Description: Free-ocean CO2 enrichment (FOCE) systems are designed to assess the impact of ocean acidification on biological communities in situ for extended periods of time (weeks to months). They overcome some of the drawbacks of laboratory experiments and field observations by enabling (1) precise control of CO2 enrichment by monitoring pH as an offset of ambient pH, (2) consideration of indirect effects such as those mediated through interspecific relationships and food webs, and (3) relatively long experiments with intact communities. Bringing perturbation experiments from the laboratory to the field is, however, extremely challenging. The main goal of this paper is to provide guidelines on the general design, engineering, and sensor options required to conduct FOCE experiments. Another goal is to introduce xFOCE, a community-led initiative to promote awareness, provide resources for in situ perturbation experiments, and build a user community. Present and existing FOCE systems are briefly described and examples of data collected presented. Future developments are also addressed as it is anticipated that the next generation of FOCE systems will include, in addition to pH, options for oxygen and/or temperature control. FOCE systems should become an important experimental approach for projecting the future response of marine ecosystems to environmental change.

Description: The crystal structure of legrandite -- Zn 2 (AsO 4 )(OH)(H 2 O), monoclinic, a 12.8052(3), b 7.9249(2), c 10.2173(2) Å, β 104.4329(3)°, V 1004.13(6) Å 3 , space group P 2 1 / c , Z = 2 -- has been refined to an R 1 value of 1.2% based on 2844 unique [| F o | 〉 4 F ] reflections measured with a Bruker D8 three-circle diffractometer equipped with a rotating-anode generator (Mo K α X-radiation), multilayer optics, and an APEX-II detector. The legrandite structure is a heteropolyhedral framework of (AsO 4 ) tetrahedra, (Zn 5 ) square pyramids, and (Zn 6 ) octahedra [ = O, (OH), (H 2 O)] with extensive hydrogen bonding across its interstices. All hydrogen positions were located, all hydrogen bonds were assigned, and the H...O distances are in reasonable accord with the published relation between O–H stretching frequency and H...O bond-length.

Description: The crystal structure of yofortierite, (Mn 2+ ,Mg,Fe 3+ ,) 5 Si 8 O 20 (OH,H 2 O) 2 (H 2 O) 7 , monoclinic, C 2/ m , Z = 4, a 14.1686(12), b 17.8583(16), c 5.2919(5) Å, β 105.878(1)°, V 1287.9(3) Å 3 , has been refined to R 1 = 4.9 % for 1795 unique ( F o 〉 4 F ) reflections collected on a Bruker D8 three-circle diffractometer equipped with a rotating-anode generator (Mo K α X-radiation), a multi-layer optics incident-beam path, and an APEX-II CCD detector. Chemical analysis by electron microprobe plus Fe 3+ determination by Mössbauer spectroscopy gave SiO 2 51.78, Al 2 O 3 0.05, TiO 2 0.15, Fe 2 O 3 1.84, MnO 22.97, ZnO 0.99, MgO 4.32, CaO 1.10, H 2 O calc 16.69, sum 99.89 wt.%. The resulting empirical formula is (Mn 3.01 Mg 1.00 Zn 0.11 Ca 0.18 Fe 3+ 0.21 Ti 0.02 Al 0.01 0.46 ) =5 Si 8.00 O 20 [(OH) 1.34 (H 2 O) 0.66 ] =2 (H 2 O) 7 . Yofortierite is a palygorskyite-group mineral. There are two tetrahedrally coordinated T sites occupied by Si with 〈Si–O〉 distances of 1.621 and 1.617 Å, and three octahedrally coordinated M sites, occupied primarily by Mn 2+ and Mg with minor Fe 3+ and , with 〈 M –O〉 distances of 2.147, 2.079, and 2.183 Å. The 〈 M –O〉 distances indicate strong order of M cations over the three M sites, with the smaller cations and vacancies ordered at the M (2) site and Ca ordered at the M (3) site. The presence of vacancies at the M (2) site locally couple with the replacement of (OH) – at the O(4) site by (H 2 O) o , giving rise to strong short-range order, and H 2 O is incorporated into the framework part of the structure by the substitution Mn 2+ + (OH) – = + (H 2 O) o which is coupled to the substitution Mn 2+ = Fe 3+ by the requirement of electroneutrality.

