Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 29 of 29
Full-Text Articles in Physical Sciences and Mathematics
Morphological And Physiological Response Of Planeleaf Willow (Salix Planifolia Pursh.) To Simulated Browsing, L Xu, J L. Dodd, M A. Smith, Q D. Skinner, W A. Laycock
Morphological And Physiological Response Of Planeleaf Willow (Salix Planifolia Pursh.) To Simulated Browsing, L Xu, J L. Dodd, M A. Smith, Q D. Skinner, W A. Laycock
IGC Proceedings (1997-2023)
Morphological and physiological responses of planeleaf willow (Salix planefolia Pursh.) to simulated browsing were studied under controlled conditions. The treatments consisted of every combination of three clipping intensities (30%, 60% and 90% of current twigs length removal) and three clipping timings (late winter, early spring and mid-summer). Increased clipping intensity stimulated bud activation; increased total leaf area and leaf size and increased the length of current year’s twigs. Mid-summer browsing increased the total number of leaves, the number of current twigs and decreased the length of current twigs. Higher browsing intensity resulted in higher photosynthetic rate of recently matured …
Dormant-Season Carbon Fluxes In Humid-Temperate Pastures, Howard Skinner
Dormant-Season Carbon Fluxes In Humid-Temperate Pastures, Howard Skinner
IGC Proceedings (1997-2023)
Human induced increases in atmospheric CO2 through the burning of fossil fuels and deforestation are considered to be a primary cause of rising global temperatures. However, carbon sequestration by terrestrial ecosystems has reduced the rate of CO2 accumulation in the atmosphere. Because of their vast size, grazing lands have the potential to sequester significant quantities of carbon, slowing the increase in atmospheric CO2 and reducing the risk of global warming. Although C uptake during the growing season can be substantial, losses following defoliation and drought, and during the winter months can significantly reduce annual sequestration, frequently turning …
Net Photosynthesis Rate And Chlorophyll Content Of Caucasian And White Clover Leaves Under Different Temperature Regimes, A. D. Black, R. J. Lucas, D. J. Moot
Net Photosynthesis Rate And Chlorophyll Content Of Caucasian And White Clover Leaves Under Different Temperature Regimes, A. D. Black, R. J. Lucas, D. J. Moot
IGC Proceedings (1997-2023)
In spring and summer in intensive temperate pastures, Caucasian clover (Cc) (Trifolium ambiguum) has higher dry matter (DM) production rates than white clover (wc) (Trifolium repens) (Black et al., 2003). An examination of the physiological basis for these differences can provide a greater insight into the suitability of Cc for inclusion in temperate pastures. Specifically, leaf photosynthesis rate is a major driver of seasonal growth and is strongly regulated by temperature and chlorophyll content. This study aimed to compare the net photosynthesis rate (Pn) and chlorophyll content of Cc and wc leaves under different temperature …
Sensitivity Of The Relationship Between Antarctic Ice Shelves And Iron Supply To Projected Changes In The Atmospheric Forcing, Michael S. Dinniman, Pierre St-Laurent, Kevin R. Arrigo, Eileen E. Hofmann, Gert L. Van Dijken
Sensitivity Of The Relationship Between Antarctic Ice Shelves And Iron Supply To Projected Changes In The Atmospheric Forcing, Michael S. Dinniman, Pierre St-Laurent, Kevin R. Arrigo, Eileen E. Hofmann, Gert L. Van Dijken
CCPO Publications
Upward advection or mixing of iron-rich deep waters due to circulation changes driven by the rate of basal ice shelf melt was shown to be a primary control on chlorophyll a production in coastal polynyas over the Antarctic continental shelf. Here, the effects of atmospheric changes projected in 2100 on this relationship were examined with a 5-km resolution ocean/sea ice/ice shelf model of the Southern Ocean with different simulated dissolved iron sources and idealized biological uptake. The atmospheric changes are added as idealized increments to the forcing. Inclusion of a poleward shift and strengthening of the winds, increased precipitation, and …
High Salinity Effects On The Components Of Relative Growth Rate In Rhodes Grass, E. Taleisnik, L. García Seffino, A. Córdoba, K. Grunberg, C. Arias, M. De Luca
