Subtidal Level Research Articles

The swash zone selects functionally specialized assemblages of beach interstitial meiofauna (Platyhelminthes, Proseriata)

Life is not a beach for those animals that survive in the rough ecological conditions found in marine sandy beaches – and yet, microscopic animals thrive on them. We explore the drivers for meiofaunal diversity in beaches by analysing taxonomic and functional patterns of 348 flatworm communities across 116 reflective beaches in the western Mediterranean, totalling 152 species (61.2% new to science). First, we confirm that species richness does not differ between beach hydrodynamic levels (swash, shoaling and surf) but rather depends on the characteristics of each beach. Second, we demonstrate that species composition across those levels depends on the species traits, in addition to geographical and abiotic factors. Third, we highlight that the species functional space has a lower richness than expected and a lower redundancy in the wave‐exposed swash level compared to the shoaling and subtidal levels, suggesting a trait‐based ecological filtering. Finally, we show that those differences depend on the higher frequency of hydrodynamics‐related traits in the species of the swash level. Our results suggest that the rough hydrodynamic conditions in the swash level favour a unique combination of species traits, which might be linked to ecological speciation in flatworms but also in other interstitial animals.

Study on vermetid worm shells in Mon coastal area of Myanmar

Vermetid worm shell of Thylacodes decussatus (Gmelin, 1791) belonging to genus Thylacodes Guettard, 1770 under the family Vermetidae collected at Kyaikkhami, Setse, Kawdut, Sitaw and Kabyarwa in Mon coastal area from January to December 2018. A total of 2561 individuals collected from rocky hard substrates, boulders, rock pool, and water-leveled benches of supra-tidal to lower sub-tidal levels. Regarding percentage species composition, September was maximum species composition, and April was minimum species composition. The range of mean was 47.67-28.67 (September-April), and the standard deviation was 40.66-18.06 (November-February). Maximum and minimum species abundance were recorded in Kawdut coastal area (792 individuals) and Sitaw coastal area (207 individuals), respectively. Moreover, the habitats, zonal distribution and coiling patterns of worm shells in intertidal and shallow water environments of Mon coastal area were studied in brief.

Morpho-structural and ecological features of a shallow vermetid bioconstruction in the Tyrrhenian Sea (Mediterranean Sea, Italy)

Biogenic formations, built up by the sessile and gregarious vermetid gastropod Dendropoma cristatum, were studied from June to October 2014 along the rocky shores of Licosa islet (Gulf of Salerno, Tyrrhenian Sea), where they build up the northernmost reefs in the Mediterranean Sea in order to shed light on possible latitudinal changes. The islet has two differently exposed sides, with three types of vermetid formations: the first consists in a thin layer composed by vermetid gastropods and the coralline alga N. brassica-florida, widespread only in the sheltered side of the islet; the second is represented by small isolated pillows (13.9±5.64cm), all around the islet at depth of more than fifteen centimetres; the third is a well-structured reef, characterized by a dense layer of mollusc shells that overgrow each other, only found in the exposed side of the islet. The vermetid reef was monitored in two sites with different substrates: ancient walls, made of calcareous lateritious material, and the flysch rocks, composed by siliceous turbiditic deposits. While no differences arise in gastropod density related to rock type (calcareous lateritious material versus siliceous turbiditic deposits), significant differences have been found along a vertical gradient, seeing density increases from the upper intertidal to the upper subtidal level. The associated algal cover seems to be inversely related to the vermetid density. In the upper intertidal, D. cristatum was almost completely covered (about 83%) by a thick layer of encrusting alga N. brassica-florida. In the lower intertidal the encrusting alga disappear but the shells of vermetid gastropods were remarkably colonized by the erected red algae of the “Laurencia complex” (70%) while in the upper subtidal, the vermetid shells were scarcely covered, mainly by other algal species (13%). By comparing present data with those of Sicilian reefs no evidences arise due to the different latitude. Innovative approaches (Remotely Piloted Aircraft Systems technology and fractal geometry) applied to these marine bioconstructions, resulted very effective in mapping and structuring the complexity of the reefs.

