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Gelatinous zooplankton control of ecological engineers and the physical habitat they create or modify. Predation by sea nettles can reduce or eliminate local populations of ctenophores. Ctenophores consume oyster larvae, but sea nettles reject these prey or egest them unharmed. Sea nettles, therefore, potentially control the spatial distribution and intensity of recruitment of oysters by controlling the abundance of ctenophores. Filtration by oysters can reduce phytoplankton densities, thereby increasing water clarity and improving the light environment for SAV growth. Oysters, phytoplankton and submersed macrophytes are important ecosystem engineers in estuaries and marine systems. 

Gelatinous zooplankton control of ecological engineers and the physical habitat they create or modify. Predation by sea nettles can reduce or eliminate local populations of ctenophores. Ctenophores consume oyster larvae, but sea nettles reject these prey or egest them unharmed. Sea nettles, therefore, potentially control the spatial distribution and intensity of recruitment of oysters by controlling the abundance of ctenophores. Filtration by oysters can reduce phytoplankton densities, thereby increasing water clarity and improving the light environment for SAV growth. Oysters, phytoplankton and submersed macrophytes are important ecosystem engineers in estuaries and marine systems. 

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Ecosystem engineers are species that alter the physical environment in ways that create new habitat or change the suitability of existing habitats for themselves or other organisms. In marine systems, much of the focus has been on species such as corals, oysters, and macrophytes that add physical structure to the environment, but organisms ranging...

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... an alternative mechanism of fluid transport that is not only unim- peded by the fluid’s viscosity, it is significantly enhanced by it. The fluid mechanical principle behind their mechanism, called ‘‘induced drift,’’ dates back to the work of Sir Charles Galton Darwin (1953) (grandson of the Origin of Species ’ author), who was a physicist interested in hydrodynamics. He showed that when a solid object moves through a fluid like water, the object tends to carry a portion of the surrounding fluid with it. The amount of fluid carried with the object relative to its size depends only on the shape of the object. Furthermore, viscosity in the fluid increases the amount of fluid trans- ported by the solid object. Using this mechanism as their foundation, Katija and Dabiri (2009) proposed a more direct mechanism of fluid transport by plankton and nekton: as the animals migrate, their solid bodies carry along a portion of the local fluid; hence, the local water and its contained chemicals and nutrients are also trans- ported. This provides a potentially powerful mechanism of ecosystem engineering because it suggests that when swimming organisms transport themselves to new environments, they also take a portion of the original environment with them. Depending on the circumstances, this may either alleviate or exacerbate extreme environments, e.g., where hypoxia or eutrophication is near threshold levels. It also presents an opportunity for animals to actively support the chemical and biological processes on which they ultimately depend. For example, by transporting from deeper water the necessary nutrients to promote photosynthesis at the ocean’s surface, the animals can ensure sufficient phytoplankton and the products of photosynthesis at lower trophic levels to support their diet. Direct evidence for the mechanism of induced drift is currently limited to the field experiments of Katija and Dabiri (2009), which studied the fluid transport achieved by jellyfish in a marine lake in Palau. By tracking dye markers delivered into the water near animals using SCUBA techniques, they observed the drifting process in situ (Fig. 4). Their data are consistent with the concept that animals carry the surrounding fluid with them as they migrate. To fully appreciate the potential of marine organisms to act at engineers of their ecosystems, further research on the physics, biology, and chemistry of the mixing processes is needed. It seems likely that the diversity of animals’ shapes and swimming kine- matics will be reflected in varied impacts on water transport in the ocean. The sensitivity of local ecosystems to biogenic mixing will depend intimately on the population dynamics of local animals (e.g., which animals are present and to what degree), and the local water chemistry and its spatial variation. In many cases, opportunities will exist for complex feedback loops between animal populations and the surrounding milieu. Trophic interactions and ecosystem engineering have typically