scholarly journals Foraging strategies under extreme events: Contrasting adaptations by benthic macrofauna to drastic biogeochemical disturbance

2020 ◽  
Author(s):  
Yiming V. Wang ◽  
Mario Lebrato ◽  
Li-Chun Tseng ◽  
Thomas Larsen ◽  
Nicolás Smith-Sánchez ◽  
...  
Keyword(s):  
Extreme Events ◽  
Hydrothermal Vents ◽  
Benthic Communities ◽  
Population Decline ◽  
Benthic Macrofauna ◽  
Foraging Strategies ◽  
Environmental Pressures ◽  
Dietary Plasticity ◽  
Marine System ◽  
Specialist Species

ABSTRACTExtreme events caused by global change are increasingly affecting the ocean’s biogeochemical cycling and ecosystem functioning, but it is challenging to observe how food webs respond to rapid habitat disturbances. Benthic communities are particularly vulnerable because their habitats are easily affected by extreme events. Here, we examined how benthic macrofauna responded to a “near shutdown” of shallow marine hydrothermal vents, triggered by M5.8 earthquake and C5 typhoon events. Despite reduced vent fluxes, we shows that the endemic vent crab Xenograpsus testudinatus continued to rely on chemosynthetic sulfur bacteria rather than photosynthetic sources. We posit this obligate nutritional dependence caused a population decline of vent crabs. In contrast, the non-endemic mollusks exhibited much greater dietary plasticity with no detectable impact on the population. Our study based on naturally occurring extreme events exemplifies how specialist species in marine system are particularly vulnerable to the unprecedented evolutionary and environmental pressures exerted by human activities worldwide.

Oil pollution studies of the Solbergstrand mesocosms

1987 ◽  
Vol 316 (1181) ◽  
pp. 641-654 ◽  
Keyword(s):  
Dominant Species ◽  
Oil Pollution ◽  
Benthic Communities ◽  
Ascophyllum Nodosum ◽  
Diesel Oil ◽  
Benthic Macrofauna ◽  
Sediment Chemistry ◽  
Littorina Littorea ◽  
Species Structure ◽  
Laminaria Digitata

Two medium-scale ecosystems (mesocosms) were built on the Oslofjord: one a hard-bottom intertidal system and the other a subtidal soft-sediment system. The hard-bottom mesocosm consists of four basins, two controls and two which were dosed with diesel-oil (129 μg 1 -1 a high oil (HO) dose and 29 μg 1 -1 a low oil (LO) dose). Both oil doses caused high mortality of Mytilus edulis and growth was reduced in the macroalgae Ascophyllum nodosum and Laminaria digitata . Recruitment of Littorina littorea was also affected by oil so that populations declined over time. Subtidal benthic communities have been established in the mesocosm and show variations in sediment chemistry within the range found in the field. Although recruitment of benthic macrofauna is reduced, dominant species and species structure remain closely similar to that in the field over six months. Bioturbation effects studied in the mesocosm have shown the important influence of large, rare species in structuring benthic communities, a finding which would not be possible in nature by diving or by the use ofsubmersibles. Preliminary results from a community taken from 200 m depth and established in the mesocosm suggest that it is now possible to do detailed manipulation experiments on communities simulating the whole continental shelf.

Food abundance and diet variation in freshwater turtles from the mid-Murray River, Australia

2018 ◽  
Vol 66 (1) ◽  
pp. 67 ◽  
Author(s):  
Kristen Petrov ◽  
Jessica Lewis ◽  
Natasha Malkiewicz ◽  
James U. Van Dyke ◽  
Ricky-John Spencer
Keyword(s):  
Green Algae ◽  
Prey Availability ◽  
Foraging Strategies ◽  
Freshwater Turtles ◽  
Food Items ◽  
Filamentous Green Algae ◽  
Invertebrate Diversity ◽  
Murray River ◽  
Specialist Species ◽  
Chelodina Longicollis

