Cooling of a gram-scale cantilever flexure to 70 mK with a servo-modified optical spring

A series of recent articles have presented results demonstrating optical cooling of macroscopic objects, highlighting the importance of this phenomenon for investigations of macroscopic quantum mechanics and its implications for thermal noise in gravitational wave detectors. In this Letter, we present a measurement of the off-resonance suspension thermal noise of a 1 g oscillator, and we show that it can be cooled to just 70 mK. The cooling is achieved by using a servo to impose a phase delay between oscillator motion and optical force. A model is developed to show how optical rigidity and optical cooling can be interchangeable using this technique

Short- and long-term consequences of larval stage exposure to constantly and ephemerally elevated carbon dioxide for marine bivalve populations

While larval bivalves are highly sensitive to ocean acidification, the basis for this sensitivity and the longer-term implications of this sensitivity are unclear. Experiments were performed to assess the short-term (days) and long-term (months) consequences of larval stage exposure to varying CO2 concentrations for calcifying bivalves. Higher CO2 concentrations depressed both calcification rates assessed using 45Ca uptake and RNA : DNA ratios in Mercenaria mercenaria and Argopecten irradians larvae with RNA : DNA ratios being highly correlated with larval growth rates (r2>0.9). These findings suggested that high CO2 has a cascading negative physiological impact on bivalve larvae stemming in part from lower calcification rates. Exposure to elevated CO2 during the first four days of larval development significantly depressed A. irradians larval survival rates, while a 10-day exposure later in larval development did not, demonstrating the extreme CO2 sensitivity of bivalve larvae during first days of development. Short- (weeks) and long-term (10 month) experiments revealed that individuals surviving exposure to high CO2 during larval development grew faster when exposed to normal CO2 as juveniles compared to individuals reared under ambient CO2 as larvae. These increased growth rates could not, however, overcome size differences established during larval development, as size deficits of individuals exposed to even moderate levels of CO2 as larvae were evident even after 10 months of growth under normal CO2 concentrations. This "legacy effect" emphasizes the central role larval stage CO2 exposure can play in shaping the success of modern-day bivalve populations

The ability of macroalgae to mitigate the negative effects of ocean acidification on four species of North Atlantic bivalve

Coastal ecosystems can experience acidification via upwelling, eutrophication, riverine discharge, and climate change. While the resulting increases in pCO2 can have deleterious effects on calcifying animals, this change in carbonate chemistry may benefit some marine autotrophs. Here, we report on experiments performed with North Atlantic populations of hard clams (Mercenaria mercenaria), eastern oysters (Crassostrea virginica), bay scallops (Argopecten irradians), and blue mussels (Mytilus edulis) grown with and without North Atlantic populations of the green macroalgae, Ulva. In six of seven experiments, exposure to elevated pCO2 levels ( ∼ 1700&thinsp;µatm) resulted in depressed shell- and/or tissue-based growth rates of bivalves compared to control conditions, whereas rates were significantly higher in the presence of Ulva in all experiments. In many cases, the co-exposure to elevated pCO2 levels and Ulva had an antagonistic effect on bivalve growth rates whereby the presence of Ulva under elevated pCO2 levels significantly improved their performance compared to the acidification-only treatment. Saturation states for calcium carbonate (Ω) were significantly higher in the presence of Ulva under both ambient and elevated CO2 delivery rates, and growth rates of bivalves were significantly correlated with Ω in six of seven experiments. Collectively, the results suggest that photosynthesis and/or nitrate assimilation by Ulva increased alkalinity, fostering a carbonate chemistry regime more suitable for optimal growth of calcifying bivalves. This suggests that large natural and/or aquacultured collections of macroalgae in acidified environments could serve as a refuge for calcifying animals that may otherwise be negatively impacted by elevated pCO2 levels and depressed Ω.</p

Fukushima 137Cs at the base of planktonic food webs off Japan

© The Author(s), 2015. This is the author's version of the work and is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Deep Sea Research Part I: Oceanographic Research Papers 106 (2015): 9-16, doi:10.1016/j.dsr.2015.09.006.The potential bioaccumulation of 137Cs in marine food webs off Japan became a concern following the release of radioactive contaminants from the damaged Fukushima nuclear power plant into the coastal ocean. Previous studies suggest that 137Cs activities increase with trophic level in pelagic food webs, however, the bioaccumulation of 137Cs from seawater to primary producers, to zooplankton has not been evaluated in the field. Since phytoplankton are frequently the largest component of SPM (suspended particulate matter) we used SPM concentrations and particle-associated 137Cs to understand bioaccumulation of 137Cs in through trophic pathways in the field. We determined particle-associated 137Cs for samples collected at 20 m depth from six stations off Japan three months after the initial release from the Fukushima nuclear power plant. At 20 m SPM ranged from 0.65 to 1.60 mg L-1 and rapidly declined with depth. The ratios of particulate organic carbon to chlorophyll a suggested that phytoplankton comprised much of the SPM in these samples. 137Cs activities on particles accounted for on average 0.04% of the total 137Cs in seawater samples, and measured concentration factors of 137Cs on small suspended particles were comparatively low (~102). However, when 137Cs in crustacean zooplankton was derived based only on modeling dietary 137Cs uptake, we found predicted and measured 137Cs concentrations in good agreement. We therefore postulate the possibility that the dietary route of 137Cs bioaccumulation (i.e., phytoplankton ingestion) could be largely responsible for the measured levels in the copepod-dominated (%) zooplankton assemblages in Japanese coastal waters. Finally, our data did not support the notion that zooplankton grazing on phytoplankton results in a biomagnification of 137Cs.This project was funded by the Gordon and Betty Moore Foundation through Grants GBMF3007 and GBMF 3423, and JSPS KAKENHI Grant-in-Aid for Scientific Research on Innovative Areas Grant Number 24110005.2016-09-2

