Intertidal Macrozoobenthos Research Articles

Community responses of intertidal soft-bottom macrozoobenthos to oil pollution in a tropical mangrove ecosystem, Niger Delta, Nigeria

Preliminary impact assessment of two large oil spill incidents at Bodo Creek, in the Niger Delta, was undertaken, focusing on intertidal macrozoobenthos. Post-spill number of species and abundance were measured against recent pre-spill baseline data from the same study area. Results show that surface and infauna communities suffered severe reduction in abundance and number of species reduced by 81% after the spills, with two of the resampled sites having no taxa at all. Capitella capitata populations increased several-fold over pre-spill numbers. The impact of the oil spills is discussed in relation to local livelihoods and ecosystem integrity. The Niger Delta endemic lucinid, Keletistes rhizoecus, is proposed as a potential bioindicator for monitoring hydrocarbon contamination in Niger Delta estuaries.

Long-term trends in juvenile flatfish indicate a dramatic reduction in nursery function of the Balgzand intertidal, Dutch Wadden Sea

Since 1975, juvenile flatfish (plaice and flounder) populations have been monitored at the Balgzand intertidal and, based on this data series (1975-2007), the interannual patterns in preda- tion pressure were quantified. Temporal patterns in abundance have changed greatly, especially for plaice. Up to the early 1980s, 3 year classes (0-, I- and II-group) were present and growing up in the area, but from the late 1980s onwards, densities of the I- and II-group plaice dropped from a few hun- dred individuals per 1000 m 2 to levels close to zero. It appears that the Balgzand intertidal has lost its nursery function for I- and II-group plaice, although feeding conditions have remained the same or even slightly increased since the late 1970s. The absence of I- and II-group flatfish in the intertidal cannot be explained at present; however, processes operating offshore are most likely involved. As a consequence, the annual predation pressure by juvenile flatfish upon the intertidal macrozoobenthos dropped by 94%, declining from an average of approximately 5 to 0.25 g ash free dry mass m -2 . Such a decline in top-down predation may not only have directly influenced the macrozoobenthic commu- nity, but may also have indirectly affected food availability and accessibility for other top predators (e.g. shorebirds).

Zostera muelleri as a structuring agent of benthic communities in a large intertidal sandflat in New Zealand

The influence of seagrass beds on intertidal infaunal communities has been widely studied, with vegetated areas typically having higher diversity and abundances than adjacent bare sand patches. Such “seagrass–sand” comparisons, however, do not reflect the gradient of seagrass cover that may exist across large landscapes. We studied the large-scale distribution of intertidal macrozoobenthos over approximately 10,000 ha of sandflat on Farewell Spit, New Zealand. The benthic fauna, sediment composition and surface cover of the seagrass Zostera muelleri were studied at 192 sites evenly spaced along 30 transects covering the length of the 30 km spit. Most sites had Zostera present, generally at low densities (1–25% surface cover). Overall, invertebrate taxon diversity increased with Zostera cover, from a median of 4 taxa at sites with no Zostera to 23 at sites with high Zostera cover. Multivariate analyses of 37 frequently occurring taxa (of the 91 recognised) indicated that there was a site gradient of taxon abundances that reflected seagrass cover, with 23 taxa increasing as Zostera cover increased. Only three taxa tended to be found more where Zostera was scarce. Seventeen taxa were identified as being significant indicators of Zostera cover; in all cases abundances peaked with high Zostera scores. Cluster analysis revealed a number of major groupings. One group was associated with low Zostera; two were strongly associated with high Zostera cover; a fourth was probably distinguished by low tidal elevation and proximity to channels. On the Farewell Spit tidal flats, large-scale patterns of abundance seem to be largely structured by the presence and density of Zostera.

Intertidal macrozoobenthos in sandy beaches of Bahía Nueva (Patagonia, Argentina) and their use as bioindicators of environmental impact

Macrozoobenthos were collected from urban sandy beaches of Puerto Madryn and adjacent areas in November 2005. Multivariate analysis techniques (ANOVA, nMDS, ANOSIM, SIMPER and RDA) were used to characterize the area based on the relationships among biological and environmental variables. The areas affected by outfall of fishery factories and pluvial effluent were defined as “perturbed zones” due to the dominance of the pollution indicator polychaetes Boccardia polybranchia and Capitella “capitata” sp., which are associated with high values of ammonium, phosphates and organic matter. However, sandy beaches located 15 km from the city were considered as “unperturbed zones” because Psammodrilidae and Puelche orensanzi dominated, and they had high values of nitrates and dissolved oxygen. These taxa seem to be good candidates as indicators of clean zones for further studies. This is the first record of the family Psammodrilidae in the South Atlantic.

