Populations Of Macoma Balthica Research Articles

The Early Life History of the Clam Macoma balthica in a High CO2 World

This study investigated the effects of experimentally manipulated seawater carbonate chemistry on several early life history processes of the Baltic tellin (Macoma balthica), a widely distributed bivalve that plays a critical role in the functioning of many coastal habitats. We demonstrate that ocean acidification significantly depresses fertilization, embryogenesis, larval development and survival during the pelagic phase. Fertilization and the formation of a D-shaped shell during embryogenesis were severely diminished: successful fertilization was reduced by 11% at a 0.6 pH unit decrease from present (pH 8.1) conditions, while hatching success was depressed by 34 and 87%, respectively at a 0.3 and 0.6 pH unit decrease. Under acidified conditions, larvae were still able to develop a shell during the post-embryonic phase, but higher larval mortality rates indicate that fewer larvae may metamorphose and settle in an acidified ocean. The cumulative impact of decreasing seawater pH on fertilization, embryogenesis and survival to the benthic stage is estimated to reduce the number of competent settlers by 38% for a 0.3 pH unit decrease, and by 89% for a 0.6 pH unit decrease from present conditions. Additionally, slower growth rates and a delayed metamorphosis at a smaller size were indicative for larvae developed under acidified conditions. This may further decline the recruit population size due to a longer subjection to perturbations, such as predation, during the pelagic phase. In general, early life history processes were most severely compromised at ∼pH 7.5, which corresponds to seawater undersaturated with respect to aragonite. Since recent models predict a comparable decrease in pH in coastal waters in the near future, this study indicates that future populations of Macoma balthica are likely to decline as a consequence of ongoing ocean acidification.

Microsatellite markers for the Baltic clam, Macoma balthica (Linné, 1758), a key species concerned by changing southern limit, in exploited littoral ecosystems

During the last 30 years, the southern European range limit of the Baltic clam Macoma balthica strongly shifted northward. To understand the consequences of such a retreat on populations located near the edge of its current geographic range, we developed nine microsatellite markers and tested their usefulness on 36 individuals from two populations. All loci were found to be polymorphic, with 5–26 alleles per locus. These results appear promising to study the fine scale genetic structure and dynamics of Macoma balthica populations near the range limit.

Salinity-related growth rates in populations of the European clam Macoma balthica and in field transplant experiments along the Baltic Sea salinity gradient

Most benthic invertebrates and plant species that survive in the brackish Baltic Sea are characterized by populations in which growth is reduced and genetic diversity is low, indicating that these species live under marginal conditions. In this study, we tested for a salinity-related growth rate reduction in 21 European Macoma balthica populations. Additionally, we transplanted clams into hyposaline environments, along the Baltic Sea salinity gradient, and compared survival, growth and condition with control groups. All transplants into hypoosmotic environments were successful. Despite the osmotic shock, the results showed no reduced growth rates in transplanted individuals. Only the clams that had been transplanted into the extremely oligohaline Gulf of Bothnia (0.5–3.0 PSU) exhibited reduced growth rates in comparison to the control group. From this study we conclude that M. balthica has an exceptional capacity to acclimatize to extremely brackish conditions, which may explain its abundance and diversity in the Baltic Sea.

Geographic and seasonal patterns and limits on the adaptive response to temperature of European Mytilus spp. and Macoma balthica populations

Seasonal variations in seawater temperature require extensive metabolic acclimatization in cold-blooded organisms inhabiting the coastal waters of Europe. Given the energetic costs of acclimatization, differences in adaptive capacity to climatic conditions are to be expected among distinct populations of species that are distributed over a wide geographic range. We studied seasonal variations in the metabolic adjustments of two very common bivalve taxa at European scale. To this end we sampled 16 populations of Mytilus spp. and 10 Macoma balthica populations distributed from 39° to 69°N. The results from this large-scale comprehensive comparison demonstrated seasonal cycles in metabolic rates which were maximized during winter and springtime, and often reduced in the summer and autumn. Studying the sensitivity of metabolic rates to thermal variations, we found that a broad range of Q 10 values occurred under relatively cold conditions. As habitat temperatures increased the range of Q 10 narrowed, reaching a bottleneck in southern marginal populations during summer. For Mytilus spp., genetic-group-specific clines and limits on Q 10 values were observed at temperatures corresponding to the maximum climatic conditions these geographic populations presently experience. Such specific limitations indicate differential thermal adaptation among these divergent groups. They may explain currently observed migrations in mussel distributions and invasions. Our results provide a practical framework for the thermal ecophysiology of bivalves, the assessment of environmental changes due to climate change and its impact on (and consequences for) aquaculture.Electronic supplementary materialThe online version of this article (doi:10.1007/s00442-007-0808-x) contains supplementary material, which is available to authorized users.