Proteome changes driven by phosphorus deficiency and recovery in the brown tide-forming alga Aureococcus anophagefferens

© The Author(s), 2011. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS One 6 (2011): e28949, doi:10.1371/journal.pone.0028949.Shotgun mass spectrometry was used to detect proteins in the harmful alga, Aureococcus anophagefferens, and monitor their relative abundance across nutrient replete (control), phosphate-deficient (−P) and −P refed with phosphate (P-refed) conditions. Spectral counting techniques identified differentially abundant proteins and demonstrated that under phosphate deficiency, A. anophagefferens increases proteins involved in both inorganic and organic phosphorus (P) scavenging, including a phosphate transporter, 5′-nucleotidase, and alkaline phosphatase. Additionally, an increase in abundance of a sulfolipid biosynthesis protein was detected in −P and P-refed conditions. Analysis of the polar membrane lipids showed that cellular concentrations of the sulfolipid sulphoquinovosyldiacylglycerol (SQDG) were nearly two-fold greater in the −P condition versus the control condition, while cellular phospholipids were approximately 8-fold less. Transcript and protein abundances were more tightly coupled for gene products involved in P metabolism compared to those involved in a range of other metabolic functions. Comparison of protein abundances between the −P and P-refed conditions identified differences in the timing of protein degradation and turnover. This suggests that culture studies examining nutrient starvation responses will be valuable in interpreting protein abundance patterns for cellular nutritional status and history in metaproteomic datasets.Research for this work was supported by a National Oceanic and Atmospheric Administration ECOHAB grant (#NA09NOS4780206) and National Science Foundation grant (#OCE-0723667) and a STAR Research Assistance Agreement No. R-83041501-0 awarded by the U.S. Environmental Protection Agency. Further support came from the Woods Hole Coastal Ocean Institute. LLW was supported by a Environmental Protection Agency STAR Fellowship (#FP916901). EMB was supported by a National Science Foundation (NSF) Graduate Research Fellowship (#2007037200) and an Environmental Protection Agency STAR Fellowship (#F6E20324)

Using Magnetically Responsive Tea Waste to Remove Lead in Waters under Environmentally Relevant Conditions

We report the use of a simple yet highly effective magnetite-waste tea composite to remove lead(II) (Pb[superscript 2+]) ions from water. Magnetite-waste tea composites were dispersed in four different types of water–deionized (DI), artificial rainwater, artificial groundwater and artificial freshwater–that mimic actual environmental conditions. The water samples had varying initial concentrations (0.16–5.55 ppm) of Pb[superscript 2+] ions and were mixed with the magnetite-waste tea composite for at least 24 hours to allow adsorption of the Pb[superscript 2+] ions to reach equilibrium. The magnetite-waste tea composites were stable in all the water samples for at least 3 months and could be easily removed from the aqueous media via the use of permanent magnets. We detected no significant leaching of iron (Fe) ions into the water from the magnetite-waste tea composites. The percentage of Pb adsorbed onto the magnetite-waste tea composite ranged from ~70% to 100%; the composites were as effective as activated carbon (AC) in removing the Pb[superscript 2+] ions from water, depending on the initial Pb concentration. Our prepared magnetite-waste tea composites show promise as a green, inexpensive and highly effective sorbent for removal of Pb in water under environmentally realistic conditions.SUTD-MIT International Design Center (Research Grant IDG11200105/IDD11200109)Singapore-MIT Allianc

