Planktonic foraminifera and their proxies for the reconstruction of surface ocean climate parameters

Planktonic foraminifera are useful organisms to assess the surface ocean's role in climate change, due to their upper water column habitat, calcium carbonate mineral structure, and preservation in the deep-sea sedimentary record. Carbonate sediments rich in the calcitic shells of foraminifera are abundant in both space and time, which allows their use in an array of paleoceanographic studies over time scales ranging from decadal to glacial-interglacial, as well as beyond and between. Here we review the most important proxy methods to reconstruct surface-ocean climatic variables using planktonic foraminifera. These methods include assemblage-based and geochemical-based (both isotopic and elemental) approaches. The natural emphasis is on temperature, the most important climatic parameter of the surface ocean, although related physical, chemical, and biological properties are addressed as well, such as salinity, productivity, nutrient utilization, weathering, circulation, and oceanic C-system properties including alkalinity, pH, and [CO3 2-]. In our systematic evaluation of each foraminiferal proxy, we provide the basis for each method, brief examples, and a glimpse into the future, when current research needs will hopefully be met.Els foraminífers planctònics són organismes que permeten avaluar el paper que té la superfície dels oceans en el procés de canvi climàtic, a causa del seu hàbitat superficial, l'estructura calcària de la seva closca i la seva preservació al registre sedimentari oceànic. De fet, l'existència abundant de sediments carbonatats rics en les closques calcítiques dels foraminífers fan d'aquests una eina útil per a una gran varietat d'estudis paleoceanogràfics a escales de temps que varien entre dècades i mil·lennis. En aquest article es revisen els mètodes proxy més importants emprats per a reconstruir variables climàtiques relacionades amb la superfície oceànica mitjançant foraminífers, que comprenen tant els mètodes geoquímics (isotòpics i elementals) com els basats en associacions. La temperatura gaudeix d'un èmfasi especial, perquè és el paràmetre climàtic més important de la superfície de l'oceà, tot i que també es tracten propietats relacionades de caràcter físic, químic i biològic com són la salinitat, la productivitat, l'ús de nutrients, la meteorització, la circulació, i propietats del sistema carbonat com l'alcalinitat, el pH i el [CO3 2-]. S'avalua cada proxy de manera sistemàtica i s'especifica, per a cada mètode, la seva base científica, alguns exemples breus i una projecció futura de la seva evolució

Diferències de forma del zooplàncton del Golf de Mèxic durant l'última desglaciació

Unidad de excelencia María de Maeztu MdM-2015-0552Especialistes en oceanografia i en l'estudi del canvi climàtic han estudiat restes fòssils de foraminífers planctònics provinents del Golf de Mèxic amb l'objectiu d'investigar la temperatura, salinitat i productivitat oceàniques durant l'última desglaciació. Els resultats mostren els canvis hidrogràfics deduïts d'aquest enfocament, que van comportar un canvi climàtic a escala global, la qual cosa permet projectar les conseqüències del canvi climàtic que actualment enfronta la Terra davant l'escalfament global

Relació entre la productivitat biològica de l'oceà i l'entrada de nutrients

Des de fa uns anys s'estan duent a terme recerques sobre la relació entre la productivitat biològica de l'oceà i l'entrada de nutrients. Recentment, l'estudi de tres nuclis de sediments procedents de l'Oceà Atlàntic Sud subantàrtic han permès als investigadors interpretar l'estimulació de la productivitat com una resposta directa a l'entrada de pols (font de micronutrients de ferro) a la regió. Aquestes variacions són interessants d'estudiar atès que es donen a una escala més petita que els cicles de períodes glacials-interglacials.Desde hace unos años se están llevando a cabo investigaciones sobre la relación entre la productividad biológica del océano y la entrada de nutrientes. Recientemente, el estudio de tres núcleos de sedimentos procedentes del Océano Atlántico Sur subantártico han permitido a los investigadores interpretar la estimulación de la productividad como una respuesta directa a la entrada de polvo (fuente de micronutrientes de hierro) en la región. Estas variaciones son interesantes de estudiar puesto que se dan a una escala más pequeña que los ciclos de periodos glaciales-interglaciales.For some years now, researches on the relationship between oceanic biological productivity and the entry of nutrients have been carried out. Recently, the study of three sediment cores from the Subantarctic South Atlantic Ocean have allowed researchers to interpret the stimulation of productivity as a direct response to dust supply (source of Fe micro- nutrients) in the region. These changes are interesting to study because they occur on a smaller scale than the glacial-interglacial cycles periods