Seasonal variability of free amino acids in two marine bivalves, Macoma balthica and Mytilus spp., in relation to environmental and physiological factors

The seasonal variability of the intracellular free amino acid (FAA) concentration was studied in 5 Macoma balthica populations and 7 Mytilus spp. populations along their European distribution. Because of the well known physiological role of FAA as organic osmolytes for salinity induced cell volume regulation in marine osmoconformers, FAA variations were compared in bivalve populations that were exposed to high vs. low intraannual salinity fluctuations. In general, seasonal FAA variations were more pronounced in M. balthica than in Mytilus spp. In both bivalve taxa from different locations in the Baltic Sea, highest FAA concentrations were found in autumn and winter and low FAA concentrations were measured in summer. Seasonal patterns were less pronounced in both taxa at locations with constant salinity conditions. In contrast to Baltic Sea populations, Atlantic and Mediterranean bivalves showed high FAA concentrations in summer and low values in winter, regardless of seasonal salinity fluctuations. Significant seasonal FAA variations at locations with constant salinity conditions showed that salinity appeared not to be the main factor in determining FAA concentrations. The seasonal patterns of the main FAA pool components, i.e. alanine, glycine and taurine, are discussed in the context of seasonal variations in environmental factors (salinity, temperature) and physiological state (glycogen content, reproductive stage).

Patterns of organic osmolytes in two marine bivalves, Macoma balthica, and Mytilus spp., along their European distribution

Patterns of nine intracellular free amino acids (FAA), which are utilized as organic osmolytes for salinity-induced cell volume regulation in marine osmoconformers, were compared in five Macoma balthica populations and seven Mytilus spp. populations along their European distribution. Three types of FAA patterns were classified within both taxa: a northern Baltic type, a southern Baltic type and an Atlantic/Mediterranean type which mainly differ regarding the share of alanine and taurine. Differences are discussed in relation to habitat salinity and population genetics. Along a salinity gradient, the total size of the intracellular FAA pool did not differ between sympatric M. balthica and Mytilus spp., and was significantly correlated with habitat osmolality in a range from 70 to 600 mmol kg−1 H2O (oligohaline to mesohaline) in both bivalves. In M. balthica, this correlation was mainly based on significant correlations of alanine (15–100 mmol kg−1 DW), glycine (30–100 mmol kg−1 DW) and taurine (0–70 mmol kg−1 DW) with habitat osmolality. In Mytilus spp., only glycine (25–100 mmol kg−1 DW) and taurine (4–180 mmol kg−1 DW) were significantly correlated with habitat osmolality. The concentration of alanine was three times lower in Mytilus spp. than in M. balthica and did not correlate with habitat osmolality. Within a habitat osmolality range from 600 to 1,100 mmol kg−1 H2O (mesohaline to marine) the concentration of FAA remained constant in both taxa. It is suggested that under marine conditions additional organic osmolytes must become more important for cell volume regulation in Macoma and Mytilus.

Microalgae, macrofauna and sediment stability: an experimental test of a reciprocal relationship

A manipulative field experiment was conducted at Blackness in the Firth of Forth, Scotland, to study the effects of differences in microphytobenthos abundance on sediment stability and macrofauna. Opaque and transparent Perspex was used to construct shaded and controlled treatments, respectively. Shading resulted in significantly lower levels of chlorophyll a recorded from the sediment. Shaded treatments showed significant reductions in populations of Macoma balthica, Hydrobia ulvae and Corophium volutator, 3 of the dominant species at this site. Largely as a result of changes in the abundance of these species, multivariate analyses showed significant differences between shaded and control communities. The impacts of shading on individual species depended on the sediment characteristics. There were no significant differences between treatments in recorded sediment accretion/erosion rates. These results demonstrate the importance of microphytobenthos for the deposit feeders M. balthica, H. ulvae and C. volutator. The absence of any effect on sediment stability might result from the reciprocal, opposite effects of macrofauna and microphytobenthos on sediment stability cancelling each other out in this experiment.

