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Coastal and deep-sea benthic diversities compared
Abstract and Figures
Most generalisations about marine benthic diversity (species richness) are derived from few studies, few samples and low species numbers. It is questionable whether the data on which most paradigms, especially about the deep sea, are based truly represent general patterns of marine diversity. Available information from deep-sea studies are summarised and compared with some extensive data sets from the shallow coasts of Norway and Australia. We show that species richness per unit area is as high, if not higher in shallow sedimentary habitats as was reported for the deep-sea data by Grassle & Maciolek (1992; Am Nat 139:313-341). Apparent high diversity in the deep sea may be explained, in part, by the vast area of this environment. All surveys in both the deep-sea and coastal habitats are shown to traverse a variety of microhabitats and thus sediment heterogeneity is not an explanation for the high species richness in coastal environments.
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... The infauna of Port Phillip Bay is relatively rich in species compared to elsewhere in the world and has been described as 'species-packed' (Barnard and Drummond 1978;Gray et al. 1997). It comprises a large fraction of the Bay wide biomass and the suspension feeding molluscs process a significant fraction of primary planktonic production (Crawford et al. 1992;Wilson et al. 1993). ...
This report describes the existing conditions relating to the infauna of Port Phillip Bay and part of the Marine Ecology Specialist Studies of the PoMC Channel Deepening EES. This information provides a basis for the risk assessment, impact assessment and environmental management components of the EES. The methods used a suction sampler. Key words: Port Phillip Bay, channel deepening, dredging, EES, infauna, sediment biota.
... In the case of the deep marine benthos -the environment in the context of which the biological cropping hypothesis is most often discussed (Dayton and Hessler 1972) -it is not even certain that diversity is actually unusually high (McClain and Schlacher 2015). The elevated diversity of the deep marine realm is often cited as an unusual ecoevolutionary phenomenon, requiring explanation (Gooch and Schopf 1972;White 1988;Gage 1996), but empirical datasets are sparse (Gray et al. 1997), and empirical analyses of the shape of the diversity-depth relationship have produced mixed results (Smith and Brown 2002;Olabarria 2006;Bridges et al. 2022). Further empirical study of the diversity and structure of deep-sea ecosystems, and the life-histories of their inhabitants, is therefore required to determine to what degree these ecosystems meet the theoretical requirements for biological cropping to play a role in influencing their diversity. ...
Ecological disturbance has been proposed to have a variety of effects on biodiversity. These mechanisms are well studied over shorter timescales through experimental manipulation of ecosystems, but the effect of disturbance on longer timescales, where evolutionary processes operate, is less well understood. This is at least in part because evolutionary processes are too slow to observe in experimental manipulations of ecosystems. Here, we use the Rapid Evolutionary Simulator system (REvoSim) to solve this problem. REvoSim is a spatially explicit, agent-based simulation tool that models both ecological and evolutionary processes and is capable of simulating many thousands of generations of evolution per hour in a population of up to 1 million organisms. We use REvoSim to evaluate the biological cropping hypothesis, which predicts that the non-selective culling of organisms from populations (“cropping”) can enhance diversity in those populations over long timescales by reducing the homogenising effects of competitive exclusion. Our experiments demonstrate that cropping alone can increase diversity within populations under certain circumstances: those where it has the net effect of reducing the selection pressure acting on those populations. However, intense cropping pressure may increase the selection pressure on organisms to reproduce rapidly, potentially offsetting the effects of reduced competitive exclusion on diversity. We also show that cropping alone is not sufficient to result in reproductive isolation within populations. This implies that, while cropping can maintain a high species diversity within an ecosystem, additional mechanisms must be invoked to generate that high diversity in the first instance.
... In cases where the species does not occur in this region, we suggested which local species may be represented by the sequences in question based on taxonomic information. As estuaries have low diversity because few species can tolerate fluctuations in environmental conditions (Gray et al., 1997), the number of candidate species representing a particular genus or family tends to be low. ...
