@article{smith_maybaum_baco_pope_carpenter_yager_macko_deming_1998, title={Sediment community structure around a whale skeleton in the deep Northeast Pacific: Macrofaunal, microbial and bioturbation effects}, volume={45}, ISSN={["0967-0645"]}, DOI={10.1016/S0967-0645(97)00043-X}, abstractNote={Chemoautotrophic communities on lipid-rich whale skeletons are known from a total of 16 modern and fossil sites in the deep Pacific Ocean. While the attached fauna of modern whale bones has been studied, the impact of whale falls on surrounding sediment assemblages remains largely unevaluated. Using the research submersible Alvin, we sampled the sediment community at distances of 0, 0.5, 1, 2, 4, and ∼100 m from the lipid-rich skeleton of a 21 m balaenopterid on the 1240 m seafloor in Santa Catalina Basin. When sampled in 1988 and 1991, the skeleton had been on the seafloor for >4 yr and supported a large attached chemoautotrophic assemblage. Sedimentary organic content, microbial biomass and bacterial abundance were not significantly different near the skeleton than in background sediments, and pore-water sulfide concentrations were only modestly elevated (to ⩽20 μM) adjacent to the bones. The species composition of infaunal macrobenthos near the skeleton was similar to that in background sediments, providing little evidence of a specialized enrichment and/or sulfophilic assemblage. Nonetheless, macrofaunal abundance within 0.5 m of the skeleton was reduced by >40%, due to a decline in the paraonid polychaete Levinsenia oculata. The reduction in L. oculata (the community dominant) caused a sharp increase in rarefaction diversity near the skeleton. Bioturbation intensities, evaluated from 234Th profiles, were also dramatically reduced in sediments near the skeleton, as were rates of extracellular lipase activity. We postulate that reduced infaunal abundance and bioturbation near the skeleton resulted from the interference effects of vesicomyid clam-shell debris, and that the low bioturbation rates in turn limited extracellular lipase activity. We conclude that whale skeletons, and the remains of their associated chemoautotrophic assemblages, may physically impact nearby sediment communities for years after the organic and sulfide enrichment effects of whale falls have dissipated, yielding changes in infaunal diversity and bioturbation.}, number={1-3}, journal={DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY}, author={Smith, CR and Maybaum, HL and Baco, AR and Pope, RH and Carpenter, SD and Yager, PL and Macko, SA and Deming, JW}, year={1998}, pages={335–364} }
 @article{berelson_anderson_dymond_demaster_hammond_collier_honjo_leinen_mcmanus_pope_et al._1997, title={Biogenic budgets of particle rain, benthic remineralization and sediment accumulation in the equatorial Pacific}, volume={44}, ISSN={["0967-0645"]}, DOI={10.1016/S0967-0645(97)00030-1}, abstractNote={Budgets of organic C (Corg), CaC03 and opal have been constructed for the Palisades, NY Pacific equatorial region at 140°W between 5°N and 5°S. Measurements of the rain and benthic remineralization rate of biogenic materials have been adjusted and normalized to account for sampling biases. Sea surface temperature serves as a master variable in normalizing sediment trap and benthic remineralization data to average conditions. The rain and remineralization rates for Corg are nearly equal: 0.40±0.05 and 0.46±0.06 mmol m−2 d−1 respectively; thus only a minor fraction of this constituent is buried. Rain and dissolution rates for biogenic opal are similarly balanced (0.3±0.06 and 0.36±0.01 mmol m−2 d−1) and consistent with the value for opal burial (0.0±0.004). The CaC03 budget appears to have changed during the Holocene. The best estimates of modern CaC03 dissolution (0.58±0.03 mmol m−2 d−1) and rain rate (0.61±0.06) are consistent with230Th-normalized carbonate accumulation rates for the late Holocene (0.1 mmol m−2 d−1). However, the balance between dissolution and rain is not consistent with early Holocene carbonate accumulation (0.3 mmol m−2 d−1 ), and this imbalance suggests: 1) a recent increase in the rate of CaC03 dissolution on the sea floor, or 2) a decrease in the rain rate of carbonate particles. Modeling230Th profiles in sediments from this region define the last 3000 years as the duration of increased dissolution or decreased particle rain. 231Pa/230Th ratios in sediments indicate that particle rain rates have remained constant or possibly increased slightly through the Holocene. Two potential causes for increased dissolution were investigated; a change in deep water carbonate saturation or a change in Co,g/CaC03 rain ratios. A model describing carbonate dissolution as a function of the degree of undersaturation and the amount of organic carbon oxidation within sediments indicates that the recent increase in dissolution is more likely due to changes in bottom water chemical composition. We propose that Pacific Ocean bottom water carbonate ion concentration has decreased by 10–15 μM over the last 3000 years.}, number={9-10}, journal={DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY}, author={Berelson, WM and Anderson, RF and Dymond, J and Demaster, D and Hammond, DE and Collier, R and Honjo, S and Leinen, M and Mcmanus, J and Pope, R and et al.}, year={1997}, pages={2251–2282} }
 @article{smith_berelson_demaster_dobbs_hammond_hoover_pope_stephens_1997, title={Latitudinal variations in benthic processes in the abyssal equatorial Pacific: control by biogenic particle flux}, volume={44}, ISSN={["0967-0645"]}, DOI={10.1016/S0967-0645(97)00022-2}, abstractNote={The equatorial Pacific forms a band of high, globally significant primary production. This productivity drops off steeply with distance from equatorial upwelling, yielding large latitudinal gradients in biogenic particle flux to the abyssal seafloor. As part of the US JGOFS Program, we studied the translation of these particle-flux gradients into the benthic ecosystem from 12°S to 9°N along 135–140°W to evaluate their control of key benthic processes, and to evaluate sediment proxies of export production from overlying waters. In October–December 1992 the remineralization rates of organic carbon, calcium carbonate and biogenic opal roughly matched the rain rates of these materials into deep sediment traps, exhibiting peak values within 3° of the equator. Rates of bioturbation near the equator were about ten-fold greater than at 9°N, and appeared to exhibit substantial dependence on particulate-organic-carbon flux, tracer time scale (i.e. age-dependent mixing), and pulsed mixing from burrowing urchins. Organic-carbon degradation within sediments near the equator was dominated by a very labile component (reaction rate constant, k approximately 15 per year) that appeared to be derived from greenish phytodetritus accumulated on the seafloor. Organic-carbon degradation at the highest latitudes was controlled by a less reactive component, with a mean k of approximately 0.075 per year. Where measured, megafaunal and macrofaunal abundances were strongly correlated with annual particulate-organic carbon flux; macrofaunal abundance in particular might potentially serve as a proxy for export production in low-energy abyssal habitats. Sedimentary microbial biomass also was correlated with the rain rate of organic carbon, but less strongly than larger biota and on shorter time scales (i.e. approximately 100 days). We conclude that the vertical flux of biogenic particlues exerts tight control on the nature and rates of benthic biological and chemical processes in the abyssal equatorial Pacific, and suggest that global changes in productivity on decadal or greater time scales could yield profound changes in deep-sea benthic ecoystems.}, number={9-10}, journal={DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY}, author={Smith, CR and Berelson, W and Demaster, DJ and Dobbs, FC and Hammond, D and Hoover, DJ and Pope, RH and Stephens, M}, year={1997}, pages={2295-+} }