ALBERT

Description: Ocean acidification and decreasing seawater saturation state with respect to calcium carbonate (CaCO3) minerals have raised concerns about the consequences to marine organisms that build CaCO3 structures. A large proportion of benthic marine calcifiers incorporate Mg2+ into their skeletons (Mg-calcite), which, in general, reduces mineral stability. The relative vulnerability of some marine calcifiers to ocean acidification appears linked to the relative solubility of their shell or skeletal mineralogy, although some organisms have sophisticated mechanisms for constructing and maintaining their CaCO3 structures causing deviation from this dependence. Nevertheless, few studies consider seawater saturation state with respect to the actual Mg-calcite mineralogy (ΩMg-x) of a species when evaluating the effect of ocean acidification on that species. Here, a global dataset of skeletal mole % MgCO3 of benthic calcifiers and in situ environmental conditions spanning a depth range of 0 m (subtidal/neritic) to 5600 m (abyssal) was assembled to calculate in situ ΩMg-x. This analysis shows that 24% of the studied benthic calcifiers currently experience seawater mineral undersaturation (ΩMg-x 〈 1). As a result of ongoing anthropogenic ocean acidification over the next 200 to 3000 years, the predicted decrease in seawater mineral saturation will expose approximately 57% of all studied benthic calcifying species to seawater undersaturation. These observations reveal a surprisingly high proportion of benthic marine calcifiers exposed to seawater that is undersaturated with respect to their skeletal mineralogy, underscoring the importance of using species-specific seawater mineral saturation states when investigating the impact of CO2-induced ocean acidification on benthic marine calcification.

Description: The contribution of carbonate-producing benthic organisms to the global marine carbon budget has been overlooked, the prevailing view being that calcium carbonate (CaCO3) is predominantly produced by marine plankton. Here, we provide the first estimation of the global contribution of echinoderms to the marine carbon cycle, based on organism-level measurements from species of the five echinoderm classes. Echinoderms global CaCO3 contribution amounts to ~0.861 Pg CaCO3 yr-1 (0.102 Pg C yr-1 of inorganic carbon) as a production rate, and ~2.11 Pg CaCO3 (0.25 Pg C of inorganic carbon) as a standing stock globally. Echinoderm inorganic carbon production (0.102 Pg C yr-1) is less than the global pelagic production (0.4-1.8 Pg C yr-1), and similar to the estimates for carbonate shelves globally (0.02-0.12 Pg C yr-1). Echinoderm CaCO3 production per unit area, is ~27.01 g CaCO3 m-2 yr-1 (3.24 g C m-2 yr-1 as inorganic carbon) on a global scale for all areas, with a standing stock of ~63.34 g CaCO3 m-2 (7.60 g C m-2 as inorganic carbon), and ~7.97 g C m-2 as organic carbon. The shelf production is 77.91 g CaCO3 m-2 yr-1 (9.35 g C m-2 yr-1 as inorganic carbon) in contrast to 2.05 g CaCO3 m-2 yr-1 (0.24 g C m-2 yr-1 as inorganic carbon) for the slope on a global scale. The biogeography of the CaCO3 standing stocks of echinoderms showed strong latitudinal variability. Roughly 80% of the global CaCO3 production from echinoderms occurs between 0 and 800 meters. The shelf and upper slope contribute the most. We provide a global distribution of echinoderm populations in the context of global calcite saturation horizons, since undersaturated waters with respect to mineral phases are surfacing. This shallowing is a direct consequence of ocean acidification, and in some places it may reach the shelf and upper slope permanently. These organism-level data contribute substantially to the assessment of global carbonate inventories, which at present are poorly estimated. Additionally, it is desirable to include these benthic compartments in coupled global biogeochemical models representing the “biological pump”, since at present all efforts have focused on pelagic processes, dominated by coccolithophores.

Description: Many marine organisms have gelatinous bodies, but the trait is most common in the medusae (phylum Cnidaria), ctenophores (phylum Ctenophora), and the pelagic tunicates (phylum Chordata, class Thaliacea). Although there are taxonomic and trophic differences between the thaliaceans and the other two closely related phyla, the collective term "jellyfish" has been used within the framework of this article. Because of the apparent increase in bloom events, jellyfish are receiving greater attention from the wider marine science community. Questions being posed include: (1) what is the role of jellyfish in pelagic food webs in a changing environment, and (2) what is the role of jellyfish in large-scale biogeochemical processes such as the biological carbon pump? In order to answer such questions, fundamental data on body composition and biomass are required. The purpose of this data set was to compile proximate and elemental body composition and length–mass and mass–mass regressions for jellyfish (i.e., medusae, siphonophores, ctenophores, salps, doliolids, and pyrosomes) to serve as a baseline data set informing studies on biogeochemical cycling, food web dynamics, and ecosystem modeling, and physiology. Using mainly published data from 1932 to 2010, we have assembled three data sets: (1) body composition (wet, dry, and ash-free dry mass, C, N, P as a percentage of wet and dry mass, and C:N), (2) length–mass biometric equations, and (3) mass–mass biometric equations. The data sets represent a total of 102 species from six classes (20 Thaliacea, 2 Cubozoa, 33 Hydrozoa, 26 Scyphozoa, 17 Tentaculata, 4 Nuda) in three phyla. Where it exists, we have included supplementary data on location, salinity, whole animal or tissue type, measured size range, and where appropriate, the regression type with values of sample size, correlation coefficients (r, r2), and level of significance for the relationship. In addition to the raw unpublished data, we have provided summary tables of mean (± SD) body composition for the main taxonomic groups.

Description: Gelatinous zooplankton (Cnidaria, Ctenophora, and Urochordata, namely, Thaliacea) are ubiquitous members of plankton communities linking primary production to higher trophic levels and the deep ocean by serving as food and transferring “jelly‐carbon” (jelly‐C) upon bloom collapse. Global biomass within the upper 200 m reaches 0.038 Pg C, which, with a 2–12 months life span, serves as the lower limit for annual jelly‐C production. Using over 90,000 data points from 1934 to 2011 from the Jellyfish Database Initiative as an indication of global biomass (JeDI: http://jedi.nceas.ucsb.edu, http://www.bco‐dmo.org/dataset/526852), upper ocean jelly‐C biomass and production estimates, organism vertical migration, jelly‐C sinking rates, and water column temperature profiles from GLODAPv2, we quantitatively estimate jelly‐C transfer efficiency based on Longhurst Provinces. From the upper 200 m production estimate of 0.038 Pg C year−1, 59–72% reaches 500 m, 46–54% reaches 1,000 m, 43–48% reaches 2,000 m, 32–40% reaches 3,000 m, and 25–33% reaches 4,500 m. This translates into ~0.03, 0.02, 0.01, and 0.01 Pg C year−1, transferred down to 500, 1,000, 2,000, and 4,500 m, respectively. Jelly‐C fluxes and transfer efficiencies can occasionally exceed phytodetrital‐based sediment trap estimates in localized open ocean and continental shelves areas under large gelatinous blooms or jelly‐C mass deposition events, but this remains ephemeral and transient in nature. This transfer of fast and permanently exported carbon reaching the ocean interior via jelly‐C constitutes an important component of the global biological soft‐tissue pump, and should be addressed in ocean biogeochemical models, in particular, at the local and regional scale.