scholarly journals An ecological study of Electra posidoniae Gautier, 1954 (Cheilostomata, Anasca), a bryozoan epiphyte found solely on the seagrass Posidonia oceanica (L.) Delile, 1813

2020 ◽  
Vol 144 (1) ◽  
Author(s):  
Gilles Lepoint ◽  
Olivier Mouchette ◽  
Corine Pelaprat ◽  
Sylvie Gobert
Keyword(s):  
Water Column ◽  
Posidonia Oceanica ◽  
Early Spring ◽  
Food Sources ◽  
Seagrass Ecosystem ◽  
Life Traits ◽  
Colonization Dynamics ◽  
Marine Angiosperms ◽  
The Relationship ◽  
Quantitative Importance

The bryozoan Electra posidoniae Gautier is found solely on the leaves of the Neptune grass Posidonia oceanica (L.) Delile, dominating the leaf epifauna of this seagrass. Epiphytes of marine angiosperms (or seagrasses) often play an important role in ecosystem functioning, for example as food web suppliers. As dysfunction of the epiphytic component is often implied in human-induced seagrass decline, it is important to understand the dynamics and life traits of this community in pristine areas. This study involved the monthly assessment of colonization dynamics, biomass seasonality, and diet composition through measurements of stable isotopes, in E. posidoniae at a depth of 10 m in the Revellata Bay (Corsica, Mediterranean Sea). Ancestrulae (i.e. colony founders) appeared towards the end of winter and were very selective in their settlement position along the leaves of P. oceanica. A maximum of 100,000 colonies per square meter was recorded. Colonies of E. posidoniae dominated the epiphytic community biomass in early spring, but were overtaken by epiphytic algae in June. Food shortage could be involved in this reduction in dominance. Although stable isotope ratios of C, N and S showed that this suspension feeder mainly relies on the water column for its food, other food sources such as re-suspended epiphytic diatoms could be important in late spring (i.e. after the phytoplanktonic bloom). Additionally, a contribution of seagrass phytodetritus to the diet of this species cannot be excluded. The species was almost absent in winter, raising the question of its recruitment in spring. This study confirms the quantitative importance of this species in the seagrass meadow and explores its role in the relationship between the water column and this seagrass ecosystem.

scholarly journals Meiofauna and harpacticoid copepods in different habitats of a Mediterranean seagrass meadow

2013 ◽  
Vol 93 (6) ◽  
pp. 1557-1566 ◽  
Author(s):  
Thibaud Mascart ◽  
Gilles Lepoint ◽  
Marleen De Troch
Keyword(s):  
Seagrass Meadow ◽  
Posidonia Oceanica ◽  
Food Sources ◽  
Harpacticoid Copepods ◽  
Isotopic Analyses ◽  
Family Level ◽  
Abundant Taxon ◽  
The Relationship ◽  
Potential Food ◽  
Isotope Analyses

This study investigated whether associated meiobenthic communities, especially harpacticoid copepods, differed amongst habitats. Five pre-defined habitats within and next to the Posidonia oceanica seagrass meadow were sampled: living seagrass canopy leaves (LL), small (SMF) and large (LMF) macrophytodetritus fragment accumulations and sand, bare (BS) and covered (CS). The highest meiofauna abundances were recorded in the BS for the core sampled habitats (BS, CS, SMF and LMF) and in the LMF for seagrass material habitats (SMF, LMF and LL). Harpacticoid copepods were the most abundant taxon in all habitats. The assemblage composition at copepod family level showed two distinct habitats clusters: a leaf (LMF and LL) and a sediment cluster (BS, CS and SMF). Subsequently, stable isotope analyses were conducted to analyse the relationship between copepods and their potential food sources in seagrass material habitats. Based on δ13C isotopic analyses and SIAR mixing model, harpacticoid copepods relied for 70% on epiphytes and for 30% on P. oceanica leaf material in the LMF and LL habitats.

scholarly journals An exploration of the relationship between recruitment communication and foraging in stingless bees

2021 ◽  
Author(s):  
Robbie I’Anson Price ◽  
Francisca Segers ◽  
Amelia Berger ◽  
Fabio S Nascimento ◽  
Christoph Grüter
Keyword(s):  
Stingless Bees ◽  
Sugar Content ◽  
Social Information ◽  
Food Resources ◽  
Food Sources ◽  
Foraging Strategies ◽  
High Quality ◽  
Recruitment Communication ◽  
Eusocial Bees ◽  
The Relationship

Abstract Social information is widely used in the animal kingdom and can be highly adaptive. In social insects, foragers can use social information to find food, avoid danger or choose a new nest site. Copying others allows individuals to obtain information without having to sample the environment. When foragers communicate information they will often only advertise high quality food sources, thereby filtering out less adaptive information. Stingless bees, a large pantropical group of highly eusocial bees, face intense inter- and intra-specific competition for limited resources, yet display disparate foraging strategies. Within the same environment there are species that communicate the location of food resources to nest-mates and species that do not. Our current understanding of why some species communicate foraging sites while others do not is limited. Studying freely foraging colonies of several co-existing stingless bee species in Brazil, we investigated if recruitment to specific food locations is linked to (1) the sugar content of forage, (2) the duration of foraging trips and (3) the variation in activity of a colony from one day to another and the variation in activity in a species over a day. We found that, contrary to our expectations, species with recruitment communication did not return with higher quality forage than species that do not recruit nestmates. Furthermore, foragers from recruiting species did not have shorter foraging trip durations than those from weakly-recruiting species. Given the intense inter- and intraspecific competition for resources in these environments, it may be that recruiting species favour food resources that can be monopolised by the colony rather than food sources that offer high-quality rewards.

