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Ecological flows across ecosystem boundaries are typically studied at spatial scales that limit our understanding of broad geographical patterns in ecosystem linkages. Aquatic insects that metamorphose into terrestrial adults are important resource subsidies for terrestrial ecosystems. Traits related to their development and dispersal should determine their availability to terrestrial consumers. Here, we synthesize geospatial, aquatic biomonitoring and biological traits data to quantify the relative importance of several environmental gradients on the potential spatial and temporal characteristics of aquatic insect subsidies across the contiguous United States. We found the trait composition of benthic macroinvertebrate communities varies among hydrologic regions and could affect how aquatic insects transport subsidies as adults. Further, several trait–environment relationships were underpinned by hydrology. Large bodied taxa that could disperse further from the stream were associated with hydrologically stable conditions. Alternatively, hydrologically variable conditions were associated with multivoltine taxa that could extend the duration of subsidies with periodic emergence events throughout the year. We also found that anthropogenic impacts decrease the frequency of individuals with adult flight but potentially extend the distance subsidies travel into the terrestrial ecosystem. Collectively, these results suggest that natural and anthropogenic gradients could affect aquatic insect subsidies by changing the trait composition of benthic macroinvertebrate communities. The conceptual framework and trait–environment relationships we present shows promise for understanding broad geographical patterns in linkages between ecosystems. [ABSTRACT FROM AUTHOR]

In marine benthic habitats, structural complexity is positively associated with diversity, and the area of hard surfaces modulates community structure. These principles are well developed on tropical coral reefs, where stony corals create complex surfaces that are favored for settlement. This study explores the relationship between substratum orientation and the distribution of arborescent octocorals on shallow reefs (< 10-m depth) in St. John, U.S. Virgin Islands. To test the hypothesis that octocorals are distributed unequally among microhabitats, their abundance on vertical, horizontal, and inclined substrata (i.e., different microhabitats) was measured. To evaluate whether octocorals were crowded in favored microhabitats, the shortest distance between pairs of octocoral was compared among microhabitats, and the consequences of microhabitat location were evaluated by measuring colony sizes for Gorgonia ventalina . The most common octocorals were G . ventalina , Eunicea spp., and Antillogorgia spp., and these taxa were distributed unequally among microhabitats, even though the microhabitats were equally abundant. Relative to a random distribution among microhabitats, more G . ventalina than expected was found on vertical substrata, more Antillogorgia spp. was found on horizontal substrata, and more Eunicea spp. was found on vertical substrata. On horizontal and inclined substrata, the mean distance between G . ventalina and the nearest octocoral was 25 ± 4 cm, but on vertical substrata, this distance was 8 ± 2 cm; most of the nearest neighbors to G . ventalina were Eunicea spp. on vertical substrata, and the mean distance between these colonies was 5 ± 1 cm (all ± SE). There was no difference in size of G . ventalina among microhabitats, suggesting that adult success was unrelated to microhabitat for this species. Together, these results show that most arborescent octocorals favor vertical substrata on the shallow reefs of St. John, and because of this preference, colonies are more crowded on vertical versus horizontal or sloping substrata. [ABSTRACT FROM AUTHOR]

The Bedford springsnail ( Pyrgulopsis bedfordensis) is one of only 2 species of the genus Pyrgulopsis discovered east of the northern Continental Divide and appears restricted to one spring in central Montana. Due to its endemism, this species was placed on the Montana Species of Concern list as S1, critically imperiled. Despite the snail's rarity, nothing was known of this population's characteristics; it was last sampled in 1999. In 2015, I quantitatively sampled this population using a Hess sampler ( n = 3) over a 40-m reach to determine the snail's benthic density and describe the associated macroinvertebrate community. Average densities of the springsnail were 30,540 live individuals per m2 (SE 2625) and 17,353 empty shells per m2 (SE 1389). Other benthic macroinvertebrates collected with the springsnail (11 taxa [SE 1.5]) were comparatively low in abundance, averaging 1533 individuals per m2 (SE 274). The Bedford springsnail population density at this Montana site ranks among one of the highest reported among its conspecifics. [ABSTRACT FROM AUTHOR]

Western Atlantic synodontid species were studied as part of an ongoing effort to reanalyze Caribbean shorefish diversity. A neighbor-joining tree constructed from cytochrome c oxidase I (COI) data revealed 2 highly divergent genetic lineages within both Synodus inter- medius (Agassiz, 1829) (Sand Diver) and S. foetens (Linnaeus, 1766) (In-shore Lizardfish). A new species, Synodus macrostigmus, is described for one of the S. intermedius lineages. Synodus macrostigmus and 5. intermedius differ in number of lateral-line scales, caudal pigmentation, size of the scapular blotch, and shape of the anterior-nostril flap. Synodus macrostigmus and S. intermedius have overlapping geographic and depth distributions, but S. macrostigmus generally inhabits deeper water (>28 m) than does S. intermedius and is known only from coastal waters of the southeastern United States and the Gulf of Mexico, in contrast to those areas and the Caribbean for S. intermedius. Synodus bondi Fowler, 1939, is resurrected from the synonymy of S. foetens for one of the S. foetens genetic lineages. The 2 species differ in length and shape of the snout, number of anal-fin rays, and shape of the anterior-nostril flap. Synodus bondi and S. foetens co-occur in the central Caribbean, but S. bondi otherwise has a more southerly distribution than does S. foetens. Redescriptions are provided for S. intermedius, S. foetens, and S. bondi. Neotypes are designated for S. intermedius and S. foetens. A revised key to Synodus species in the western Atlantic is presented. [ABSTRACT FROM AUTHOR]