Fouling community dominated by <em>Metridium senile</em> (Cnidaria: Anthozoa: Actiniaria) in Bahía San Julián (southern Patagonia, Argentina)

The objective of this study is to provide information about a harbour-fouling community dominated by Metridium senile in southern Patagonia. Several steel tubes from the wharf of Puerto San Julian were extracted to perform repair tasks, allowing the attached benthic community to be studied. Sampling was conducted at three levels: lower intertidal, 3-4 m depth and 6-7 m depth. In the lower intertidal, M. senile had a relative abundance of 43%, the most abundant accompanying species being Perumytilus purpuratus, Mytilus edulis platensis and Aulacomya atra atra . At subtidal level, the anemone showed relative abundances of 64% and 65%, and was accompanied by Monocorophium insidiosum at 3-4 m depth and by polychaetes of families Sabellidae and Syllidae at 6-7 m at depth. In the lower intertidal, epibiosis was more frequent on P. purpuratus, A. atra atra and M. edulis platensis , while in the subtidal, the richness of substrate-organisms increased significantly and the anemone was fixed to A. atra atra, M. edulis platensis, Paramolgula gregaria, Crepipatella dilatata, Austromegabalanus psittacus, Hiatella arctica, Polyzoa opuntia, Pyura sp. and Sabellidae tubes. The ability of M. senile to settle on many different organisms, along with other strategies, makes it a colonizer able to displace other species that could compete with it for substratum. Given the cosmopolitan nature of M. senile , the fact that this species has not been previously reported in the coastal zone of the region, and the results of our study, we discuss the possibility that this sea anemone is an invasive alien species in southern Patagonia, or at least a cryptogenic species.

Can thallus color of red algae be used as an environmental indicator in shallow waters?

Red algae sometimes turn yellow, but few studies have been conducted on the yellowing of subtidal bed-forming species and on the relationship between the color and environmental factors. We examined the seasonal changes in thallus color of macroscopic subtidal red algae and nutrient levels as in shallow waters at two sites: Hirasawa (0 to 3 m in depth) and Okinoshima Island (0 to 6 m in depth), central Pacific coast of Japan from April 2011 to March 2012. Yellowed red algae were found at all depths of the two sites. At Hirasawa, the ratio of yellowed species among the red algae (yellowing ratio, YR) calculated with data on a total of 23 species (3 to 14 species month−1) was high in months in which nitrate nitrogen (NO3-N) was low (1.73 to 2.19 μmol L−1); in months with higher NO3-N (5.91 to 6.01 μmol L−1), YR was 0 but exceptionally high in April probably because of the duration of fine days. At Okinoshima Island, YR calculated with data on a total of 40 species (3 to 22 species month−1) was high from March to July (except May), in which NO3-N was low (0.93 to 2.16 μmol L−1), but low from October to February among the months with higher NO3-N (4.56 to 5.62 μmol L−1). Totally, YR was negatively correlated with nitrate concentrations and NO3-N, which supports the possibility to use the value of YR as an indicator of nitrogen level although attention should also be paid to light conditions.

Benthic diversity and assemblage structure of a north Patagonian rocky shore: a monitoring legacy of the NaGISA project

The rocky shore of Punta Este, Golfo Nuevo (Patagonia, Argentina), was sampled by means of the standardized NaGISA (CoML) protocol, that was aimed to generate biodiversity baseline data in six levels, from high intertidal to 10 m depth. Based on the generated data, we analysed the benthic assemblage structure, species richness, mean abundance and the distribution pattern of invertebrate functional groups, typifying species in each intertidal and subtidal level. The intertidal sampled is exposed to extreme physical conditions higher than any other rocky shore system studied, with air temperature variation of 40°C during the year, maximum winds of 90 km/h and semidiurnal tides of 5 m amplitude; on the other hand subtidal presents less thermal variation (ΔT 10°C throughout the year) and more homogeneous physical conditions. We identified 64 taxa represented by six animal phyla: Mollusca, Arthropoda, Annelida (Polychaeta), Echinodermata, Cnidaria and Nemertea; and three algal phyla: Chlorophyta, Rhodophyta and Heterokontophyta (class: Phaeophyceae). Ordination non-metric multidimensional scaling plots showed three different assemblages in terms of species composition (intertidal, subtidal 1 m level and subtidal 5–10 m levels). The intertidal was represented by suspension feeders, mainly Mollusca. The tiny mussels Brachidontes rodriguezii and Brachidontes purpuratus, and the algae Corallina officinalis dominated the intertidal and promote positive interaction (amelioration), preventing other species from the extreme physical stress. The subtidal was mainly represented by grazers. Our results showed a tendency of suspension feeders to decrease and grazers and predators to increase from high intertidal to subtidal, probably driven by decreasing physical stress. The gastropod Tegula patagonica, the sea urchins Arbacia dufresnii and Pseudechinus magellanicus and the invasive algae Undaria pinnatifida were the most abundant species in 1 m–10 m levels. Based on previous work performed in the region, we hypothesize that the differences registered between intertidal and subtidal levels could be explained in part by an increase in physical stress at the intertidal, with low predation pressure that promotes positive interactions, while in the subtidal the increase in consumers and decrease of physical stress could lead to associational defences. Our results could be useful as baseline data to develop a sustainable network for long-term monitoring of benthic community changes due to anthropogenic activities.