Understanding the dietary preferences of endangered species can be useful in implementing conservation strategies, including habitat restoration, translocation, and captive breeding. Environmental DNA (eDNA) from feces provides a non-invasive method for analysing animal diets. Currently, metabarcoding, a PCR-based approach, is the method of choice for analysing such data. However, this method has limitations, specifically PCR bias, which can result in the overestimation of the importance of certain taxa and failure to detect other taxa because they do not amplify. The present study compared metabarcoding with metagenomics, a PCR-free method, to assess the diversity of prey items in the feces of a critically endangered South African estuarine pipefish, Syngnathus watermeyeri, and its widely distributed congener S. temminckii to investigate potential dietary competition. The metabarcoding results showed a distinct difference between the diets of S. watermeyeri and S. temminckii, with the former mainly consuming calanoid copepods and the latter preferring caridean shrimp. In each case, a single species dominated the sequences generated by metabarcoding. Metagenomics produced more species identifications, and although the same trend was found regarding the preference of S. watermeyeri for copepods and that of S. temminckii for shrimp, this approach identified additional, albeit yet unidentified, copepod species as being important in the diet of S. watermeyeri. We conclude that the lower number of species identified using metabarcoding was most likely a result of amplification bias, resulting in key copepod species missing from the dietary analysis. These findings suggest that metagenomics is not only a useful complementary method for molecular dietary analysis, but may in some cases outperform metabarcoding. However, metagenomics is even more strongly affected by the lack of reference sequences than is metabarcoding, as the majority of sequences originate from genomic regions that have not yet been sequenced for the putative prey species in question.
... Additionally, it is particularly sensitive to the effects of climate change, since it is exposed to a wide range of environmental conditions at the extreme edge of both marine and terrestrial environment (Harley et al. 2006;Benedetti-Cecchi and Trussell 2014;Danovaro 2019). Among the main effects, a reduction of biodiversity on a local scale can be observed, mainly due to pollution, exploitation (Fraschetti et al. 2005;Arévalo et al. 2007;Sales et al. 2011), coastal development (Mangialajo et al. , 2008aBeck and Airoldi 2007) and recreational activities (Gray et al. 1997;Milazzo et al. 2002;Casu et al. 2006;Hewitt et al. 2008). In areas altered and/or subjected to anthropic disturbance, compared to well-preserved and protected ones, the trends are: decrease in specific richness, decrease in the abundance of individual species and increase in Rhodophyta/Phaeophyta ratio Mannino et al. 2011a;De La Fuente et al. 2018;Orfanidis et al. 2021). ...
Ericaria amentacea (C. Agardh) Molinari & Guiry, 2020 is an endemic alga of the Mediterranean Sea that lives in the littoral rocky fringe. The species is very sensitive to natural and anthropogenic stressors, so it is used as a key species to assess the water ecological quality. Nevertheless, E. amentacea is deeply impacted by coastal development and environmental changes which cause rapid regression despite data on its distribution and healthy status still are limited. Moreover, E. amentacea is still little known by people outside the scientific community. In this context, Portofino Seaweed Garden was born, a conservation and citizen science project aim to involve marine outdoor enthusiasts in protecting and restoring E. amentacea, creating a submerged garden using the ex-situ technique. In fact, restoration measures have been encouraged by EU regulations for renew its populations. Here, using a citizen science approach, I evaluated 1) the spatial variability of E. amentacea abundance along the central-eastern Ligurian coast, to evaluate its status and to choose donor and restoration sites. 2) I carried out an E. amentacea restoration (with outplanting lab-cultured embryos on clay tiles) and a characterization of the algal community associated with the brown alga in the restoration site. Finally, 3) I assessed the community involvement and education of volunteers in acting for marine conservation. Simple protocol has been created to train volunteers on the monitoring method. Unprecedented reproductive mismatch in E. amentacea affected the restoration performance, probably caused by marine heat wave that hit the Mediterranean in summer 2022. After fertile apices collection in Pontetto (GE) and during laboratory culture phase, gametes spawned on the clay discs didn’t settle as expected. Only 16 of 50 tiles showed E. amentacea juveniles and they were outplanted at Punta Castello (C zone of the Portofino MPA). Unfortunately, juveniles didn’t survive in the field due to an interplay of physical and biological factors. From citizen science point of view, the project demonstrated positive outcomes of collaborations between people and scientists by involving more than 100 participants. Citizen scientists became specialize in the protocol providing quality data that gave useful information for E. amentacea conservation. Current results suggest that E. amentacea outplanting should be further tested and improved, to guarantee success in the sea.