Toxicity-based sediment quality guidelines (SQGs) are often used to assess the potential of sediment contamination to adversely affect benthic macrofauna, yet the correspondence of these guidelines to benthic community condition is poorly documented. This study compares the performance of 5 toxicity-based SQG approaches to a new benthos-based SQG approach relative to changes in benthic community condition. Four of the toxicity-based SQG approaches-effects range median, logistic regression modeling (LRM), sediment quality guideline quotient 1 (SQGQ1), and consensus-were derived in previous national studies in the United States, and one was developed as a regional variation of LRM calibrated to California data. The new benthos-based SQG approach, chemical score index, was derived from Southern California benthic community data. The chemical-specific guidelines for each approach were applied to matched chemical concentration, amphipod mortality, and benthic macrofauna abundance data for Southern California. Respective results for each SQG approach were then combined into a summary metric describing the overall contamination magnitude (e.g., mean quotient) and assessed in accordance with a set of thresholds in order to classify stations into 4 categories of expected biological effect. Results for each SQG approach were significantly correlated with changes in sediment toxicity and benthic community condition. Cumulative frequency plots and effect category thresholds for toxicity and benthic community condition were similar, indicating that both types of effect measures had similar sensitivity and specificity of response to contamination level. In terms of discriminating among multiple levels of benthic community condition, the toxicity-based SQG indices illustrated moderate capabilities, similar to those for multiple levels of toxicity. The National LRM, California LRM, and the chemical score index had the highest overall agreement with benthic categories. However, only the benthos-based chemical score index was consistently among the highest performing SQG indices for all measures of association (correlation, percent agreement, and weighted kappa) for both toxicity and benthos. Integr Environ Assess Manag 2012; 8: 610-624. © 2011 SETAC [ABSTRACT FROM AUTHOR]

Hydroids are a species-rich component of the benthic fauna inhabiting deep, cold-water coral habitats. Fertile colonies of the leptothecate species Halecium macrocephalum Allman, 1877 collected from cold-water coral habitats off the southeastern USA exhibited morphologically peculiar male gonophores, distinct from those described and illustrated for the holotype. We redescribe H. macrocephalum based on this new material, and consider the gonophores of the holotype to be either damaged or immature. Following re-examination of non-type material (the holotype being lost), we characterize H. macrocephalum as a strictly subtropical western North Atlantic bathyal species, occurring between North Carolina and Florida, the Straits of Florida inclusive of the Bahamas, and the eastern Gulf of Mexico including the Tortugas. This study also provides a taxonomic distinction between H. macrocephalum and its morphologically similar Southern Ocean congener, Halecium jaederholmi Vervoort, 1972. [ABSTRACT FROM AUTHOR]

Abstract: This study shows that spatially and temporally recurring benthic macrofauna–habitat patterns validate the ecological relevance of habitat types to benthic macrofauna and suggest they can serve as elements in ecological periodic tables of benthic macrofaunal usage. We discovered patterns across nine habitat types (intertidal eelgrass [Zostera marina], dwarf eelgrass [Zostera japonica], oyster [Crassostrea gigas] ground culture, burrowing mud shrimp [Upogebia pugettensis], burrowing ghost shrimp [Neotrypaea californiensis], shell, sand, mud, and subtidal) on a variety of benthic macrofaunal community state variables in Grays Harbor, Washington, USA and compared them to those in Willapa Bay, Washington, USA. There were nominal differences in benthic macrofaunal Bray–Curtis similarity between all the habitats investigated except eelgrass and oyster in both estuaries. Across-habitat patterns on mean benthic macrofaunal species richness, abundance, biomass, abundance of deposit, suspension and facultative feeders, a dominance and a diversity index for the five habitats common to both studies were the same on a rank measurement scale: eelgrass ≈ oyster > mud shrimp > ghost shrimp ≈ subtidal. The patterns for most of the habitats and benthic macrofaunal measures were the same on a ratio measurement scale. [Copyright &y& Elsevier]

The benthic macroinvertebrate community of East Fork Poplar Creek (EFPC) in East Tennessee was monitored for 18 years to evaluate the effectiveness of a water pollution control program implemented at a major United States (U.S.) Department of Energy facility. Several actions were implemented to reduce and control releases of pollutants into the headwaters of the stream. Four of the most significant actions were implemented during different time periods, which allowed assessment of each action. Macroinvertebrate samples were collected annually in April from three locations in EFPC (EFK24, EFK23, and EFK14) and two nearby reference streams from 1986 through 2003. Significant improvements occurred in the macroinvertebrate community at the headwater sites (EFK24 and EFK23) after implementation of each action, while changes detected 9 km further downstream (EFK14) could not be clearly attributed to any of the actions. Because the stream was impacted at its origin, invertebrate recolonization was primarily limited to aerial immigration, thus, recovery has been slow. As recovery progressed, abundances of small pollution-tolerant taxa (e.g., Orthocladiinae chironomids) decreased and longer lived taxa colonized (e.g., hydropsychid caddisflies, riffle beetles, Baetis). While assessments lasting three to four years may be long enough to detect a response to new pollution controls at highly impacted locations, more time may be needed to understand the full effects. Studies on the effectiveness of pollution controls can be improved if impacted and reference sites are selected to maximize spatial and temporal trending, and if a multidisciplinary approach is used to broadly assess environmental responses (e.g., water quality trends, invertebrate and fish community assessments, toxicity testing, etc.). [ABSTRACT FROM AUTHOR]

Abstract: Benthic macroinvertebrates in lotic habitats are influenced by a wide range of physical and chemical environmental factors that change over a temporal continuum. Within a year, different species can occupy the same space at different points in time. Thus, the community structure itself is in flux from season to season. This study analyzed the structure of a riffle macroinvertebrate community in a single stream from a series of monthly samples over a year cycle. The goals of this study were to: (1) identify community measures that were least variable over the continuum and predict them in test samples from the next year; (2) explore the usefulness of maturity data in analyzing community structure; (3) construct a temporal River Invertebrate Prediction and Classification System like (RIVPACS-like) model that classifies seasons based on biota and predicts an expected community for any season. From a set of 120 metrics, nine metrics representing 5 measurement categories displaying low variability over the annual continuum were selected for multiple regression analysis. The Biotic Index was fairly predictable between years, regardless of season, whereas other measures were less so. Metrics with standard abundances compared to their maturity-weighted analogues revealed that measures based on finer taxonomic resolution or functional groups were more likely to differ. Three biologically determined seasons were identified from cluster analysis during the process of creating a multivariate predictive model. Temporal environmental variables were used to determine test date group membership and comparisons of expected to observed communities revealed that 1 of 3 test dates was predicted well by the model. Our results demonstrate that macroinvertebrate community structures can express high variability over a short period of time and this phenomenon deserves more understanding with regard to interpreting biological assessment results. [ABSTRACT FROM AUTHOR]

