Part I. Introduction to the Nature of Monitoring Problems and to Rivers: 1. Why we need well-designed monitoring programs 2. The ecological nature of flowing waters 3. Assessment of perturbation Part II. Principles of Inference and Design: 4. Inferential issues for monitoring 5. The logical bases of monitoring design 6. Problems in applying designs 7. Alternative models for impact assessment Part III. Applying Principles of Inference and Design: 8. Applying monitoring designs to flowing waters 9. Inferential uncertainty and multiple lines of evidence 10. Variables that are used for monitoring in flowing waters 11. Defining important changes 12. Decisions and trade-offs 13. Optimization 14. The special case of monitoring attempts at restoration 15. What's next?

Monitoring Ecological Impacts – Concepts and Practice in Flowing Waters

The present work summarizes the progress attained in the study of sponge larval ecology since the state-of-the-art reviews performed in the 1970s and stresses the major weaknesses in our current understanding. Most available information on this subject comes from laboratory studies, with just occasional field observations or experiments. The data are also strongly biased because they are mostly derived from just one larval type out the eight types known in the phylum Porifera. Descriptive studies on larval histology are relatively abundant, but investigations directed at unravelling the cytological basis of the main larval behaviors are scarce. Most aspects of basic larval metabolism and sensing processes remain largely not investigated. Modelling of larval ecology is virtually lacking, with no serious attempt to investigate how the major features of larval ecology affect the structure and dynamics of sponge populations. In summary, the ecology of the sponge larva needs further research attention if we ar...

The ecology of the sponge larva

Demosponges are considered part of the most basal evolutionary lineage in the animal kingdom. Although the sponge body plan fundamentally differs from that of other metazoans, their development includes many of the hallmarks of bilaterian and eumetazoan embryogenesis, namely fertilization followed by a period of cell division yielding distinct cell populations, which through a gastrulation-like process become allocated into different cell layers and patterned within these layers. These observations suggest that the last common ancestor (LCA) to all living animals was developmentally more sophisticated than is widely appreciated and used asymmetric cell division and morphogen gradients to establish localized populations of specified cells within the embryo. Here we demonstrate that members of a range of transcription factor gene classes, many of which appear to be metazoan-specific, are expressed during the development of the demosponge Reniera, including ANTP, Pax, POU, LIM-HD, Sox, nuclear receptor, Fox (forkhead), T-box, Mef2, and Ets genes. Phylogenetic analysis of these genes suggests that not only the origin but the diversification of some of the major developmental metazoan transcription factor classes took place before sponges diverged from the rest of the Metazoa. Their expression during demosponge development suggests that, as in today's sophisticated metazoans, these genes may have functioned in the regulatory network of the metazoan LCA to control cell specification and regionalized gene expression during embryogenesis.

Developmental expression of transcription factor genes in a demosponge: insights into the origin of metazoan multicellularity

Sponges (phylum Porifera) are a diverse taxon of benthic aquatic animals of great ecological, commercial, and biopharmaceutical importance. They are arguably the earliest-branching metazoan taxon, and therefore, they have great significance in the reconstruction of early metazoan evolution. Yet, the phylogeny and systematics of sponges are to some extent still unresolved, and there is an on-going debate about the exact branching pattern of their main clades and their relationships to the other non-bilaterian animals. Here, we review the current state of the deep phylogeny of sponges. Several studies have suggested that sponges are paraphyletic. However, based on recent phylogenomic analyses, we suggest that the phylum Porifera could well be monophyletic, in accordance with cladistic analyses based on morphology. This finding has many implications for the evolutionary interpretation of early animal traits and sponge development. We further review the contribution that mitochondrial genes and genomes have made to sponge phylogenetics and explore the current state of the molecular phylogenies of the four main sponge lineages (Classes), that is, Demospongiae, Hexactinellida, Calcarea, and Homoscleromorpha, in detail. While classical systematic systems are largely congruent with molecular phylogenies in the class Hexactinellida and in certain parts of Demospongiae and Homoscleromorpha, the high degree of incongruence in the class Calcarea still represents a challenge. We highlight future areas of research to fill existing gaps in our knowledge. By reviewing sponge development in an evolutionary and phylogenetic context, we support previous suggestions that sponge larvae share traits and complexity with eumetazoans and that the simple sedentary adult lifestyle of sponges probably reflects some degree of secondary simplification. In summary, while deep sponge phylogenetics has made many advances in the past years, considerable efforts are still required to achieve a comprehensive understanding of the relationships among and within the main sponge lineages to fully appreciate the evolution of this extraordinary metazoan phylum.

Deep Phylogeny and Evolution of Sponges (Phylum Porifera)

The origin of nervous systems has traditionally been discussed within two conceptual frameworks. Input–output models stress the sensory-motor aspects of nervous systems, while internal coordination models emphasize the role of nervous systems in coordinating multicellular activity, especially muscle-based motility. Here we consider both frameworks and apply them to describe aspects of each of three main groups of phenomena that nervous systems control: behaviour, physiology and development. We argue that both frameworks and all three aspects of nervous system function need to be considered for a comprehensive discussion of nervous system origins. This broad mapping of the option space enables an overview of the many influences and constraints that may have played a role in the evolution of the first nervous systems.

/pdf/an-option-space-for-early-neural-evolution-dht65cxq92.pdf

An option space for early neural evolution.