Hydrodynamic response of Thassos Passage (N. Aegean Sea) to Nestos River discharge and meteorological forcing

The hydrodynamic response, in terms of the competitive stratification–destratification processes and the along- and cross-shore circulation in Thassos Passage, was studied. This passage is a narrow and shallow channel, located in the vicinity of Nestos River mouth, connecting the eastern and western Thracian Seas. Stratification-mixing conditions were studied in terms of the water column potential energy anomaly ϕ, and the quantification of the along- and cross-channel dynamic equation terms, utilizing the results of a regional three-dimensional model. Circulation conditions were assessed by separating the tidal and non-tidal seasonal signals recorded from a bottom-mounted ADCP, and cross-correlating residual circulation to the meteorological influence. Results showed that short-term mixing events, produced under strong south-west winds (8–14ms−1), and stratification incidents under high river discharge conditions (>100m3s−1), may alter the potential energy anomaly of the water column with a time-lag of 3–6h. Such ϕ-changes were attributed to the along- and cross-channel advective and straining terms, with significant spatial variability, due to the Thassos Island sheltering effect. The along-channel potential energy anomaly flux was computed heading westwards, having a mean value of 22.5Jm−2s−1. North-northeast winds tend to increase the sub-tidal level in the channel, while south and south-west winds are responsible for its reduction. At the northern part of Thassos Passage, the development of an elongated sandbar enhances frictional effects, favoring the development of a clockwise rotation system, supported further by southern wind events. Cross-correlations of residual flows and wind effects indicated a wind transfer coefficient of 8%, rotating the wind-induced surface flow by 14o rightwards. Overall, the impact of seasonal water column stratification on the water flow of Thassos Passage was limited, due to the reduced Nestos River runoff after its damming.

First record of the sea anemone Anthopleura nigrescens (Cnidaria: Actiniaria: Actiniidae) on the Pacific coast of Central America

We report the first record of the sea anemone Anthopleura nigrescens on the Pacific coast of Central America. Five specimens from Mata Limón (Costa Rica) were collected from rocks of a man-made breakwater at sub-tidal level. Images of live specimens are presented. A map with its worldwide distribution is included and we concluded that this actiniarian can be considered widely distributed in the Indo-Pacific.

Larval development, sensory mechanisms and physiological adaptations in acorn barnacles with special reference to Balanus amphitrite

Barnacles have drawn the attention of many naturalists and often dominate fouling communities. Balanus amphitrite, is a shallow water acorn barnacle capable of inhabiting expanses from supralittoral to subtidal levels, and as an epibiont. Its potential to survive and successfully establish local population is endorsed by various physiological adaptations and larval sensory perceptions. The larval life cycle of this species has both planktrotrophic naupliar and non-feeding cyprid stages. The naupliar energetics has a bearing on the capabilities of cypris larvae to explore surfaces for settlement and also the recruitment success of juveniles. The most complete nervous system in the barnacles is established in the cypris larva. Although there has been considerable research with reference to their settlement and metamorphosis, not much is known about the olfactory, photo and auditory sensory mechanisms with respect to settlement and metamorphosis, which need further attention. Understanding the response of most sensitive life stages of barnacles to environmental changes in intertidal habitats can also serve as important models for understanding the effect of climate change on species distribution.