Abstract: The successful use of macroinvertebrates as indicators of stream condition in bioassessments has led to heightened interest throughout the scientific community in the prediction of stream condition. For example, predictive models are increasingly being developed that use measures of watershed disturbance, including urban and agricultural land-use, as explanatory variables to predict various metrics of biological condition such as richness, tolerance, percent predators, index of biotic integrity, functional species traits, or even ordination axes scores. Our primary intent was to determine if effective models could be developed using watershed characteristics of disturbance to predict macroinvertebrate metrics among disparate and widely separated ecoregions. We aggregated macroinvertebrate data from universities and state and federal agencies in order to assemble stream data sets of high enough density appropriate for modeling in three distinct ecoregions in Oregon and California. Extensive review and quality assurance of macroinvertebrate sampling protocols, laboratory subsample counts and taxonomic resolution was completed to assure data comparability. We used widely available digital coverages of land-use and land-cover data summarized at the watershed and riparian scale as explanatory variables to predict macroinvertebrate metrics commonly used by state resource managers to assess stream condition. The “best” multiple linear regression models from each region required only two or three explanatory variables to model macroinvertebrate metrics and explained 41–74% of the variation. In each region the best model contained some measure of urban and/or agricultural land-use, yet often the model was improved by including a natural explanatory variable such as mean annual precipitation or mean watershed slope. Two macroinvertebrate metrics were common among all three regions, the metric that summarizes the richness of tolerant macroinvertebrates (RICHTOL) and some form of EPT (Ephemeroptera, Plecoptera, and Trichoptera) richness. Best models were developed for the same two invertebrate metrics even though the geographic regions reflect distinct differences in precipitation, geology, elevation, slope, population density, and land-use. With further development, models like these can be used to elicit better causal linkages to stream biological attributes or condition and can be used by researchers or managers to predict biological indicators of stream condition at unsampled sites. [Copyright &y& Elsevier]

The article presents a study that aimed to model whether disturbance at local and regional spatial scales would cause different patterns of dominance and extinction, linking dominance patterns to four benthic animal species representative of the community states observed in the Long Island Sound. Researchers investigated the influence of variation in scale on species interactions and the connectivity among habitats by simulating two spatial levels of disturbance. They also examined the implications of the synergy for invasive species and ecosystem management.

The article presents a study regarding the investigation of the responses of benthic macroinvertebrates to urbanization in several metropolitan regions in the U.S. It highlights the changes in assemblage condition which were based on ordination scores and the mean pollution-tolerance value of organisms. It states that assemblages were degraded at low levels of urbanization.

Along the Louisiana, USA continental shelf, sandy shoals are shallow, possibly oxygen-rich ''islands'' surrounded by deeper muddy deposits prone to hypoxia. Shoals also contain significant quantities of fine sand that may be mined in the future for coastal restoration. The ecological role of shoals remains poorly understood and we hypothesized that shoals provide critical habitat for benthic invertebrates. Using Ship Shoal as a model system, we assessed the diversity and structure of macrobenthic assemblages and how community structure varies with season and environmental parameters. High biomass (averaging 26.7 g m-2) and high diversity (161 species) of macrobenthos was found in 2006. Polychaetes (45%-72 species) and crustaceans comprised most of the species (28%-46 species); spionids and amphipods dominated the polychaete and crustacean groups respectively, both in terms of number of species and abundances. Sharp decreases in diversity, abundance and biomass occurred from spring to autumn. Species diversity and total abundance significantly increased with decreasing sediment grain size and increasing bottom water dissolved oxygen. Across seasons, mole crabs Albunea paretii and amphioxus Branchiostoma floridae typified the community and contributed most of the biomass. The polychaetes Nephtys simoni, Neanthes micromma, Dispio uncinata, Mediomastus californiensis and Magelona sp. A, the amphipod Acanthohautorius sp. A and the burrowing shrimp Ogyrides alphaerostris also contributed to variation in community composition. Cluster analyses quantified seasonal variation, mainly based on sharp decreases in abundance, as well as spatial differences in species composition oriented along both east- west and north-south gradients. Variation in benthic assemblages was correlated with water depth and sediment characteristics (mean grain size and percentage of gravel-sized shell debris). We conclude that Ship Shoal is an unrecognized biodiversity hotspot and a hypoxia refuge compared to the immediate surrounding area where the benthic community is affected by seasonal hypoxia events and we discuss how sand-mining may influence this community. [ABSTRACT FROM AUTHOR]

Biological indicators, particularly benthic macroinvertebrates, are widely used and effective measures of the impact of urbanization on stream ecosystems. A multimetric biological index of urbanization was developed using a large benthic macroinvertebrate dataset ( n = 1,835) from the Baltimore, Maryland, metropolitan area and then validated with datasets from Cleveland, Ohio ( n = 79); San Jose, California ( n = 85); and a different subset of the Baltimore data ( n = 85). The biological metrics used to develop the multimetric index were selected using several criteria and were required to represent ecological attributes of macroinvertebrate assemblages including taxonomic composition and richness (number of taxa in the insect orders of Ephemeroptera, Plecoptera, and Trichoptera), functional feeding group (number of taxa designated as filterers), and habit (percent of individuals which cling to the substrate). Quantile regression was used to select metrics and characterize the relationship between the final biological index and an urban gradient (composed of population density, road density, and urban land use). Although more complex biological indices exist, this simplified multimetric index showed a consistent relationship between biological indicators and urban conditions (as measured by quantile regression) in three climatic regions of the United States and can serve as an assessment tool for environmental managers to prioritize urban stream sites for restoration and protection. [ABSTRACT FROM AUTHOR]