... Oggi questi ecosistemi risultano particolarmente vulnerabili all'impatto antropico. Tra i principali effetti, legati principalmente ad attività umane che si svolgono sulle coste, si può osservare una riduzione della biodiversità a scala locale, dovuta soprattutto all'inquinamento (Fraschetti et al., 2005), allo sviluppo costiero (Airoldi et al., 2007; e alle attività ricreative (Gray et al., 1997;Hewitt et al., 2008). ...
Ericaria amentacea (C. Agardh) Molinari & Guiry 2020 è un’alga bruna endemica del Mar Mediterraneo che si sviluppa tra il piano mesolitorale e quello infralitorale (tra 0 - 2 metri di profondità). Viene elencata come una delle più sensibili per la valutazione della qualità ecologica delle acque ed è ecologicamente rilevante come "specie ingegnere dell'ecosistema". Le popolazioni mediterranee di questa specie si sono recentemente ridotte a causa soprattutto dell’alterazione e perdita dei suoi habitat e alla presenza di inquinanti chimici in mare. Ad Aprile 2021, grazie ad un progetto di Outdoor Portofino, è nato il Portofino Seaweed Garden: l’intento dello studio è quello di indagare la fattibilità dell’impianto di talli giovanili di Ericaria amentacea mediante la creazione di un “giardino sommerso” nell’Area Marina Protetta di Portofino, come strumento di conservazione e crescita delle popolazioni mediterranee di quest’alga bruna, utilizzando l’approccio della “Scienza partecipata marina”. Obiettivo è sensibilizzare e coinvolgere le persone che praticano lo sport outdoor marino (kayak, SUP, snorkeling e coasteering) nel monitorare la crescita di Ericaria amentacea su 25 dischetti di argilla impiantati presso Punta Castello (zona C dell’AMP di Portofino), utilizzando un protocollo di monitoraggio creato “ad hoc” per quest’alga. Dopo la fase di prelievo di 150 apici fertili di Ericaria amentacea presso Punta Chiappa (zona B dell’AMP di Portofino), la coltura in laboratorio (durata 29 giorni) e l’impianto, è iniziato il periodo di monitoraggio della crescita dell’alga da parte della comunità outdoor di Portofino, durante i mesi di Agosto, Settembre ed Ottobre (per un totale di 10 giornate di monitoraggio). Tramite un campionamento fotografico ai 25 dischetti, divisi in 5 gruppi, da parte della comunità outdoor, è stato valutato il ricoprimento percentuale (%) di Ericaria amentacea nel tempo tramite il programma Fiji. La risposta della comunità outdoor nel periodo di monitoraggio è stata soddisfacente: 24 persone hanno partecipato utilizzando kayak e il campionamento fotografico ha evidenziato un buona crescita di Ericaria amentacea soprattutto da fine Settembre a metà Ottobre (> 25%). Questo studio rappresenta un lavoro preliminare per valutare la capacità di crescita di Ericaria amentacea presso Punta Castello. L’approccio partecipativo delle persone al monitoraggio è uno dei punti di maggiore forza di questo studio. Tutti i dati e risultati di questo studio saranno utilizzati dall’estate 2022, quando inizierà un nuovo ciclo di prelievo, coltura e monitoraggio di Ericaria amentacea.
... It is now largely accepted that the deep-sea supports one of the highest levels of biodiversity on Earth and that it greatly differs from shallow marine and terrestrial ecosystems (e.g., Gray et al. 1997;Ramirez-Llodra et al. 2010;Rex and Etter 2010). However, the mechanisms and events that shaped this diversity are still debated. ...