Phragmatopoma spp are marine, reef-building polychaetes that inhabit the intertidal and shallow subtidal zones of both coasts of the Americas Phragmatopoma californica is found in the Pacific Ocean along the California coast south to Mexico, while Phragmatopoma caudata inhabits the Caribbean islands and Atlantic Ocean from the Florida coast south to Brazil Although apparently geographically isolated, P californica and P caudata have been found to interbreed (Pawlik 1988a) and thus their specific taxonomic relationship has been unclear In this study, two genes, cytochrome c oxidase subunit I (COI) and the first internal transcribed spacer region (ITS-1), were sequenced to assess the specific status of P californica and P caudata as well as Phragmatopoma virgini Comparison of sequences revealed that samples of P californica shared no COI haplotypes or ITS-1 sequences with P caudata Phylogenetic analyses, including maximum parsimony and Bayesian methods, clustered each species in separate, well-supported clades with genetic distances between them being greater than between either contested species or the uncontested, valid species, P virgini Thus, the molecular data support that P californica and P caudata are separate species However, the sample of individuals of P virgini included one genetically divergent individual, whose morphology was found to match that of a species formerly recognized as P moerchi but since synonymized with P virgini Divergences among lineages were dated using the COI sequences, after adjustment for non-clock-like behavior Consequently, we suggest that P virgini and P caudata are sister taxons and that P californica diverged from the P virgini/P caudata clade ∼57 mya with P virgini diverging from P caudata ∼3 mya

Molecular relationships and species divergence among Phragmatopoma spp. (Polychaeta: Sabellaridae) in the Americas

Water-borne gametes are known to cue mass spawning in externally fertilizing marine invertebrates. In motile animals, such as sea urchins, they might also cue behavior to enhance fertil- ization success by either (1) increasing movement and thus the number of intraspecific encounters for numerous small-scale events or (2) causing the formation of small-sized aggregations for single spawning events. This study investigated the ability of water-borne gametes to induce spawning and aggregation behavior in the echinoid Lytechinus variegatus. In the field, 1 individual from each of 40 pairs of urchins was induced to spawn to test whether spawning would be induced in the other urchin. Additionally, 5 urchins were induced to spawn upstream from 20 individuals placed in a group. Thirteen replicates of this experiment were conducted to test whether the larger volume of gametes combined with more urchins would induce spawning. Ripe and nonripe urchins were also videotaped in a 2 m diameter pool with and without sperm in the water (n = 3). All urchins were found to move rapidly (50 cm min -1 ), although the amount of movement, distance apart, and number and duration of encounters was the same regardless of their reproductive status or the presence/absence of sperm in the water. Urchins never spawned in response to water-borne gametes although most were found to be ripe.

/pdf/effects-of-water-borne-gametes-on-the-aggregation-behavior-2tqubh1hul.pdf

Effects of water-borne gametes on the aggregation behavior of Lytechinus variegatus

. In Florida, the reef-building polychaete Phragmatopoma lapidosa is important in enhancing local biodiversity via the shelter it provides for various fish and invertebrate species. While the range of P. lapidosa extends south to Brazil, it is rare to find well-established populations in the Caribbean islands. In this study, we examined an intertidal worm reef recently discovered in St. Croix, U.S. Virgin Islands. The worm species was positively identified as P. lapidosa (also known as P. caudata). Analyses of measured worm lengths and mound photographs revealed multiple size cohorts that likely included recent recruits, and mature adults. An examination of the organisms living within small worm clumps collected from the reef, revealed a number of invertebrates including various mollusks, crabs, shrimp and echinoids. Combined, these data suggest that continuous recruitment is likely to maintain this worm reef which is similar to Florida worm reefs, and likely to enhance local biodiversity in St. C...

https://bioone.org/journals/caribbean-journal-of-science/volume-44/issue-2/cjos.v44i2.a10/The-Ecological-Importance-of-a-Recently-Discovered-Intertidal-Sabellariid-Reef/10.18475/cjos.v44i2.a10.pdf

The Ecological Importance of a Recently Discovered Intertidal Sabellariid Reef in St. Croix, U.S. Virgin Islands

Islands in the Sand: Ecology and Management of Nearshore Hardbottom Reefs of East Florida

The primary anthropogenic impacts to shallow nearshore reefs of east Florida occur from their burial by large quantities of sediments (fill) that are imported to widen beaches. Most of these projects involve the excavation and dumping of 300,000 to 1,500,000 cubic yards of sediments. Fill projects can also subject deeper hardbottom systems to elevated levels of sedimentation and turbidity. We characterize stressors in terms of potential responses by diverse algae, invertebrate, fish, and sea turtle species in systems that are already subject to high levels of natural turbidity, particularly in northern regions of the study area. Individuals of almost all species of macroalgae and invertebrates that are physically attached to nearshore hardbottom will die within several days after their habitats are completely buried. This is also the case for >30 species of cryptic fishes. Large burial events can terminate reproductive outputs from these habitats over multiple years which can affect local and downstream population replenishment. Due to impacts on nearshore hardbottom and coral resources, federal, state, and local agencies manage permitting provisions within state and federal laws with a focus on mitigating impacts by use of artificial reefs. We summarize some attributes of structure and placement of artificial reefs used for nearshore reef mitigation in east Florida. The effects of mitigation upon algae, invertebrates, fishes, and sea turtles are characterized with a focus that includes monitoring studies to improve the measurement and ultimate performance of efforts to compensate for habitat loss in dynamic in dynamic, shallow-water environments.

Management of Nearshore Hardbottom Reef Resources

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