The effect of energy reserves and cryoprotectants on overwintering mortality in Mercenaria mercenaria notata (Say 1822) at two tidal levels

The objective of this study is to identify possible causes of the high winter mortality noted in juvenile Mercenaria mercenaria notata in eastern Canada. The percentage mortality, shell growth, concentration of energy reserves, and production of cryoprotectant molecules were compared between notata and native quahogs kept at intertidal and subtidal levels. Overwintering mortality of the notata strain reached 47.2% and was 3–9 times higher than that of the native strain. Shell increment was higher in the native than in the notata strain and also at the intertidal than at the subtidal level. The quahogs from the subtidal zone had a higher concentration of protein than those from the intertidal zone in August and April but a lower concentration in February. The notata strain had a lower concentration of lipids and glucose (34.9 and 0.21 mg g−1 dry weight) than the native strain (42.2 and 0.28 mg g−1 dry weight). Thermal hysteresis was detected in none of the quahog groups. High winter mortality in the notata strain seems to be caused, in part, by a lower capacity to stock lipid compared with the native strain. The higher concentration of glucose in the native strain may favour survival in cold water by helping to reduce the freezing point of the animals’ fluids.

Reproduction of Halicarcinus planatus (crustacea, decapoda, hymenosomatidae) in the Deseado River estuary, southwestern Atlantic Ocean

The small spider crab Halicarcinus planatus, is a common resident in the rocky coasts of the Magellanic region in South America. The H. planatus population in the Deseado River estuary differs from other populations of the same species in the spatial segregation of sexes. Between March 2002 and October 2003, samples were taken monthly from the lower intertidal and upper subtidal levels. All crabs captured were females. Additional samplings were carried out at the subtidal level to search for the presence of males. A total of 3,346 females were captured and their relative age was determined. Some of these females were maintained in the laboratory to study the terminal moult and the spawning seasons. The analysis of the ovary development of adolescents (ADO) and mature (MAT) females, and the times when females of different ages appear, when spermatophores are found inside spermathecae, and when post-spawning mortality takes place allowed us to establish the whole reproductive process. Adolescents are impregnated only once before the terminal moult. There are seven or eight spawnings after the moult, with a brief resting period between two successive reproductive seasons. The life span of mature females ranges between 15 and 22 months. Results indicate that the H. planatus population of the Deseado River estuary differs greatly from that of the Kerguelen Islands.

Postlarval development of <i>Halicarcinus planatus</i> females (Crustacea, Decapoda, Hymenosomatidae) in the estuary of the Deseado River, Argentina

This study analyses morphology and morphometric growth changes of Halicarcinus planatus females until their terminal moult, and characterises new juvenile stages. Monthly samples were collected in the estuary of the Deseado River, Santa Cruz Province, Argentina. Crabs were sampled between the mid-intertidal and upper subtidal levels. Intermoult stages were analysed in sub-samples of adolescents and adults, and the presence of epizoic organisms was registered. Juveniles and adults were reared at the laboratory and examined for moult changes. All 3376 crabs caught were females, indicating a clear spatial segregation between sexes. Five juvenile stages (immature 1, 2, 3, 4 and adolescent) and a mature one were recognised on the basis of morphology and morphometry. All immature stages differed in cephalothorax width (CW) and abdomen width (AW). Positive allometry was observed in some juvenile stages and isometry in an immature stage and in mature females. Adolescents and adults encompassed a wide range of sizes, and the considerable size overlap between them suggests an anomalous growth process. Moult staging analysis indicated that adolescents have a high incidence of pre-moult stages in winter, when the terminal moult occurs. The measurements performed in laboratory-reared females indicated no abnormal increases during the moult. The terminal moult occurs within a wide size range, perhaps in association with mating.

Algae-based biotopes of the Azores (Portugal): spatial and seasonal variation

The increasing importance of coastal management created the need for a systematic classification and characterization of marine communities. Accurate quantitative methodologies for rocky shore algae-based biotope definition, were developed and tested on the Islands of São Miguel and Santa Maria (Azores). Shores of both islands were surveyed, covering all rocky substrate types. Biotopes were defined by assessing the associated habitat and species characteristics, using ANOSIM and SIMPER analysis, respectively. A total of ten biotopes were identified. Generally both islands’ biotopes are characterized by the same taxa/ecological categories, in summer and in winter. However, association between these taxa/ecological categories and the shore height at which they occur differs geographically and temporally. There is a generalized gradual succession of taxa/ecological categories from upper intertidal down to deepest subtidal, although geographical differences occur. Diversity is highest at the land–water interface and decreases towards both extremes (upper intertidal and deepest subtidal level). The strongest evidence of seasonal variation occurs at the upper intertidal. The methodology used proves to be effective in broad scale shoreline assessment of biological communities in warm-temperate coastal marine environments, and thus suitable for the purpose it was developed for. As a consequence it should be applied to the remaining islands of the Azorean archipelago as well as to other macaronesian islands, e.g. Madeira and the Canaries.