Consumers usually respond to variations in prey availability by altering their foraging strategies. Generalist consumers forage on a diversity of resources and have greater potential to ‘switch’ their diet in response to fluctuations in prey availability, in comparison to specialist consumers. We aimed to determine how the diets of two specialist species (the eastern long-necked turtle (Chelodina longicollis) and the broad-shelled turtle (Chelodina expansa) and the more generalist Murray River short-necked turtle (Emydura macquarii) respond to variation in habitat and prey availability. We trapped and stomach-flushed turtles, and compared their diets along with environmental variables (turbidity, macrophyte and filamentous green algae cover, and aquatic invertebrate diversity and abundance) at four wetlands in north-central Victoria. Diets of E. macquarii differed from those of both Chelodina species, which overlapped, across all four sites. However, samples sizes for the two Chelodina species were too small to compare among-wetland variation in diet. Dietary composition of E. macquarii was variable but did not differ statistically among sites. Emydura macquarii preferentially selected filamentous green algae at three of the four sites. Where filamentous green algae were rare, total food bolus volume was reduced and E. macquarii only partially replaced it with other food items, including other vegetation, wood, and animal prey. Many turtles at these sites also had empty stomachs. Thus, filamentous green algae may be a limiting food for E. macquarii. Although E. macquarii has previously been described as a generalist, it appears to have limited ability to replace filamentous green algae with other food items when filamentous green algae are rare.

scholarly journals Dietary plasticity in an invasive species and implications for management: the case of the monk parakeet in a Mediterranean city

2021 ◽  
pp. 185-194
Author(s):  
J. L. Postigo ◽  
J. Carrillo-Ortiz ◽  
J. Domènech ◽  
X. Tomàs ◽  
L. Arroyo ◽  
...  
Keyword(s):  
Invasion Success ◽  
Crop Damage ◽  
Foraging Strategies ◽  
Behavioural Flexibility ◽  
Monk Parakeet ◽  
Myiopsitta Monachus ◽  
Relevant Role ◽  
Dietary Plasticity ◽  
Anthropogenic Food ◽  
Food Consumed

Behavioural flexibility may play a relevant role during invasion of a new habitat. A typical example of behavioural flexibility favouring invasion success refers to changes in foraging behaviour. Here we provide data on changes in the foraging strategies of monk parakeets Myiopsitta monachus over a period of 17 years (2001–2017) in Barcelona city. During this time, consumption of food on the ground increased by more than 25 % and the consumption of anthropogenic food increased by 8 %. Detailed information about the food consumed is provided. Feeding on the ground and consumption of low plants allow parakeets to reach not only anthropogenic food but also crops, thereby increasing the risk of crop damage as the invasion evolves. Early detection of damage to crops is crucial in order to prevent further harm, and makes the precautionary principle highly relevant.

scholarly journals The Importance of Marine Research Infrastructures in Capturing Processes and Impacts of Extreme Events

2021 ◽  
Vol 8 ◽  
Author(s):  
Nadia Lo Bue ◽  
Mairi M. R. Best ◽  
Davide Embriaco ◽  
Dilumie Abeysirigunawardena ◽  
Laura Beranzoli ◽  
...  
Keyword(s):  
Climate Change ◽  
Extreme Events ◽  
Extreme Event ◽  
Ecological Integrity ◽  
Human Society ◽  
Marine Research ◽  
Process Dynamics ◽  
Current State ◽  
Research Infrastructures ◽  
Marine System

Extreme events have long been underestimated in the extent to which they shape the surface of our planet, our environment, its ecological integrity, and the sustainability of human society. Extreme events are by definition rarely observed, of significant impact and, as a result of their spatiotemporal range, not always easily predicted. Extremes may be short-term catastrophic events such as tsunamis, or long-term evolving events such as those linked to climate change; both modify the environment, producing irreversible changes or regime shifts. Whatever the driver that triggers the extreme event, the damages are often due to a combination of several processes and their impacts can affect large areas with secondary events (domino effect), whose effects in turn may persist well beyond the duration of the trigger event itself. Early studies of extreme events were limited to opportunistic approaches: observations were made within the context of naturally occurring events with high societal impact. Given that climate change is now moving us out of a relatively static climate regime during the development of human civilization, extreme events are now a function of underlying climate shifts overlain by catastrophic processes. Their impacts are often due to synergistic factors, all relevant in understanding process dynamics; therefore, an integrated methodology has become essential to enhance the reliability of new assessments and to develop strategies to mitigate societal impacts. Here we summarize the current state of extreme event monitoring in the marine system, highlighting the advantages of a multidisciplinary approach using Research Infrastructures for providing the temporal and spatial resolution required to monitor Earth processes and enhance assessment of associated impacts.

