[MARMAM] New publication on the effect of warming on the NAP ecosystem, from phytoplankton to top predators

Elisa Seyboth elisaseyboth at hotmail.com
Thu Jan 11 05:52:10 PST 2018


Dear colleagues,


my co-authors and I are pleased to announce the publication of the following article on Deep-Sea Research Part II:



Seyboth, E., Botta, S., Mendes, C.R.B., Negrete, J., Dalla Rosa, L. & Secchi, E.R. 2017. Isotopic evidence

of the effect of warming on the northern Antarctic Peninsula ecosystem.


Abstract

The Antarctic Peninsula (AP) region is one of the areas under faster warming rates worldwide, and where food web changes have been observed in the last decades. Among these changes are the development of cryptophytes under warmer conditions in detriment of diatoms, and the reduced krill availability in the environment. An isotopic approach was used to investigate whether the temporal and spatial patterns of energy transfer from phytoplankton (using particulate organic matter – POM – as a proxy of primary producers) to baleen whales (humpback – Megaptera novaeanglieae, fin – Balaenoptera physalus, Antarctic minke – Balaenoptera bonaerensis), and killer whales – Orcinus orca – is similar in areas under different effects of warming around the northern Antarctic Peninsula (NAP). Samples of POM (n = 65), krill (n = 29) and skin of baleen (n = 106) and, opportunistically, killer whales (n = 5) were collected in Gerlache and Bransfield Straits (western AP) and the Powell Basin (northeastern AP) during the austral summers of 2013–2016. Mean isotope values for δ13C and δ15N values were, respectively, ‐26.3‰ (±2.9) and 0.9‰ (±1.7) for POM, ‐25.6‰ (±0.9) and 5.3‰ (±1.1) for krill, ‐24.1‰ (±2) and 8.9‰ (±1.5) for humpback, ‐24.6‰ (±1.2) and 8.2‰ (±0.7) for fin, ‐24.4‰ (±1.6) and 8.7‰ (±1) for Antarctic minke whales, and −23.6‰ (±1.2) and 8.9‰ (±1.7) for killer whales. Interannual significant differences were found for δ13C values of POM and fin whales’ samples, while spatial differences were found for δ13C values of POM samples and humpback whales and for δ15N values of POM, humpbackand Antarctic minke whales. Lowerδ13C andδ15N valuesfor the baseof the food web tended to be observedtowards opensea regions(Powell Basinand anareaunder the influence ofthe Bellingshausen Sea waters). The isoscapes generated for the baseline of the NAP ecosystem provided unprecedented information, to thebestofourknowledge,ofhowtheδ13Candδ15NvaluesofPOMvariedspatiallyandtemporallyintheregion. HPLC-CHEMTAXpigmentanalysis indicatedthattwoofthemainphytoplanktongroupsinthe studyregionwere diatoms and cryptophytes. The contribution of these groups to the total phytoplankton biomass was positively and negatively correlated with the POM δ13C values, respectively. Despite the spatial and temporal limited interpretation of our results due to our reduced sampling effort to the east of the AP and to the relatively short temporal range investigated, the differences observed in the isotopic composition are considered representative of contrasting environmental conditions. The present study provides new insights on stable isotope values in the Antarctic ecosystem and may help to foresee the consequences of physico-chemical changes in water properties to the biota due to global warming.



The full text can be downloaded using the links bellow:


https://www.researchgate.net/publication/322091834_Isotopic_evidence_of_the_effect_of_warming_on_the_Northern_Antarctic_Peninsula_ecosystem


https://www.sciencedirect.com/science/article/pii/S0967064517303946



Best regards,

Elisa.



M.Sc. Elisa Seyboth

PhD Candidate
Laboratório de Ecologia e Conservação da Megafauna Marinha - EcoMega
Instituto de Oceanografia
Universidade Federal do Rio Grande - FURG - Brasil

APECS Council Member (2016-2018)
APECS-Brazil Member and National Committee Representative (2017-2018)

Tel.: +55(53) 32336537/981093713

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