Description: Seagrass meadows are important shallow-water ecosystems that provide habitat for numerous associated organisms and play a crucial role in nutrient cycling, but their detection in the fossil record is problematic. Indirect indicators are often needed to discriminate seagrass beds from other shallow marine paleohabitats. Here, the stable isotope signatures of mollusk shells are examined to determine if they might provide such an indicator in addition to the faunal composition of mollusk assemblages. Aragonitic shells of 167 gastropods and bivalves from Burdigalian and Tortonian deposits in Java and East Kalimantan (Indonesia) are analyzed for their 18 O and 13 C ratios. The faunas represent fully marine to brackish water environments and include seagrass meadows (with dispersed corals), mixed seagrass-coral, and coral-dominated habitats (with dispersed seagrass). We assess processes and settings that shape inorganic isotope signals in the Miocene ambient waters and fractionation processes occurring at the time of shell deposition. Depleted 18 O and 13 C ratios are shown in brackish water samples. Furthermore, chemosymbiotic species show depleted 13 C ratios. A significant difference is found between the carbon isotopic signatures of coral- and seagrass-dominated environments within a stratigraphic interval. Seagrass communities consistently yield comparatively enriched 13 C ratios. Hence, stable isotope ratios may provide additional evidence for distinguishing paleoenvironments and are helpful in identifying ecological processes and settings within these environments.

Description: Two late Miocene Tridacna (giant clam) shells from East Kalimantan (Indonesia) were investigated in order to evaluate their potential as subannually resolved paleoenvironmental archives. Via a combination of X-ray diffraction (XRD), laser ablation–inductively coupled plasma–mass spectrometry (LA-ICPMS) trace element analysis, scanning electron microscopy (SEM) and cathodoluminescence (CL) imaging, pristine versus diagenetically altered domains within the shells were identified. LA-ICPMS transects targeting altered aragonite and calcite zones reveal distinct compositional differences in elemental ratios (B/Ca, Mg/Ca, Sr/Ca/ Ba/Ca, Mn/Ca, Al/Ca, La/Ca, Ce/Ca) relative to primary shell aragonite. Pristine shell domains are characterized by an intact banding pattern of alternating dark and light growth bands, with which spatially resolved LA-ICPMS element/Ca and micromilled 18 O records were aligned. Light 18 O values correspond to dark growth bands, indicating growth during warm seasons. The Mg/Ca and/or Sr/Ca ratios covary with oscillating stable oxygen isotope profiles. Progressive increase in Mg/Ca with age demonstrates that besides temperature, growth kinetics exert control over Mg incorporation. If interpreted as temperature controlled only, 18 O from both shells represents average seasonal sea-surface temperature (SST) variability of 2.7 ± 2.1 and 4.6 ± 1.7 °C, respectively. Using published temperature equations and assuming 18 O sw = –0.88, corresponding mean annual paleo–sea-surface temperatures of 27.8 ± 0.2 and 28.5 ± 0.2 °C are estimated. Although the fossil Tridacna shells were noticeably affected by alteration on their external surfaces, their internal aragonitic structure is, to a large extent, well preserved. These corresponding paleoproxy records provide detailed insight into tropical SST variability of the Indo-Pacific region during the late Miocene.

Description: This study is a preliminary assessment of an extremely diverse Tortonian (late Miocene) mollusk assemblage from a coral carpet environment preserved at Bontang (East Kalimantan, Indonesia). Even though coral-associated aragonitic faunas are rarely well preserved, the composition of the assemblage described here can be used to address the following questions: (1) How do the mollusk assemblages in coral habitats differ from other habitats, and (2) What is the effect of sampling on estimates of taxon richness? The mollusk assemblage is dominated by predatory snails and includes typical modern coral-associated taxa such as the gastropod Coralliophila and the bivalve Tridacna . Our investigation implies that adequate documentation of Cenozoic mollusk diversity in the Indo-Pacific is even more challenging than previously expected as very large samples are required to capture species richness. Further assessments of fossil faunas from coral-dominated habitats will be required to provide insight to development of Indo-Pacific biodiversity through time.

Description: There is a considerable controversy about whether western Amazonia was ever covered by marine waters during the Miocene [23 to 5 Ma (million years ago)]. We investigated the possible occurrence of Miocene marine incursions in the Llanos and Amazonas/Solimões basins, using sedimentological and palynological data from two sediment cores taken in eastern Colombia and northwestern Brazil together with seismic information. We observed two distinct marine intervals in the Llanos Basin, an early Miocene that lasted ~0.9 My (million years) (18.1 to 17.2 Ma) and a middle Miocene that lasted ~3.7 My (16.1 to 12.4 Ma). These two marine intervals are also seen in Amazonas/Solimões Basin (northwestern Amazonia) but were much shorter in duration, ~0.2 My (18.0 to 17.8 Ma) and ~0.4 My (14.1 to 13.7 Ma), respectively. Our results indicate that shallow marine waters covered the region at least twice during the Miocene, but the events were short-lived, rather than a continuous full-marine occupancy of Amazonian landscape over millions of years.

