scholarly journals Connecting pH with body size in the marine gastropod Trophon geversianus in a latitudinal gradient along the south-western Atlantic coast

Author(s):  
Mariano E. Malvé ◽  
Sandra Gordillo ◽  
Marcelo M. Rivadeneira

There is growing concern about the impact of contemporaneous ocean acidification on marine ecosystems, but strong evidence for predicting the consequences is still scant. We have used the gastropod Trophon geversianus as a study model for exploring the importance of oceanographic variables (sea surface temperature, chlorophyll a, oxygen, calcite and pH) on large-scale latitudinal variation in mean shell length and relative shell weight. Data were collected from a survey carried out in 34 sites along ~1600 km. Neither shell length nor relative shell weight showed any monotonic latitudinal trend, and the patterns of spatial variability were rather complex. After correcting for spatial autocorrelation, only pH showed a significant correlation with mean shell length and relative shell weight, but contrary to expectations, the association was negative in both cases. We hypothesize that this could mirror the negative effect of acidification on growth rate, which may cause larger asymptotic size. Latitudinal trends of body size variation are not easy to generalize using ecogeographic rules, and may be the result of a complex interaction of environmental drivers and life-history responses.

2021 ◽  
Author(s):  
Carey James Garland ◽  
Victor D Thompson ◽  
Matthew C Sanger ◽  
Karen Y Smith ◽  
Fred T Andrus ◽  
...  

Circular shell rings along the Atlantic Coast of southeastern North America are the remnants of some of the earliest villages that emerged during the Late Archaic Period (5000 – 3000 BP). Many of these villages, however, were abandoned during the Terminal Late Archaic Period (ca 3800 – 3000 BP). Here, we combine Bayesian chronological modeling with multiple environmental proxies to understand the nature and timing of environmental change associated with the emergence and abandonment of shell ring villages on Sapleo Island, Georgia. Our Bayesian models indicate that Native Americans occupied the three Sapelo shell rings at varying times with some generational overlap. By the end of the complex’s occupation, only Ring III was occupied before abandonment ca. 3845 BP. Ring III also consists of statistically smaller oysters ( Crassostrea virginica ) that people harvested from less saline estuaries compared to earlier occupations. These data, when integrated with recent tree ring analyses, show a clear pattern of environmental instability throughout the period in which the rings were occupied. We argue that as the climate became unstable around 4300 BP, aggregation at shell ring villages provided a way to effectively manage fisheries that are highly sensitive to environmental change. However, with the eventual collapse of oyster fisheries and subsequent rebound in environmental conditions ca. 3800 BP, people dispersed from shell rings, and shifted to non-marine subsistence economies and other types of settlements. This study provides the most comprehensive evidence correlations between large-scale environmental change and societal transformations on the Georgia coast during the Late Archaic period.


2018 ◽  
Vol 96 (11) ◽  
pp. 1196-1202 ◽  
Author(s):  
Brett A. DeGregorio ◽  
Gabriel Blouin-Demers ◽  
Gerardo L.F. Carfagno ◽  
J. Whitfield Gibbons ◽  
Stephen J. Mullin ◽  
...  

Because body size affects nearly all facets of an organism’s life history, ecologists have long been interested in large-scale patterns of body-size variation, as well as why those large-scale patterns often differ between sexes. We explored body-size variation across the range of the sexually dimorphic Ratsnake complex (species of the genus Pantherophis Fitzinger, 1843 s.l.; formerly Elaphe obsoleta (Say in James, 1823)) in North America. We specifically explored whether variation in body size followed latitudinal patterns or varied with climatic variables. We found that body size did not conform to a climatic or latitudinal gradient, but instead, some of the populations with the largest snakes occurred near the core of the geographic range and some with the smallest occurred near the northern, western, and southern peripheries of the range. Males averaged 14% larger than females, although the degree of sexual size dimorphism varied between populations (range: 2%–25%). There was a weak trend for male body size to change in relation to temperature, whereas female body size did not. Our results indicate that relationships between climate and an ectotherm’s body size are more complicated than linear latitudinal clines and likely differ for males and females.