The U.S. Atlantic coast and Gulf of Mexico commercial shark fisheries have greatly expanded over the last 30 years, yet fishery managers still lack much of the key information required to accurately assess many shark stocks. Fishery observer programs are one tool that can be utilized to acquire this information. The Commercial Shark Fishery Observer Program monitors the U.S. Atlantic coast and Gulf of Mexico commercial bottom longline (BLL) large coastal shark fishery. Data gathered by observers were summarized for the 10-year period, 1994 to 2003. A total of 1,165 BLL sets were observed aboard 96 vessels, with observers spending a total of 1,509 days at sea. Observers recorded data regarding the fishing gear and methods used, species composition, disposition of the catch, mortality rates, catch per unit of effort (sharks per 10,000 hook hours), and bycatch of this fishery. Fishing practices, species composition, and bycatch varied between regions, while catch rates, mortality rates, and catch disposition varied greatly between species. [ABSTRACT FROM AUTHOR]

The effects of Hurricane Katrina on benthic fauna and habitat quality in coastal waters of Louisiana, Mississippi, and Alabama, USA, were assessed in October, 2005, 2 months after the hurricane made landfall between New Orleans, LA and Biloxi, MS. Benthic macrofaunal samples, sediment chemical concentrations, and water quality measurements from 60 sites in Lake Pontchartrain and Mississippi Sound were compared with pre-hurricane conditions from 2000–2004. Post-hurricane benthic communities had significant reductions in numbers of taxa, H′ diversity, and abundance as well as shifts in composition and ranking of dominant taxa. These effects were not associated with changes in chemical contamination, organic enrichment of sediments, or hypoxia and were likely due to hurricane-related scouring and changes in salinity. [ABSTRACT FROM AUTHOR]

• Mollusc-only M-AMBI outperformed mollusc-only AMBI in assessing ecological quality. • Mollusc-only M-AMBI identified environmental remediation needs with > 90% precision. • Molluscs provide a cost- and time-effective means of assessing ecological quality. AMBI and M-AMBI are widely used biotic indices for assessing the ecological quality status of benthic macroinvertebrate communities in estuarine and coastal soft-bottom habitats. Identifying the species needed for estimating these indices, however, is both expensive and time-consuming, and requires a high degree of taxonomic expertise. The use of proxy taxa as a means of subsampling the target community may save time, resources, and the breadth of taxonomic expertise needed. Our study used macroinvertebrate benthic survey data from the Atlantic Coast of the United States to test the fidelity of molluscs as proxies of the whole community. We calculated the AMBI and M-AMBI scores for both the molluscan and whole communities and then adjusted the molluscan-only index scores to that of the whole community using the linear relationship between the two communities within a Bayesian framework. We found that the mollusc-only AMBI approach underperformed at classifying the ecological quality of the whole community, particularly regarding sample sites classified as needing remediation. The low performance of the mollusc-only AMBI approach is likely due to the dearth of molluscs with high environmental stress tolerances. In contrast, the mollusc-only M-AMBI outperformed AMBI at classifying ecological quality. The M-AMBI linear model correctly classified nearly all of the adjusted mollusc-only sample sites needing remediation. The increased efficacy of mollusc-only M-AMBI may be due to the incorporation of species richness and diversity into the index, as both metrics were highly correlated between the molluscan and whole communities. Mollusc-only M-AMBI did have some drawbacks, however, with fidelity decreasing as ecological quality decreased. Overall, our study highlights the potential utility of a mollusc-only approach for assessing the ecological quality of estuarine and coastal soft-bottom habitats. [ABSTRACT FROM AUTHOR]

In 2003, we compared two benthic macroinvertebrate sampling methods that are used for rapid biological assessment of wadeable streams. A single habitat method using kick sampling in riffles and runs was compared to a multiple habitat method that sampled all available habitats in proportion of occurrence. Both methods were performed side-by-side at 41 sites in lower gradient streams of the Piedmont and Northern Piedmont ecoregions of the United States, where riffle habitat is less abundant. Differences in sampling methods were examined using similarity indices, two multimetric indices [the family-level Virginia Stream Condition Index (VSCI) and the species-level Macroinvertebrate Biotic Integrity Index (MBII)], their component metrics, and bioassessment endpoints based on each index. Index scores were highly correlated between single and multiple habitat field methods, and sampling method comparability, based on comparison of similarities between and within sampling methods, was particularly high for species level data. The VSCI scores and values of most of its component metrics were not significantly higher for one particular method, but relationships between single and multiple habitat values were highly variable for percent Ephemeroptera, percent chironomids, and percent Plecoptera and Trichoptera (Hydropsychidae excluded). A similar level of variability in the relationship was observed for the MBII and most of its metrics, but Ephemeroptera richness, percent individuals in the dominant five taxa, and Hilsenhoff Biotic Index scores all exhibited differences in values between single and multiple habitat field methods. When applied to multiple habitat samples, the MBII exhibited greater precision, higher index scores, and higher assessment categories than when applied to single habitat samples at the same sites. In streams with limited or no riffle habitats, the multiple habitat method should provide an adequate sample for biological assessment, and at sites with abundant riffle habitat, little difference would be expected between the single and multiple habitat field methods. Thus, in geographic areas with a wide variety of stream types, the multiple habitat method may be more desirable. Even so, the variability in the relationship between single and multiple habitat methods indicates that the data are not interchangeable, and we suggest that any change in sampling method should be accompanied by a recalibration of any existing assessment tool (e.g., multimetric index) with data collected using the new method, regardless of taxonomic level. [ABSTRACT FROM AUTHOR]

