scholarly journals Dataset on the isotopic (ẟ13C, ẟ15N) and elemental (C, N) composition of estuarine primary producers in the subtropical Southwestern Atlantic coast

2021 ◽  
Vol 1 (1) ◽  
pp. 8-15
Author(s):  
Marianna Lanari ◽  
Bianca Possamai ◽  
Margareth Copertino ◽  
Alexandre Miranda Garcia

Benthic and pelagic primary producers had their isotopic (ẟ13C, ẟ15N) and elemental (C, N) composition monitored in the Patos Lagoons estuary, in southern Brazil. The present dataset comprises temporal data obtained through seasonal samplings of C3 (Scirpus spp.) and C4 (Spartina densiflora) salt marsh plants, ephemerous bloom-forming drift macroalgae (Ulvophyceae), the widgeon grass Ruppia maritima, particulate (POM) and sedimentary (SOM) organic matter in shallow waters (< 2m) of a subtropical estuary from austral summer 2010 to autumn 2016. POM and SOM were collected as proxies of phytoplankton and microphytobenthos, respectively. Salt marsh plants were randomly sampled (N = 126) at a regularly flooded low marsh area, whereas submerged drift macroalgae (N = 29) and Ruppia plants (N = 14) were collected in adjacent mudflats. POM was collected (N = 33) by filtering water samples using glass fiber filter. SOM was obtained (N = 35) by removing superficial sediment. In laboratory, samples were processed and further analyzed for total organic carbon (TOC), total nitrogen (TN) and carbon (13C/12C) and nitrogen (15N/14N) stable isotopes ratios. With a total of 237 samples analyzed, this dataset provides key information on the isotopic and elemental composition of distinct estuarine primary producers and sources of particulate organic matter (POM and SOM) and their temporal variability in a highly variable aquatic environment. Such knowledge may add to ecological studies investigating food webs, biogeochemical cycles and sources tracking in coastal systems.

2014 ◽  
Vol 76 (4) ◽  
pp. 595-609 ◽  
Author(s):  
Xuchen Wang ◽  
Robert F. Chen ◽  
Jaye E. Cable ◽  
Jennifer Cherrier

2011 ◽  
Vol 93 (4) ◽  
pp. 415-419 ◽  
Author(s):  
Pedro N. Carvalho ◽  
Pedro Nuno R. Rodrigues ◽  
Rafael Evangelista ◽  
M. Clara P. Basto ◽  
M. Teresa S.D. Vasconcelos
Keyword(s):  

Author(s):  
Paola V. Silva ◽  
Tomás A. Luppi ◽  
Eduardo D. Spivak

Chasmagnathus granulatus is a semiterrestrial intertidal burrowing crab that inhabits both the unvegetated mudflats and the cordgrass (Spartina densiflora) salt marshes in Mar Chiquita Lagoon (Argentina), where it is considered the ecologically key species. The mass of C. granulatus eggs incubated by females is colonized by epibiotic micro-organisms and accumulates detritus. The type of epibionts that use eggs as a substrate, the infestation degree, the maternal care behaviour and the protection of the incubation chamber were compared between females living on mudflats and on Spartina-dominated areas. In both places, the epibiosis by bacteria and filamentous fungi and peritrichid colonial ciliate was significantly higher in the periphery than in the centre of the brood mass. The accumulation of detritus was higher in the periphery in mudflat females but not in salt marsh females. Moreover, the level of detritus was significantly higher in mudflat than in salt marsh females only in the periphery of the brood. The infestation level of bacteria and fungi, and peritrichids, increased throughout the embryonic development only in mudflat females. The periphery of the brood mass was significantly more contaminated in mudflat than in marsh females, while the central region of the brood mass did not differ between habitats. The pleopods were significantly more contaminated by bacteria and filamentous fungi and peritrichid colonial ciliates in premoult females than in postmoult females, independently from the collection site. The percentage of females with abnormal embryos was significantly higher in mudflats (26.7%) than in marshes (12.3%). Females with late embryos spent more time flapping the abdomen and probing the embryos with the chela. Non-ovigerous females did not perform specific maternal care activities. The volume of brood mass both in early or late stage of development is greater than that of the incubation chamber and, consequently, peripheral embryos are more exposed.