Spatial variation in the intertidal bivalve Macoma balthica: biotic variables in relation to density and abiotic factors

We studied the spatial variation in biotic variables of a Macoma balthica population. Systematic sampling was carried out over an environmentally heterogeneous intertidal bay of the St. Lawrence Estuary. Several biotic (density, body tissue and shell mass, reproductive effort, shell length and growth) and abiotic (intertidal level, sediment characteristics) variables were concur- rently analysed to quantify the part of the variance accounted for by the abiotic factors and the part accounted for by density (density was also studied as an explanatory variable). Redundancy analysis and multiple regression were used. The variables examined were mapped to show the trends in their spatial variation. Density was highly variable, from 0 to 2700 ind. m -2 , and was mainly positively related to the percentage of sand in the sediment. Most biotic variables were spatially variable, and the variables accounting for most of this variation were shore level and density. Body tissue and shell mass were negatively affected by increasing shore level and density. Shell length decreased with increasing shore level and increased with increasing pore water content. Reproductive effort was enhanced at high density.

Different degrees of tolerance to hydrogen sulphide in populations of Macoma balthica (Bivalvia, Tellinidae)

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 154:185-196 (1997) - doi:10.3354/meps154185 Different degrees of tolerance to hydrogen sulphide in populations of Macoma balthica (Bivalvia, Tellinidae) Jahn A, Theede H Populations of the Baltic clam Macoma balthica show different degrees of sulphide tolerance in relation to sulphide contamination of their habitats. Specimens from sulphidic habitats such as the Gulf of Gda´nsk (Baltic Proper) and shallow waters near the island of Hiddensee (Southern Baltic Sea) have higher survival capacities during sulphide exposure than those from low sulphide contaminated environments such as Kiel Bight (Western Baltic Sea) and the Wadden Sea near Dorum-Neufeld (Weser estuary, North Sea). The tolerant clams are better able to protect cytochrome c oxidase against sulphide toxification. It can be assumed that this protection is due to slower sulphide diffusion into the tissues. Sulphide-tolerant specimens from highly sulphidic habitats have apparent sulphide diffusion coefficients which are roughly half those of sulphide-sensitive specimens from low sulphidic stations. Higher sulphide influx into the sensitive clams will negatively affect their metabolism, combined with longer inhibition of cytochrome c oxidase, resulting in higher mortality. Macoma balthica · Population · Hydrogen sulphide · Apparent diffusion coefficient · Apparent detoxification constant · Cytochrome c oxidase · Macrofauna · Baltic Sea · North Sea Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 154. Publication date: July 31, 1997 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1997 Inter-Research.

Reproductive output of Macoma balthica populations in relation to winter-temperature and intertidal-height mediated changes of body mass

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 149:155-162 (1997) - doi:10.3354/meps149155 Reproductive output of Macoma balthica populations in relation to winter-temperature and intertidal-height mediated changes of body mass Honkoop PJC, van der Meer J To study relationships between environmental conditions and reproductive output, numbers and sizes of eggs produced by the intertidal bivalve Macoma balthica were determined after the winters of 1995 and 1996 at 3 stations at different intertidal levels in the Dutch Wadden Sea. At all field stations significantly more (1.5 to 7 times) eggs were produced after the cold winter of 1996 than after the mild winter of 1995 when individual body masses were lower than in early 1996. At 2 stations the eggs were also significantly larger in 1996. In both years, eggs were larger at low than at high mud flats. Egg size was significantly positively correlated with adult body mass in the preceding summer (when gametogenesis takes place). Egg numbers, on the other hand, were only significantly positively correlated with the body mass just prior to spawning. Below a body mass of 5.6 mg ash-free dry mass per cm3 (cubic shell length), M. balthica did not produce any eggs. Above this body mass, egg numbers increased by about 7700 per mg ash-free dry mass at a shell length of 15 mm. Macoma balthica · Bivalve · Body mass · Egg number · Egg size · Reproductive output Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 149. Publication date: April 10, 1997 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1997 Inter-Research.

Annual changes in selected aspects of soft-shore biology

SynopsisAnnual variations in a number of parameters over the period 1977–84 are described: they were generally site-specific in character. Linear shell dimensions of Cerastoderma edule populations (seven sites) remained stable but trends in both shell and soft-tissue dry weights changed over this period. Population structure and growth rates of C. edule are described using growth-ring analysis: they provide evidence of sporadic recruitment and persistent dominance by one or more yearclasses, although several populations are particularly individual in character. Populations of Macoma balthica (two sites) had a stable structure. Populations of both species at one site (inner Houb of Scatsta) declined markedly following the Esso Bernicia oil spill in 1982 and had not recovered before the study was terminated. Studies of transects at two sites are described: sedimentary changes were small while infaunal community characteristics showed both persistent environmental trends for some species and random fluctuations in others. The communities at each site showed high diversity, with generally stable structures upon which are superimposed annual and site-specific fluctuations in abundance of component species.