Pacific hake, Merluccius productus, the most abundant groundfish in the California Current Large Marine Ecosystem (CCLME), is a species of both commercial significance, supporting a large international fishery, and ecological importance, connecting other species as both predator and prey. Coastal Pacific hake migrations are characterized by movements between northern summer feeding areas and southern winter spawning areas, with variations in annual abundance, distribution, and the extent of these movements associated with varying climate-ocean conditions. In general, warm (cool) years with enhanced (reduced) stratification and poleward (equatorward) transport are often related to good (poor) recruitment, increased (decreased) northward distribution, and reduced (enhanced) growth. However, the classic periodic pattern of annual migration and distribution may no longer be fully representative. Based on recent advances in the understanding of climate-ocean variability off the U.S. west coast, we hypothesize that the annual movements of Pacific hake are more responsive to climate-ocean variability than previously thought, and further, that changes observed in Pacific hake distributions may reflect long-term changes in climate-ocean conditions in the CCLME. Therefore, an updated model of these relations is key to effective monitoring and management of this stock, as well as to devising scenarios of future change in the CCLME as a result of climate variations. The current state of knowledge of the relationship between the Pacific hake and its environment is reviewed, highlighting emerging ideas compared to those of the past, and priorities for future research are suggested. [ABSTRACT FROM AUTHOR]

We designed, constructed, and tested a new grab sampler to collect benthic macroinvertebrates and sediments from shallow (<3 m) aquatic systems. This light (4.5 kg), inexpensive sampler is easy to construct and has a higher rate of successful closure and sample retention than the Peterson, petite Ponar, or Ekman samplers. In field tests conducted at three central Arkansas (USA) lakes, the estimated mean densities of macroinvertebrates collected by our device did not differ significantly from the Ekman, Peterson or petite Ponar grabs in muddy benthic habitats but were significantly less than the Ekman and petite Ponar grabs in woody and clay habitats. However, there were no significant differences in the taxa obtained or their representation in the samples collected with the tested grab samplers. [ABSTRACT FROM AUTHOR]

1. Pacific salmon are thought to stimulate the productivity of the fresh waters in which they spawn by fertilizing them with marine-derived nutrients (MDN). We compared the influence of salmon spawners on surface streamwater chemistry and benthic biota among three southeastern Alaska streams. Within each stream, reaches up- and downstream of barriers to salmon migration were sampled during or soon after spawners entered the streams. 2. Within streams, concentrations of dissolved ammonium and soluble reactive phosphorus (SRP), abundance of epilithon (chlorophyll a and ash-free dry mass) and biomass of chironomids were significantly higher in reaches with salmon spawners. In contrast, biomass of the mayflies Epeorus spp. and Rhithrogena spp. was significantly higher in reaches lacking spawners. 3. Among streams, significant differences were found in concentrations of dissolved ammonium, dissolved organic carbon, nitrate and SRP, abundance of epilithon, and the biomass of chironomids and Rhithrogena. These differences did not appear to reflect differences among streams in spawner density, nor the changes in water chemistry resulting from salmon spawners. 4. Our results suggest that the 'enrichment' effect of salmon spawners (e.g. increased streamwater nutrient concentrations) was balanced by other concurrent effects of spawners on streams (e.g. sediment disturbance). Furthermore, the collective effect of spawners on lotic ecosystems is likely to be constrained by conditions unique to individual streams, such as temperature, background water chemistry and light attenuation. [ABSTRACT FROM AUTHOR]

The mining of sand resources from the inner continental shelf for beach nourishment may lead to impacts or increase stress on commercial and noncommercial living resources that utilize these areas. The objective of our work was to characterize benthos present in areas likely to be mined and to predict impacts of sand mining. In 1998 and 1999 we used a combination of methods (grab samples, sediment profile cameras, video sled, and trawl) to collect data on the benthos, both fishes and invertebrates, which utilized several potential sand mining areas. We found benthic communities and fish assemblages to be typical of middle Atlantic sandy inner continental shelf habitats. A sand mining scenario that removed the top meter of sand from Fenwick Shoal would disturb approximately 7.7 km² with the potential acute impact on noncommercial sessile species being the loss of about 150 × 106 individuals representing 300 kg of wet weight biomass that could have functioned as trophic support to fishes. In addition, mobile species would be displaced and have to search for replacement habitat. To minimize impacts and promote recolonization of mined areas the total removal of substrate should be avoided. Small areas with a project area should be left to serve as refuge patches that would promote recolonization and serve as habitat for mobile species. Predicted impacts on demersal fishes would be lessened by a rapid recolonization, particularly the recovery of mobile epifaunal crustacean that serve as the primary trophic support species. Project timing and engineering could also be used to lessen impacts on fishes by reducing stress on crustaceans. For example, mining activities that ended in time for Spring/Summer recruitment would favor crustaceans while a Fall/Winter end would favor annelids. [ABSTRACT FROM AUTHOR]

The formation of chimeric colonies following allogeneic contact between benthic invertebrates may strongly affect colony fitness. Here we show that, in a field population of the colonial ascidian Botryllus schlosseri in Monterey Bay, California, more than 20% of all colonies occur in allogeneic contact with conspecifics. We experimentally assessed the effects of allogeneic contact on the following life-history traits under natural field conditions: growth, age and size at first reproduction, and egg production (fecundity). When compared with isolated colonies, and in some cohorts also with colonies that rejected allogeneic neighbors, colonies that fused with neighbors incurred reduced fitness in terms of most life-history traits measured. We propose that one of the benefits of precise allorecognition is that, in fused colonies, it limits the unit of selection to chimeric individuals composed of closely related kin. [ABSTRACT FROM AUTHOR]

Summary 1. Patches of stable substratum in streams may be important refugia for benthic organisms during scouring floods. Streambed stone stability, packing and embeddedness were assessed within and adjacent to beds of the macrophyte Justicia americana in five Alabama streams. 2. The force needed to dislodge stones and embeddedness was about two times lower outside Justicia beds than within them. Significant positive correlations between stone stability and (i) degree of embeddedness, and (ii) the abundance of binding rhizomes and the presence of attached roots indicate that Justicia may physically modify the local streambed, indirectly enhancing substratum stability and reducing flow, thereby increasing sand deposition. 3. Despite higher stability (i.e. physical refugia during bed-moving spates) within Justicia beds, the abundance of epilithic plants (moss and Podostemum ceratophyllum ) and pleurocerid snails (Elimia spp.) was similar both inside and outside the macrophyte beds. Several physical characteristics within macrophyte beds, such as low light, reduced current and increased sand intrusion, may create suboptimal conditions for benthic organisms in these habitats. 4. Additional work is needed to determine if Justicia biogenically enhances substratum stability or if its presence merely reflects patches of stable substratum within the streambed. Regardless of the mechanism, there is an association between Justicia beds and streambed characteristics. [ABSTRACT FROM AUTHOR]