been considered distinct classes of ecological processes that alter the suitability of a habitat in quite different ways. In practice, however, the ability of consumers to affect spatial distributions of engineers, and thus the location, extent, and characteristics of the engineered landscape blur that distinction (Jones et al. 1994). Classic examples of keystone species include direct or indirect control by predators of organisms that create or modify the physical habitat in terrestrial, marine, and freshwater environments (Paine 1966; Estes and Palmisano 1974; Power et al. 1996). A particular kind of spatially varying trophic in- teraction, which we call ‘‘predator-mediated landscape structure’’ (PMLS) may form an important link between the trophic and engineering mechanisms of ecological control. PMLS is a case in which consumers, themselves, create a landscape mosaic that varies in suitability for their prey and the species with which their prey interact. Where PMLS affects the abundance or distribution of ecosystem engineers, it can either directly or indirectly control characteristics and the landscape-level orga- nization of the engineered environment. PMLS may be especially important in aquatic environments in which physical variation within the pelagic habitat has less effect than do trophic interactions in defin- ing the spatial pattern of survival probabilities of species. We provide an example of PMLS based on a study of the distribution of gelatinous zooplankton in the Patuxent River (a sub-estuary of Chesapeake Bay; Fig. 6A) and its tributaries by Breitburg et al. (2009). Two gelatinous zooplanktonic species—the scyphomedusa Chrysaora quinquecirrha (sea nettle) and the lobate ctenophore Mnemiopsis leidyi (referred to as ctenophores, below) are dominant consumers in Chesapeake Bay (Purcell and Decker 2005) that can directly and indirectly control abundances of an important ecosystem engineer, the Eastern oyster Crassostrea virginica (Fig. 5). Ctenophores consume oyster larvae, but sea nettles reject these prey or ejest them unharmed (Purcell et al. 1991). Oysters provide a wide range of ecosystem services including creation of physical habitat and improve- ment of water clarity (Coen et al. 2007; Grabowski and Peterson 2007). Filtration of water by oysters also has cascading effects in an environment by affecting other ecosystem engineers such as phytoplankton and submersed macrophytes (Fig. 5). Gelatinous zooplankton were sampled at 12 sites with a 244- m m mesh 1-m 2 Tucker trawl weekly during summer of 2004. Duplicate tows of surface and bottom layers, each lasting 90 seconds and sampling an average of 51 m 3 , were taken at each site on each date. Sea nettles and ctenophores were counted in total or through sub-samples containing ! 200 individuals. Total volume of each species was deter- mined, and up to 25 individuals were measured (bell diameter or length). Below, we describe the patterns found in the surface layer and near the surface in shallow waters. The seasonal progression of abundances and spatial distributions of sea nettles and ctenophores created a temporally shifting landscape of habitat that varied in suitability for important ecological engineers, including the Eastern oyster. In mid-May, ctenophores appeared in low abundances at sampling sites in the main stem Patuxent River and one of the three sampled tributaries, but no sea-nettle medusa were collected at any site (Fig. 6B). By early June, ctenophores were abundant in surface waters at all sampling sites, including the most upstream shallow sites within each of the tributaries (Fig. 6C). Sea nettles had begun to appear in the tributaries, but were primarily small individuals averaging 2.4-cm bell diameter, and were below the 0.16 ind m À 3 density at which they can eliminate ctenophores in the field (Breitburg and Fulford 2006). During the next few weeks, densities and sizes of sea nettles increased, especially in the tributaries so that by 11 August there was near-complete separation of the two gelatinous species with large populations of sea nettles in the tributaries and large populations of ctenophores in the main stem river (Fig. 6D). The spatial patterning in the predation landscape created by spatial patterns of abundances and subtle differences in the diets of the two gelatinous species potentially had strong consequences for other organisms (Fig. 6E). At biovolumes found in the main stem river, ctenophores could consume the majority of oyster larvae (Breitburg and Fulford 2006), potentially reducing or eliminating local recruitment by this important ecosystem engineer. In contrast, the protective effect of sea nettles created a refuge from predation by ctenophores in tributary creeks, potentially increasing local recruitment of oysters. In the absence of filtration by oysters, a larger fraction of the phytoplankton biomass in the main