Mediterranean Coastal Ecosystems Research Articles

Crustacean and aquatic insect assemblages in the Mediterranean coastal ecosystems of Emporda wetlands (NE Iberian peninsula)

Crustacean and aquatic insect assemblages in the Mediterranean coastal ecosystems of Emporda wetlands (NE Iberian peninsula)

A preliminary study of an eastern Mediterranean coastal ecosystem: Summer Resorts and Benthic ecosystems

The present study investigates whether coastal benthic communities are affected by tourist activities along the coast, which persist for a limited time period. The analysis of benthic macrofauna is based on the ecological parameters (quantitative analyses) as well as on the ecological identity of the species (qualitative analyses). Microbial contamination and some population statistics are correlated with ecological parameters. The disturbance of benthic communities in the vicinity of summer resorts is summarized by a reduction in species number and dominance of opportunistic species characteristic of disturbed and polluted environments. It is found that community diversity and evenness of distribution decrease with the deterioration of water quality, expressed as grade of microbial contamination, which implies that benthic community is also a significant element in assessing the quality of coastal waters. The above parameters were statistically negatively correlated with the number of tourists.

Comparative analysis of species diversity of Isopoda Oniscidea and Collembola communities in burnt and unburnt habitats in central Italy

The structure and diversity of Isopoda and Collembola communities are described and compared in burnt and unburnt sites occupied by oak and pine forests within a Mediterranean coastal ecosystem in central Italy (near Rome) to assess the effect of fire on these soil arthropods. The community succession, starting just after the fire, proceeded differently in the examined sites, showing distinct ecological responses between Collembola and Isopoda, as evinced by cluster analysis among sites and comparisons of species abundances. The burnt oak forest communities, less damaged by fire, were quite different from the burnt pine forests, which had few species, usually more abundant in individuals. Examining the mean of the whole abundance of each site, particularly in isopods, burnt sites showed greatly reduced values in comparison with unburnt sites. Both springtail and isopod communities of burnt sites showed a continuous turnover, evidenced by both temporally restricted species and temporal variations in species richness determined by post‐fire recolonisation. The species succession produced disequilibria of monthly and yearly abundances, which interacted with monthly variations in community structure determined by meteorological factors. The community structure stabilisation in burnt ecosystems during the succession is also demonstrated by the increasing of Shannon diversity and evenness values, particularly in Collembola. On the basis of temporal values of species richness and Shannon diversity values recorded for each site, two main patterns can be recognised: (1) oak forests were more diverse than pinewoods, and (2) unburnt sites were temporally more diverse than the burnt ones, because they host communities mostly subject to seasonal changes, especially due to some variations in humidity, rainfall and temperature. Burnt habitats tended to change their species composition more drastically, without any clear relationship with seasonally, because of the interaction of recolonisation with seasonal replacing of species, which determine a greater value of final “entropy”, as observed by the total annual values of Shannon diversity.

Islands, Exotic Herbivores, and Invasive Plants: Their Roles in Coastal California Restoration

Abstract The Pacific islands off southern California, U.S.A. and Baja California, Mexico hold potential for the conservation and restoration of California Mediterranean coastal ecosystems. However, the presence of exotic herbivores and invasive plants pose threats to these systems. Here, we use introduced herbivore removal as a large‐scale experimental manipulation to examine the importance of top‐down and bottom‐up processes to a large‐scale restoration effort. Using a paired approach on the Todos Santos Islands, Mexico we removed herbivores from one island, while they temporarily remained on an adjacent and similar island. We augmented this experiment with smaller scale herbivore exclosures on the control island. At both scales we failed to detect an herbivore effect on the plant community; rather plant community dynamics appeared to be dominated by El Niño related precipitation and exotic annuals. A parallel experiment on the San Benito Islands, Mexico revealed a different dynamic: Top‐down effects on the plant community by exotic herbivores were evident. Differences in the response from the plant communities to both exotic herbivore presence and removal between these two island groups, along with Santa Barbara Island, U.S.A., where restoration has been on‐going, raise important questions in ecosystem restoration. The history of anthropogenic disturbance, exotic plant abundance, and aridity play roles in postherbivore removal recovery. Although island conservation practitioners have honed the ability to remove exotic mammals from islands, development of invasive plant removal techniques is needed to fully capitalize on the conservation potential of California island ecosystems.