Author(s):  
S. Vanhove ◽  
H.J. Lee ◽  
M. Beghyn ◽  
D. Van Gansbeke ◽  
S. Brockington ◽  
...  

The metazoan meiobenthos was investigated in an Antarctic coastal sediment (Factory Cove, Signy Island, Antarctica). The fine sands contained much higher abundances compared to major sublittoral sediments worldwide. Classified second after Narrangansett Bay (North Atlantic) they reached numbers of 13 × 106ind m-2. The meiofauna was highly abundant in the surface layers, but densities decreased sharply below 2 cm. Vertical profiles mirrored steep gradients of microbiota, chloropigments and organic matter and were coincident with chemical stratification. Spatial patchiness manifested especially in the surface layer. Nematodes dominated (up to 90%), andAponema, Chromctdorita, Diplolaimella, Daptonema, MicrolaimusandNeochromadoraconstituted almost the entire community. Overall, the nematode fauna showed a strong similarity with fine sand communities elsewhere. The dominant trophic strategies were epistrarum and non-selective deposit feeding, but the applied classification for feeding guild structure of the nematodes of Factory Cove is discussed. High standing stock, low diversity and shallow depth distribution may have occurred because of the high nutritive (chlorophyll exceeded lOOOmgm-2and constituted almost 50% of the organic pool) and reductive character of the benthic environment. These observations must have originated from the substantial input of fresh organic matter from phytoplankton and microphytobenthic production, typical for an Antarctic coastal ecosystem during the austral summer.


2015 ◽  
Vol 68 (3) ◽  
pp. 276-284 ◽  
Author(s):  
Elizabeth J. Jacobo ◽  
Adriana M. Rodriguez ◽  
Clara M. Fariña ◽  
Yanina Paggi

2019 ◽  
Vol 15 (5) ◽  
pp. 1845-1859 ◽  
Author(s):  
Ignacio A. Jara ◽  
Antonio Maldonado ◽  
Leticia González ◽  
Armand Hernández ◽  
Alberto Sáez ◽  
...  

Abstract. Modern precipitation anomalies in the Altiplano, South America, are closely linked to the strength of the South American summer monsoon (SASM), which is influenced by large-scale climate features sourced in the tropics such as the Intertropical Convergence Zone (ITCZ) and El Niño–Southern Oscillation (ENSO). However, the timing, direction, and spatial extent of precipitation changes prior to the instrumental period are still largely unknown, preventing a better understanding of the long-term drivers of the SASM and their effects over the Altiplano. Here we present a detailed pollen reconstruction from a sedimentary sequence covering the period between 4500 and 1000 cal yr BP in Lago Chungará (18∘ S; 4570 m a.s.l.), a high-elevation lake on the southwestern margin of the Altiplano where precipitation is delivered almost exclusively during the mature phase of the SASM over the austral summer. We distinguish three well-defined centennial-scale anomalies, with dry conditions between 4100–3300 and 1600–1000 cal yr BP and a conspicuous humid interval between 2400 and 1600 cal yr BP, which resulted from the weakening and strengthening of the SASM, respectively. Comparisons with other climate reconstructions from the Altiplano, the Atacama Desert, the tropical Andes, and the southwestern Atlantic coast reveal that – unlike modern climatological controls – past precipitation anomalies at Lago Chungará were largely decoupled from north–south shifts in the ITCZ and ENSO. A regionally coherent pattern of centennial-scale SASM variations and a significant latitudinal gradient in precipitation responses suggest the contribution of an extratropical moisture source for the SASM, with significant effects on precipitation variability in the southern Altiplano.


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