stem river would likely go un-grazed, sinking into the bottom layer as cells senesce, and die, and providing sub- strate for microbial decomposition that consumes oxygen and leads to hypoxia or anoxia. In the presence of filtration by oysters in the tributaries, phytoplankton densities and their effect on light penetration could be reduced, thereby improving habitat suitability for submersed macrophytes. In summary, PMLS has the potential to strongly influence the spatial pattern of ecosystem engineers and their effect in the aquatic landscape. This form of predatory control represents a potential mechanis- tic and conceptual bridge between trophic ecology and ecosystem engineering. The combined trophic control (by gelatinous zooplankton) and engineering (by oysters) can greatly alter the physical habitat for a wide range or organisms and have cascading effects translated through a series of engineers (oysters, phytoplankton, SAV), each affecting the other. The examples we provide demonstrate the profound effects that ecosystem engineers ranging from bacteria to gelatinous zooplankton have on their environment. Ecosystem engineers in the pelagic realm and near-shore water column create physiologically meaningful oxygen structure, create and eliminate toxicity, influence water motion and circulation, and affect the penetration of light, the amount and distribution of heat, and the depth of stratification. In addition, consumers alter landscape structure through trophic control of structural ecosystem engineers. We provide the example of PMLS to high- light the importance of linkages between food web and engineering activities on aquatic landscape structure. We also intentionally include effects of microbial metabolism because they so completely transform the suitability of the water column habitat for organisms that are dependent on aerobic respiration or are susceptible to the toxic effects of sulfides. Although these microbial ‘‘engineers’’ are smaller, the process is fundamentally the same as described for ...
Context 2
... carry a portion of the surrounding fluid with it. The amount of fluid carried with the object relative to its size depends only on the shape of the object. Furthermore, viscosity in the fluid increases the amount of fluid trans- ported by the solid object. Using this mechanism as their foundation, Katija and Dabiri (2009) proposed a more direct mechanism of fluid transport by plankton and nekton: as the animals migrate, their solid bodies carry along a portion of the local fluid; hence, the local water and its contained chemicals and nutrients are also trans- ported. This provides a potentially powerful mechanism of ecosystem engineering because it suggests that when swimming organisms transport themselves to new environments, they also take a portion of the original environment with them. Depending on the circumstances, this may either alleviate or exacerbate extreme environments, e.g., where hypoxia or eutrophication is near threshold levels. It also presents an opportunity for animals to actively support the chemical and biological processes on which they ultimately depend. For example, by transporting from deeper water the necessary nutrients to promote photosynthesis at the ocean’s surface, the animals can ensure sufficient phytoplankton and the products of photosynthesis at lower trophic levels to support their diet. Direct evidence for the mechanism of induced drift is currently limited to the field experiments of Katija and Dabiri (2009), which studied the fluid transport achieved by jellyfish in a marine lake in Palau. By tracking dye markers delivered into the water near animals using SCUBA techniques, they observed the drifting process in situ (Fig. 4). Their data are consistent with the concept that animals carry the surrounding fluid with them as they migrate. To fully appreciate the potential of marine organisms to act at engineers of their ecosystems, further research on the physics, biology, and chemistry of the mixing processes is needed. It seems likely that the diversity of animals’ shapes and swimming kine- matics will be reflected in varied impacts on water transport in the ocean. The sensitivity of local ecosystems to biogenic mixing will depend intimately on the population dynamics of local animals (e.g., which animals are present and to what degree), and the local water chemistry and its spatial variation. In many cases, opportunities will exist for complex feedback loops between animal populations and the surrounding milieu. Trophic interactions and ecosystem engineering have typically been considered distinct classes of ecological processes that alter the suitability of a habitat in quite different ways. In practice, however, the ability of consumers to affect spatial distributions of engineers, and thus the location, extent, and characteristics of the engineered landscape blur that