scholarly journals Growth Parameters of Sentani Gudgeon Fish (Oxyeleotris heterodon) in Sentani Lake, Papua

2021 ◽  
Vol 2 (1) ◽  
pp. 10
Author(s):  
Herlan Herlan ◽  
Tuah Nanda Merlia Wulandari
Keyword(s):  
Mortality Rate ◽  
Native Species ◽  
Growth Parameters ◽  
Population Decline ◽  
Total Mortality ◽  
Environmental Pressures ◽  
Growth Coefficient ◽  
Asymptotic Size ◽  
The Family ◽  
Average Catch

ABSTRACTThe Sentani Gudgeon Fish (Oxyeleotris heterodon, Weber 1907) from the family Butidae with the general name Sentani Gudgeon is known locally as Gabus Malas and Himen. Sentani Snakehead Fish is one source of animal protein that is very important for the community around Lake Sentani. The population of the Sentani Gudgeon Fish species is at a crucial level. The issue could be affected by environmental pressures, continuous catches, competition with introduced species from outside Papua, intensive predation systems, and imbalances in ecological systems. The condition made a decline in population size until it became extinct. Gudgeon Sentani fish is the main target of catching in the lake. This condition significantly affects stock, size when first captured, population decline, reproductive cycle, and average catch. Until now, data and information on the growth of snakehead fish as the basis for fisheries management in the waters of Lake Sentani are not widely known. Considering the importance of preserving the native species of Lake Sentani, especially the Snakehead Fish, efforts to manage the fisheries in Lake Sentani's waters are urgent. This research was conducted in March - October 2020, located at Lake Sentani. The specimens were obtained from the catch of fishers with various gill nets and chopsticks. Enumerators or field assistants assisted the recording of the number and measurement of the total length of fish caught by fishermen daily. The results of the analysis showed: asymptotic size (L?) 46.20 cm, growth coefficient (K) 0.29, the total mortality rate (Z) 0.80 per year, natural mortality (M) 0.74 per year, the mortality rate due to fishing (F) 0.06 per year and exploitation rate (E) 0.075 per year.

scholarly journals Icebergs, sea ice, blue carbon and Antarctic climate feedbacks

2018 ◽  
Vol 376 (2122) ◽  
pp. 20170176 ◽  
Author(s):  
David K. A. Barnes ◽  
Andrew Fleming ◽  
Chester J. Sands ◽  
Maria Liliana Quartino ◽  
Dolores Deregibus
Keyword(s):  
Sea Ice ◽  
Carbon Storage ◽  
Carbon Capture ◽  
Benthic Communities ◽  
Rapid Change ◽  
Blue Carbon ◽  
Polar Regions ◽  
Phytoplankton Blooms ◽  
West Antarctic ◽  
Marine System

Sea ice, including icebergs, has a complex relationship with the carbon held within animals (blue carbon) in the polar regions. Sea-ice losses around West Antarctica's continental shelf generate longer phytoplankton blooms but also make it a hotspot for coastal iceberg disturbance. This matters because in polar regions ice scour limits blue carbon storage ecosystem services, which work as a powerful negative feedback on climate change (less sea ice increases phytoplankton blooms, benthic growth, seabed carbon and sequestration). This resets benthic biota succession (maintaining regional biodiversity) and also fertilizes the ocean with nutrients, generating phytoplankton blooms, which cascade carbon capture into seabed storage and burial by benthos. Small icebergs scour coastal shallows, whereas giant icebergs ground deeper, offshore. Significant benthic communities establish where ice shelves have disintegrated (giant icebergs calving), and rapidly grow to accumulate blue carbon storage. When 5000 km 2 giant icebergs calve, we estimate that they generate approximately 10 6 tonnes of immobilized zoobenthic carbon per year (t C yr −1 ). However, their collisions with the seabed crush and recycle vast benthic communities, costing an estimated 4 × 10 4  t C yr −1 . We calculate that giant iceberg formation (ice shelf disintegration) has a net potential of approximately 10 6  t C yr −1 sequestration benefits as well as more widely known negative impacts. This article is part of the theme issue ‘The marine system of the West Antarctic Peninsula: status and strategy for progress in a region of rapid change’.