scholarly journals Wintertime stress, nursing, and lead exposure in Neanderthal children

2018 ◽  
Vol 4 (10) ◽  
pp. eaau9483 ◽  
Author(s):  
Tanya M. Smith ◽  
Christine Austin ◽  
Daniel R. Green ◽  
Renaud Joannes-Boyau ◽  
Shara Bailey ◽  
...  
Keyword(s):  
Climate Change ◽  
Weight Loss ◽  
Human Evolution ◽  
Lead Exposure ◽  
Multidisciplinary Approach ◽  
Modern Human ◽  
Early Spring ◽  
Metal Exposure ◽  
Developmental Stress ◽  
The Relationship

Scholars endeavor to understand the relationship between human evolution and climate change. This is particularly germane for Neanderthals, who survived extreme Eurasian environmental variation and glaciations, mysteriously going extinct during a cool interglacial stage. Here, we integrate weekly records of climate, tooth growth, and metal exposure in two Neanderthals and one modern human from southeastern France. The Neanderthals inhabited cooler and more seasonal periods than the modern human, evincing childhood developmental stress during wintertime. In one instance, this stress may have included skeletal mobilization of elemental stores and weight loss; this individual was born in the spring and appears to have weaned 2.5 years later. Both Neanderthals were exposed to lead at least twice during the deep winter and/or early spring. This multidisciplinary approach elucidates direct relationships between ancient environments and hominin paleobiology.

scholarly journals Student Column: The Relationship between Local Food Sources and Open Space to Body Mass Index in Urban Children

2011 ◽  
Vol 126 (6) ◽  
pp. 890-900 ◽  
Author(s):  
James J. Burns ◽  
Sarah Goff ◽  
Greg Karamian ◽  
Coleen Walsh ◽  
Lela Hobby ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Open Space ◽  
Local Food ◽  
Urban Children ◽  
Food Sources ◽  
The Relationship

scholarly journals The Relationship of Megazoobenthos Association with Seagrass Ecosystem Conditions in Ujung Genteng Waters, Sukabumi

2020 ◽  
pp. 1-10
Author(s):  
Gilang Primanagita Rachman ◽  
Indah Riyantini ◽  
Zahidah Hasan ◽  
Herman Hamdani
Keyword(s):  
Diversity Index ◽  
Close Association ◽  
Strong Relationship ◽  
Survey Method ◽  
Association Pattern ◽  
Seagrass Ecosystem ◽  
Relationship Of ◽  
The Relationship ◽  
Seagrass Density ◽  
Diadema Setosum

Seagrass beds in Ujung Genteng waters are one of the shallow marine ecosystems that have relatively high biodiversity. Seagrass ecosystem as one of the coastal ecosystems in these waters has a diversity of marine life that is associated with it. The purpose of this study was to establish the association pattern and the correlation of mega zoobenthos to seagrass ecosystem conditions. The method used was a survey method by conducting a survey direct observation of the stations that have been determined.  Three seagrass species were identified, namely: Thallasia hemprichii, Cymodoceae rotundata and Enhalus acoroides. The highest density of seagrass was found in station 2 with the type of seagrass Thallasia hemprichii as much as 207 ind/m2. Fifteen mega zoobenthos species were identified representing 3 phyla. Species Mega zoobenthos which is most commonly found in Ujung Genteng waters is Ophiothrix fragilis, Ophiocoma erinaceus, and Diadema setosum. The mega zoobenthos Diversity Index at the observation station is included in the medium category that is 2.33-2.66 and the evenness index is 0.63-0.84. Correlation of seagrass density with mega zoobenthos obtained by 0.92 shows that there is a very strong relationship between seagrass density with mega zoobenthos. The result shows that there are 4 patterns of close association and 2 patterns of very close association. Ophiocoma erinaceus of the ophiuroidea class has a pattern of very close positive associations with seagrass Cymodoceae rotundata and Dendrodoris sp of the order nudibranchia has a pattern of very close negative associations with seagrass Cymodoceae rotundata.

scholarly journals Trait gradients inform predictions of seagrass meadows changes to future warming

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Arianna Pansini ◽  
Gabriella La Manna ◽  
Federico Pinna ◽  
Patrizia Stipcich ◽  
Giulia Ceccherelli
Keyword(s):  
Global Warming ◽  
Posidonia Oceanica ◽  
Shoot Density ◽  
Western Mediterranean ◽  
Seagrass Meadows ◽  
Western Mediterranean Sea ◽  
Seagrass Ecosystem ◽  
Rhizome Biomass ◽  
And Function ◽  
Time Substitution