The Clinch-Powell River system of Virginia and Tennessee, USA, is among the most biologically diverse ecosystems in the world, and has been identified as a conservation priority of national importance. Other researchers have attributed declines in Powell River freshwater mussel populations to coal mining-related activities. The objectives of this paper are to synthesize the results of several studies aimed at assessing acid mine drainage (AMD) impacts in the Powell River watershed, and to describe the relative roles of AMD, nutrient loading, and urban runoff in structuring the benthic macroinvertebrate communities of the Powell River. Impacts ranged from acute toxicity due to the combination of acid and metals, acute aluminum toxicity in circumneutral pH waters, and physical impacts from solid ferrihydrite, to decreased clam growth due to urban runoff. These findings support the concern that AMD negatively impacts aquatic biota in the Powell River watershed in a variety of ways, and emphasize the importance of taking measures to properly reclaim areas that are producing mine drainage. However, past-mining related pollutants are not the only source of aquatic-community impact in these watersheds, as nutrient loading and urban runoff both were associated with substantial changes in community structure and clam growth. [ABSTRACT FROM AUTHOR]

Concern about declining trends in coral reef habitats and reef fish stocks in the Florida Keys contributed to the implementation of a network of no-take marine protected areas in 1997. In support of the efforts of the Dry Tortugas National Park and Florida Keys National Marine Sanctuary to implement additional no-take areas in the Tortugas region in 2001, we expanded the scale of our fisheries independent monitoring program for coral reef fishes in the region. To provide a foundation for the habitat-based, stratified random sampling design of the program, we created a digital benthic habitat map of coral reef and hard-bottom habitats in a geographic information system by synthesizing data from bathymetric surveys, side-scan sonar imagery, aerial photogrammetry, existing habitat maps, and in situ visual surveys. Existing habitat maps prior to 1999 were limited to shallow-water (< 20 m depth) soft-sediment, coral reef, and hard-bottom habitats within Dry Tortugas National Park and did not include deeper areas such as the Tortugas Bank, now partially contained within no-take marine protected area boundaries. From diver observations made during the 1999 survey, we developed a classification scheme based on habitat relief and patchiness to describe nine hard-bottom and coral reef habitats encountered from 1-33 m depth. We provide estimates of area by habitat type for no-take marine protected areas in the Tortugas region. Updated information on the spatial distribution and characteristics of benthic habitats will be used to guide future monitoring, assessment, and management activities in the region. Significant data gaps still exist for the western area of the Florida Keys National Marine Sanctuary and are a priority for future research. [ABSTRACT FROM AUTHOR]

As part of the Ocean Margins Program (OMP), organic carbon 14C measurements have been made on benthic fauna and kasten core sediments from the North Carolina continental slope. These analyses are used to evaluate the nature and burial flux of organic matter in the OMP study area off Cape Hatteras. Despite the fact that surface sediment 14C contents ranged from −41 to −215 per mil, the benthic fauna (primarily polychaetes) all contained significant amounts of bomb-14C (body tissue 14C contents ranging from +20 to +82 per mil). Bomb-14C clearly is reaching the seabed on the North Carolina slope, and the labile planktonic material carrying this signal is a primary source of nutrition to the benthic ecosystem. The enrichment of 14C in benthic faunal tissue relative to the 14C content of bulk surface-sediment organic matter (a difference of ∼150 per mil) is attributed to a combination of particle selection and selective digestive processes. Organic carbon burial rates from 12 stations on the North Carolina slope varied from 0.02 to 1.7 mol of C m−2 yr−1, with a mean value of 0.7 mol of C m−2 yr−1. The accumulation of organic matter on the upper slope accounts for <1% of the primary production in the entire continental margin system. The North Carolina margin was deliberately selected because of its potential for offshore transport and high sediment deposition rates, and even in this environment, burial of organic carbon accounts for a very small fraction of the primary production occurring in surface waters. [Copyright &y& Elsevier]

Patterns of benthic faunal abundances, biomass, and productivity were examined in the continental shelf-break/upper-slope and mid-slope region of the Ocean Margins Program study area off Cape Hatteras, NC in July 1994, and July and August 1996. Macrofaunal abundances were comparable to or slightly higher than other shelf-slope locales in the North Atlantic. Similar to previous studies in the region, there were no clear depth (75–900 m) or latitudinal (36°20′N–35°25′) trends. Sta. S300 in 300 m had greatest abundances (539,000±38,400 m−2) for individuals >0.3 mm, more than 3 times higher than the average for all stations. Annelids of all sizes dominated numerically, equaling >80% of all macrofauna regardless of size. The majority of infauna were found in the upper 5 cm, but direct visual observations and geochemical evidence from other studies imply a deep-burrowing benthos. Meiofauna (excluding benthic foraminifera) were twice as abundant at shelf-break/upper-slope stations than mid-slope stations, while foraminifera were more abundant at deeper stations. Meiofaunal-sized polychaetes and nematodes were found to at least 7–8 cm below the sediment surface. Bacterial inventories at shelf-break/upper-slope depths were high relative to other shelf regions, but declined precipitously deeper than 500 m. Relative biomass patterns were similar for all stations, highest for macrobenthos and lowest for bacteria. Although densities were high, the contribution of nematodes to benthic biomass was <1%. Macrofaunal biomass averaged 54±47 g C m−2 and ranged from 6 g C m−2 at station N455 to 188 g C m−2 (>0.3 mm) at station S300, while metazoan meiofauna contributed from 0.6 g C m−2 at station N-274 to 11 g C m−2 at M76, averaging 2.2±2.4 g C m−2. Bacterial biomass over the upper 10 cm was ∼4 times higher at shelf-break/upper-slope stations than mid-slope stations, averaging 1.05±1.14 g C m−2 and ranging from 5 g C m−2 at M76 to 0.12 g C m−2 at MLB-679Rb. Benthic production estimates track biomass patterns and are estimated at 188 g C m−2 yr−1 for shelf-break/upper-slope and 87 g C m−2 yr−1 for mid-slope stations, respectively. Although bacterial biomass was considerably less than macrobenthos, production estimates for bacteria were almost 4 times higher on average at shelf-break/upper-slope stations than for macrofauna (147 compared with 40 g C m−2 yr−1). Sustained inputs of labile planktonic debris likely contribute to the abundant, deep-burrowing, and extremely active benthic community off Cape Hatteras, and are probably higher than presently estimated. [Copyright &y& Elsevier]