Spatial variation in growth of the bivalve Macoma balthica (L.) on a tidal flat: effects of environmental factors and intraspecific competition

A descriptive field study was conducted on a tidal flat of the Lower St. Lawrence Estuary to examine spatial variations in shell growth of the infaunal bivalve Macoma balthica (L.) in relation to tidal level, sediment characteristics, and local density. This study was based on 83 0.3 × 0.3 m 2 sediment samples randomly located on a 1.6 km 2 tidal flat where maximal amplitude of tide was 4.8 m. Mean density of Macoma balthica for the whole sampling area was 1254 m −2 ( S x = 87 m −2 ) and densities were higher and more variable near the mean water level. Variations in the effects of density and environmental factors along the tidal gradient were studied after a stratification of the stations by immersion time. Overall, shell growth rate increased with immersion time, the latter accounting for about 5 to 63% of the spatial variation of mean shell length for the six youngest generations. Fifty-two to 61% of the adjusted annual shell growth was explained by a linear relationship with tidal level. A significant but weaker linear relationship was obtained between growth and density, and between growth and sediment grain size. For the whole sampling area, a linear model with tidal level and density as independent variables explained 37 to 80% of the spatial variability of mean shell length for each generation and 59 to 77% of the spatial variability in adjusted annual growth rates. The effect of density was not significant in the lower part of the tidal flat, however, it became significant when immersion time was ≈ 50%, and had a maximum effect when immersion time was about 40%. About 65 to 85% of the spatial variability of the growth rate along the tidal gradient can be explained by stepwise multiple regressions involving density as the first independent variable. Overall, the results suggested that intraspecific competition played a major role in ≈ 67% of the population of Macoma balthica within the study area.

Spatial variability of length-specific production in shell, somatic tissue and sexual products of Macoma balthica in the Lower St. Lawrence Estuary

A field study on the spatial variability of production and some demographic parameters was conducted in 1988 in ten populations of Macoma balthica located on the north and south shores along the entire length (230 km) of the Lower St. Lawrence Estuary (LSLE, Canada) at the same intertidal level. Standard-length estimates (10 mm) of shell and somatic tissue production for the period of May to November were highly variable between stations and greater on the north shore than on the south shore. Standard-length estimates of the gamete production for the period of July to November were also highly variable between stations but there was no variation between shores. The inter-population variability of the standard-length estimates of production in shell, somatic tissue and sexual products was as large as the intrapopulation variability between both the upper and lower tidal levels measured in previous studies. There were no significant linear relationships between standard-length estimates of production and biotic (density) or abiotic (temperature, chlorophyll-a in top sediment, mean phi, water salinity) factors, but we observed some significant quadratic relationships between standard-length estimates of production and mean sediment-surface temperature during the growing season. The standard-length estimates of production were lower at the coldest and warmest stations than at the more temperature stations. There was also a significant negative linear relationship between mean sediment-surface temperature during the growing season and the grain size structure of sediment, indicating that the sediment texture, indirectly, largely influenced the inter-station and the inter-shore variability of production in shell, somatic tissue and sexual products of M. balthica in the LSLE.

Contrasting influences of suspension-feeding and deposit-feeding populations of Macoma balthica on infaunal recruitment

Contrasting influences of suspension-feeding and deposit-feeding populations of Macoma balthica on infaunal recruitment

Recruitment and year-to-year variability in a population of Macoma balthica (L.)

Because of methodological problems, macrobenthic studies usually neglect the juvenile stages of invertebrate communities, due to the fact that appearance of recruits in samples is only detected some weeks or even months after their true recruitment. During this period, the temporary meiobenthos undergoes high rates of mortality. From year to year, juvenile survival rate is thus responsible for temporal patterns observed in adult population densities.

Naturally occurring activity variation of an alkaline phosphatase isozyme associated with physiological fitness in an intertidal population of Macoma balthica

We observed variability in the level of an isozyme for the enzyme alkaline phosphatase (AKP, EC 3.1.3.1) in a Macoma balthica population from Hudson Bay. The distribution of "high" and "no" activity AKP-2 variants were different in samples from "high" tide as compared with "low" tide areas. Furthermore, the AKP-2 activity level is associated with survival at high temperature (32 °C), but in the "high" tide subpopulation only. Although this striking association between the activity level of an isozyme and an environmental parameter in a natural population is one of the very few in the literature, further studies are required to establish the genetic basis for the level of the enzyme activity and the biochemical basis for this relationship.Key words: isozyme, alkaline phosphatase, natural selection, evolution.