Soft-Bottom macrobenthic communities of the Vitória Bay estuarine system, South-eastern Brazil

The present work describes and analyses the structure of the macrobenthic epi- and infaunal assemblage of the estuarine system of Vitória Bay, South-eastern Brazil, from January 1998 to June 1999. Replicated sampling at intertidal and subtidal levels was conducted quarterly at ten stations. Intertidal and subtidal sediment composition was characterised. Water physico-chemical parameters were measured in situ. A total of 10,695 individuals, belonging to 144 taxa, were collected. Molluscs, crustaceans and polychaetes were the most abundant groups. The bivalves Anomalocardia brasiliana, Mytella guyanensis and M. falcata were the most abundant species. Locally, significant discharges of residential and industrial wastewater resulted in high organic content in the sediment (up to 30%) and low dissolved oxygen concentration in the water (< 1mg.l-1). Near the two entrances of the bay, high hydrodynamic activity and coarse sand reduced the detrimental effects of raw and treated sewage inputs. Species richness (S), diversity (H') and total abundance (A) decreased from outer-bay stations (22 < S < 72; 1.99 < H' < 2.85; 320 < A < 1737) towards inner-bay stations (2 < S < 45; 0.59 < H' < 2.67; 2 < A < 1317), where salinity and dissolved oxygen were lowest and organic matter content highest.

Colonization potential of the genus Ulva (Chlorophyta, Ulvales) in Comodoro Rivadavia Harbor (Chubut, Argentina)

Temporal and spatial changes in the coverage of five Ulva L. species (U. prolifera O.F. Müller, U. intestinalis L., U. hookeriana (Kützing) Hayden et al., U. compressa L. and U. linza L.) were analyzed on rocky substrata experimentally immersed in Comodoro Rivadavia Harbor (Argentina). Colonization was studied during an annual period at three levels: upper intertidal, middle intertidal and subtidal. Coverage was significantly higher in the middle intertidal and subtidal levels than in the upper intertidal level, where all species of Ulva were absent. Seasonal changes were also significant: coverage in summer and spring was significantly higher than in autumn and winter. Most species showed high spatial variability among replicates from the same level and season. Zonation patterns within the harbor differed from those observed in natural areas, probably due to low wave exposure and its interaction with herbivory and desiccation stress. Colonization patterns observed in this study indicate nichesegregation in closely related species of the genus Ulva.

Benthic macrofauna in Tasmanian estuaries: scales of distribution and relationships with environmental variables

Information on the distribution of species richness, faunal density, biomass and estimated productivity of benthic invertebrates in Tasmanian estuaries was quantified at a variety of spatial and temporal scales to assess general hypothesis relating community metrics to such environmental variables as salinity, seagrass biomass and sediment particle size. An associated aim was to assess appropriate scales of investigation for soft-sediment biota distributed in estuaries, including whether patterns identified at individual sites, estuaries, tidal levels or times are likely to have more general relevance. Faunal biomass and productivity varied principally at between-estuary (10 to 1000 km) and replicate-sample (1 m) scales, indicating that these two community metrics were largely responding to estuary-wide effects, such as nutrient loading, and to microhabitat features, rather than to locality characteristics at intermediate scales such as salinity, anoxia or sediment particle size. By contrast, faunal density showed greater response to tidal height (1 to 100 m) and to factors distributed at the locality scale within estuary (10 km) than to factors between estuary. Both faunal density and species richness in estuaries declined over three- and fivefold ranges down the shore from high water mark to the shallow sublittoral, while estimated productivity and biomass showed highest overall levels at low water mark. The greatest component of variance in species richness was associated with tidal height, with variance then distributed approximately evenly between other spatial scales examined. At the low-tide and shallow subtidal levels, species richness, faunal biomass and estimated productivity were all highly correlated with salinity and biomass of macrophytes, whereas faunal density was highly correlated with biomass of macrophytes only. Relationships between environmental and biological variables examined were poorly defined at high tidal levels. Seasonal plus interannual variance was much lower than spatial variance—a clear indication that sampling effort in studies would generally be better directed across a range of localities than for a single locality to be repeatedly investigated over time.