Examines benthic macroinvertebrate community characteristics and their associations with vascular and nonvascular macrophyte communities on differing substrates in a northeastern impoundment, Aquetong Lake in Bucks County, Pennsylvania. Information on benthic macroinvertebrates; Factors that affect abundance and characteristics of benthic macroinvertebrates; Impact of a vascular plant community on benthic macroinvertebrate biomass and diversity.

Examines the benthic eukaryotic diversity in the Guaymas Basin hydrothermal vent environment in the Gulf of California. Emphasis on molecular microbial ecology; Characteristics of anoxic, hydrocarbon-rich sedimentary habitats; Extraction of DNA for gene sequencing.

Investigates the effects of dredge material placement on benthic macroinvertebrates of the Illinois River. Changes of sediment composition in the river; Importance of benthic macroinvertebrates as a component of the food web; Densities of several benthic marcoinvertebrate taxa.

Examines the distribution and seasonal dynamics of benthic invertebrates found in Salton Sea, California. Indication of highest numbers of invertebrates per unit area on the rocky shoreline; Increase in the density nearly in one order of magnitude between January and November; Absence of Neanthes from all offshore sites during spring and summer.

Part IV. Presents a study that described the general types of benthic species according to the U.S. Environmental Protection Agency's Environmental Monitoring and Assessment Program. Distribution and native status of fish species; Discussion on benthic fishes; Background on small, water-column fishes which include killifishes and sticklebacks.

Reports on a small benthic juvenile scrawled cowfish from the Hudson River in New York City. Life stage of the fish; Basis of identification of the fish; Morphological characters of the fish.

Stream bioassessments are usually based on a single taxonomic assemblage, often fishes or macroinvertebrates, with the assumption that this assemblage is representative of ecological conditions. However, ecological and physiological differences between taxonomic groups may result in different assessment results. In this study, concurrent fish and macroinvertebrate bioassessments from South Carolina coastal plain streams were compared on the basis of precision, sensitivity, accuracy, and agreement. Multimetric indices used in this comparison were a modified Index of Biotic Integrity based on electrofishing data and a benthic macroinvertebrate multimetric index based on data collected with Hester-Dendy artificial substrates. Benthic macroinvertebrates were also collected from natural substrates for comparative purposes. The Index of Biotic Integrity was more precise than the HesterDendy multimetric index but the average difference between disturbed and reference sites was greater for the latter resulting in equal sensitivity (i.e., ability to measure disturbance in relation to index variability). The two indices were significantly correlated (r=0.62, p<0.001), but agreement between them was weak for slightly and moderately disturbed sites. Analysis of species richness and abundance data indicated that fish and macroinvertebrates responded differently to some disturbances regardless of whether macroinvertebates were collected from HesterDendy samplers or natural substrates. Disagreement between macroinvertebrate and fish assessments at moderately disturbed sites indicated that biological condition could not always be adequately evaluated from a single taxonomic group. Identification of disturbed sites was most accurate when based on both indices suggesting that future research should emphasize cost-effective sampling and integration of information from multiple taxonomic groups. [ABSTRACT FROM AUTHOR]

Estimates the magnitudes of changes in third-order eustasy for Oligocene sequences based on boreholes drilled on the New Jersey coastal plain. Depth range of benthic foraminiferal biofacies; Geometry of Oligocene sedimentary surfaces; Miocene record of Kirkwood Formation; Rate of fall of sea-level; Advantages of using two-dimensional backstripping approach.

Assesses the relationship of depth, sediment grain size and latitude with the distribution of benthic infaunal assemblages in the coastal shelf of southern California. Distinctive species in the shallow assemblage and in the mid-depth assemblage; Description of the benthic assemblages; Impact of upwelling waters and other oceanic regimes on benthic abundance and diversity.

Examines the physical habitat integrity in relation to the benthic invertebrate communities of the streams in Missouri. Derivation of reference conditions; Sensitivity of the biological metrics; Documentation of the biological responses of the invertebrate to habitat alterations.

Summary AimThe community composition of benthic macroinvertebrates from 295 estuarine sites was examined in order to either confirm or challenge established boundaries of zoogeographical provinces. We also investigated the postulate that, while local distributions were determined by natural habitat characteristics such as salinity, sediment type and depth, distributions on a large geographical scale would be correlated with temperature. LocationThe Atlantic coast of the United States (on a latitudinal gradient from 42° to 25°N). MethodsUsing the descriptive techniques of cluster analysis and nonmetric multi-dimensional scaling, we determined the similarities in benthic community composition between sites within 1° latitudinal bands and compared the biotic ordinations to natural habitat characteristics such as salinity, sediment type and depth. We then evaluated the overall community composition within each 1° latitudinal band and established whether or not similarities existed between adjacent 1° latitudinal bands. In this manner, we were able to confirm that a latitudinal gradient existed in estuarine benthic community composition along the western Atlantic coast. This latitudinal gradient was demarcated by biogeographical boundaries at (1) Biscayne Bay, Florida, (2) the southern end of the Indian River Lagoon, Florida, (3) St John's River, Florida, (4) Cape Island, South Carolina, (5) the mouth of the Cape Fear River, North Carolina and (6) Cape Cod, Massachusetts, with a subprovince boundary just north of Cape May at Wildwood, New Jersey. ResultsThe major divisions approximated widely recognized biogeographical boundaries. Average summer water temperatures correlated better than sediment type, depth, or salinity with the latitudinal groupings of sites determined by cluster analysis. ConclusionsBased on this relationship, we speculate on the potential impacts of current global climate change scenarios on the distribution of benthic macroinvertebrates along the western Atlantic coast. [ABSTRACT FROM AUTHOR]

