Short-range dispersal maintains a volatile marine metapopulation: the brown alga Postelsia palmaeformis.

The annual brown alga Postelsia palmaeformis is dependent for its survival on short-distance dispersal (SDD) where it is already established, as well as occasional long-distance colonization of novel sites. To quantify SDD, we transplanted Postelsia to sites lacking established plants within ≥10 m. The spatial distribution of the first naturally produced sporophyte generation was used to fit dispersal kernels in a hierarchical Bayesian framework. Mean dispersal distance within a year ranged from 0.16 to 0.50 m across sites; 95% of the recruits were within 0.38-1.32 m of the transplant. The fat-tailed exponential square root kernel was the best among the candidate models at describing offspring density and dispersal. Independent measurements of patch size over two to five generations permitted an evaluation of whether models parameterized by individual-level data could adequately predict longer-term persistence and spread at the patch scale. The observed spread rates generally fell within the 95% predictive intervals. Finally, Postelsia was eliminated from 14 occupied sites that were then followed for ≥27 yr. The probability of invasion when unoccupied declined and the probability of extinction when occupied increased with distance from the nearest propagule source. Sites >10 m from a source were rarely invaded, and one initially densely populated site isolated by 39 m has remained Postelsia-free since 1981. In spite of dispersal that is almost entirely within 2 m of the parent, the ability of our models to capture the observed dynamics of Postelsia indicates that short-range dispersal adequately explains the persistent and thriving Postelsia metapopulation on Tatoosh Island. However, the presence of Postelsia over a 2000-km coastal range with many gaps >1 km makes it clear that rare long-distance dispersal must be required to explain the geographic range of the species.

Historical baselines and the future of shell calcification for a foundation species in a changing ocean.

Seawater pH and the availability of carbonate ions are decreasing due to anthropogenic carbon dioxide emissions, posing challenges for calcifying marine species. Marine mussels are of particular concern given their role as foundation species worldwide. Here, we document shell growth and calcification patterns in Mytilus californianus, the California mussel, over millennial and decadal scales. By comparing shell thickness across the largest modern shells, the largest mussels collected in the 1960s-1970s and shells from two Native American midden sites (∼1000-2420 years BP), we found that modern shells are thinner overall, thinner per age category and thinner per unit length. Thus, the largest individuals of this species are calcifying less now than in the past. Comparisons of shell thickness in smaller individuals over the past 10-40 years, however, do not show significant shell thinning. Given our sampling strategy, these results are unlikely to simply reflect within-site variability or preservation effects. Review of environmental and biotic drivers known to affect shell calcification suggests declining ocean pH as a likely explanation for the observed shell thinning. Further future decreases in shell thickness could have significant negative impacts on M. californianus survival and, in turn, negatively impact the species-rich complex that occupies mussel beds.

Consistency in a marine algal-grazer interaction over multiple scales.

Coralline algae are conspicuous members of many marine assemblages, especially those characterized by intense grazing pressure. We explored whether articulated species, especially Corallina vancouveriensis, depend on grazing invertebrates to both establish and flourish in an exposed rocky intertidal setting, and whether this plant-grazer relationship varied over more than three orders of magnitude (≈100->300,000 µm). Three experimental manipulations, supplemented by observations on recruitment, demonstrated that (i) C. vancouveriensis failed to recover rapidly from disturbed areas when grazers were experimentally excluded; (ii) recruitment occurred in the presence of grazers; (iii) increasing surface texture of molded surfaces enhanced coralline recruitment more when grazers were present; and (iv) settlement occurred predominately in microtopographical low areas of a molded surface, whereas a competitively superior fleshy red alga tended to recruit to high areas. These results confirm that coralline algal establishment and persistence are enhanced by grazers and reveal that this relationship is consistent over a range of biologically relevant scales.

Synthesis and lanthanide coordination chemistry of phosphine oxide decorated dibenzothiophene and dibenzothiophene sulfone platforms.

