Challenges and directions in analytical paleobiology.

Over the last 50 years, access to new data and analytical tools has expanded the study of analytical paleobiology, contributing to innovative analyses of biodiversity dynamics over Earth's history. Despite-or even spurred by-this growing availability of resources, analytical paleobiology faces deep-rooted obstacles that stem from the need for more equitable access to data and best practices to guide analyses of the fossil record. Recent progress has been accelerated by a collective push toward more collaborative, interdisciplinary, and open science, especially by early-career researchers. Here, we survey four challenges facing analytical paleobiology from an early-career perspective: (1) accounting for biases when interpreting the fossil record; (2) integrating fossil and modern biodiversity data; (3) building data science skills; and (4) increasing data accessibility and equity. We discuss recent efforts to address each challenge, highlight persisting barriers, and identify tools that have advanced analytical work. Given the inherent linkages between these challenges, we encourage discourse across disciplines to find common solutions. We also affirm the need for systemic changes that reevaluate how we conduct and share paleobiological research.

Three common sampling techniques in Pleistocene coral reefs of the Red Sea: a comparison.

Line Intercept Transects (LIT), Point Intercept Transects (PIT), and Photoquadrats (PQ) are the most common quantitative sampling techniques in modern and fossil coral reefs. Data from coral reefs obtained by the different methods are generally compared between various reef ages and localities. Quaternary reefs from warmer interglacial periods, which represent climate scenarios projected for the future, are particularly interesting for comparisons with modern reefs. Importantly, fossil reefs differ from modern reefs because they are diagenetically altered and time averaged. While several studies have compared different quantitative methods in modern reefs, very few have dealt with the comparability among fossil and between fossil and modern reefs. Here, we compare LIT, PIT at 10, 20 and 50 cm intervals, and PQ in two Pleistocene reef localities in Egypt. We find that alpha diversity, reef cover and community composition are dependent on the method. Results gained with plotless methods (LIT, PIT) differ strongly from results gained with plot methods (PQ). However, coral cover results are similar between LIT and PIT, and community composition is indistinguishable between the two, but alpha diversity depends on the interval used for PIT. We discuss the implications of our findings for comparing coral reefs of various ages and localities. We recommend surveying Pleistocene reefs with PIT at 20 cm intervals. This is because A) alpha diversity is well captured, B) the amount of time averaging recorded by PIT is reduced compared to PQ, C) the PIT results can be directly compared to reefs analyzed by LIT, and D) the method is less time consuming than LIT and PQ.

Impact of dissolved CO2 on calcification in two large, benthic foraminiferal species.

Rising atmospheric CO2 shifts the marine inorganic carbonate system and decreases seawater pH, a process often abbreviated to 'ocean acidification'. Since acidification decreases the saturation state for crystalline calcium carbonate (e.g., calcite and aragonite), rising dissolved CO2 levels will either increase the energy demand for calcification or reduce the total amount of CaCO3 precipitated. Here we report growth of two large benthic photosymbiont-bearing foraminifera, Heterostegina depressa and Amphistegina lessonii, cultured at four different ocean acidification scenarios (400, 700, 1000 and 2200 ppm atmospheric pCO2). Using the alkalinity anomaly technique, we calculated the amount of calcium carbonate precipitated during the incubation and found that both species produced the most carbonate at intermediate CO2 levels. The chamber addition rates for each of the conditions were also determined and matched the changes in alkalinity. These results were complemented by micro-CT scanning of selected specimens to visualize the effect of CO2 on growth. The increased chamber addition rates at elevated CO2 concentrations suggest that both foraminifera species can take advantage of the increased availability of the inorganic carbon, despite a lower saturation state. This adds to the growing number of reports showing the variable response of foraminifera to elevated CO2 concentrations, which is likely a consequence of differences in calcification mechanisms.

The potential of large rafting objects to spread Lessepsian invaders: the case of a detached buoy.

A diverse and abundant fouling community dominated by Lessepsian non-indigenous species was identified on a 13.5-m-long steel buoy stranded on the Israeli coast but originating from Port Said, at the Mediterranean entrance of the Suez Canal, Egypt. The molluscan community was sampled quantitatively by scraping. Three quarters of the individuals and more than half of the species were non-indigenous. Among the latter, a mytilid bivalve, Gregariella cf. ehrenbergi, was first recorded in the Mediterranean Sea on the basis of these samples, suggesting that the full consideration of all potential vectors can contribute to non-indigenous species detection. Large floating objects in coastal waters, such as buoys, are particularly suitable for colonization by Lessepsian species because hard substrates, and artificial ones in particular, are highly susceptible to the establishment of non-indigenous species. Moreover, their size and persistence enable the development of abundant and mature fouling communities that can disseminate propagules as eggs and larvae over long distances and for extended periods if detached. This report highlights the potential for large rafting debris as a vector of the spread of non-indigenous biota within the Mediterranean Sea.

New records of non-indigenous molluscs from the eastern Mediterranean Sea.

We report new findings of non-indigenous Indo-Pacific molluscs from shallow water habitats off Israel, Greece and Egypt, eastern Mediterranean Sea. The bivalves Pillucina vietnamica Zorina, 1978 and Alveinus miliaceus (Issel, 1869) were collected from sandy bottoms off Israel, whereas Gregariella cf. ehrenbergi (Issel, 1869) was recovered from a buoy originating from Port Said, Egypt, and stranded on the Israeli coast. The three species are first records for the Mediterranean Sea. Additionally, we report range extensions for several gastropods: Varicopeza pauxilla (A. Adams, 1855) is recorded from Israel, Phidiana militaris (Alder and Hancock, 1864) from southern Israel (Ashqelon), and Viriola cf. bayani Jousseaume, 1884 from Israel and Crete. Shells and valves of an unidentified lucinid bivalve morphologically distinct from any known Mediterranean species were found along the Israeli Mediterranean shore.