Sperm motility and fertilisation success in an acidified and hypoxic environment

The distribution and function of many marine species is largely determined by the effect of abiotic drivers on their reproduction and early development, including those drivers associated with elevated CO2 and global climate change. A number of studies have therefore investigated the effects of elevated pCO2 on a range of reproductive parameters, including sperm motility and fertilisation success. To date, most of these studies have not examined the possible synergistic effects of other abiotic drivers, such as the increased frequency of hypoxic events that are also associated with climate change. The present study is therefore novel in assessing the impact that a hypoxic event could have on reproduction in a future high CO2 ocean. Specifically, this study assesses sperm motility and fertilisation success in the sea urchin Paracentrotus lividus exposed to elevated pCO2 for 6 months. Gametes extracted from these pre acclimated individuals were subjected to hypoxic conditions simulating an hypoxic event in a future high CO2 ocean. Sperm swimming speed increased under elevated pCO2 and decrease under hypoxic conditions resulting in the elevated pCO2 and hypoxic treatment being approximately equivalent to the control. There was also a combined negative effect of increased pCO2 and hypoxia on the percentage of motile sperm. There was a significant negative effect of elevated pCO2 on fertilisation success, and when combined with a simulated hypoxic event there was an even greater effect. This could potentially affect cohort recruitment and in turn reduce the density of this ecologically and economically important ecosystem engineer therefore potentially effecting biodiversity and ecosystem services

Ocean and coastal acidification off New England and Nova Scotia

Author Posting. © The Oceanography Society, 2015. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 28, no. 2 (2015): 182-197, doi:10.5670/oceanog.2015.41.New England coastal and adjacent Nova Scotia shelf waters have a reduced buffering capacity because of significant freshwater input, making the region’s waters potentially more vulnerable to coastal acidification. Nutrient loading and heavy precipitation events further acidify the region’s poorly buffered coastal waters. Despite the apparent vulnerability of these waters, and fisheries’ and mariculture’s significant dependence on calcifying species, the community lacks the ability to confidently predict how the region’s ecosystems will respond to continued ocean and coastal acidification. Here, we discuss ocean and coastal acidification processes specific to New England coastal and Nova Scotia shelf waters and review current understanding of the biological consequences most relevant to the region. We also identify key research and monitoring needs to be addressed and highlight existing capacities that should be leveraged to advance a regional understanding of ocean and coastal acidification.This project was supported in part by an appointment to the Internship/Research Participation Program at the Office of Water, US Environmental Protection Agency (EPA), administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the US Department of Energy and the EPA. JS acknowledges support from NASA grant from NNX14AL84G NASA-CCS

Effects of Elevated Temperature and Carbon Dioxide on the Growth and Survival of Larvae and Juveniles of Three Species of Northwest Atlantic Bivalves

Rising CO2 concentrations and water temperatures this century are likely to have transformative effects on many coastal marine organisms. Here, we compared the responses of two life history stages (larval, juvenile) of three species of calcifying bivalves (Mercenaria mercenaria, Crassostrea virginica, and Argopecten irradians) to temperatures (24 and 28°C) and CO2 concentrations (∼250, 390, and 750 ppm) representative of past, present, and future summer conditions in temperate estuaries. Results demonstrated that increases in temperature and CO2 each significantly depressed survival, development, growth, and lipid synthesis of M. mercenaria and A. irradians larvae and that the effects were additive. Juvenile M. mercenaria and A. irradians were negatively impacted by higher temperatures while C. virginica juveniles were not. C. virginica and A. irradians juveniles were negatively affected by higher CO2 concentrations, while M. mercenaria was not. Larvae were substantially more vulnerable to elevated CO2 than juvenile stages. These findings suggest that current and future increases in temperature and CO2 are likely to have negative consequences for coastal bivalve populations

Niche of harmful alga Aureococcus anophagefferens revealed through ecogenomics

Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of National Academy of Sciences for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences 108 (2011): 4352-4357, doi:10.1073/pnas.1016106108.Harmful algal blooms (HABs) cause significant economic and ecological damage worldwide. Despite considerable efforts, a comprehensive understanding of the factors that promote these blooms has been lacking because the biochemical pathways that facilitate their dominance relative to other phytoplankton within specific environments have not been identified. Here, biogeochemical measurements demonstrated that the harmful 43 Aureococcus anophagefferens outcompeted co-occurring phytoplankton in estuaries with elevated levels of dissolved organic matter and turbidity and low levels of dissolved inorganic nitrogen. We subsequently sequenced the first HAB genome (A. anophagefferens) and compared its gene complement to those of six competing phytoplankton species identified via metaproteomics. Using an ecogenomic approach, we specifically focused on the gene sets that may facilitate dominance within the environmental conditions present during blooms. A. anophagefferens possesses a larger genome (56 mbp) and more genes involved in light harvesting, organic carbon and nitrogen utilization, and encoding selenium- and metal-requiring enzymes than competing phytoplankton. Genes for the synthesis of microbial deterrents likely permit the proliferation of this species with reduced mortality losses during blooms. Collectively, these findings suggest that anthropogenic activities resulting in elevated levels of turbidity, organic matter, and metals have opened a niche within coastal ecosystems that ideally suits the unique genetic capacity of A. anophagefferens and thus has facilitated the proliferation of this and potentially other HABs.Joint Genome Institute is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. Efforts were also supported by awards from New York Sea Grant to Stony Brook University, National Oceanic and Atmospheric Administration Center for Sponsored Coastal Ocean Research award #NA09NOS4780206 to Woods Hole Oceanographic Institution, NIH grant GM061603 to Harvard University, and NSF award IOS-0841918 to The University of Tennessee