AbstractComparing populations across temperature gradients can inform how global warming will impact the structure and function of ecosystems. Shoot density, morphometry and productivity of the seagrass Posidonia oceanica to temperature variation was quantified at eight locations in Sardinia (western Mediterranean Sea) along a natural sea surface temperature (SST) gradient. The locations are spanned for a narrow range of latitude (1.5°), allowing the minimization of the effect of eventual photoperiod variability. Mean SST predicted P. oceanica meadow structure, with increased temperature correlated with higher shoot density, but lower leaf and rhizome width, and rhizome biomass. Chlorophyll a (Chl-a) strongly impacted seagrass traits independent of SST. Disentangling the effects of SST and Chl-a on seagrass meadow shoot density revealed that they work independently, but in the same direction with potential synergism. Space-for-time substitution predicts that global warming will trigger denser seagrass meadows with slender shoots, fewer leaves, and strongly impact seagrass ecosystem. Future investigations should evaluate if global warming will erode the ecosystem services provided by seagrass meadows.

scholarly journals A 900-year New England temperature reconstruction from <i>in situ</i> seasonally produced branched glycerol dialkyl glycerol tetraethers (brGDGTs)

2018 ◽  
Author(s):  
Daniel R. Miller ◽  
M. Helen Habicht ◽  
Benjamin A. Keisling ◽  
Isla S. Castañeda ◽  
Raymond S. Bradley
Keyword(s):  
New England ◽  
Water Column ◽  
Lacustrine Sediments ◽  
Temperature Reconstruction ◽  
Early Spring ◽  
Pollen Record ◽  
The North ◽  
The North Atlantic Oscillation ◽  
Glycerol Dialkyl Glycerol Tetraethers

Abstract. Paleotemperature reconstructions are essential for distinguishing anthropogenic climate change from natural variability. An emerging method in paleoclimatology is the use of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in lacustrine sediments to reconstruct temperature, but their application is hindered by a limited understanding of their sources, seasonal production, and transport. We report seasonally resolved measurements of brGDGT production within the water column, in catchment soils and in a sediment sequence from a small, deep inland lake in Maine, USA. BrGDGT distributions in the water column are distinct from catchment soils but similar to the distributions in lake sediments, suggesting that (1) brGDGTs are produced within the lake and (2) this in situ production dominates the downcore sedimentary signal. Seasonally, depth-resolved measurements indicate that the dominant production of brGDGTs occurs in late fall/early spring and at intermediate depths (18–30 meters) in the water column. We apply these observations to help interpret a 900-year-long brGDGT-based temperature reconstruction and find that it shows similar trends to a pollen record from the same site and to regional and global syntheses of terrestrial temperatures over the last millennium. However, the record also shows higher-frequency variability than has previously been captured by such an archive in the Northeastern United States, potentially attributed to the North Atlantic Oscillation and volcanic/solar activity. This is the first brGDGT- based multi-centennial paleoreconstruction from this region and contributes to our understanding of the production and fate of brGDGTs in lacustrine systems.

scholarly journals Abundance and diversity of soil arthropods and fungi in shelterbelts integrated with pastures in the central tablelands of New South Wales, Australia

2012 ◽  
Vol 58 (No. 12) ◽  
pp. 560-568 ◽  
Author(s):  
E.W. Mbuthia ◽  
J.H. Shariff ◽  
A. Raman ◽  
D.S. Hodgkins ◽  
H.I. Nicol ◽  
...  
Keyword(s):  
Organic Matter ◽  
Biological Diversity ◽  
Soil Depth ◽  
Soil Surface ◽  
Early Spring ◽  
Late Winter ◽  
Soil Arthropods ◽  
South Wales ◽  
Abundance And Diversity ◽  
The Relationship

Shelterbelts are important for the sustainability of agriculture because they provide a variety of benefits to farmers and the society. Several published papers demonstrate that integration of shelterbelts with agroecosystems offers positive outcomes, such as better yield, more congenial microclimate, and greater organic matter levels. Nonetheless, soil biological diversity, the driver of greater organic matter levels, has not been convincingly tested and verified yet. In addressing this gap, we measured abundance and diversity of populations of arthropods and fungi in three<br />11-year old shelterbelts integrated with pasture to determine whether a correlation exists between the abundance of and diversity in populations of arthropods and fungi in two seasons: late autumn-early winter (May&ndash;June 2011) and late winter-early spring (August&ndash;September 2011). Litter from the soil surface and soil from two depths were sampled at increasing distance from the midpoint of shelterbelts for the extraction of arthropods and isolation culturing of fungi. The relationship among distance, depth and biodiversity of different groups of arthropods and fungi was analysed using linear regression. We found that over both seasons arthropod abundance in the litter and soil declined with increasing distance from the midpoint of the shelterbelts, and with soil depth. However, fungi abundance in either season was not affected by proximity to the shelterbelt but increased with greater soil depth. Distance from the shelterbelt midpoints did not bear an impact on the diversity richness of both arthropods and fungi.

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