distinction (Jones et al. 1994). Classic examples of keystone species include direct or indirect control by predators of organisms that create or modify the physical habitat in terrestrial, marine, and freshwater environments (Paine 1966; Estes and Palmisano 1974; Power et al. 1996). A particular kind of spatially varying trophic in- teraction, which we call ‘‘predator-mediated landscape structure’’ (PMLS) may form an important link between the trophic and engineering mechanisms of ecological control. PMLS is a case in which consumers, themselves, create a landscape mosaic that varies in suitability for their prey and the species with which their prey interact. Where PMLS affects the abundance or distribution of ecosystem engineers, it can either directly or indirectly control characteristics and the landscape-level orga- nization of the engineered environment. PMLS may be especially important in aquatic environments in which physical variation within the pelagic habitat has less effect than do trophic interactions in defin- ing the spatial pattern of survival probabilities of species. We provide an example of PMLS based on a study of the distribution of gelatinous zooplankton in the Patuxent River (a sub-estuary of Chesapeake Bay; Fig. 6A) and its tributaries by Breitburg et al. (2009). Two gelatinous zooplanktonic species—the scyphomedusa Chrysaora quinquecirrha (sea nettle) and the lobate ctenophore Mnemiopsis leidyi (referred to as ctenophores, below) are dominant consumers in Chesapeake Bay (Purcell and Decker 2005) that can directly and indirectly control abundances of an important ecosystem engineer, the Eastern oyster Crassostrea virginica (Fig. 5). Ctenophores consume oyster larvae, but sea nettles reject these prey or ejest them unharmed (Purcell et al. 1991). Oysters provide a wide range of ecosystem services including creation of physical habitat and improve- ment of water clarity (Coen et al. 2007; Grabowski and Peterson 2007). Filtration of water by oysters also has cascading effects in an environment by affecting other ecosystem engineers such as phytoplankton and submersed macrophytes (Fig. 5). Gelatinous zooplankton were sampled at 12 sites with a 244- m m mesh 1-m 2 Tucker trawl weekly during summer of 2004. Duplicate tows of surface and bottom layers, each lasting 90 seconds and sampling an average of 51 m 3 , were taken at each site on each date. Sea nettles and ctenophores were counted in total or through sub-samples containing ! 200 individuals. Total volume of each species was deter- mined, and up to 25 individuals were measured (bell diameter or length). Below, we describe the patterns found in the surface layer and near the surface in shallow waters. The seasonal progression of abundances and spatial distributions of sea nettles and ctenophores created a temporally shifting landscape of habitat that varied in suitability for important ecological engineers, including the Eastern oyster. In mid-May, ctenophores appeared in low abundances at sampling sites in the main stem Patuxent River and one of the three sampled tributaries, but no sea-nettle medusa were collected at any site (Fig. 6B). By early June, ctenophores were abundant in surface waters at all sampling sites, including the most upstream shallow sites within each of the tributaries (Fig. 6C). Sea nettles had begun to appear in the tributaries, but were primarily small individuals averaging 2.4-cm bell diameter, and were below the 0.16 ind m À 3 density at which they can eliminate ctenophores in the field (Breitburg and Fulford 2006). During the next few weeks, densities and sizes of sea nettles increased, especially in the tributaries so that by 11 August there was near-complete separation of the two gelatinous species with large populations of sea nettles in the tributaries and large populations of ctenophores in the main stem river (Fig. 6D). The spatial patterning in the predation landscape created by spatial patterns of abundances and subtle differences in the diets of the two gelatinous species potentially had strong consequences for other organisms (Fig. 6E). At biovolumes found in the main stem river, ctenophores could consume the majority of oyster larvae (Breitburg and Fulford 2006), potentially reducing or eliminating local recruitment by this important ecosystem engineer. In contrast, the protective effect of sea nettles created a refuge from predation by ctenophores in tributary creeks, potentially increasing local recruitment of oysters. In the absence of filtration by oysters, a larger fraction of the phytoplankton biomass in the main stem river would likely go un-grazed, sinking into the bottom layer as cells senesce, and die, and providing sub- strate for microbial decomposition that consumes oxygen and leads to hypoxia or anoxia. In the presence of filtration by oysters in the tributaries, phytoplankton densities and their effect