Influence of spring phytodetritus sedimentation on intertidal macrozoobenthos in the eastern English Channel

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 270:41-53 (2004) - doi:10.3354/meps270041 Influence of spring phytodetritus sedimentation on intertidal macrozoobenthos in the eastern English Channel Nicolas Desroy*, Lionel Denis Station Marine de Wimereux, Université de Lille 1, CNRS UMR 8013 ELICO, 28 Avenue Foch, 62930 Wimereux, France *Email: nicolas.desroy@univ-lille1.fr ABSTRACT: The North Sea shallow waters of the eastern English Channel are recurrently affected by the high algal spring bloom of the Prymnesiophyte Phaeocystis spp. When the bloom has run its course, foam accumulations resulting from the release of mucilaginous polysaccharides can be observed both on the sea surface and on beaches. Four beach sites, 2 that were affected and 2 that were not, were sampled from April to December 2001 and from April to August 2001 respectively. The physical and chemical conditions of the sediment, as well as the macrofauna associated with it, were assessed in the Canche Bay before, during and after the phytodetritus sedimentation period. Phaeocystis spp.-derived material significantly changed the grain-size distribution in accumulation areas as shown by the resulting fine-particle input (>60%) observed. Due to the rapid decomposition of decaying colonies, organic content increased in the sediments towards the end of the bloom, marked by a single peak on sands or strong, persistent enrichment on muds. As a result of this increase in organic matter, oxygen flux increased over time. In the low-energy silty environment, severe anoxic conditions rapidly occurred whereas on areas subject to tidal or wind-induced turbulence, superficial residual crusts resulting from drying foam prevented oxygen diffusion into sandy sediment. At the impacted sites, all macrobenthic taxa were affected, and both the number of species and their densities were simultaneously reduced. Sandy assemblages showed a better recovery, starting in July, due to more suitable environmental conditions, while on muddy assemblages full recovery had still not occurred by the end of the year. Spring recruit mortality was partly responsible for the lack of faunal recovery, which was mainly dependant on the migration of adults from the surrounding area. KEY WORDS: Phaeocystis spp. bloom · Organic matter input · Macrobenthos · Recovery Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 270. Online publication date: April 14, 2004 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2004 Inter-Research.

Évolution du macrozoobenthos intertidal de la baie des Veys de 1985 à 2000

The distribution of intertidal macrozoobenthos in the ‘Baie des Veys’ (French coast of the eastern English Channel) has been studied in 2000. Results were compared with those of 1985, which are included in a long-term monitoring program established since 1973. The populations remained distributed along an estuarine-marine gradient, with a particularity on the eastern side, which is isolated from the rest of the bay by a river channel. The western and central tidal flats became more subjected by marine influence, which led to a homogenisation of the benthic communities. Oyster farming locally caused a fast decrease of the typical eastern community, which was characterized by Scoloplos armiger and Urothoe poseidonis. To cite this article: O. Timsit et al., C. R. Biologies 327 (2004).

Variation of the Intertidal Macrozoobenthos Community of a Sandy Beach during El Niño/Southern Oscillation, Lambayeque, Peru

Variation of the Intertidal Macrozoobenthos Community of a Sandy Beach during El Niño/Southern Oscillation, Lambayeque, Peru

Fractal properties of spatial distribution of intertidal benthic communities

We studied the spatial distribution of intertidal macrozoobenthos, microphytobenthos (diatom algae) and sediments at scales from decimeters to kilometers using an index of spatial homogeneity, DI. Sediments were found to be randomly distributed, making up a mosaic of silty and sandy sites. On the contrary, the estimated spatial variability of macrofauna within all the scales up to 5500 m depended upon neither extent (total area covered) nor grain (finest spatial resolution) but only their ratio. We treat this as evidence of statistical self-similarity (fractal property) of the pattern. For diatoms, spatial heterogeneity of community structure was also self-similar in the range from 0.25 to 75 m (within a single bight). At larger scales, microalgae showed a combination of patchy structure with pronounced gradient along the shoreline from brackish-water to marine flora. Thus, fractal properties of both groups became manifested at scales corresponding to their mean body size. The ranges of fractal patterns were approximately equal to 103–105 if measured in body size units. We suggest that fractal-like spatial structures may be a general feature of communities, and speculate on the nature of such patterns.