Syntheses for new ligands based upon dibenzothiophene and dibenzothiophene sulfone platforms, decorated with phosphine oxide and methylphosphine oxide donor groups, are described. Coordination chemistry of 4,6-bis(diphenylphosphinoylmethyl)dibenzothiophene (8), 4,6-bis(diphenylphosphinoylmethyl)dibenzothiophene-5,5-dioxide (9) and 4,6-bis(diphenylphosphinoyl)dibenzothiophene-5,5-dioxide (10) with lanthanide nitrates, Ln(NO3)3·(H2O)n is outlined, and crystal structure determinations reveal a range of chelation interactions on Ln(III) ions. The nitric acid dependence of the solvent extraction performance of 9 and 10 in 1,2-dichloroethane for Eu(III) and Am(III) is described and compared against the extraction behavior of related dibenzofuran ligands (2, 3; R = Ph) and n-octyl(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide (4) measured under identical conditions.

Synthesis, lanthanide coordination chemistry, and liquid-liquid extraction performance of CMPO-decorated pyridine and pyridine N-oxide platforms.

Syntheses for a set of new ligands containing one or two carbamoylmethylphosphine oxide (CMPO) fragments appended to pyridine and pyridine N-oxide platforms are described. Molecular mechanics analyses for gas phase lanthanide-ligand interactions for the pyridine N-oxides indicate that the trifunctional NOPOCO molecules, 2-{[Ph2P(O)][C(O)NEt2]C(H)}C5H4NO (7) and 2-{[Ph2P(O)][C(O)NEt2]CHCH2}C5H4NO (8), and pentafunctional NOPOP'O'COC'O' molecules, 2,6-{[Ph2P(O)][C(O)NEt2]C(H)}2C5H3NO (9) and 2,6-{[Ph2P(O)][C(O)NEt2]CHCH2}2C5H3NO (10), should be able to adopt, with minimal strain, tridentate and pentadentate chelate structures, respectively. As a test of these predictions, selected lanthanide coordination chemistry of the N-oxide derivatives was explored. Crystal structure analyses reveal the formation of a tridentate NOPOCO chelate structure for a 1:1 Pr(III) complex containing 7 while 8 adopts a mixed bidentate/bridging monodentate POCO/NO binding mode with Pr(III). Tridentate and tetradentate chelate structures are obtained for several 1:1 complexes of 9 while a pentadentate chelate structure is observed with 10. Emission spectroscopy for one complex, [Eu(9)(NO3)3], in methanol, shows that the Eu(III) ion resides in a low-symmetry site. Lifetime measurements for methanol and deuterated methanol solutions indicate the presence of four methanol molecules in the inner coordination sphere of the metal ion, in addition to the ligand, with the nitrate anions most likely dissociated. The solvent extraction performance of 7-10 in 1,2-dichloroethane for Eu(III) and Am(III) in nitric acid solutions was analyzed and compared with the performance of 2,6-bis(di-n-octylphosphinoylmethyl)pyridine N-oxide (TONOPOP'O') and n-octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (OPhDiBCMPO) measured under identical conditions.

Synthesis and coordination chemistry of phosphine oxide decorated dibenzofuran platforms.