on light penetration could be reduced, thereby improving habitat suitability for submersed macrophytes. In summary, PMLS has the potential to strongly influence the spatial pattern of ecosystem engineers and their effect in the aquatic landscape. This form of predatory control represents a potential mechanis- tic and conceptual bridge between trophic ecology and ecosystem engineering. The combined trophic control (by gelatinous zooplankton) and engineering (by oysters) can greatly alter the physical habitat for a wide range or organisms and have cascading effects translated through a series of engineers (oysters, phytoplankton, SAV), each affecting the other. The examples we provide demonstrate the profound effects that ecosystem engineers ranging from bacteria to gelatinous zooplankton have on their environment. Ecosystem engineers in the pelagic realm and near-shore water column create physiologically meaningful oxygen structure, create and eliminate toxicity, influence water motion and circulation, and affect the penetration of light, the amount and distribution of heat, and the depth of stratification. In addition, consumers alter landscape structure through trophic control of structural ecosystem engineers. We provide the example of PMLS to high- light the importance of linkages between food web and engineering activities on aquatic landscape structure. We also intentionally include effects of microbial metabolism because they so completely transform the suitability of the water column habitat for organisms that are dependent on aerobic respiration or are susceptible to the toxic effects of sulfides. Although these microbial ‘‘engineers’’ are smaller, the process is fundamentally the same as described for macrophytes by Caraco et al. (2006), who sug- gest that the most important chemical change engineered by organisms may be their effect on oxygen levels. There are many examples of organisms that create complex 3D structure in the pelagic realm at scales ranging from millimeters to kilometers in addition to those described in detail above. For example, another way that both phytoplankton and bacteria affect the physical structure of the water column is through their ...

Citations

... As top predators, gelatinous zooplankton have long been considered trophic dead-ends. However, their role as a source of nitrogen-rich organic matter for microbes (Condon et al., 2011) and biological engineers in the pelagic environment (Breitburg et al., 2010) is being increasingly recognized. Gelatinous zooplankton carcasses decompose faster than nongelatinous zooplankton (e.g., copepods), and their decomposition affects the bacterial phylotypes in microbial assemblages and may accelerate the nitrogen cycle (Kos Kramar et al., 2019;Tinta et al., 2010Tinta et al., , 2012Tinta et al., , 2016Chapter 7). ...
Chapter
Mesozooplankton and gelatinous zooplankton communities in Chesapeake Bay (CB) and the northern Adriatic Sea (NAS) have been subject to similar stressors over recent decades, including warming waters, overfishing, urbanization, and eutrophication. Direct comparisons between the systems are clouded by the lack of standardized and sustained long‐term monitoring programs in both, which have covered different temporal and spatial scales, and employed different methodologies. Data that are available show that the systems differ in community composition, with CB having fewer species compared with the more diverse NAS. Both systems have seen an altered gelatinous zooplankton community over recent decades. In the NAS, these changes in part have been due to the recent introduction of nonindigenous species, a phenomenon not yet documented in CB. Chesapeake Bay has seen a long‐term decline in the abundance of the dominant copepod taxa, attributed to increases in ctenophore abundance and/or increased seasonal hypoxia. Given the importance of mesozooplankton and gelatinous organisms in marine food webs, it is imperative that future ecosystem‐based management efforts for marine resources include coordinated, consistent, and standardized monitoring of mesozooplankton and gelatinous zooplankton. Such data would allow for the development of robust indices to help achieve management goals for water quality, ecosystem health, and marine resources.
... As top predators, gelatinous zooplankton have long been considered trophic dead-ends. However, their role as a source of nitrogen-rich organic matter for microbes (Condon et al., 2011) and biological engineers in the pelagic environment (Breitburg et al., 2010) is being increasingly recognized. Gelatinous zooplankton carcasses decompose faster than nongelatinous zooplankton (e.g., copepods), and their decomposition affects the bacterial phylotypes in microbial assemblages and may accelerate the nitrogen cycle (Kos Kramar et al., 2019;Tinta et al., 2010Tinta et al., , 2012Tinta et al., , 2016Chapter 7). ...