Temporal scaling and relevance of bivalve nutrient excretion on a tidal flat of the Seto Inland Sea, Japan

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 198:139-155 (2000) - doi:10.3354/meps198139 Temporal scaling and relevance of bivalve nutrient excretion on a tidal flat of the Seto Inland Sea, Japan Paolo Magni1, Shigeru Montani1,*, Chika Takada1, Hiroaki Tsutsumi2 1Department of Life Sciences, Kagawa University, 761-0795 Miki, Japan 2Faculty of Environmental & Symbiotic Sciences, Prefectural University of Kumamoto, Tsukide 3-1-100, 862-0920 Kumamoto, Japan *Corresponding author. E-mail: montani@ag.kagawa-u.ac.jp ABSTRACT: Using an indirect and integrated approach, we quantified the magnitude and temporal variability of the contribution of macrozoobenthos to the upward flux of inorganic nitrogen and phosphorus on a sandy tidal flat of the Seto Inland Sea, Japan. From April 1994 to April 1996, we conducted monthly field surveys on the abundance and faunal composition of the macrozoobenthic communities inhabiting the lower part of the intertidal zone. Subsequently, we carried out 24 h day/night laboratory experiments on the nutrient excretion rate by various size-classes of the dominant species. We then obtained the animal nutrient excretion over a 2 yr period, multiplying the species-specific excretion rates by the actual animal biomass found on the tidal flat. Additionally, for all different seasons, we calculated the upward diffusive flux from the sediments from the vertical profiles of nutrient concentrations in the porewater. On the flat, the bivalves Ruditapes philippinarum (Veneridae) and Musculista senhousia (Mytilidae) were dominant, making up 86 ± 5.6% when the total biomass exceeded 100 g DW (dry weight) m-2. From our laboratory experiments, the mean (day and night) nutrient excretion rates at 20 to 22ºC by the 2 bivalve species were 18.9 µmol NH4+-N g-1 DW h-1, 4.8 µmol (NO3- + NO2-)-N g-1 DW h-1 and 3.3 µmol PO43--P g-1 DW h-1. In addition, NH4+-N excretion by R. philippinarum, but not that by M. senhousia, was significantly higher during the day than during the night. This occurred while the food (Thalassiosira sp.) offered in spikes was rapidly taken up irrespective of the concentration (within a field relevant spring-summer range of 10 to 60 µg l-1 chl a) and in day/night treatments. The release of nitrogen (N) and the release of phosphorus (P) were highly correlated with each other, for both R. philippinarum and M. senhousia, with a N/P ratio of 7.8 ± 3.0 and 9.9 ± 3.5, respectively. In the field, the bivalve excretion rates of nutrients were calculated to be up to 35.2 mmol NH4+-N m-2 d-1, 8.8 mmol (NO3- + NO2-)-N m-2 d-1 and 5.8 mmol PO43--P m-2 d-1. These values rank in the upper range of nutrient excretion by intertidal macrozoobenthos and are comparable to those found on dense assemblages (800 to 2000 g ash free DW m-2) of the most investigated mussel, Mytilus edulis. In addition, nutrient fluxes through bivalve excretion varied strongly within a few months, up to 10-fold (R. philippinarum) and 100-fold (M. senhousia) between April 1994 and August 1994, as related to the temporal change of bivalve standing stock. The extent of nutrient regeneration through diffusive flux was comparable to that reported for other intertidal zones of Japan and in the eutrophic Seto Inland Sea, within a range of 0.2 to 1.5 mmol NH4+-N m-2 d-1 and 0.01 to 0.05 mmol PO43--P m-2 d-1, thus more than 1 order of magnitude lower than that due to the excretory activity by R. philippinarum and M. senhousia. Our results indicate that the dominant bivalves, R. philippinarum and M. senhousia, play a major role in the processes of benthic nutrient regeneration within the intertidal zone, rapidly and efficiently recycling the inorganic forms of N and P available to primary producers. This study highlighted the importance of considering the temporal scaling of intertidal macrozoobenthos distribution in the quantification of the processes of benthic nutrient regeneration in these highly variable systems. KEY WORDS: Bivalve excretion · Ruditapes philippinarum · Musculista senhousia · Benthic nutrient regeneration · Scale · Diffusive flux · Nitrogen · Phosphorus · Tidal flat · Seto Inland Sea Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 198. Publication date: June 05, 2000 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 2000 Inter-Research.