The benthic environment of the Gulf of Maine is characterized by a thick and basin-wide nepheloid layer, classically defined as a near-bottom region of permanent sediment resuspension. The high frequency of commercial bottom trawling in particular regions of the Gulf of Maine, documented by records compiled by the National Marine Fisheries Service, may strongly affect measured resuspension fluxes and contribute to the maintenance of the nepheloid layer. Indirect evidence of the effects of bottom trawling on sediment resuspension is observed in the seasonal collection of large, benthic infaunal worms, along with substantial amounts of resuspended bottom sediment, in a sediment trap deployed 25 m off the bottom in the western gulf region of Wilkinson Basin. These collections appear to be coincident with seasonal periods of intensive bottom trawling in this area. By comparison, the western gulf region of Jordan Basin is typified by significantly reduced annual bottom-trawling activity, and very few infaunal worms are found in the seasonal collections of a sediment trap located 25–30 m off the bottom. The extent to which trawling-induced bottom sediment excavation and resuspension occurs has important implications for regional nutrient budgets in terms of the input of sedimentary nitrogen and silica into the water column via this anthropogenic activity. Sediment mixing and frequent bottom disturbance from trawling activity may also produce changes in the successional organization of soft-sediment infaunal communities. The potential effects of trawling require serious examination and quantification to accurately determine the impact of such anthropogenic activity on the benthic ecosystems of continental margin environments. [ABSTRACT FROM AUTHOR]

Discusses the stability and resilience in benthic macroinvertebrate assemblages of Bushkill Creek in Northampton County, Pennsylvania studied during 1970s and 1980s. Impact of cold temperatures during winter of 1994 on assemblages; Effect of multiple physical disturbances on recovery time of assemblages.

Looks at the effects of a complete diet, a supplemental diet, and the supplemental diet with an adjunct organic fertilization regimen, on benthic macroinvertebrate populations in the United States. Details on the three types of diets; Effects of the three diets on water quality in experimental ponds used to culture freshwater pawns.

Focuses on species composition, distribution, density and abundance of the resident benthic megafaunal invertebrates in California. Comparison of megafaunal abundance and density between trawl samples and camera sleds; Assessment of the differences among different areas at the same depth; Identification of benthic macroinvertebrate specimens to ground truth concurrent camera sled.

Determines the effects of urbanization on fish and benthic macroinvertebrate communities of Valley Creek and its tributary, Little Valley Creek, in southeastern Pennsylvania. Description of study site; Materials and methods used in the study; Total abundance of fish species collected in 1993-1994 for the Valley Creek branch and Little Valley Creek branch above their confluence.

• NLCD %IC was with ± 6% of high-resolution reference %IC. • NLCD %IC and %IC-aquatic condition uncertainties appear to be about equal. • NLCD %IC is a useful proxy for high-resolution %IC except for small urbanized areas. The emergence of high-resolution land cover data has created the opportunity to assess the accuracy of impervious cover (IC) provided by the National Land Cover Database (NLCD). We assessed the accuracy of the 900 m2 NLCD2011 %IC for 18 metropolitan areas throughout the conterminous United States using reference data from 1 m2 land cover data developed as part of the United States Environmental Protection Agency's EnviroAtlas project. Agreement was assessed from two perspectives: 1) sensitivity to the size of the assessment unit used for the comparison, and 2) utility of NLCD %IC to serve as a proxy for high-resolution IC. The former perspective was considered because statistical relationships can be sensitive to assessment unit size and shape, and the latter perspective was considered because high resolution (reference) %IC data are not available nationwide. The utility of NLCD %IC as a proxy for the high resolution data was assessed for seven lattice (square) cell sizes ranging from 1 ha to 200 ha using four EnviroAtlas IC indicators: 1) %IC per 100 ha (1 km2); 2) %IC by Census block group; 3) %IC within a 15 m (radius) of the riparian zone, and; 4) %IC within a 50 m (radius) of the riparian zone. Agreement was quantified as per assessment unit deviation (NLCD %IC – reference %IC) and summarized as Mean Absolute Deviation (MAD) and Mean Deviation (MD) both within and across the 18 metropolitan areas. Ordinary least squares (OLS) regression (y = reference %IC and x = NLCD %IC) was also used to evaluate the quality of the NLCD %IC data. MAD was ≤ 5% for six of the seven lattice cell sizes. MAD was also ≤ 5% for Census block groups > 100 ha and for both riparian units. These results suggest that uncertainty attributable to the measurement of %IC was no greater than the uncertainty related to the effect of IC on aquatic resources that have been derived from studies of aquatic condition (e.g., benthic fauna) over a range of %IC. Overall, agreement was variable from one metropolitan area to the next. Agreement improved as assessment unit size increased and declined as the level of urbanization (NLCD %IC) increased. NLCD %IC tended to underestimate reference %IC overall, but NLCD %IC was sometimes greater than reference %IC in urbanized settings. [ABSTRACT FROM AUTHOR]

Examines the algal standing stock and abundance of benthic invertebrates in Greenwood Creek and Club Head Creek in Massachusetts to address the impact of sewage effluent on benthic communities. Impact of sewage effluent input on nitrate levels; Difference between the benthic invertebrate populations in the creeks; Influence of sewage effluent on algal and benthic invertebrate communities.

Details the Praise Acres Project, an outdoor education activity for high school students in Indiana. Development of wetlands and outdoor laboratory facility in a piece of property; Discussion on the importance of clean water resources; Identification of the presence of coliforms and collection of benthic microinvertebrates.