Secondary production by siphon regeneration in a tidal flat population of Macoma balthica

The share of cropped siphon tips in the secondary production of the bivalve Macoma balthica (L.) was estimated in a tidal flat area in the westernmost part of the Dutch Wadden Sea. Basic data were year-round measurements of siphon- and body weights in the field and regeneration rates of siphons in the laboratory. The completeness of the inhalant siphon was expressed as the Siphon Condition: SC = siphon weight divided by the square root of the body weight. In field populations the SC values showed a seasonal pattern, viz. low in summer and high in winter. Regeneration of the siphons was rapid under simulated tidal flat conditions, hardly depended on temperature and season and was faster as siphons were lighter. Siphon growth stopped when a SC value of 0.36 was reached. In tidal flat animals, SC values between 0.03 and 0.36 were observed. The estimated amounts of Macoma siphon tissue lost during 1975 at 4 tidal flat transects varied from 0.31 to 1.66 g ADW·m −2·a −1, i.e. nearly half of the annual mean biomass of the soft parts and hardly different from elimination in the form of whole Macoma. Only about 13% of the siphon tip biomass lost was consumed by flatfish. Other epibenthic predators, like gobies, shrimps and shore crabs will have cropped the rest. Individual Macoma will have lost an average of several siphon tips per day. The loss and subsequent regeneration of siphon tips must be an important factor in the ecology of Macoma, affecting feeding behaviour, burying depth and body weight. In tidal flat ecosystems, regeneration of siphon tips and other cropped body parts will significantly contribute to benthic secondary production.

Effects of temperature on the length of the annual growing season in the tellinid bivalve Macomabalthica (L.) living on tidal flats in the Dutch Wadden Sea

Frequent inspection of the shell margins during a 15-yr study of tidal flat populations of Macoma balthica (L.) in the western part of the Wadden Sea revealed that the annual growing season starts earlier (viz. early March compared with late March) if preceding winter temperatures were higher. The reversal of weight gain to weight loss used as an indicator of the end of the growing season occurs earlier in July if early-summer temperatures are higher. Thus, growth is restricted to the range of water temperatures between 4 and 16°C in spring. No growth was observed during the autumn at the same temperatures. Although low and high temperatures appear to delimit the annual spring growing season, total annual growth is not related to the length of the growing season nor to temperatures prevailing during this period. Feeding conditions appear to prevent growth in autumn and determine the highly variable growth rates within the temperature-set growing period in spring.

Food intake of Macoma balthica (mollusca) in relation to seasonal changes in its potential food on a tidal flat in the Dutch Wadden Sea

Food intake, absorption and presumed origin of the food were studied simultaneously throughout the year for a tidal flat population of Macoma balthica in the westernmost part of the Dutch Wadden Sea. The rate of food intake was calculated from the amount of chlorophyll a in the stomach and the rate of stomach evacuation. Highest rates of intake by Macoma were found during the first 4 hours of submersion and during the months April, May and June. During the emersion period and in winter the feeding activity was low. The total intake per submersion period was positively correlated with the concentration of chlorophyll a in the water, but not with that in the top layer of the sediment. Moreover, the season with high rates of intake coincided with the short maxima in spring for the concentrations of organic carbon and chlorophyll a in the water, but not with the longer seasonal maxima (from April to October) for these concentrations in the sediment. In the sediment mainly pennate diatoms were found, in the water centric diatoms. The algal species composition of the stomach content showed a strong resemblance to the composition of the water samples. Observations on siphon movements in the laboratory showed that Macoma spent more time with the siphon near the bottom than with the siphon extended into the water column. It is concluded that Macoma, although it behaves most of the time as a deposit feeder, depends for its food intake for the greater part on food present in the water column.

An energy budget for a Macoma balthica (mollusca) population living on a tidal flat in the Dutch Wadden Sea

Seasonal and annual energy budgets were compiled for individuals and for a tidal flat population of Macoma balthica in the western part of the Dutch Wadden Sea, based on independent estimates of their numbers, biomass, food consumption and absorption, production and respiration. The consumption of food reached a maximum in late winter and remained high during spring. The absorption of food was maximal in spring and minimal in autumn and early winter. The absorption of food related to chlorophyll a was high only during April, May and June. The respiration was high during spring and summer and reached a minimum in winter. Somatic growth and gonad output were high only in the months April, May and June, whereas weight. Indeed, estimates for the absorption of chlorophyll a related food minus respiration were only high during the three months. The production of Macoma appears to depend primarily on the concentration of chlorophyll a related food in the water. The maintenance ration on basis of total consumption amounted to 1.3% of the body weight per day or, when based on the absorbed chlorophyll a related food to 0.4%. The net growth efficiency was 19% on the basis of all absorbed food, and 28% on the basis of chlorophyll a related food.