... This could potentially lead to shifts in the abundance and biogeographic distribution of jellyfish species. Additionally, natural habitat loss caused by the destruction of oyster reefs may also affect the population and spatial dynamics of jellyfish species, as the polyp stage prefers hard substrate for settlement (Breitburg and Fulford 2006, Breitburg et al. 2010, Hubot et al. 2017. Within estuarine systems, settlement and growth of polyp colonies often occur in semisheltered, shallow areas (Cargo and Schultz 1966, Purcell and Grover 1990, Purcell 1992, Olesen et al. 1994, Breitburg and Burrell 2014, Shahrestani and Bi 2018. ...
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Untangling organisms' multi-scale spatial distributions is challenging due to their interactions with environments at multiple spatial and temporal scales. We deployed an Adaptive Resolution Imaging Sonar (ARIS) in a Chesapeake Bay sub-estuary to investigate multi-scale spatial distributions of the bay nettle (Chrysaora chesapeakei) in May-September of 2016 and 2017. Nettles were found to be dispersed in aggrega-tions of multiple individuals. The average density of bay nettles in 2017 was higher than in 2016. Small aggre-gations (<5 m) were persistent in both years but only contributed <10% of total observed nettles. Large patches (>30 m) contributed~40% of the total observed nettles. Large patches were more common in creek habitat where nettle density was higher. Nettle density was found to hit a peak value once in 2016, while there were two density peaks in 2017. Different aggregation patterns were observed during the second peak period in 2017 in which the number of large patches increased dramatically. Within the surveyed waterscape, the spatial patterns were consistent over time with higher abundance in the source creek than in the river channel, which underscores that C. chesapeakei requires hard substrate in shallow creeks for its benthic polyp stage. Using the ratio between nettles in the creek and near creek mouth as a proxy for dispersal rate, more nettles were transported out of the creek in 2017 than in 2016. The increase in patch size and high dispersion rate in peak periods in 2017 suggests that individuals were moving out of the creek habitat as density increased. Results highlight the complex spatial structure of bay nettles, which has major impacts on density estimates and subsequently affects our understanding of jellyfish population dynamics and long-term trends.
... Determining whether migratory species of zooplankton can indeed be considered ecosystem engineers has proved challenging [1,2]. While in situ studies of swimming jellyfish have shown that self-propelled swimmers may achieve large scale transport via Darwinian drift [3], coastal field microscale measurements in the vicinity of migrating krill aggregations have commonly detected low turbulence production, e.g. ...
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Understanding the hydrodynamics of self-propelled organisms is critical to evaluate the role of migrating zooplankton aggregations in sustaining marine ecosystems via transport of nutrients and mixing of fluid properties. Analysis of transport and mixing during swimming is thus essential to assess whether biomixing is a relevant source of kinetic energy in the upper ocean. In this study, dilute swarms of the ephyral \emph{Aurelia aurita} were simulated under different configurations to analyze the effects of inter-organism spacing and structure of a migrating aggregation on fluid transport. By using velocimetry data instead of numerically simulated velocity fields, our study integrates the effects of the near- and far-field flows. Lagrangian analysis of simulated fluid particles, both in homogeneous and stratified fluid, shows that the near-field flow ultimately dictates fluid dispersion. The discrepancy between our results and predictions made using low-order models (both in idealized fluid and within the Stokes limit) highlights the need to correctly represent the near-field flow resulting from swimming kinematics and organism morphology. Derived vertical stirring coefficients for all cases suggest that even in the limit of dilute aggregations, self-propelled organisms can play an important role in transporting fluid against density gradients.
... Alligators (Alligator mississippiensis) rearrange sediments and remove vegetation, creating small ponds (alligator holes) that sustain many aquatic and semiaquatic vertebrates and invertebrates ( Figure 1C) [63,64]. APs can also engineer ecosystems via trophic interactions, whereby predators influence other organisms that create or modify habitat [65]. For example, sea otters (Enhydra lutris) feed on herbivorous sea urchins that would otherwise consume kelp, thereby promoting kelp forests and several kelp-associated fishes and invertebrates [66]. ...