The nature and timing of mechanisms and events that shaped the deep-sea biodiversity are still debated. The present contribution provides an analysis and discussion of the distribution of off-shelf ostracods in the Late Paleozoic–Early Mesozoic. A taxonomic revision introduces Kozuria gen. nov. to accommodate Triassic species of Acanthoscapha, traditionally seen as Devonian–Carboniferous holdover, archetypal of the Middle Triassic deep-sea of the western Tethys. The taxonomic composition as well as the temporal and geographic distribution of Permian and Triassic off-shelf assemblages are summarized and discussed in the light of climatic and biotic events. This analysis illustrates the Triassic uniformization of the composition of off-shelf assemblages and two possible periods of offshore migration in the late Permian (Changhsingian) and Middle Triassic (Anisian).
... Moreover it appears that these different indices of -diversity are not affected in the same manner by sampling eff o r t (Rumohr et al. 2001). The major problem associated with the assessment of -diversity is also linked to insuff i c i e n t sampling, which has led to the development of several mathematical approaches to better infer the true number of species present in a sampled area (Chao 1984, 1987, Grassle & Maciolek 1992, Karakassis 1995, Gray et al. 1997. There are 2 ways of assessing -d i v e r s i t y. ...
... 8.2, 8.7, and 8.8;Table 8.5;also in Oliver et al. 2011). The next most diverse shelf community was from Bass Straights in Australia (Coleman et al. 1997;Gray et al. 1997), which likely will be as high or higher than Monterey Bay with further sampling (Oliver et al. 2011). There are a number of slope communities with high diversity, but only one of these has the extremely high number of species found in Monterey Bay (Blake and Grassle 1994;Oliver et al. 2011). ...
We observed high diversity (species density) of infaunal invertebrates from the mid-shelf (50 m) to the upper slope (325 m) with high abundance and low dominance along 4 depth transects ranging from 10 to 2000 m. The highest shallow water diversity recorded worldwide was at the shelf-slope break (109–150 m) with a peak of 185 species 0.1 m-2 (449 m-2, this work and Oliver JS, Hammerstrom K, McPhee-Shaw E, Slattery P, Oakden J, Kim S, Hartwell SI, Mar Ecol 32:278–288, 2011). The peak included a large number of species and individuals of small nestling amphipods. The most abundant genera were Photis, Aoroides, and Gammaropsis. The percentages of crustacean species (40%) and individuals (60%) were extremely high as well. A large caprellid amphipod, Tritella tenuissima, was the most abundant animal found in our survey (387 individuals 0.1 m-2), and characterized the mixed gravel bottoms on the upper slope. We discovered a dense tube mat of relatively large ampeliscid amphipods at the upper margin of the oxygen minimum zone (700 m). This was the most distinct community cluster and was dominated by Ampelisca unsocalae and Byblis barbarensis. The percentage of crustacean species (40%) and individuals (67%) were also highest here. This is the only ampeliscid tube mat known from deep water and is ecologically similar to extensive shallow-water ampeliscid mats in the Bering and Chukchi Seas, the primary feeding grounds of gray whales. The diverse and abundant continental margin communities occurred in a dynamic, current-swept upwelling center with complex topography. Diversity decreased below the upper slope and on the wave-swept inner shelf, where there was another dramatic crustacean pattern. These shifting sands were dominated by burrowing amphipods (phoxocephalids and haustoriids) and small ostracods in the 1970s that were rare in the present survey. In total, we collected 938 invertebrate species, including 431 polychaetes, 270 crustaceans, 171 mollusks, and 38 echinoderms in 123 samples. More than any other taxa, the crustaceans characterized the most unique and interesting community patterns along the continental margin of the Monterey Bay area.