2021 ◽  
Author(s):  
Jeff Clements ◽  
Matthew N. George

1. Many bivalve molluscs settle and attach to surfaces using adhesive byssal threads – proteinaceous fibers that together form a network known as the byssus. Since these bivalves rely on byssus for survival, strong byssal attachment promotes a myriad of broad ecological services, including water filtration, nutrient extraction, sediment stabilization, and enhancing biodiversity through habitat creation.2. Numerous studies have documented weakened byssal attachment strength under ocean acidification (OA); however, a comparable number report no effect, even within the same species. Consequently, whether elevated CO2 levels expected under near-future OA will affect byssal attachment strength in nature remains hotly contested.3. We used a systematic literature search and meta-analysis to explore factors that could potentially explain observed effect size variation in byssal attachment strength following OA exposure. 4. A systematic literature search uncovered 20 studies experimentally testing the impact of OA on byssal attachment strength (or some proxy thereof). Meta-analysis revealed that body size (mean shell length) was the strongest predictor of effect size variation, with no significant effect of climate, species, year, study temperature, study location, exposure time, food amount, and pH offset. Functionally, a negative linear relationship was observed between body size and effect size.5. Our finding that the byssal strength of larger bivalves is more susceptible to negative OA effects runs counter to prevailing wisdom that larger, older animals of a given species are more robust to OA than earlier life history stages. 6. This highlights that body size and age may be important factors that determine OA sensitivity in adult calcifiers. In addition to body size, a critical review of each study revealed commonly neglected factors that could influence byssal thread attachment strength which we highlight to provide suggestions for future research in this area.


Polar Biology ◽  
2020 ◽  
Vol 43 (11) ◽  
pp. 1693-1705
Author(s):  
Miriam L. S. Hansen ◽  
Dieter Piepenburg ◽  
Dmitrii Pantiukhin ◽  
Casper Kraan

Abstract In times of accelerating climate change, species are challenged to respond to rapidly shifting environmental settings. Yet, faunal distribution and composition are still scarcely known for remote and little explored seas, where observations are limited in number and mostly refer to local scales. Here, we present the first comprehensive study on Eurasian-Arctic macrobenthos that aims to unravel the relative influence of distinct spatial scales and environmental factors in determining their large-scale distribution and composition patterns. To consider the spatial structure of benthic distribution patterns in response to environmental forcing, we applied Moran’s eigenvector mapping (MEM) on a large dataset of 341 samples from the Barents, Kara and Laptev Seas taken between 1991 and 2014, with a total of 403 macrobenthic taxa (species or genera) that were present in ≥ 10 samples. MEM analysis revealed three spatial scales describing patterns within or beyond single seas (broad: ≥ 400 km, meso: 100–400 km, and small: ≤ 100 km). Each scale is associated with a characteristic benthic fauna and environmental drivers (broad: apparent oxygen utilization and phosphate, meso: distance-to-shoreline and temperature, small: organic carbon flux and distance-to-shoreline). Our results suggest that different environmental factors determine the variation of Eurasian-Arctic benthic community composition within the spatial scales considered and highlight the importance of considering the diverse spatial structure of species communities in marine ecosystems. This multiple-scale approach facilitates an enhanced understanding of the impact of climate-driven environmental changes that is necessary for developing appropriate management strategies for the conservation and sustainable utilization of Arctic marine systems.


Biology ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 16
Author(s):  
Valeria B. Salinas-Ramos ◽  
Paolo Agnelli ◽  
Luciano Bosso ◽  
Leonardo Ancillotto ◽  
Víctor Sánchez-Cordero ◽  
...  

Body size in animals commonly shows geographic and temporal variations that may depend upon several environmental drivers, including climatic conditions, productivity, geography and species interactions. The topic of body size trends across time has gained momentum in recent years since this has been proposed as a third universal response to climate change along with changes in distribution and phenology. However, disentangling the genuine effects of climate change from those of other environmental factors is often far from trivial. In this study, we tested a set of hypotheses concerning body size variation across time and space in Italian populations of a rhinolophid bat, the lesser horseshoe bat Rhinolophus hipposideros. We examined forearm length (FAL) and cranial linear traits in a unique historical collection of this species covering years from 1869 to 2016, representing, to the best of our knowledge, the longest time series ever considered in a morphological assessment of a bat species. No temporal changes occurred, rejecting the hypotheses that body size varied in response to climate change or urbanization (light pollution). We found that FAL increased with latitude following a Bergmann’s rule trend, whereas the width of upper incisors, likely a diet-related trait, showed an opposite pattern which awaits explanation. We also confirmed that FAL is sexually dimorphic in this species and ruled out that insularity has any detectable effect on the linear traits we considered. This suggests that positive responses of body size to latitude do not mean per se that concurring temporal responses to climate change are also expected. Further investigations should explore the occurrence of these patterns over larger spatial scales and more species in order to detect the existence of general patterns across time and space.