A four-step synthesis for 4,6-bis(diphenylphosphinoylmethyl)dibenzofuran (4) from dibenzofuran and a two-step synthesis for 4,6-bis(diphenylphosphinoyl)dibenzofuran (5) are reported along with coordination chemistry of 4 with In(III), La(III), Pr(III), Nd(III), Er(III), and Pu(IV) and of 5 with Er(III). Crystal structure determinations for the ligands, 4·CH(3)OH and 5, the 1:1 complexes [In(4)(NO(3))(3)], [Pr(4)(NO(3))(3)(CH(3)CN)]·0.5CH(3)CN, [Er(4)(NO(3))(3)(CH(3)CN)]·CH(3)CN, [Pu(4)Cl(4)]·THF and the 2:1 complex [Nd(4)(2)(NO(3))(2)](2)(NO(3))(2)·(H(2)O)·4(CH(3)OH) are described. In these complexes, ligand 4 coordinates in a bidentate POP'O' mode via the two phosphine oxide O-atoms. The dibenzofuran ring O-atom points toward the central metal cations, but in every case it is more than 4 Å from the metal. A similar bidentate POP'O' chelate structure is formed between 5 and Er(III) in the complex, {[Er(5)(2)(NO(3))(2)](NO(3))·4(CH(3)OH)}(0.5), although the nonbonded Er···O(furan) distance is reduced to ∼3.6 Å. The observed bidentate chelation modes for 4 and 5 are consistent with results from molecular mechanics computations. The solvent extraction performance of 4 and 5 in 1,2-dichloroethane for Eu(III) and Am(III) in nitric acid solutions is described and compared against the extraction behavior of n-octyl(phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide (OΦDiBCMPO) measured under identical conditions.

Contingencies and compounded rare perturbations dictate sudden distributional shifts during periods of gradual climate change.

Ecological responses to climate change may occur gradually with changing conditions, or they may occur rapidly once some threshold or "tipping point" has been reached. Here, we use a high-resolution, 30-year data set on the upper vertical limit of a high intertidal alga to demonstrate that distributional shifts in this species do not keep pace with gradual trends in air temperature or sea level, but rather occur in sudden, discrete steps. These steps occur when unusually warm air temperatures are associated with unusually calm seas and are contingent in the sense that neither atmospheric nor sea conditions by themselves were sufficient to generate the underlying physiological challenge. Shifts in the upper limit did not correlate with large environmental perturbations such as El Niños; rather, they appeared to be associated with stochastic departures from otherwise gradual environmental trends. Our results exemplify the view that multiple environmental factors should be considered when attempting to understand ecological responses to climate change. Furthermore, punctuated responses such as those we have identified urge caution when attempting to infer causal mechanisms and project future distributional shifts using data of limited temporal resolution or scope.

Macroecology: does it ignore or can it encourage further ecological syntheses based on spatially local experimental manipulations? (American Society of Naturalists address).

Detailed natural history coupled to experimental ecology has provided a rich harvest of insights into how natural communities in all ecosystems function, insights that cannot be gleaned from macroecological analyses. That detail, generated by small-spatial-scale but often lengthy experiments, is essential to managing and even restoring ecosystems. My essay focuses primarily on the ecology of exposed rocky intertidal shores, but I believe the derived implications are generalizable to all ecosystems. A mainly experimental approach has tended to avoid a preoccupation with niches but instead has focused on the ecological roles exercised by particular species. Attention to roles has produced a growing appreciation for trophic cascades and their consequences, with obvious implications for the management of fisheries and the conservation significance of apex predators. Some studies are more phenomenological and others more reductionist in focus, but all provide pathways toward understanding abundance and body size variation or a miscellany of indirect effects. Microecology in all ecosystems should continue to prosper independently of a macroecological, predominately terrestrial perspective.

Reactions of organyl and silyl alanes with 1,3,4,5,6-pentamethyl-2-aminoborazine.

The reactions of (Me(3)Si)(3)Al, Me(3)Al, Et(3)Al, and i-Bu(3)Al with 1,3,4,5,6-pentamethyl-2-aminoborazine have been examined. An amine alane adduct (Me(3)Si)(3)Al.NH(2)B(3)(Me)(2)N(3)Me(3) (1) and several elimination products [(Me(3)Si)(2)AlN(H)B(3)(Me)(2)N(3)Me(3)](2) (2), [(Me(3)SiAl)(4)(Me(3)SiN)(3)NH] (3), [Me(2)AlN(H) B(3)(Me)(2)N(3)Me(3)](2) (4), [Et(2)AlN(H) B(3)(Me)(2)N(3)Me(3)](2) (5), and [i-Bu(2)AlN(H) B(3)(Me)(2)N(3)Me(3)](2) (6) have been isolated. Compounds 1, 2, 4-6 have been spectroscopically characterized, and single crystal X-ray diffraction structure determinations have been completed for 1-4 and 6. The molecular chemistry provides insight into the reaction of Me(3)Al and 1,3,5-N-trimethyl-2,4,6-B-triaminoborazine that, upon pyrolysis, produces AlN/BN composite ceramic materials.