The effects of a strong winter storm on physical and biological variables at a shelf site in the Mediterranean

A survey involving both permanent mooring and high frequency sampling was carried in the Bay of Banyuls-sur-Mer during the fall of 1999 to assess the effect of strong and unpredictable meteorological events on the functioning of a coastal Mediterranean ecosystem. A severe winter storm took place on 12 November, which generated waves with a significant height of 7 m and a sea surface rise of about 0.5 m. The near-bottom current speed at 24 m reached 30 cm s –1. This storm induced a significant increase in total suspended matter through resuspension and then a subsequent increase in gross sedimentation rates. It also resulted in an increase of the proportion of refractory particulate organic matter in the water column. It also tended to increase nutrient availability in the water column through resuspension and desorption processes. The kinetic of this increase differed among nutrients. Bacterial biomass and production were significantly enhanced by the storm. These effects were transitory and probably not due to resuspension alone. The distribution of plant pigments was modified at the immediate vicinity of the water-sediment interface due to differential resuspension and sedimentation but the storm had no effect on integrated phytoplanktonic biomass. Such a lack of response may be linked to low precipitations and/or light limitation. The storm resulted in a transitory increase of the abundance of fine particles at the water-sediment interface. These particles were coated with refractory organic matter. The storm induced a significant decrease of meiofauna abundance. The duration of the relaxation periods varied among parameters. It lasted 2 weeks for total suspended matter, surface sediment granulometry and carbohydrate contents.

Vegetation composition and soil salinity in a Spanish Mediterranean coastal ecosystem

An analysis is made of vegetation and edaphic features along a catena in a protected marshland area near Castellon, Spain. Vegetation was studied using the Braun- Blanquet approach followed by multivariate data analysis. This paper describes 17 coastal plant communities belonging to the following classes: Thero-Suaedetea, Salicornie- tea fruticosae, Juncetea maritimi, Potametea, Charetea, Phragmito-Magno- caricetea, Cakiletea maritimae, Ammophiletea, Rosmarinetea officinalis and Quercetea ilicis. Primary Correspondence Analysis (CA) distingished marshland, dune and aquatic habitats. Further Correspondence Analysis separated the main syntaxo- nomical units. Canonical Correspondence Analysis (CCA) related plant distribution with the electrical conductivity of the soils and the amount of Na+ and K+.

The Tenebrionidae (Coleoptera) of a Tyrrhenian coastal area: diversity and zoogeographical composition

Biogeographia vol. XXIII - 2002 (Pubblicato il 1° ottobre 2002) Biogeografia degli ambienti costieri The Tenebrionidae (Coleoptera) of a Tyrrhenian coastal area: diversity and zoogeographical composition SIMONE FATTORINI Dzpaifimento di Biologizz Animzzlc e a’e[[’U0mo (Zoologia), Uni:/erritfz di Roma qLa Szzpz'mzzz”, Vizzle de[l’Uniz/em'tz‘z 32, [—00]85 Roma (Italy) Key words: tenebrionid beetles, biogeography, ecology, Mediterranean, Central Italy, Castelfusano SUMMARY The family Tenebrionidae represents an important faunal component of Mediterranean coastal ecosystems. Until a recent fire Ouly 2000), which unfortunately destroyed large sectors of an introduced pine forest, the protected area of Castelfusano (about 1000 hectares, near Rome, Latium) was a Tyrrhenian coastal site where psammophilous vegetation, maquis, oak forests, hygrophilous forests, and an introduced pine forest occurred. The aim of this work was: (1) to provide a flunal inventory of the tenebrionids of Castelfusano before fire, and (2) to analyse this fauna from both an ecological and a zoogeographical point of view. A total of 29 tenebrionid species, belonging to three main ecological guilds, were recorded: (1) sand dwelling species inhabiting the beach—dune system; (2) geophilous species of maquis and open areas; (3) xylophilous species, especially associated with the pine forest. Based on their general distribution, the tenebrionid beetles ofCastelh1sano can be grouped into eight chorological categories. As to the environmental Factors responsible for this chorological spectrum, a relationship can be observed between species ranges and ecological preferences. In accordance with the Tyrrhenian location of the study area, most of the species appear to be more or less widely distributed in the Mediterranean basin, with a high proportion of West Mediterranean and S—European elements. Species with such types of distribution are also typically thermophilic species. Therefore, the climate of the study area, favouring species with thermophilic preferences, can be responsible for a high incidence of species with such ranges. Species with more northern distributions are relatively scarce, including some euryoecious or xylophilous elements. The presence of species with such ranges can be related to the occurrence of patches of mesophilic vegetation in the study area. Most probably, such species largely colonised Italian coastal areas during Pleistocene glaciations. As the climate became drier and warmer, d‘l€SE species were forced to assume more northern distributions. However, isolated populations were able to survive also in areas like Castelfusano, where favourable habitats persisted. Therefore, these relict populations are a result of vicariance events determined by the fragmentation of Pleistocene mesophilic habitats. Most of the species recorded for the forest vegetation of Castelfusano also occurs in the adjacent Presidential Estate of Castelporziano, a large and wellfipreserved area. Therefore, Castelporziano will operate as a source area for the renebrionid colonisation of the Castelfusano area destroyed by fires if favourable habitats will be restored. INTRODUCTION The family Tenebrionidae represents a conspicuous faunal component of arid and semi—arid environments, and the importance of these beetles in Mediterranean