2020 ◽  
Vol 154 ◽  
pp. 104827 ◽  
Author(s):  
Vanessa F. Carvalho ◽  
Jorge Assis ◽  
Ester A. Serrão ◽  
José M. Nunes ◽  
Antônio B. Anderson ◽  
...  

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Maximilian T. Stockdale ◽  
Michael J. Benton

AbstractEver since Darwin, biologists have debated the relative roles of external and internal drivers of large-scale evolution. The distributions and ecology of living crocodilians are controlled by environmental factors such as temperature. Crocodilians have a rich history, including amphibious, marine and terrestrial forms spanning the past 247 Myr. It is uncertain whether their evolution has been driven by extrinsic factors, such as climate change and mass extinctions, or intrinsic factors like sexual selection and competition. Using a new phylogeny of crocodilians and their relatives, we model evolutionary rates using phylogenetic comparative methods. We find that body size evolution follows a punctuated, variable rate model of evolution, consistent with environmental drivers of evolution, with periods of stability interrupted by periods of change. Regression analyses show warmer environmental temperatures are associated with high evolutionary rates and large body sizes. We confirm that environmental factors played a significant role in the evolution of crocodiles.


2018 ◽  
Vol 5 (7) ◽  
pp. 180707 ◽  
Author(s):  
Tomoya Dobashi ◽  
Midori Iida ◽  
Kazuhiro Takemoto

Body-size relationships between predators and their prey are important in ecological studies because they reflect the structure and function of food webs. Inspired by studies on the impact of global warming on food webs, the effects of temperature on body-size relationships have been widely investigated; however, the impact of environmental factors on body-size relationships has not been fully evaluated because climate warming affects various ocean environments. Thus, here, we comprehensively investigated the effects of ocean environments and predator–prey body-size relationships by integrating a large-scale dataset of predator–prey body-size relationships in marine food webs with global oceanographic data. We showed that various oceanographic parameters influence prey size selection. In particular, oxygen concentration, primary production and salinity, in addition to temperature, significantly alter body-size relationships. Furthermore, we demonstrated that variability (seasonality) of ocean environments significantly affects body-size relationships. The effects of ocean environments on body-size relationships were generally remarkable for small body sizes, but were also significant for large body sizes and were relatively weak for intermediate body sizes, in the cases of temperature seasonality, oxygen concentration and salinity variability. These findings break down the complex effects of ocean environments on body-size relationships, advancing our understanding of how ocean environments influence the structure and functioning of food webs.


2021 ◽  
Author(s):  
Jian-Wen Bao ◽  
Sara Michelson ◽  
Evelyn Grell

<p>Shallow cumulus clouds play an important role in the weather in the Atlantic Tropical Convergence Zone.  Their interaction with the atmospheric environment and oceanic mixing processes has a significant impact on the convective organization and tropical dynamics.  It is still a scientific challenge for numerical weather prediction models to accurately simulate them due to deficiencies in the model’s representation of physical processes. </p><p>In this study, we investigate how the physics parameterization schemes in NOAA’s most recent operational global forecast system (GFSv16) perform in the simulation of shallow cumulus clouds in the western Atlantic in terms of their interaction with the large-scale atmospheric dynamics.  Previous studies have indicated that the impact of physics parameterization schemes on model’s tendencies during the first few hours can provide critical information on their suitability for short- and medium-range forecasts.<strong> </strong> Therefore, we first evaluate the GFSv16 forecasts against the observations obtained from the European field campaign called the ATOMIC/EUREC4A that occurred between 12 January and 23 February 2020.  We then diagnose the sensitivity of the GFSv16 physics tendencies to changes to the physics parameterization schemes over the first 6 hours of the forecast, which is the timescale before dynamical feedback becomes significant. Using the information from the observational evaluation and physics tendency diagnosis, we further explore possible improvement in the physical process representation that can positively affect the physics tendencies and lead to overall forecast improvement beyond 6 hours.</p>


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