Synthesis and reactivity of (benzoxazol-2-ylmethyl)phosphonic acid.

An efficient three step synthesis of (benzoxazol-2-ylmethyl)phosphonic acid (6-H(2)) is described along with IR, mass spectrometry (MS), and (1)H, (13)C, and (31)P NMR spectroscopic characterization data, and a single crystal X-ray diffraction structure determination. 6-H(2) is unstable in acidic aqueous solutions (pH < 4) undergoing ring-opening to give [(2-hydroxyphenylcarbamoyl)methyl] phosphonic acid (7-H(2)) that is characterized by IR, MS, and NMR methods. The protonation constants (pK(a)) for 7-H(2) have been measured, and crystal structure determinations for (NH(4))(7-H) and K(7-H)·DMF are described. Reactions of NaOH and KOH with 6-H(2) in MeOH/H(2)O solutions led to isolation and crystal structure determinations of the salts [Na(6-H)·H(2)O](2), K(6-H), Na(3)(6)(6-H)·H(2)O, and [K(2)(6)](2)·3H(2)O. The complexation reactions of 7-H(2) with La(III), Nd(III), and Gd(III), as a function of pH, were also examined by titrametric methods, and a model for the 1:1 anion binding with Ln(III) cations is proposed.

Synthesis and coordination properties of trifluoromethyl decorated derivatives of 2,6-bis[(diphenylphosphinoyl)methyl]pyridine N-oxide ligands with lanthanide ions.

Phosphinoyl Grignard-based substitutions on 2,6-bis(chloromethyl)pyridine followed by N-oxidation of the intermediate 2,6-bis(phosphinoyl)methylpyridine compounds with mCPBA give the target trifunctional ligands 2,6-bis[bis(2-trifluoromethylphenyl)phosphinoylmethyl]pyridine 1-oxide (2a) and 2,6-bis[bis(3,5-bis(trifluoromethyl)phenyl)phosphinoylmethyl]pyridine 1-oxide (2b) in high yields. The ligands have been spectroscopically characterized, the molecular structures confirmed by single crystal X-ray diffraction methods, and the coordination chemistry surveyed with lanthanide nitrates. Single crystal X-ray diffraction analyses are described for the coordination complexes Nd(2a)(NO(3))(3), Nd(2a)(NO(3))(3) x (CH(3)CN)(0.5), Eu(2a)(NO(3))(3), and Nd(2b)(NO(3))(3) x (H(2)O)(1.25); in each case the ligand binds in a tridentate mode to the Ln(III) cation. These structures are compared with the structures found for lanthanide coordination complexes of the parent NOPOPO ligand, [Ph(2)P(O)CH(2)](2)C(5)H(3)NO.

Humans as a Hyperkeystone Species.

Ecologists have identified numerous keystone species, defined as organisms that have outsized ecological impacts relative to their biomass. Here we identify human beings as a higher-order or 'hyperkeystone' species that drives complex interaction chains by affecting other keystone actors across different habitats. Strong indirect effects and a global reach further characterize these interactions and amplify the impacts of human activities on diverse ecosystems, from oceans to forests. We require better understanding of hyperkeystone interaction chains most urgently, especially for marine species and terrestrial large carnivores, which experience relatively higher exploitation rates than other species. This requires innovative approaches that integrate the study of human behavior with food-web theory, and which might provide surprising new insights into the complex ecology of our own species.

Synthesis and Structural Characterization of New Polyphosphorus Ring and Cage Compounds.