scholarly journals Global dispersion and local diversification of the methane seep microbiome

2015 ◽  
Vol 112 (13) ◽  
pp. 4015-4020 ◽  
Author(s):  
S. Emil Ruff ◽  
Jennifer F. Biddle ◽  
Andreas P. Teske ◽  
Katrin Knittel ◽  
Antje Boetius ◽  
...  
Keyword(s):  
Hydrothermal Vents ◽  
Benthic Communities ◽  
Coastal Sediments ◽  
Methane Seep ◽  
Methane Seeps ◽  
Transition Zones ◽  
Sulfate Reducing ◽  
Subsurface Sediments ◽  
Gas Leaks ◽  
Globally Distributed

Methane seeps are widespread seafloor ecosystems shaped by the emission of gas from seabed reservoirs. The microorganisms inhabiting methane seeps transform the chemical energy in methane to products that sustain rich benthic communities around the gas leaks. Despite the biogeochemical relevance of microbial methane removal at seeps, the global diversity and dispersion of seep microbiota remain unknown. Here we determined the microbial diversity and community structure of 23 globally distributed methane seeps and compared these to the microbial communities of 54 other seafloor ecosystems, including sulfate–methane transition zones, hydrothermal vents, coastal sediments, and deep-sea surface and subsurface sediments. We found that methane seep communities show moderate levels of microbial richness compared with other seafloor ecosystems and harbor distinct bacterial and archaeal taxa with cosmopolitan distribution and key biogeochemical functions. The high relative sequence abundance of ANME (anaerobic methanotrophic archaea), as well as aerobic Methylococcales, sulfate-reducing Desulfobacterales, and sulfide-oxidizing Thiotrichales, matches the most favorable microbial metabolisms at methane seeps in terms of substrate supply and distinguishes the seep microbiome from other seafloor microbiomes. The key functional taxa varied in relative sequence abundance between different seeps due to the environmental factors, sediment depth and seafloor temperature. The degree of endemism of the methane seep microbiome suggests a high local diversification in these heterogeneous but long-lived ecosystems. Our results indicate that the seep microbiome is structured according to metacommunity processes and that few cosmopolitan microbial taxa mediate the bulk of methane oxidation, with global relevance to methane emission in the ocean.

scholarly journals Facilitation by macroalgae [full paper published in Algae 32 (1): 41-46, 2017]

2017 ◽  
Author(s):  
Ricardo Augusto Scrosati
Keyword(s):  
Benthic Communities ◽  
Algal Species ◽  
High Stress ◽  
Canopy Cover ◽  
Community Level ◽  
Rocky Intertidal ◽  
Marine System ◽  
Sources Of Variation ◽  
Intertidal Habitats ◽  
High Elevations

In rocky intertidal habitats, abiotic stress due to desiccation and thermal extremes increases with elevation because of tides. A study in Atlantic Canada showed that, at low elevations where conditions are benign due to the brief low tides, fucoid algal canopies (Ascophyllum nodosum and Fucus spp.) do not affect the structure of benthic communities. However, at middle and high elevations, where low tides last longer, fucoid canopies limit abiotic extremes and increase the richness (number of invertebrate and algal species, except fucoids) of benthic communities. Using the data from that study, this paper compares the intensity of facilitation and its importance (relative to all other sources of variation in richness) between middle and high elevations, which represent intermediate and high stress, respectively. Facilitation intensity was calculated as the percent increase in benthic richness between quadrats with low and high canopy cover, while the importance of facilitation was calculated as the percentage of variation in richness explained by canopy cover. Data for 689 quadrats spanning 350 km of coastline were used. Both the intensity and importance of facilitation were greater at middle elevations than at high elevations. As canopies do not affect benthic communities at low elevations, this study suggests that the facilitation-stress relationship at the community level is unimodal for this marine system. Such a pattern was found for some terrestrial systems dominated by canopy-forming plants. Thus, it might be ubiquitous in nature and, as further studies refine it, it might help to predict community-level facilitation depending on environmental stress.