Long-term development of biomass of intertidal macrozoobenthos in different parts of the Wadden Sea. Governed by nutrient loads?

Long-term data sets on intertidal macrozoobenthos from Danish, German and Dutch parts of the international Wadden Sea were analysed for trends in biomass of molluscs, polychaetes and crustaceans. Patterns in long-term development were compared with data on nutrient loads from freshwater sources and with regional data on chlorophyll a and nutrient concentrations in the water column. Fluctuation patterns of total biomass were strongly determined by fluctuations of bivalve biomass. Especially in bivalves these fluctuation patterns show synchronisation due to the different impact of severe winters (1979, 1985–87) and mild winters (1988–90). Indications were found for a consistent increasing trend in polychaetes. Most of the data sets do not allow a proper analysis of a possible causal relationship between nutrient input and biomass development of macrozoobenthos. Moreover, for such an analysis better information on nutrient load related food supply for macrozoobenthos is necessary.

Long-term changes (1977–1994) in intertidal macrozoobenthos of the Dollard (Ems estuary) and effects of introduction of the North American spionid polychaeteMarenzelleria cf.wireni

Intertidal macrozoobenthos was monitored twice a year at three permanent transects in the Dollard (Ems estuary) from 1977 till 1994. In this period organic waste discharges in August-December into the Dollard decreased from 25×l06 kg BOD5 (1970s) to 10×106 kg BOD5 (early 1980s), and finally to 0.5×l06 kg BOD5 (early 1990s). Few long-term trends in numerical density or biomass of separate benthos species could be demonstrated. Crustaceans, mainly the amphipodCorophium volutator, increased in abundance and biomass. In the bivalveMacoma balthica and the polychaeteNereis diversicolor decreasing trends were observed especially in biomass. No relationships with changes in environmental conditions as caused by the decrease in organic waste load could be demonstrated.

Long-term changes (1979–89) in the intertidal macrozoobenthos of the Oosterschelde estuary: are patterns in total density, biomass and diversity induced by the construction of the storm-surge barrier?

Long-term changes (1979–89) in the intertidal macrozoobenthos of the Oosterschelde estuary: are patterns in total density, biomass and diversity induced by the construction of the storm-surge barrier?

Use of the Abundance/Biomass Comparison Method for Detecting Environmental Stress: Some Considerations Based on Intertidal Macrozoobenthos and Bird Communities

Use of the Abundance/Biomass Comparison Method for Detecting Environmental Stress: Some Considerations Based on Intertidal Macrozoobenthos and Bird Communities

Response of Macrozoobenthos to a Temporal Lowering of Chlorinity: A Large-Scale Field Experiment in the Dutch Delta Area1

During the winter 1979/1980 the chlorinity in the Keeten-Krammer-Volkerak-area was considerably lowered, due to an experimental doubling of the freshwater discharge at the Volkerak sluices. To assess the possible impact, species composition, abundance and biomass of the intertidal macrozoobenthos was studied prior to (1978, 1979) and after (1980, 1981) the experiment. In order to prevent damage to the local commercial mussel-stocks, the condition of Mytilusedulis and water-quality-parameters were studied during the experiment. The species that were frequently found before the experiment were still abundant afterwards. Nevertheless, species number directly after the experiment was lower than before. Some of the relatively rare species that were not found immediately after the experiment, were present again later in 1980. The Shannon-Weaver diversity index did not show a significant change. Sample-classification using the Bray-Curtis dissimilarity-index, indicated that most pre-experimental samples were similar to post-experimental samples. Dissimilarity was found between March and October samples. Although locally high values of ammonia and E. colibacteria occurred, the water quality in general remained relatively good. The condition of the mussels was not demonstrably influenced by the experiment. Moreover, young mussels transferred to a control area in the Oosterschelde showed good growth, indicating also a recovery from the exposure to lower chlorinities.