Phytoplankton Blooms in Black Sea and Mediterranean Coastal Ecosystems Subjected to Anthropogenic Eutrophication: Similarities and Differences

The similarities and differences in phytoplankton response to anthropogenic nutrient enrichment were studied in coastal sites of the Western Black Sea and the Eastern Mediterranean (Aegean Sea). Although by physico-chemical parameters, two different environments have been compared, the two regions exhibited similar features: 14 common bloom species in the list of bloom producing algae, the highest rate of occurrence and variety of microalgae involved in summer, the highest average level of competitors-strategies species during the summer outbursts, the similar range of maximum bloom densities attained, and similar capacity to sustain critical biomass during all seasons. The low taxonomic similarity (Bray-Curtis index lower than 30%) between the different basins and among sites, could be attributed to both natural factors and dissimilarities and to the gradients in nutrient levels and their ratios, as affected by the different nature and severity of the anthropogenic pressures on the coastal ecosystems. The results of the PCA analysis indicate that temperature and salinity are factors contributing to the differences outlined between the Aegean Sea and the Black Sea ecosystems, but the differences among the selected sites give support to the importance of nutrients and their ratios. Although competitive outcomes in phytoplankton species selection and succession cannot yet be predicted, the analysis suggests that anthropogenic nutrient enrichment could play an important role in driving the phytoplankton bloom performance. The comparative studies between different basins could be a step forward to highlight common patterns and modes of ecosystem response to anthropogenic eutrophication and to suggest common indices to scale eutrophication impact.

Detrital stocks and dynamics of the seagrass Posidonia oceanica (L.) Delile in the Spanish Mediterranean

Previous studies have shown that most leaf production (>90%) of the seagrass Posidonia oceanica is shed after senescence and that a substantial percentage (up to 80%) may thereafter be exported off the seagrass meadows by waves and currents. It has also been reported that P. oceanica meadows can accumulate large stocks of belowground detritus due to slow decomposition rates. However, the generality of these results across broad spatial scales is poorly known. In this report, we examine the fate of leaf production and the magnitude and dynamics of belowground detritus in 16 P. oceanica meadows distributed along the Spanish Mediterranean. Herbivores removed a small percentage of leaf production in all the meadows (≤13%), with most leaf production (>85%) being shed after senescence. Most shed leaves (>90%) were exported off the meadows by physical agents, such as waves and currents. The amount of belowground detritus stored within 10–15 cm from the sediment surface varied from ca. 70 to 7500 g DW m −2 among the meadows examined, and they accumulated at rates ranging from ca. 65 to 650 g DW m −2 per year. These values are large when compared to other communities of aquatic and terrestrial macrophytes. Our results show that P. oceanica meadows in the Spanish Mediterranean support high values of secondary production in other systems by exporting large amounts of leaf detritus as well as acting as substantial carbon sinks by accumulating large reservoirs of belowground detritus. Therefore, the increasing anthropogenic threats on P. oceanica could entail an important loss of secondary production and carbon storage in Mediterranean coastal ecosystems.