Description: Wopmayite, ideally Ca 6 Na 3 Mn(PO 4 ) 3 (PO 3 OH) 4 , is a new secondary mineral from the Tanco mine, Bernic Lake, Manitoba. It occurs in vugs in a single 5–10 cm mass of phosphate-carbonate mineralization in a spodumene-rich boulder found in the dumps of the Tanco Mine, Bernic Lake, Manitoba, Canada. It is a secondary mineral that crystallized together with rhodochrosite, quartz, whitlockite, apatite, and other phases after dissolution of primary lithiophosphate by hydrothermal solutions. The initial crystal of wopmayite was a corroded {101} rhomb ~150 microns across. Wopmayite is colorless to white to pale pink with a white streak and a vitreous luster, and does not fluoresce under ultraviolet light. It has a Mohs hardness of 5, is brittle, has an irregular to subconchoidal fracture, and shows no cleavage or parting. The calculated density is 3.027 g/cm 3 . It is uniaxial (-), = 1.617, = 1.613, both ± 0.002. Wopmayite is hexagonal-rhombohedral, space group R 3 c , a 10.3926(2), c 37.1694(9) Å, V 3476.7(2) Å 3 , Z = 6, a:c = 1:3.577. The seven strongest lines in the X-ray powder-diffraction pattern are as follows: d (Å), I , ( h k l ): 2.858, 100, (02.10); 3.186, 88, (34); 2.589, 68, (40); 5.166, 33, (20); 6.421, 32, (14); 8.017, 31, (012); and 3.425, 29, (110). Chemical analysis by electron microprobe gave P 2 O 5 46.40, Al 2 O 3 0.38, Fe 2 O 3 0.80, FeO 0.96, MnO 3.74, MgO 0.41, CaO 37.65, SrO 0.91, Na 2 O 5.43, and H 2 O(calc) 2.00, sum 98.68 wt.%. The H 2 O content was determined by crystal-structure analysis. On the basis of 28 O apfu , the empirical formula is (Ca 7 .19 Na 1.88 Sr 0.09 ) 9.16 (Mn 0.56 Mg 0.11 Fe 2+ 0.14 Fe 3+ 0.11 Al 0.08 ) 1.00 (PO 4 ) 4.63 (PO 3 OH) 2.37 , and the endmember formula is Ca 6 Na 3 Mn(PO 4 ) 3 (PO 3 OH) 4 . The crystal structure of wopmayite was solved by direct methods and refined to an R 1 index of 2.21% based on 2288 unique observed reflections collected on a three-circle rotating-anode ( M o K α X-radiation) diffractometer equipped with multilayer optics and an APEX-II detector. Wopmayite has a structural unit consisting of an [M 2+ (PO 4 ) 6 ] arrangement that is topologically the same as the structural units in the whitlockite and merrillite structures. The [M 2+ (PO 4 ) 6 ] clusters are linked by Ca polyhedra and (PO 3 ) groups of the form {Ca 9 X (PO 3 )} where = O,OH and X = (, Na, Ca), depending on the mineral species. Wopmayite is related to whitlockite by the substitution Na + H -〉 Ca + , whereby Na is incorporated primarily at the Ca (3) site and H attaches to the P (1) tetrahedron to produce an acid-phosphate group. Thus merrillite contains no acid-phosphate group, whitlockite contains a single acid-phosphate group at P (3), and wopmayite contains acid-phosphate groups at both P (1) and P (3).