The 1:1 and 2:1 reactions of (Me(3)Si)(2)PLi.2THF with several amino chlorophosphanes have been surveyed. With (i)()Pr(2)NPCl(2), both reactant stoichiometries produce the four-membered ring compound (3) via different reaction schemes. Compound 3 combines with Fe(2)(CO)(9) to produce a monometallic complex (4) in which the Fe(CO)(4) fragment is bonded to one of the Me(3)SiP centers. With the cyclic hydrazino phosphane ClP(MeNNMe)(2)PCl only the bis-phosphane substitution product, (Me(3)Si)(2)PP(MeNNMe)(2)PP(SiMe(3))(2), is isolated. With the cyclic diazadiphosphetidine ((t)()BuNPCl)(2) a bis-phosphane substitution product [(t)()BuNPP(SiMe(3))(2)](2) (10) is formed along with a cage compound [((t)()BuNP)(2)P(SiMe(3))](2) (11). The new compounds have been characterized by spectroscopic techniques, and the molecular structure of 4 and 11 have been determined by X-ray crystallography.

Formation of Cage Compounds Containing Boron, Phosphorus, and Transition Metal Atoms.

The 1:1 reactions with (R(3)P)(2)MCl(2) (M = Ni, Pd, and Pt) have been surveyed, and bicyclic cage compounds containing boron, phosphorus and transition metal (Ni, Pd, or Pt) atoms have been isolated and characterized. The molecular structures of the species (Et(3)P)(2)Pd(PBN(i)Pr(2))(2) (2), (Et(3)P)(2)Pd(PBtmp)(2) (3), and (Et(3)P)(2)Pt(PBN(i)Pr(2))(2) (4) have been determined by single-crystal X-ray diffraction techniques. 2 crystallized in the monoclinic space group C2/c with a = 20.212(4) Å, b = 10.225(1) Å, c = 17.460(2) Å, beta = 107.72(1) degrees, and Z = 4. 3 crystallized in the orthorhombic space group P2(1)2(1)2(1) with a = 12.606(1) Å, b = 12.618(1) Å, c = 24.221(3) Å, and Z = 4. 4 crystallized in the monoclinic space group C2/c with a = 20.195(3) Å, b = 10.187(2) Å, c = 17.280(2) Å, beta = 107.53(7) degrees, and Z = 4. The spectroscopic and structural features of the new cage compounds are discussed in relation to their main group element cage analogs.

Synthesis and Chemistry of Bis(borylphosphino)silanes and -germanes.

The reactions of Me(2)SiCl(2), Ph(2)SiCl(2), and Ph(2)GeCl(2) with LiP(H)B(N(i)Pr(2))(2) in a 1:2 ratio and the reaction of Ph(2)SiCl(2) with LiP(H)B(N(i)Pr(2))[N(SiMe(3))(2)] in a 1:2 ratio give good yields of the respective diphosphinosilanes, Me(2)Si[P(H)B(N(i)Pr(2))(2)](2), Ph(2)Si[P(H)B(N(i)Pr(2))(2)](2), Ph(2)Ge[P(H)B(N(i)Pr(2))(2)](2), and Ph(2)Si[P(H)B(N(i)Pr(2))[N(SiMe(3))(2)]](2). These species, when combined with BuLi in a 1:2 ratio, give lithium diphosphinosilanes and -germanes of the general type (DME.Li)(2){[PB(NR(2))(2)](2)ER'(2)}. All of the species have been characterized by spectroscopic methods. The molecular structures of three of the lithio compounds, (DME.Li)(2){[PB(N(i)Pr(2))(2)](2)SiPh(2)} (11), (DME.Li)(2){[PB(N(i)Pr(2))N(SiMe(3))(2)](2)SiPh(2)} (15), and (DME.Li)(2){[PB(N(i)Pr(2))(2)](2)GePh(2)} (13), have been determined by X-ray diffraction techniques. 11 crystallized in the triclinic space group P&onemacr; with a = 11.071(2) Å, b = 14.937(3) Å, c = 18.080(4) Å, alpha = 91.31(3) degrees, beta = 101.23(3) degrees, gamma = 109.95(3) degrees, and Z = 2, and 13 crystallized in the triclinic space group P&onemacr; with a = 11.083(1) Å, b = 14.978(2) Å, c = 18.134(2) Å, alpha = 91.17(1) degrees, beta = 101.43(1) degrees, gamma = 110.05(1) degrees, and Z = 2. 15 crystallized in the monoclinic space group P2(1)/n with a = 11.939(2) Å, b = 24.516(3) Å, c = 21.572(3) Å, beta = 101.52(1) degrees, and Z = 4. The reactions of the lithio compounds were surveyed with R(2)ECl(2) reagents. The metathesis reactions are sluggish, but the 1:1 reaction of (DME.Li)(2){[PB(N(i)Pr(2))(2)](2)GePh(2)} with (t)Bu(2)SnCl(2) gave the four-membered-ring compound The 1:2 reaction of Me(2)(Cl)SiSi(Cl)Me(2) with LiP(H)B(N(i)Pr(2))(2) yielded the (borylphosphino)silane [Me(2)SiP(H)B(N(i)Pr(2))(2)](2).

