Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Extensive morphological variability in asexually produced planktic foraminifera
Marine protists are integral to the structure and function of pelagic ecosystems and marine carbon cycling, with rhizarian biomass alone accounting for more than half of all mesozooplankton in the oligotrophic oceans. Yet, understanding how their environment shapes diversity within species and across taxa is limited by a paucity of observations of heritability and life history. Here, we present observations of asexual reproduction, morphologic plasticity, and ontogeny in the planktic foraminifer Neogloboquadrina pachyderma in laboratory culture. Our results demonstrate that planktic foraminifera reproduce both sexually and asexually and demonstrate extensive phenotypic plasticity in response to nonheritable factors. These two processes fundamentally explain the rapid spatial and temporal response of even imperceptibly low populations of planktic foraminifera to optimal conditions and the diversity and ubiquity of these species across the range of environmental conditions that occur in the ocean.  more » « less
Award ID(s):
1631977
PAR ID:
10197656
Author(s) / Creator(s):
; ; ; ; ; ;
Date Published:
Journal Name:
Science Advances
Volume:
6
Issue:
28
ISSN:
2375-2548
Page Range / eLocation ID:
eabb8930
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; (, Biogeosciences)
    null (Ed.)
    Abstract. Oxygen-depleted regions of the global ocean are rapidly expanding, with important implications for global biogeochemical cycles. However, our ability to make projections about the future of oxygen in the ocean is limited by a lack of empirical data with which to test and constrain the behavior of global climatic and oceanographic models. We use depth-stratified plankton tows to demonstrate that some species of planktic foraminifera are adapted to life in the heart of the pelagic oxygen minimum zone (OMZ). In particular, we identify two species, Globorotaloides hexagonus and Hastigerina parapelagica, living within the eastern tropical North Pacific OMZ. The tests of the former are preserved in marine sediments and could be used to trace the extent and intensity of low-oxygen pelagic habitats in the fossil record. Additional morphometric analyses of G. hexagonus show that tests found in the lowest oxygen environments are larger, more porous, less dense, and have more chambers in the final whorl. The association of this species with the OMZ and the apparent plasticity of its test in response to ambient oxygenation invites the use of G. hexagonus tests in sediment cores as potential proxies for both the presence and intensity of overlying OMZs. 
    more » « less
  2. ; ; ; ; ; ; (, Journal of Geophysical Research: Biogeosciences)
    Abstract Ocean Alkalinity Enhancement (OAE) in coastal and open‐ocean environments has been proposed as a scalable method for atmospheric CO2removal. However, the effects of OAE on marine calcifiers, such as foraminifera, remain under‐constrained. Determining the response of marine calcifiers to OAE is critical because alkalinity uptake during calcification reduces the intended CO2removal from the atmosphere. Here we utilize X‐Ray Micro‐Computed Tomography imaging to quantify the calcification response ofGlobigerina bulloides grown in culture under two OAE scenarios. These scenarios most closely simulate equilibration with atmospheric CO2, corresponding to modest increases in the saturation state, and using NaHCO3as an alkalinity source. We assess changes in calcification using two metrics: shell density as indicated by mean CT number, and calcite mass added relative to the amount of shell elongation. An alkalinity increase of 350 μmol/kg significantly increased both metrics, indicating enhanced calcification ofG. bulloidesas a result of alkalinity addition. We extrapolate our culture results fromG. bulloidesto estimate increases in CaCO3flux driven by planktic foraminifera in response to large‐scale OAE deployment, and discuss factors that will impact the global, multi‐species nature of the planktic foraminiferal calcification response in the open ocean. While our preliminary results fromG. bulloidespoint to a minor mitigating impact of foraminifera calcification on OAE efficacy, we argue that pelagic calcification should be considered when estimating OAE efficacy and future potential for deployment in the open ocean as a method for atmospheric CO2removal. 