Description: Pieczkaite, ideally Mn 5 (PO 4 ) 3 Cl, is a new apatite-supergroup mineral from Cross Lake, Manitoba, Canada. It occurs as small patches and narrow veins in large crystals of apatite and (Mn,Cl)-bearing apatite in phosphate pods in the quartz core of a granitic pegmatite. Veins of Mn-bearing apatite narrow to ~25 μm where the Mn content becomes high enough to constitute pieczkaite. It is gray with a grayish-white streak, does not fluoresce under ultraviolet light, and has no observable cleavage or parting. Mohs hardness is 4–5, and pieczkaite is brittle with an irregular fracture. The calculated density is 3.783 g/cm 3 . Optical properties were measured using a Bloss spindle stage at a wavelength of 590 nm (using a gel filter). Pieczkaite is uniaxial (–) with indices of refraction = 1.696, = 1.692, both ±0.002. Pieczkaite is hexagonal, space group P 6 3 / m , a = 9.504(4), c = 6.347(3) Å, V = 496.5(1) Å 3 , Z = 2, c : a = 1:0.6678. The six strongest lines in the X-ray powder diffraction pattern are as follows: d (Å), I , ( hkl ): 2.794, 100, (31, 31); 2.744, 88, (030); 2.639, 34, (22); 2.514, 25, (031, 022); 1.853, 25, (42, 42); 3.174, 24, (002). Chemical analysis by electron microprobe gave P 2 O 5 37.52, MnO 41.77, FeO 2.45, CaO 13.78, Cl 3.86, H 2 O 0.60, OCl –0.87, sum 99.11 wt% where the H 2 O content was calculated as 1 – Cl apfu. The resulting empirical formula on the basis of 12 O anions is (Mn 3.36 Fe 0.20 Ca 1.40 ) 4.96 (P 1.01 O 4 ) 3 (Cl 0.62 OH 0.38 ) 1.00 , and the end-member formula is Mn 5 (PO 4 ) 3 Cl. The crystal structure of pieczkaite was refined to an R 1 index of 4.07% based on 308 observed reflections collected on a three-circle rotating-anode diffractometer with Mo K α X-radiation. Pieczkaite is isostructural with apatite, Mn is the dominant cation at both the [9]- and [7]-coordinated-cation sites in the structure, and Cl is the dominant monovalent anion.

Description: Phosphoran olivine (1–7 wt% P 2 O 5 ) is a metastable phase known from fewer than a dozen meteoritic or terrestrial occurrences. We have thoroughly examined phosphoran olivine in the Springwater pallasite to characterize its distribution, textural relationships, and geochemistry. Phosphoran olivine is abundant in Springwater as randomly distributed millimeter-scale partial overgrowths on the P-free olivine crystals. Geochemical analyses support the substitution mechanism of P into the tetrahedral Si site with octahedral site vacancies for charge balance; observed trace element variations, on the other hand, are not related to P substitution. Element mapping reveals fine-scale oscillatory P zoning in unusual serrate patterns, indicating rapid crystal nucleation from a melt as proposed by Boesenberg and Hewins (2010) and a subsequently variable rate of crystallization. The timing of phosphoran olivine formation in Springwater is constrained to after the period of macroscopic olivine rounding but before the cooling of the metal matrix; because the phosphoran overgrowths overprint specific host grain boundary modifications, we suggest that the episode of extremely rapid cooling necessary to crystallize and preserve this rare phase may have been triggered by an additional impact to the parent body.

Description: Trichodesmium , a colonial cyanobacterium typically associated with tropical waters, was observed between January and April 2014 in the western English Channel. Sequencing of the heterocyst differentiation ( hetR ) and 16S rRNA genes placed this community within the Clade IV Trichodesmium , an understudied clade previously found only in low numbers in warmer waters . Nitrogen fixation was not detected although measurable rates of nitrate uptake and carbon fixation were observed. Trichodesmium RuBisCO transcript abundance relative to gene abundance suggests the potential for viable and potentially active Trichodesmium carbon fixation. Observations of Trichodesmium when coupled with a numerical advection model indicate that Trichodesmium communities can remain viable for 〉3.5 months at temperatures lower than previously expected. The results suggest that Clade IV Trichodesmium occupies a different niche to other Trichodesmium species, and is a cold- or low-light-adapted variant.