Synthesis of Cage Compounds Containing Boron, Tin, and Phosphorus Atoms.

The 1:1 reactions of [((i)()Pr(2)N)BP(H)B(N(i)()Pr(2))PLi.DME] (1) and [(tmp)BP(H)B(tmp)PLi.DME] (2; tmp = 2,2,6,6-tetramethylpiperidino) with organylhalostannanes have been examined, and stannyl-substituted diphosphadiboretanes, (R(2)N)BP(H)B(NR(2))PSn(Cl)R'(2) (R(2)N = (i)()Pr(2)N, tmp; R' = Me, (t)()Bu) have been isolated and characterized. Dehydrohalogenation of these compounds with (t)()BuLi produced bicyclic cage compounds P(2)(R(2)NB)(2)SnR'(2) (R(2)N = (i)()Pr(2)N (9), tmp (8); R' = (t)()Bu) or an oligomer [-P(R(2)NB)(2)PSn(R'(2))-] (R(2)N = tmp; R' = Me). The 2:1 reactions of R'(2)SnCl(2) with 1 and 2 have been studied, and with a small R' group (Me) a disubstitution product, [HP(tmpB)(2)P](2)SnMe(2) (11), is obtained. With a larger R' group ((t)()Bu), cage products P(2)(tmpB)(2)Sn(t)()Bu(2) and P(2)((i)()Pr(2)NB)(2)Sn(t)()Bu(2) are isolated. The molecular structures of 8 and 9 have been determined by single crystal X-ray diffraction techniques, and these structures and their spectroscopic features are discussed in relation to other boron-phosphorus cage compounds.

Synthesis, Characterization, and Explosive Properties of the Nitrogen-Rich Borazine [H(3)N(3)B(3)(N(3))(3)].

The azidoborazines [Me(3)N(3)B(2)(Me)(2)B(N(3))] and [H(3)N(3)B(3)(N(3))(3)] were prepared from the combination of Me(3)SiN(3) and the chloroborazines [Me(3)N(3)B(2)(Me)(2)BCl] and (H(3)N(3)B(3)Cl(3)). The compounds have been characterized by analytical and spectroscopic methods. The molecular structure of [H(3)N(3)B(3)(N(3))(3)] has been confirmed by single-crystal X-ray diffraction techniques: triclinic space group P&onemacr; with a = 8.579(1) Å, b = 9.182(1) Å, c = 12.043(1) Å, alpha = 104.62(1) degrees, beta = 90.26(1) degrees, gamma = 110.74(1) degrees, and Z = 4. The thermal behavior of the azides have been examined by TGA/DTA. The explosion sensitivity of [H(3)N(3)B(3)(N(3))(3)], which contains 82.58% nitrogen by weight, has been accessed by drop weight impact, spark, and friction tests. These measurements indicate that [H(3)N(3)B(3)(N(3))(3)] is a relatively sensitive explosive. The Staudinger reactivity of the azides with Ph(3)P was examined, and [H(3)N(3)B(3)(N(3))(3)] was found to produce [Ph(3)P=NH(2)](N(3)). The molecular structure of this compound was determined by single-crystal X-ray diffraction techniques: orthorhombic space group P2(1)2(1)2(1) with a = 10.649(2) Å, b = 11.737(3) Å, c = 13.364(4) Å, alpha = beta = gamma = 90 degrees, Z = 4.