Description: Quaternary Caspian Sea level variations depended on geophysical processes (affecting the opening and closing of gateways and basin size/shape) and hydro-climatological processes (affecting water balance). Disentangling the drivers of past Caspian Sea level variation, as well as the mechanisms by which they impacted the Caspian Sea level variation, is much debated. In this study we examine the relative impacts of hydroclimatic change, ice-sheet accumulation and melt, and isostatic adjustment on Caspian Sea level change. We performed model analysis of ice-sheet and hydroclimate impacts on Caspian Sea level and compared these with newly collated published palaeo-Caspian sea level data for the last glacial cycle. We used palaeoclimate model simulations from a global coupled ocean-atmosphere-vegetation climate model, HadCM3, and ice-sheet data from the ICE-6G_C glacial isostatic adjustment model. Our results show that ice-sheet meltwater during the last glacial cycle played a vital role in Caspian Sea level variations, which is in agreement with hypotheses based on palaeo-Caspian Sea level information. The effect was directly linked to the reorganization and expansion of the Caspian Sea palaeo-drainage system resulting from topographic change. The combined contributions from meltwater and runoff from the expanded basin area were primary factors in the Caspian Sea transgression during the deglaciation period between 20 and 15 kyr BP. Their impact on the evolution of Caspian Sea level lasted until around 13 kyr BP. Millennial scale events (Heinrich events and the Younger Dryas) negatively impacted the surface water budget of the Caspian Sea but their influence on Caspian Sea level variation was short-lived and was outweighed by the massive combined meltwater and runoff contribution over the expanded basin.

Description: PRIDE (Drivers of Biodiversity RIse and DEmise) is an EU funded Innovative Training Network (ITN) that trains 15 early stage researchers (ESRs) over a period of 4 years. We study the evolution of unique Pontocaspian lake biota (molluscs, ostracods and dinoflagellates) in the Caspian Sea-Black Sea region integrating climate, geology and biological approaches. Effective and efficient outreach is an integral part of the PRIDE ITN that engaged all ESRs in the formulation of this plan. The result is an outreach plan that identified stakeholder target groups, developed an outreach strategy and describes pilot studies proposed by ESRs. This document will be at the basis of all outreach activities by program participants for the period 2016-2019. This document was approved by the Supervisory Board and the Scientific Advisory Board in October 2016. “To raise awareness of the unique and diverse Pontocaspian biota, to understand their role in ecosystems and to mitigate their demise” is the main message of the PRIDE programme. The Pontocaspian area has a unique and spectacular geological history that has produced an abundance of endemic Pontocaspian biota (molluscs, ostracods and dinoflagellates) over millions of years. Some of them survive today, but many have also gone extinct as results of natural but dramatic changes in their environment. At present, these unique endemic biota are threatened by anthropogenic factors of pollution, aquatic infrastructures, fisheries, climate change, invasive species, etc. This is causing extinctions right now and what will remain is an impoverished fauna. An impoverished fauna is more vulnerable to catastrophic events, i.e. one disease can decimate entire populations. This is not only a problem for the mollusc fauna, but also the food chain as a whole. One disastrous event can have a cascading effect through the entire food pyramid. Therefore it is of the utmost importance to understand, protect and conserve the diversity of the Pontocaspian fauna. For each of five stakeholder groups the PRIDE project has developed specific messages and devised appropriate means to reach out at different levels of engagement. The first stakeholder group represents the scientific community including scientist and employees at academia, governmental and non-governmental organisations in the Pontocaspian region that will be reached through our partner institutes and associated partners, but PRIDE is also open to further participation with the wider scientific community. PRIDE will reach out to the general public, the EU and ‘Pontocaspian’ citizens with an interest in nature conservation through communication of the main PRIDE message, and with a more detailed approach towards organisations and citizens in the coastal areas of the Danube delta in both Romania and Ukraine. Additionally, two specific stakeholder groups were identified, namely port authorities in the Caspian Sea (for the so-called green port agenda) and the mollusc specialist group of the International Union for the Conservation of Nature (IUCN) in order to seek wider impact of our work on threatened Pontocaspian biota. The PRIDE outreach program uses three online tools to support its outreach activities: the PRIDE project website http://pontocaspian.eu/), the Pontocaspian taxonomic platform (PC-TAX - http://mollusca.myspecies.info/) and the interactive Pontocaspian information system (PC-IS – to be launched in 2018). This outreach plan outlines our activities for the remainder of the PRIDE program (2016-2019). This version has been discussed with ESRs and external experts in Reading (August 2016) and has been approved by the Supervisory Board and the Scientific Advisory Board (November 2016). MSCA-ITN-2014-ETN, grant agreement no 642973