Phosphate, nitrogen and iron enrichment in the polluted Izmir Bay, Aegean Sea

Izmir Bay is one of the most polluted estuaries in the Mediterranean Sea. The extent of pollution due to anthropogenic inputs in the Izmir Bay is investigated on the basis of nutrients together with basic oceanographic parameters. Significant phosphate, nitrogen (N) and iron (Fe) enrichment has been found in the water of inner Izmir Bay. The situation of middle Izmir Bay is also similar but not as critical as in inner Izmir Bay, whereas outer Izmir Bay shows ‘typical Mediterranean coastal marine ecosystem’ characteristics. The average atomic ratios of apparent oxygen utilization (AOU) and nutrient fractions (N and phosporous [P]) have been found as AOU:P (49:1), AOU:N (48:1) and N:P (5:1). A comparative evaluation of these ratios leads to the conclusion that they are too low; e.g. such a low AOU:P ratio supports fairly high P enrichment. Principal component analysis (PCA) indicates that 31% of the variation in the data is related to enrichment parameters, i.e. dissolved inorganic phosphate, NH 4 +, reactive Fe, 15% is related to NO 3 −, pH and 13% is related to temperature and total Fe. Additionally, PCA shows that the middle Izmir Bay has an ecological transient character between the inner and outer Izmir Bay.

106th congress: Who will be the key players?

Harmful events associated with epibenthic dinoflagellates, have been reported more frequently over the last decades. Occurrence of potentially toxic benthic dinoflagellates, on the leaves of two magnoliophytes (Cymodocea nodosa and Zostera noltei) and thalli of the macroalgae (Ulva rigida), was monitored over one year (From May 2015 to April 2016) in the Bizerte Bay and Lagoon (North of Tunisia, Southern Mediterranean Sea). The investigated lagoon is known to be highly anthropized. This is the first report on the seasonal distribution of epibenthic dinoflagellates hosted by natural substrates, from two contrasted, adjacent coastal Mediterranean ecosystems. The environmental factors promoting the development of the harmful epibenthic dinoflagellates Ostreopsis spp., Prorocentrum lima and Coolia monotis were investigated. The highest cell densities were reached by Ostreopsis spp. (1.9 × 103 cells g−1 FW, in October 2015), P. lima (1.6 × 103 cells g−1 FW, in June 2015) and C. monotis (1.1 × 103 cells g−1 FW, in May 2015). C. nodosa and Z. noltei were the most favorable host macrophytes for C. monotis (in station L2) and Ostreopsis spp. (in station L3), respectively. Positive correlations were recorded between Ostreopsis spp. and temperature. Densities of the epibenthic dinoflagellates varied according to the collection site, and a great disparity was observed between the Bay and the Lagoon. Maximum concentrations were recorded on C. nodosa leaves from the Bizerte Bay, while low epiphytic cell abundances were associated with macrophytes sampled from the Bizerte Lagoon. The observed differences in dinoflagellate abundances between the two ecosystems (Bay-Lagoon) seemed not related to the nutrients, but rather to the poor environmental conditions in the lagoon.

Spatial and temporal trends of paraquat, diquat, and difenzoquat contamination in water from marsh areas of the valencian community (Spain)

The levels and distribution of diquat, paraquat, and difenzoquat were determined by solid phase extraction (SPE) and high-performance liquid chromatography (HPLC) in water samples from irrigation channels, rivers, and lagoons taken during 1 year from three different marsh areas of the Valencian community. These areas are representative of the typical Mediterranean coastal ecosystems. All three compounds were detected. Diquat was found most frequently at all the sampling sites. Although the spatial distribution of diquat and paraquat showed a maximum concentration near the fields where they were originally applied, their location fluctuated due to irregular large spill and/or loading. The herbicide concentration tended to be highest during the summer (June, July, and August) because these are the months with the least rainfall and highest evaporation rates, when weeds grow best and pesticides are needed more often. The average concentration found for diquat was 0.09 &mgr;g/L, with a maximum of 3.10 &mgr;g/L. The average concentration for paraquat was 0.01 &mgr;g/L, with a maximum of 3.95 &mgr;g/L. Samples that were below the method detection limit are included in the mean calculation as zero. Difenzoquat was only detected in one sample at a concentration of 1.75 &mgr;g/L.