Sea-urchin Embryo Bioassay for in situ Evaluation of the Biological Quality of Coastal Seawater

The Paracentrotus lividus sea-urchin embryo bioassay, consisting of incubation of fertilized eggs in test water and measurement of the percentage of four-armed plutei larvae developed after the incubation period (2–3 days), has been adapted for in situ evaluation of seawater quality in coastal areas. Mature sea-urchins are dissectedin situ and fertilization is performed in the field; fertilized eggs are delivered into screw lid 50-ml cylinders with 20μm nylon mesh in both ends filled with sieved local seawater. The cylinders, tied to 60-cm ropes with weights on one end and buoys in the other one, are placed by scuba divers in the test sites at subtidal level and recovered after the incubation period. The contents of each cylinder are then transferred into a vial, fixed with formalin and observed directly under an inverted microscope to record the percentage (N=100) and size (length, N=25) of four-arm pluteus larvae. Our results show that the bioassay can discriminate between well known polluted and unpolluted sites, but further improvement is needed in order to: (1) take into account differences of temperature between sites; (2) minimize larval mortality due to reasons other than pollution.

Phenology of two Acanthophora najadiformis (Rhodophyta, Ceramiales) Populations in the Ionian Sea (Mediterranean Sea)

Both an intertidal and a subtidal population of Acanthophora najadiformis near the Cheradi Islands (Ionian Sea, Mediterranean Sea) were studied in order to know the life cycle of the species and both seasonal variation in plant size and the phenology of reproduction. The proportions of gametophytes, tetrasporophytes and propagule-bearing plants were analysed. Acanthophora najadiformis proved to be a perennial alga present only with the overwintering basal system in winter and spring and well developed fronds in summer and autumn, when it is the dominant species in the subtidal community. Differences in both plant size and reproductive plant number were detected between the intertidal and subtidal levels. In the intertidal zone plants grow faster and reach greater sizes than the subtidal ones; tetrasporophytes and propagule-bearing plants are more numerous than at the subtidal level. In both zones, tetrasporophytes seem to be dominant and propagule-bearing plants are by far the most numerous.

Experimentally induced effects of water temperature and immersion time on reproductive output of bivalves in the Wadden Sea

Results of experiments are reported on the effects of water temperature and immersion time in winter on egg size and egg numbers in three intertidally living bivalves in the Dutch Wadden Sea, the Baltic tellin Macoma balthica, the common cockle Cerastoderma edule and the common mussel Mytilus edulis. Macoma (14–17 mm shell length) produced large eggs (diameter of 107 μm) in relatively small numbers (20 000–70 000) in early spring. Later in spring, Cerastoderma (28–33 mm shell length) produced smaller eggs (77 μm, excluding the surrounding jelly layer) in tenfold larger numbers (200 000–700 000). Mytilus (45–55 mm shell length) spawned even smaller eggs (72 μm) in high (but not easily assessed) numbers over a more extended period. In Macoma egg size was not affected by winter temperatures or immersion time. Effects of winter–spring temperatures and immersion time on egg size could be demonstrated in Cerastoderma. Smaller eggs were produced at the higher temperatures. Effects of immersion time were non-consistent: at lower water temperatures larger, but at higher temperatures smaller eggs were produced by animals kept at longer immersion times. In Mytilus, no temperature effects were observed. However, a longer immersion time resulted in larger eggs. In Macoma as well as in Cerastoderma significantly more eggs were produced at the lower temperature. Immersion time effects were most pronounced at the lower temperature, where more eggs were produced at the subtidal level than at the tidal level. At the higher water temperature differences between egg numbers produced at the two tidal levels were small. Just prior to spawning, egg numbers were strongly positively related to body mass at a certain shell length.

Matching pursuit by undecimated discrete wavelet transform for non-stationary time series of arbitrary length

We describe how to formulate a matching pursuit algorithm which successively approximates a periodic non-stationary time series with orthogonal projections onto elements of a suitable dictionary. We discuss how to construct such dictionaries derived from the maximal overlap (undecimated) discrete wavelet transform (MODWT). Unlike the standard discrete wavelet transform (DWT), the MODWT is equivariant under circular shifts and may be computed for an arbitrary length time series, not necessarily a multiple of a power of 2. We point out that when using the MODWT and continuing past the level where the filters are wrapped, the norms of the dictionary elements may, depending on N, deviate from the required value of unity and require renormalization. We analyse a time series of subtidal sea levels from Crescent City, California. The matching pursuit shows in an iterative fashion how localized dictionary elements (scale and position) account for residual variation, and in particular emphasizes differences in construction for varying parts of the series.