Evaluaciones recientes sobre el conocimiento de la biodiversidad registran que las especies marinas corresponden apenas a un 15% del total de los taxones conocidos en el planeta. La falta de conocimiento de la diversidad marina se suma a una acelerada tasa de pérdida de la misma, debido esencialmente a causas antropogénicas. El objetivo de este trabajo es presentar una revisión de las principales amenazas de origen humano a la biodiversidad marina, tales como sobrepesca, descarga de nutrientes, derrames de petróleo, destrucción de hábitat, bioinvasiones, florecimientos algales nocivos y cambios globales. Cada una de estas amenazas pone en riesgo una o varias especies, y a largo plazo, modifica hábitats y ecosistemas completos, causando una pérdida de biodiversidad, muchas veces difícil de evaluar. Mientras en los ecosistemas terrestres el principal factor de riesgo es la destrucción de hábitat, en ambientes marinos la sobreexplotación de recursos es la causa principal de pérdida de biodiversidad. La percepción que los ecosistemas marinos son más resilientes a los disturbios que los ecosistemas terrestres necesita ser reevaluada, ya que probablemente no corresponde a la realidad.
Dispersion patterns and species diversities of deep-sea macrobenthos were examined for evi-dence that diversity-controlling processes operate predominantly on any one of several spatial scales . Identification of such scales, if any, would aid in the identification of the diversity-regu-lating processes themselves. The specific hypothesis that species diversity is independent of scale and location within the deep sea was tested with replicated, partitioned box cores taken at one station in the Santa Catalina Basin (1130 m) and one station in the San Diego Trough (1230 m) of the Southern California continental borderland . Attention was focused on within-community scales. Bathyal rather than abyssal sampling areas were selected to provide ade-quate animal densities for quantitative treatment . The hypothesis was discredited for some taxa at all sampling scales : between the two locali-ties, roughly 100 km apart ; within localities, between 0 .25-m' cores on the order of 1 km apart ; and, within cores, between 0 .01-m' subcores . Species diversity depended, to a different degree in the various taxa, on the sampling scale and pattern . Although a complete explana-tion of deep-sea species diversity must thus invoke processes operant at all the sampled scales, the observed degree of discordance in species' abundances did not suggest any particularly domi-nant scales or processes peculiar to the deep sea . Inferential evidence implied, however, that the characteristic scale of such processes in the deep sea may be smaller than 0 .01 m°, i.e ., ap-proaching the size of areas affected most heavily by single macrofaunal individuals, and that their effects were probably aliased in the present sampling program.
The benthic infauna in 3 areas along 50 km of the coast of Victoria, south-east Australia, was investigated. Grab samples (0.1 m(2)) were collected from a depth range of 11 to 51 m at 12 to 14 sites within each area. Sediments at the sample sites were medium to coarse sand. The distribution of the fauna was related to depth and sediment type. Numbers of individuals and species increased as depth increased and as sediments became more poorly sorted. Species diversity, H-1, increased as sediments became more poorly sorted. Species diversity and evenness, J(1), were greatest at intermediate values for mean grain size. The fauna was extremely species rich. The 104 samples (= a total sample area of 10.4 m(2)) yielded 60 258 individuals and 803 species. Few species were highly abundant and 51% of species collected are apparently undescribed. The data show that species richness may be as high in shallow water as in the deep sea.
High species diversity in samples of macrobenthos of deep-sea sediments is now well established. But a consensus on the processes regulating this unexpectedly species-rich coexistence in metazoan species at the deep-sea bed is still elusive. This review takes a broad approach by examining differences between marine and terrestrial biodiversity in the context of the following: scale of sampling effort on which our knowledge is based; the species concept as applied in the past to taxonomic studies on deep-sea benthic organisms; scaling differences and size related patterns in community structure and habitat complexity and differences in potential for co-evolution. Latitudinal and bathymetric patterns are summarised in relation to habitat variability and distributional range and in relation to J.S. Gray's (1994) claim that benthic diversity may be equally high on the continental shelf.
Analysis of deep-sea benthic samples gathered with a new collecting device reveals a greater diversity (defined ab absolute number of species) of fauna in single environments than has ever been measured before. This high diversity is not an artifact of sampling procedure and demonstrates tat the deep-sea benthos is not faunally depauperate, as is commonly believed. The previous idea of low diversity stems from lack of appreciation of the fact that apparent diversity is dependent on sample size, especially in small samples. Diversity in the deep-sea is much greater han in equivalent shallow marine environments from temperate latitudes and is of the some magnitude as in the shallow marine tropics. High diversity in the deep-sea is best explained as resulting from the great stability of the physical environment.