scholarly journals Diversity and Distribution Patterns of Hard Bottom Polychaete Assemblages in the North Adriatic Sea (Mediterranean)

Diversity ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 408
Author(s):  
Barbara Mikac ◽  
Margherita Licciano ◽  
Andrej Jaklin ◽  
Ljiljana Iveša ◽  
Adriana Giangrande ◽  
...  
Keyword(s):  
Adriatic Sea ◽  
Benthic Communities ◽  
Structural Similarity ◽  
Distribution Patterns ◽  
Northern Adriatic Sea ◽  
Environmental Pressures ◽  
Northern Adriatic ◽  
The North ◽  
The Family ◽  
Abundance And Diversity

The knowledge on the hard bottom polychaete assemblages in the Northern Adriatic Sea, a Mediterranean region strongly affected by environmental pressures, is scarce and outdated. The objective of this paper was to update the information on polychaete diversity and depict their patterns of natural spatial variation, in relation to changes in algal coverage at increasing depth. Hard bottom benthos was quantitatively sampled by scraping off the substrate from three stations at Sveti Ivan Island (North Adriatic) at three depths (1.5 m, 5 m and 25 m). Polychaete fauna comprised 107 taxa (the majority of them identified at species level) belonging to 22 families, with the family Syllidae ranking first in terms of number of species, followed by Sabellidae, Nereididae, Eunicidae and Serpulidae. Considering the number of polychaete species and their identity, the present data differed considerably from previous studies carried out in the area. Two alien species, Lepidonotus tenuisetosus, which represented a new record for the Adriatic Sea, and Nereis persica, were recorded. The highest mean abundance, species diversity and internal structural similarity of polychaete assemblages were found at 5 m depth, characterised by complex and heterogeneous algal habitat. The DISTLM forward analysis revealed that the distribution of several algal taxa as well as some algal functional-morphological groups significantly explained the observed distribution patterns of abundance and diversity of polychaete assemblages. The diversity of the North Adriatic hard bottom polychaete fauna is largely underestimated and needs regular updating in order to detect and monitor changes of benthic communities in the area.

scholarly journals Taxonomic and Functional Patterns of Benthic Communities in Southern Temperate Tidal Flats

2021 ◽  
Vol 8 ◽  
Author(s):  
Orlando Lam-Gordillo ◽  
Ryan Baring ◽  
Sabine Dittmann
Keyword(s):  
Functional Diversity ◽  
Functional Traits ◽  
Environmental Conditions ◽  
Ecosystem Functioning ◽  
Latent Variable ◽  
Benthic Communities ◽  
Benthic Macrofauna ◽  
Temporal Differences ◽  
Holistic Understanding ◽  
Functional Patterns

Coastal ecosystems are vulnerable to anthropogenic disturbances which can cause loss of benthic macrofauna and their ecosystem functioning. Despite the importance of functional assessments for conservation and management, knowledge gaps persist on the generality of how the diversity and functional traits of benthic communities influence ecosystem functioning. We investigated eight sites in three different habitats across ~1,260 km of coastline, to evaluate patterns between taxonomic and functional diversity of benthic macrofauna, and the relationship between benthic macrofauna, functional traits and environmental conditions. A total of 74 benthic macrofauna taxa were identified. Significant differences across sites and season were found for metrics based on taxonomic and functional traits. Multivariate analysis revealed spatial-temporal differences, which were more evident based on taxa than functional traits. Functional diversity also showed spatial and temporal differences and was positively correlated with the number of taxa. The dominant functional traits modalities were deposit feeders, with large (>20 mm) body size, burrowers, bioirrigators, deeper than 3 cm in sediments, and irregular morphology. Novel Generalized Linear Latent Variable Models (GLLVM) uncovered several site-dependent relationships between taxa, traits and environmental conditions. Functional redundancy was lowest in a highly modified lagoon, and highest in a more pristine embayment. The outcomes from this study showed site-dependent patterns of benthic communities based on either taxonomic or functional metrics, highlighting that both perspectives are complementary to obtain a holistic understanding of the functioning in marine sediments under environmental change.

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