In situ bioturbation and hydrocarbon fate in an experimental contaminated Mediterranean coastal ecosystem

An in situ experiment was conducted in the French Mediterranean littoral (Gulf of Fos) from July 1992 to January 1993 using cores containing defaunated or natural sediment. Particulate tracers (luminophores) and hydrocarbons (Arabian Light crude oil) were deposited at the sediment surface. After 1, 4 and 6 months, luminophore and hydrocarbon (saturated fraction) distribution patterns in the sedimentary column were studied. After 6 months, in presence of bioturbation, 23.7 % of the luminophores and 14.2 % of the hydrocarbons initialy deposited were buried, down to depths of 10 cm and 6 cm depth respectively. Hydrocarbons were biodegraded both at the surface and within the sediment.

Composition and metabolizable energy of feed used by fallow deer ( Dama dama) in a coastal Mediterranean ecosystem

Data on the impact of a population of about 1000 (spring estimate) fallow deer ( Dama dama) on eight shrubs and mono- and dicotyledonous plants were collected in a coastal Mediterranean environment from December 1990 to March 1992. Four species of shrubs ( Cistus salvifolius, Phillyrea latifolia, Rubus ulmifolius, Quercus ilex) and mixed graminoids were preferentially consumed. In autumn-winter the acorns of several species, Q. cerris and Q. ilex in particular, were also consumed. We determined the chemical composition, in vivo digestibility coefficients and metabolizable energy content of the feed. On average, R. ulmifolius had the lowest fibre content (18% DM) and the highest protein content (12% DM), organic matter digestibility (59%) and metabolizable energy value (2083 kcal ME kg −1 DM). C. salvifolius, P. latifolia and mixed graminoids did not differ significantly in organic matter digestibility (OMD) and nutritive value (1801, 1765 and 1557 kcal ME kg −1 DM, respectively), while Q. ilex had the lowest nutrient estimates with 32% OMD and 1362 kcal ME kg −1 DM. Forage quality traits usually peaked in spring and autumn. Metabolizable energy was positively correlated with protein, neutral detergent fibre and N-free extractives contents, and negatively correlated with the acid detergent fibre content. Acorns were generally highly digestible; in particular, the seed of Q. farnia and Q. ilex showed 80% and 83% OMD, respectively. In a Mediterranean environment the summer seems the most critical season for fallow deer. The results of this work are important for assessing the carrying capacity of wild Mediterranean ecosystems for fallow deer.

The effects of bioturbation on particle redistribution in Mediterranean coastal sediment. Preliminary results

In order to quantify bioturbation processes in a coastal Mediterranean ecosystem, experiments were performed to determine sediment mixing rates resulting from macrobenthos activity. Particle flux was measured in situ for 22 days using luminophores, which are colored sediment particles with sizes ranging from 10 to 200 µm.

A pelagic ecosystem model simulating production and sedimentation of biogenic particles: role of salps and copepods

Production and sedimentation of biogenic particles are investigated by a depth-dependent model of a Mediterranean coastal pelagic ecosystem during spring. The model considers living and dead phytoplankton (chiefly diatoms) and its sedimentation, 2 herbivores, salps and copepods, and sedimentation of their fecal pellets and carcases; a sediment trap is assumed to be set up at 200 m depth. Results underline the major role played by fecal pellets and by both living and dead salps in vertical matter flux. Fecal pellets of salps and copepods constitute 65 % of the material in the trap after a 40 d simulation period. Although salp and copepod biomasses are similar, the magnitude and composition of the particle flux are much more influenced by salps than by copepods: salp fecal pellets and carcases account for 72 % of the maximum overall flux. The fluxes calculated by this model are in good agreement with those generally recorded in the field: at 200 m depth, up to 72.3 mgC m 2 d ' and a mean of 44.7 mgC m 2 d over 40 d.

Modelling the distribution of radionuclides in a Mediterranean coastal ecosystem

The present paper deals with the modelling process in relation to the class of well-mixed compartment models (box models). A box model has been described and tested for radionuclides released by a BWR Nuclear Power plant (2 × 1000 MWe; under construction at Montalto di Castro, Central Italy) into the Tyrrhenian Sea. The model predicts the radionuclide transport between the most important components of the coastal marine ecosystem (water, pore-water, sediments and biota), but only the possibility of determining radionuclide concentrations associated with abiotic components is discussed. In the context of modelling, the requirements for information concerning the behaviour of radionuclides in a coastal ecosystem are discussed, with reference to chemical, physical and biological considerations. A validation for the radionuclide transport model was made using literature data on the Sellafield (Windscale) site. The major sources of uncertainty in the model were evaluated by sensitivity analysis and parameter imprecision analysis using site-specific parameter values obtained at Montalto di Castro.