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Arguments for the need to conserve aquatic predator (AP) populations often focus on the ecological and socioeconomic roles they play. Here, we summarize the diverse ecosystem functions and services connected to APs, including regulating food webs, cycling nutrients, engineering habitats, transmitting diseases/parasites, mediating ecological invasions, affecting climate, supporting fisheries, generating tourism, and providing bioinspiration. In some cases, human-driven declines and increases in AP populations have altered these ecosystem functions and services. We present a social ecological framework for supporting adaptive management decisions involving APs in response to social and environmental change. We also identify outstanding questions to guide future research on the ecological functions and ecosystem services of APs in a changing world.
... The dynamics of coastal benthic communities are mediated by a combination of physical, chemical and biological processes. Benthic species are known to be active agents in the interaction between these different components (Berke et al., 2010;Breitburg et al., 2010;Callaway et al., 2010;Woodin et al., 2010). On Algodoal-Maiandeua Island, the presence of D. cuprea tubes is associated with fine sediments. ...
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Tube-building polychaetes are an important group of marine bioengineers in soft-bottom habitats, where they provide structures that potentially influence the composition of the benthic community. The present study investigated the effects of Diopatra cuprea tubes on the structure of the macrobenthic fauna found on a sandy beach of the Amazon coast. Samples were collected in June (rainy season) and September (dry season) 2012 in two different areas: (1) an area in which D. cuprea tubes were present, and (2) a control area, in which worm tubes were absent. A total of 53 taxa were found, of which 30 were associated exclusively with D. cuprea tubes. While large aggregations of D. cuprea were not found in the study area, the presence of even a single tube may have a significant influence on the environmental conditions available for other organisms, especially those adapted to consolidated or muddy substrates. The two areas presented different seasonal patterns. A significant increase in the abundance and richness of the macrofauna was observed in area 1 in the rainy season, when the density of worm tubes increased and the hydrodynamic conditions were less intense. The results of the study highlight the importance of this organism as an ecosystem engineer on the sandy beaches of the Amazon coast.
... Community structure is typically defined by the dominant species present or those that structure or engineer the system ( Breitburg et al. 2010). In Barnegat Bay, the increase in abundance of Chrysaora quinquecirrha over the last decade has changed the pelagic trophic structure to where this species assumed the role of an apex predator and exerted strong top-down control of the food web ( Bologna et al. 2017). ...
Article
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... More recently, their proliferation in the North and Baltic seas has generated substantial research into the potential top-down and competitive structuring forces in pelagic food webs (Hosia and Titelman, 2011;Javidpour et al., 2009;Kellnreitner et al., 2013; but see Hamer, Malzahn, and Boersma, 2011;Jaspers et al., 2011) and species interactions between M. leidyi and other gelatinous zooplankton species (Riisgård, Barth-Jensen, and Madsen., 2010;Riisgård et al., 2012). Within its native range, M. leidyi has always played an important role in pelagic food webs (Deason and Smayda, 1982;Mountford, 1980;Nelson, 1925), but with increasing anthropogenic stresses related to eutrophication and overfishing, their relative abundance and influence on communities has led to broader structuring effects in coastal communities (Breitburg et al., 2010;McNamara, Lonsdale, and Cerrato, 2010;. Often, it is the interactions and predatorprey relationships of other gelatinous zooplankton that seem to balance communities or minimize the impacts of M. leidyi as a keystone species (Hosia and Titelman, 2011;Purcell and Cowan, 1995;Tilves et al., 2013). ...
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... Marine turtles http://dx.doi.org/10.1016/j.jembe.2017.08.009 Received 10 December 2016; Received in revised form 2 July 2017; Accepted 22 August 2017 provide habitats that are favorable to a diverse range of organisms, which, in turn, can play bio-constructing or bio-engineering roles on the carapaces themselves by modifying the carapace habitat and interacting with other species, thereby affecting community structure and diversity of the whole epibiont community, and this on different spatial and temporal scales (Breitburg et al., 2010;Corrêa et al., 2014;Jones et al., 1997). ...