Local reports of climate change impacts in Sierra Nevada, Spain : sociodemographic and geographical patterns

Altres ajuts: acord transformatiu CRUE-CSICUnidad de excelencia María de Maeztu CEX2019-000940-MWhile we know that climate change is having different impacts on various ecosystems and regions of the world, we know less how the perception of such impacts varies within a population. In this study, we examine patterns of individual variation in climate change impacts reports using data from a sample (n = 238) drawn from 33 mountainous municipalities of Sierra Nevada, Spain. Sierra Nevada inhabitants report multiple climate change impacts, being the most frequently reported changes in snowfall and snow cover, abundance of terrestrial fauna, freshwater availability, and extreme temperatures. Reports of climate change impacts vary according to informants' sociodemographic characteristics and geographical location. People with life-long bonds with the environment and higher connection and dependence upon ecosystem services report more climate change impacts than other informants, as do people with lower level of schooling. We also found that reports of climate change impacts vary according to geographic areas,which reinforces the idea that climate change generates differentiated impacts even at small geographical scales. Understanding intracultural variation in reports of climate change impacts not only gives an enriched picture of the human dimensions of climate change but might also help design more targeted mitigation and adaptation responses

Including indigenous and local knowledge in climate research : an assessment of the opinion of Spanish climate change researchers

Unidad de excelencia María de Maeztu CEX2019-000940-MResearchers have documented that observations of climate change impacts reported by indigenous peoples and local communities coincide with scientific measurements of such impacts. However, insights from indigenous and local knowledge are not yet completely included in international climate change research and policy fora. In this article, we compare observations of climate change impacts detected by indigenous peoples and local communities from around the world and collected through a literature review (n = 198 case studies) with climate scientists' opinions on the relevance of such information for climate change research. Scientists' opinions were collected through a web survey among climate change researchers from universities and research centres in Spain (n = 191). In the survey, we asked about the need to collect local-level data regarding 68 different groups of indicators of climate change impacts to improve the current knowledge and about the feasibility of using indigenous and local knowledge in climate change studies. Results show consensus on the need to continue collecting local-level data from all groups of indicators to get a better understanding of climate change impacts, particularly on impacts on the biological system. However, while scientists of our study considered that indigenous and local knowledge could mostly contribute to detect climate change impacts on the biological and socioeconomic systems, the literature review shows that information on impacts on these systems is rarely collected; researchers instead have mostly documented the impacts on the climatic and physical systems reported by indigenous and local knowledge

Eco-biostratigraphic advances in late quaternary geochronology and palaeoclimate : the marginal Gulf of Mexico analogue

This study combines high-resolution planktonic foraminiferal eco-biostratigraphy and palaeoclimatic data from the high-sedimentation-rate core JPC-26 from the northwestern margin of the Gulf of Mexico (GoM). The eco-biozones recognized (GOMPFE1-12) being correlated with published Mg/Ca-based sea surface temperatures. This updated palaeoclimatic and stratigraphic reference record facilitates correlations with the Greenland ice core events and their climatic relationships, and also provides a solid stratigraphic framework for correlations with other palaeoclimatic and palaeoceanographic records in the circum-GOM/Caribbean region. This multidisciplinary approach underlines the utility of supporting conventional dating methodologies with different constraints, and further reveals a powerful tool for reliably correlating marine records between comparable deep-sea marginal settings and coeval sequences of this region

Latitudinal variation of planktonic foraminifera shell masses during Termination I

Unidad de excelencia María de Maeztu MdM-2015-0552The oceans' surface layer holds large amounts of dissolved inorganic carbon that is exchanged rapidly with the atmosphere. Carbon enters the ocean mainly through the dissolution of atmospheric carbon dioxide (CO2), and a part of it is converted into carbonate by marine organisms. Calcifying marine organisms include planktonic foraminifers that contribute to the marine carbon turnover by generating inorganic carbon production (CaCO3 shells). Anthropogenic CO2 acidifies the surface ocean, changes the carbonate chemistry and decreases the saturation state of carbonate minerals in sea water, thus affecting the biological precipitation of carbonate shells. Relative changes in average foraminiferal shell mass can be interpreted as variations in test thickness and the extent of calcification that subsequently impacts the global carbonate budgets. The response of calcifying marine organisms to elevated atmospheric pCO2 is diverse and complex with studies reporting from reduced rates of net calcification to neutral receptivity or even increased calcification intensities. This diverse behavior implies that the concentration of dissolved inorganic carbon may not be the dominant factor controlling the amount of carbonate shell masses. Here we provide further evidence that glacial/interglacial variations of planktonic foraminifera shell masses are invariant to atmospheric pCO2. We identify that differences in shell weights of several planktonic foraminiferal species from narrow size intervals, over the most recent deglaciation (Termination I) vary systematically as a function of latitude. Past intervals of abruptly changing pCO2 and temperatures, such as the terminations, can offer a glimpse into the response of marine calcifying plankton to changes in surface oceans. We have compiled all the available bibliographic data of planktonic foraminifera shell weights from restricted sieve fractions of different species from the Atlantic, Pacific and Indian Oceans and we find that for the same pCO2 conditions planktonic foraminifera from equatorial regions may alter their shell mass only as little as 8.2%, while towards higher latitudes changes in shell mass reach up to 54% during the transition from the last glacial to interglacial conditions. We attribute this low variability in the shell mass of planktonic foraminifera from the equator to the stability of the physical oceanographic conditions that characterize the equatorial zone