Composition chimique �l�mentaire (C, H, N) et �quivalent �nergie d'Acartia clausi (Crustacea: Copepoda), esp�ce importante dans la bio�nerg�tique des �cosyst�mes c�tiers de M�diterran�e nord-occidentale

Carbon, hydrogen and nitrogen content were investigated in natural populations of the crustacean copepod Acartia clausi collected during 1980–1982 from different areas near Marseilles, France — the coastal area of Cortiou which receives waste waters from the Marseilles Conurbation; the eutrophic and polluted Golfe de Fos, with its open basins; and the offshore areas of the Marseilles' Gulf. Energy equivalents were determined in order to examine the ecological role of A. clausi from a bioenergetic point of view. Carbon content ranged from 38.9% of body dry weight (DW) in the open sea off Marseilles to 45.5% of DW in an open basin at Fos in winter, nitrogen content from 10.4% of DW in the open sea off Marseilles in winter to 13.6% of DW in the open basins at Fos in summer. These values agree with the ranges reported in the literature for non-lipidic copepods. Carbon to nitrogen ratios ranged between 3.22 and 3.80. In the open basins at Fos, the mean value in summer (3.30) was significantly different from that in winter (3.70). In the Cortiou area, no seasonal differences emerged. For the three areas, energy equivalents ranged from 4.28 to 5.00 cal mg-1 DW. Highest values were recorded for the populations of the Cortiou area and of the open basins at Fos, i.e., from environments where particulate organic matter is abundant and relatively invariable. In these populations, the energy equivalent per unit dry weight did not change significantly throughout the year. The values recorded agreed with the means reported in the literature for non-lipidic species, but were far below those recorded for species which are able to store lipids. A. clausi is one of the most abundant copepod species throughout the year in the plankton of these coastal areas, and its steady energy content, with little seasonal variation, makes it an important element in the bioenergetics of the northwest Mediterranean coastal ecosystems.

Unesco reports in marine science 20: Quantitative analysis and simulation of Mediterranean coastal ecosystems: The Gulf of Naples, a case study.–158 pp. Paris: Unesco 1983

Internationale Revue der gesamten Hydrobiologie und HydrographieVolume 70, Issue 2 p. 308-308 Book Review Unesco reports in marine science 20: Quantitative analysis and simulation of Mediterranean coastal ecosystems: The Gulf of Naples, a case study.–158 pp. Paris: Unesco 1983 H. Caspers, H. CaspersSearch for more papers by this author H. Caspers, H. CaspersSearch for more papers by this author First published: 1985 https://doi.org/10.1002/iroh.19850700240AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume70, Issue21985Pages 308-308 RelatedInformation

Biogeochemical processes affecting the distribution and vertical transport of hydrocarbon residues in the coastal Mediterranean

Sediments, sediment trap material, dominant surface plankton and collected fecal material were sampled concurrently with surface seawater in a coastal Mediterranean ecosystem and analyzed for non-volatile hydrocarbons and chlorinated hydrocarbons. Results showed consistent partitioning of hydrocarbon classes between dissolved and particulate phases of surface waters which appeared to be related to component solubility and particle availability. Analysis of biological materials showed the biota were important not only in packaging residues into large, fast sinking particles, but also in modifying the composition of components through metabolism and selective incorporation into body tissues and feces. Apparent sedimentation rate was calculated by analysis of 210Pb in sediment core samples and used to estimate average deposition rates of organics to the sea/sediment interface. The flux of particles through 100 m, as measured in the trap material in this sampling interval, was sufficient to balance most of the petroleum input to the sediments but accounted for only 17% of the average flux of PCBs to the sediments, and virtually none of the more soluble chlorinated hydrocarbon flux. Vertical transport via large fecal material compared to average background particles was seasonally low corresponding to a seasonal minimum in plankton biomass in late summer. Results show that hydrocarbon residues transported long distances away from input sources are highly modified, pointing to the geochemical significance of physical-chemical partitioning between seawater phases, incorporation into organisms and fecal material and biological/chemical degradation.