaunal assemblage as well as that of rare taxa seemed to detect variations not directly related to pollution and likely due to the different hydrodynamic conditions of Lido and Malamocco inlets. On the basis of our results, we have also critically discussed the usefulness of the various faunal parameters in the monitoring assessment of the TEs. 相似文献
17.
Barbara Urban-Malinga Jozef Wiktor Aleksandra Jabłońska Tom Moens 《Polar Biology》2005,28(12):940-950
Meiofauna communities of four intertidal sites, two sheltered and two more exposed, in Kongsfjorden (Svalbard) were investigated
in summer 2001 at two different tidal levels (i.e. the low-water line and close below the driftline, referred to as mid-water
(MW) level). A total of seven meiofaunal higher taxa were recorded with nematodes, oligochaetes and turbellarians being numerically
dominant. Mean total meiofaunal densities ranged between 50 ind. 10 cm−2 and 903 ind. 10 cm−2. Our data showed a clear decrease in total meiofaunal densities with increasing coarseness of the sediment. Total meiofaunal
biomass varied from 0.2 g dwt m−2 to 2 g dwt m−2 and, in general, was high even at low meiofaunal densities, i.e. larger interstitial spaces in coarser sediments supported
larger meiofauna, especially turbellarians. The results on the vertical distribution of meiofauna contrasted sharply with
typical meiobenthic depth profiles on other beaches, probably in response to ice-scouring and concomitant salinity fluctuations.
Oligochaetes were the most abundant taxon, with a peak density of 641 ind. 10 cm−2 at Breoyane Island. They were mainly comprised of juvenile Enchytraeidae, which prohibited identification to species/genus
level. Nematode densities ranged between 4 ind. 10 cm−2 and 327 ind. 10 cm−2. Nematodes were identified up to genus level and assigned to trophic guilds. In total, 28 nematode genera were identified.
Oncholaimus and Theristus were the most abundant genera. The composition of the nematode community and a dominance of predators and deposit feeders
were in agreement with results from other arctic and temperate beaches. Nematode genus diversity was higher at the more sheltered
beaches than at the more exposed ones. Low-water level stations also tended to harbour a more diverse nematode communities
than stations at the MW level. Differences in nematode community structure between low- and MW stations of single beaches
were more pronounced than community differences between different beaches and were mainly related to resources quality and
availability. 相似文献
18.
Elias Broman Caroline Raymond Christian Sommer Jonas S. Gunnarsson Simon Creer Francisco J. A. Nascimento 《Molecular ecology》2019,28(16):3813-3829
Coastal benthic biodiversity is under increased pressure from climate change, eutrophication, hypoxia, and changes in salinity due to increase in river runoff. The Baltic Sea is a large brackish system characterized by steep environmental gradients that experiences all of the mentioned stressors. As such it provides an ideal model system for studying the impact of on‐going and future climate change on biodiversity and function of benthic ecosystems. Meiofauna (animals < 1 mm) are abundant in sediment and are still largely unexplored even though they are known to regulate organic matter degradation and nutrient cycling. In this study, benthic meiofaunal community structure was analysed along a salinity gradient in the Baltic Sea proper using high‐throughput sequencing. Our results demonstrate that areas with higher salinity have a higher biodiversity, and salinity is probably the main driver influencing meiofauna diversity and community composition. Furthermore, in the more diverse and saline environments a larger amount of nematode genera classified as predators prevailed, and meiofauna‐macrofauna associations were more prominent. These findings show that in the Baltic Sea, a decrease in salinity resulting from accelerated climate change will probably lead to decreased benthic biodiversity, and cause profound changes in benthic communities, with potential consequences for ecosystem stability, functions and services. 相似文献
19.
Paul A. Montagna 《Journal of experimental marine biology and ecology》1984,76(2):177-190
Meiobenthos, small invertebrates inhabiting the surface layers of marine sediments, can absorb dissolved organic matter (DOM). Experiments were performed to test if meiobenthos can compete with sediment microbes for uptake of small amounts of [14C]glucose. Meiofaunal glucose uptake rates were measured by themselves and in the presence of sediment microbes. Glucose uptake by meiofauna was not inhibited by the presence of bacteria, nor did it appear that bacterial uptake was inhibited by meiofauna. Thus, there was no direct or interference competition. Uptake rates by 1 cm3 of sediment (bacteria) were four orders of magnitude greater than those of individual meiofauna, but on a biomass specific basis, meiofaunal uptake was in the same range if not higher than that of sediment bacteria. Thus, the potential for indirect or resource competition exists. Since bacterial biomass dominated the system studied, uptake of glucose was dominated by bacteria. The results support the hypothesis that in natural sediments, where the biomass of bacteria is higher than that of meiofauna, heterotrophic uptake is primarily a microbial process. However, resource competition between meiofauna and bacteria for DOM in sediments probably exists where bacterial biomass is low relative to meiofaunal biomass. 相似文献
20.
为了解污水排海对小型底栖生物丰度和生物量的影响,于2011年4、8、10、12月对青岛汇泉湾第一海水浴场中潮带一个排污口附近不同距离站位的小型底栖生物进行了春、夏、秋、冬4个季度的采样调查.结果表明: 研究区域小型底栖生物年平均丰度为(1859.9±705.1) ind·10 cm-2,最高值出现在距离排污口20和40 m的站位S2和S3,分别为(2444.9±1220.5)和(2492.2±1839.9) ind·10 cm-2,最低值出现在距离排污口0 m的站位S1,为(327.9±183.2) ind·10 cm-2.小型底栖生物的年平均生物量为(1513.4±372.7) μg·10 cm-2.小型底栖生物在丰度和生物量上呈现明显的季节变化,最高值出现在春季,最低值出现在夏季.共鉴定出11个小型底栖生物类群,包括线虫、桡足类、多毛类、寡毛类、缓步动物、海螨、涡虫、介形类、等足类、甲壳类幼体及其他类.自由生活海洋线虫是最优势的类群,占总丰度的83.1%,其次为底栖桡足类,占12.8%.在垂直分布上,小型底栖生物在0~2 cm表层分布最多,向深层呈现递减趋势,冬季部分向下迁移.Pearson相关分析表明,小型底栖生物丰度和生物量与沉积物中值粒径和有机质含量呈极显著负相关.此外,旅游等人为扰动也是影响小型底栖生物数量及分布的因素.与历史资料中的同类研究结果进行了比较,并探讨了线虫与桡足类丰度的比值
在有机质污染监测中的适用性. 相似文献