Low planktic foraminiferal diversity and abundance observed in a spring 2013 west-east Mediterranean Sea plankton tow transect

Unidad de excelencia María de Maeztu MdM-2015-0552Planktic foraminifera were collected with 150 µm BONGO nets from the upper 200 m water depth at 20 stations across the Mediterranean Sea between 2 May and 2 June 2013. The main aim is to characterize the species distribution and test the covariance between foraminiferal area density (ρA) and seawater carbonate chemistry in a biogeochemical gradient including ultraoligotrophic conditions. Average foraminifera abundances are 1.42 ± 1.43 ind. 10 m⁻³ (ranging from 0.11 to 5.20 ind. 10 m⁻³), including 12 morphospecies. Large differences in species assemblages and total abundances are observed between the different Mediterranean sub-basins, with an overall dominance of spinose, symbiont-bearing species indicating oligotrophic conditions. The highest values in absolute abundance are found in the Strait of Gibraltar and the Alboran Sea. The western basin is dominated by Globorotalia inflata and Globigerina bulloides at slightly lower standing stocks than in the eastern basin. In contrast, the planktic foraminiferal assemblage in the warmer, saltier, and more nutrient-limited eastern basin is dominated by Globigerinoides ruber (white). These new results, when combined with previous findings, suggest that temperature-induced surface water stratification and food availability are the main factors controlling foraminiferal distribution. In the oligotrophic and highly alkaline and supersaturated with respect to calcite and aragonite Mediterranean surface water, standing stocks and ρA of G. ruber (white) and G. bulloides are affected by both food availability and seawater carbonate chemistry. Rapid warming increased surface ocean stratification impacting food availability and changes in trophic conditions could be the causes of reduced foraminiferal abundance, diversity, and species-specific changes in planktic foraminiferal calcification

Planktic foraminiferal changes in the western Mediterranean Anthropocene

Unidad de excelencia María de Maeztu CEX2019-000940-MAltres ajuts: Acord transformatiu CRUE-CSICThe increase in anthropogenic induced warming over the last two centuries is impacting marine environment. Planktic foraminifera are a globally distributed calcifying marine zooplankton responding sensitively to changes in sea surface temperatures and interacting with the food web structure. Here, we study two high resolution multicore records from two western Mediterranean Sea regions (Alboran and Balearic basins), areas highly affected by both natural climate change and anthropogenic warming. Cores cover the time interval from the Medieval Climate Anomaly to present. Reconstructed sea surface temperatures are in good agreement with other results, tracing temperature changes through the Common Era (CE) and show a clear warming emergence at about 1850 CE. Both cores show opposite abundance fluctuations of planktic foraminiferal species (Globigerina bulloides, Globorotalia inflata and Globorotalia truncatulinoides), a common group of marine calcifying zooplankton. The relative abundance changes of Globorotalia truncatulinoides plus Globorotalia inflata describe the intensity of deep winter mixing in the Balearic basin. In the Alboran Sea, Globigerina bulloides and Globorotalia inflata instead respond to local upwelling dynamics. In the pre-industrial era, changes in planktic foraminiferal productivity and species composition can be explained mainly by the natural variability of the North Atlantic Oscillation, and, to a lesser extent, by the Atlantic Multidecadal Oscillation. In the industrial era, starting from about 1800 CE, this variability is affected by anthropogenic surface warming, leading to enhanced vertical stratification of the upper water column, and resulting in a decrease of surface productivity at both sites. We found that natural planktic foraminiferal population dynamics in the western Mediterranean is already altered by enhanced anthropogenic impact in the industrial era, suggesting that in this region natural cycles are being overprinted by human influences