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Although nematodes are the most abundant metazoans in marine environments and present an important biological and ecological model organism to assess marine ecosystem processes and functions, there are in fact very few studies that use nematodes to investigate ecological communities and relationships on "mobile" ecosystems. Arguably one of the most mobile or dynamic marine ecosystems is a sea turtle carapace, hosting tens to hundreds or even thousands of epibiotic organisms; and as the turtle breeds, feeds and migrates, provides an ecosystem that is continuously exposed to changes and potential colonizers. In this study we investigated the nematode communities associated with 19 Hawksbill sea turtle carapaces (Eretmochelys imbricata), and compared nematode structural (composition, richness and diversity) and functional (trophic types and gender/life stages) community parameters with those of other comparable epibiotic substrates (macrophytes, natural and artificial hard substrates) to see whether turtle carapaces are hotspots of nematode diversity and function among substrates suitable for epifauna. We also addressed potential epibiotic macrofauna-nematode interactions by looking at the relationships between macrofauna richness and nematode richness, diversity and community composition. Results suggest that the macrofauna play a bioconstructing role, creating several microenvironments, and thereby enhancing the richness and diversity of the associated nematode assemblages. This was supported by a direct and positive relationship between macrofauna and nematode richness, and implies a genera enrichment process across size classes and phyla. All heterotrophic nematode feeding guilds were recovered from the carapaces, with dominance of predators/omnivores and epistrate feeders. Nematode juveniles dominated in terms of abundance, and a female/male ratio of 1.11 was observed. Nematode richness and diversity were higher than found on other substrates, but feeding guild, gender and life stage structure did not differ compared to nematode communities from all other epibiotic substrates. As a result, we argue that turtle carapaces can be seen as hotspots for nematode biodiversity compared to other epibiotic substrates, but this is not reflected in the function of the nematode community. This study is the first to investigate in detail sea turtle carapace nematode communities, their richness, diversity, trophic and life cycle structure, and potential interactions with their co-epibionts, the macrofauna.
... Only recently have some begun to explore the potential for other marine organisms to act as ecosystem engineers. Examples in the open ocean include phytoplankton and zooplankton (Jones et al., 1994;Breitburg et al., 2010), and baleen and sperm whales (Roman et al., 2014). ...
... They are critical to ecosystem function, and their abundance and biomass determines the distribution and productivity of marine life (Chassot et al., 2010;Watson et al., 2015). However, plankton may also be considered ecosystem engineers-affecting the photic, chemical and thermal regimes of water and consequently the suitability of that habitat for other life (Haury et al., 1978;Duffy and Stachowicz, 2006;Breitburg et al., 2010). For example, Antarctic krill (Euphausia superba) are a fundamental food source for predators from squid to baleen whales (Constable et al., 2000), play a major role in ocean productivity by recycling iron in surface waters , alter organic matter and trace element concentrations in surface waters during molting (Nicol and Stolp, 1989), and may be an important carbon sink (Swadling, 2006;Tarling and Johnson, 2006). ...
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Areas beyond national jurisdiction (ABNJ) lie outside the 200 nautical mile limits of national sovereignty and cover 58% of the ocean surface. Global conservation agreements recognize biodiversity loss in ABNJ and aim to protect ≥10% of oceans in marine protected areas (MPAs) by 2020. However, limited mechanisms to create MPAs in ABNJ currently exist, and existing management is widely regarded as inadequate to safeguard biodiversity. Negotiations are therefore underway for an “internationally legally binding instrument” (ILBI) to the United Nations Convention on the Law of the Sea to enable biodiversity conservation beyond national jurisdiction. While this agreement will, hopefully, establish a mechanism to create MPAs in ABNJ, discussions to date highlight a further problem: namely, defining what to protect. We have a good framework for terrestrial and coastal habitats, however habitats in ABNJ, particularly the open ocean, are less understood and poorly defined. Often, predictable broad oceanographic features are used to define open ocean habitats. But what exactly, constitutes the habitat—the water, or the species that live there? Complicating matters, species in the open sea are often highly mobile. Here, we argue that mobile marine organisms provide the structure-forming biomass and constitute “habitat” in the open ocean. For an ABNJ ILBI to offer effective protection to marine biodiversity it must consider habitats a function of their inhabitants and represent all marine life within its scope. Only by enabling strong protection for every element of biodiversity can we hope to be fully successful in conserving it.