Synthesis and f-element ligation properties of NCMPO-decorated pyridine N-oxide platforms.

Stepwise syntheses of 2-{[2-(diphenylphosphoryl)acetamido]methyl}pyridine 1-oxide, 2-[Ph2P(O)CH2C(O)N(H)CH2]C5H4NO (6), 2-{[2-(diphenylphosphoryl)acetamido]methyl}-6-[(diphenylphosphoryl)methyl]pyridine 1-oxide, 2-[Ph2P(O)CH2C(O)N(H)CH2]-6-[Ph2P(O)CH2]C5H3NO (7) and 2,6-bis{[2-(diphenylphosphoryl)acetamido]methyl}pyridine 1-oxide, 2,6-[Ph2P(O)CH2C(O)N(H)CH2]2C5H3NO (8), are reported along with spectroscopic characterization data and single crystal X-ray diffraction structure determination for 6·2H2O, 7 and 2,6-[Ph2P(O)CH2C(O)N(H)CH2]2C5H3N·MeOH 18·MeOH, the pyridine precursor of 8. Molecular mechanics computations indicate that 6, 7 and 8 should experience minimal steric hindrance to donor group reorganization that would permit tridentate, tetradentate and pentadentate docking structures for the respective ligands on lanthanide cations. However, crystal structure determination for the lanthanide complexes, {[Yb(6)(NO3)3]·(MeOH)}n, {[Lu(6)(NO3)3]·(MeOH)}n, [Er(6)2(H2O)2](NO3)3·(H2O)4}n, {[La(13)(NO3)3(MeOH)]·(MeOH)}n, {[Eu(7)(NO3)2(EtOAc)0.5(H2O)0.5](NO3)}2·MeOH and [Dy3(7)4(NO3)4(H2O)2](NO3)5·(MeOH)5·(H2O)2 reveal solid-state structures with mixed chelating/bridging ligand : Ln(III) interactions that employ lower than the maximal denticity. The binding of 6 and 7 with Eu(III) in the solid state and in MeOH solutions is also accessed by emission spectroscopy. The acid dependence for solvent extractions with 6 and 7 in 1,2-dichloroethane for Eu(III) and Am(III) in nitric acid solutions is described and compared with the behavior of n-octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (OPhDiBCMPO, 1b) and 2-[(diphenyl)phosphinoylmethyl]pyridine N-oxide (DPhNOPO, 4a).

Trophic downgrading of planet Earth.

Until recently, large apex consumers were ubiquitous across the globe and had been for millions of years. The loss of these animals may be humankind's most pervasive influence on nature. Although such losses are widely viewed as an ethical and aesthetic problem, recent research reveals extensive cascading effects of their disappearance in marine, terrestrial, and freshwater ecosystems worldwide. This empirical work supports long-standing theory about the role of top-down forcing in ecosystems but also highlights the unanticipated impacts of trophic cascades on processes as diverse as the dynamics of disease, wildfire, carbon sequestration, invasive species, and biogeochemical cycles. These findings emphasize the urgent need for interdisciplinary research to forecast the effects of trophic downgrading on process, function, and resilience in global ecosystems.