    more » « less
  3. ; ; ; ; (, Biogeosciences)
    Abstract. The close association between planktic foraminiferal assemblages and local hydrography make foraminifera invaluable proxies for environmental conditions. Modern foraminiferal seasonality is important for interpreting fossil distributions and shell geochemistry as paleoclimate proxies. Understanding this seasonality in an active upwelling area is also critical for anticipating which species may be vulnerable to future changes in upwelling intensity and ocean acidification. Two years (2012–2014) of plankton tows, along with conductivity–temperature–depth profiles and carbonate chemistry measurements taken along the north-central California shelf, offer new insights into the seasonal dynamics of planktic foraminifera in a seasonal coastal upwelling regime. This study finds an upwelling affinity for Neogloboquadrina pachyderma as well as a seasonal and upwelling associated alternation between dominance of N. pachyderma and Neogloboquadrina incompta, consistent with previous observations. Globigerina bulloides, however, shows a strong affinity for non-upwelled waters, in contrast to findings in Southern California where the species is often associated with upwelling. We also find an apparent lunar periodicity in the abundances of all species and document the presence of foraminifera even at very low saturation states of calcite. 
    more » « less
  4. ; ; ; ; ; ; ; ; (, Geological Society, London, Special Publications)
    Abstract We investigated the biogeography of benthic foraminifera in a highly urbanized tropical seascape, i.e. Hong Kong, in order to assess their utility as bioindicators relative to other marine fauna. Hong Kong is one of the largest coastal cities on the planet and studies of other benthic fauna in the region are available for comparison. We found that: (1) turbid, muddy habitats host a unique foraminiferal fauna; (2) areas with intermediate levels of eutrophication have the highest foraminiferal species diversity; (3) semi-enclosed and heavily polluted environments host a distinct foraminiferal fauna, characterized by low taxonomic diversity and/or high dominance, and that is acclimated to stressful marine conditions. Biodiversity patterns of foraminifera in Hong Kong are generally consistent with those of other soft-sediment macro- and meio-fauna (e.g. polychaetes, molluscs and ostracods); however, foraminifera may be more sensitive than these other groups to eutrophication and associated changes in coastal food webs. The tolerance of some, but not other, species to eutrophic and hypoxic conditions means that foraminiferal faunas can serve as bioindicators across a wide array of environmental conditions, in contrast with corals whose sensitivity to eutrophication results in their absence from eutrophied settings. The well-known autoecology of foraminifera taxa can help to characterize environmental conditions of different habitats and regional environmental gradients. Although the use of fauna as bioindicators may be most robust when data are compared for multiple taxonomic groups, when such broad sampling is not available, benthic foraminifera are particularly well suited for environmental assessments due to their ubiquity, interspecific environmental breadth, and the well-understood environmental preference of individual taxa. 
    more » « less
  5. ; ; ; ; (, American Geophysical Union)
    The rapid response of foraminiferal assemblages to changing climate makes their shells an invaluable geological record of the past. The drivers of shell assemblage composition and abundance, however, are complex and involve both oceanographic and ecological processes. Understanding how modern foraminifera respond to and record a climate event that would appear nearly instantaneous in the sediment record can inform paleontological interpretations and help to place foraminifera in a broader ecological context. We focus on the impact of rapid climate change on planktic foraminifera in the California Current ecosystem, providing insight into how foraminiferal response to abrupt environmental change informs their use as paleoenvironmental proxies. The Santa Barbara Basin sediment trap, located off the coast of California, USA, provides a record of particulate and foraminiferal flux to the basin since 1993. The 30-year deployment of the sediment trap captures the superposition of the annual cycle of seasonal upwelling in Santa Barbara Basin, Pacific multiannual ENSO-driven temperature changes, and anthropogenically forced climate change. We present data on planktic foraminiferal flux collected between 2014-2021, at two-week intervals (> 150 samples) and compare results to previously published data from 1993-1998. Consistent with previous studies, the most abundant species between 2014-2021 are Globigerina bulloides, Neogloboquadrina incompta, and Turborotalita quinqueloba, with peak flux in the spring and late summer. The winter season is characterized by low flux and an increase in abundance of N. incompta and subtropical species. Seasonal and interannual variability affect the interpretation of foraminiferal records across geologic time. For example, G. bulloides exhibits strong seasonal trends within any single year, but has an inconsistent seasonality across multiple years, making G. bulloides a poor proxy for spring upwelling conditions in Santa Barbara. We find that the most modern samples (2018-2021) show a decrease in subtropical species abundance (Globigerinoides ruber, Globigerina rubescens, Orbulina universa, Neogloboquadrina dutertrei) compared to the 1990s, contrary to expectations if assemblages were to primarily follow a trend dominated by anthropogenic warming. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Text Encoded Conversion
  • XML
  • Save / Share this Record
  • Send to Email