High Salinity Effects On The Components Of Relative Growth Rate In Rhodes Grass, E. Taleisnik, L. García Seffino, A. Córdoba, K. Grunberg, C. Arias, M. De Luca
IGC Proceedings (1997-2023)
Rhodes grass (Chloris gayana Kunth), is widely cultivated in the semiarid tropics and favored for its salt tolerance. Nevertheless, productivity decreases significantly under saline conditions, especially in tetraploid cultivars. The purpose of this work was to explore, in tetraploid cultivar Boma, the physiological causes for the observed salt-associated growth reduction. The effects of high salinity (200 mM NaCl) on the components of relative growth rate were analyzed in greenhouse experiments. An early reduction in leaf area expansion was observed, which later resulted in decreased dry matter accumulation. Plant leafiness was reduced by effects both on dry matter allocation to …
Photosynthetic Light Response Of Tanzania Grass Under Four Levels Of Leaf Temperature, A. C. L. De Mello, P. M. Santos, Carlos G. S. Pedreira, M. Corsi, C. T. Dos S. Dias
Photosynthetic Light Response Of Tanzania Grass Under Four Levels Of Leaf Temperature, A. C. L. De Mello, P. M. Santos, Carlos G. S. Pedreira, M. Corsi, C. T. Dos S. Dias
IGC Proceedings (1997-2023)
The purpose of this paper is to establish photosynthetic light response curves for Tanzania grass (Panicum maximum Jacq.) under four leaf temperature levels. Photosynthetic rate was measured as a response to levels of photosynthetic photon flux density (PPFD) on the youngest fully expanded leaves of 12 representative tillers with an infra red gas analyzer. The effect of PPFD was tested for each leaf temperature level in a randomized complete block design. Photosynthetic light response curves were adjusted for each leaf temperature using a non-linear hyperbolic model. The maximum photosynthetic response was 25,59; 31,43; 34,57 and 27,53 µmol CO2 …
Effect Of The Hierarchical Position Of Individuals In A Medicago Sativa Stand On Shoot Respiration, M. Lötscher, Hans Schnyder
Effect Of The Hierarchical Position Of Individuals In A Medicago Sativa Stand On Shoot Respiration, M. Lötscher, Hans Schnyder
IGC Proceedings (1997-2023)
The influence of the hierarchical position on the relationship between C gains and C losses (respiration) of individuals was investigated in a alfalfa (Medicago sativa) stand. The hierarchical position that an individual occupied was defined by its height relative to the stand height. Stands were established by arranging potted individual plants at a density of 400 plants m-2. Stands were grown in growth cabinets. 13C steady-state labelling was used to assess C fixation (Cnew) by individuals during a photoperiod of 16 h. Respiration of shoots was measured during the following 8 h dark …
Salinity Effects On Plant Growth, Photosynthesis, And Ion Content Of Covered And Naked Oat, Guiqin Zhao, Baoluo Ma
Salinity Effects On Plant Growth, Photosynthesis, And Ion Content Of Covered And Naked Oat, Guiqin Zhao, Baoluo Ma
IGC Proceedings (1997-2023)
No abstract provided.
How Wetland Plants Deal With Stress, Taylor M. Sloey
How Wetland Plants Deal With Stress, Taylor M. Sloey
Biological Sciences Faculty Publications
We all get stressed. To deal with that stress, some of us may exercise, take a bubble bath, cry, or simply leave the stressful situation. But how can you cope with stress if you are rooted in place? Plants that live in estuaries are exposed to many types of stresses from the environment, including flooding, high salt levels, low soil oxygen, and waves. Fortunately, wetland plants have developed ways to survive within these conditions, from excreting salt, to growing faster, to even breaking down cell walls to maximize air flow. Plants can tolerate different levels of stress depending on their …
Carbon Balance In Stand Of An Annual Herb At An Elevated Co2 Concentration, Almaz Borjigidai, Kouki Hikosaka, Tadaki Hirose
Carbon Balance In Stand Of An Annual Herb At An Elevated Co2 Concentration, Almaz Borjigidai, Kouki Hikosaka, Tadaki Hirose
IGC Proceedings (1997-2023)
No abstract provided.
Effect Of Grazing Intensity On Photosynthesis And Soil Respiration Of Alpine Grassland In Tibet, Y. F. Wan, Q. Z. Gao, Y. Li, X. B. Qin, W. Z. Jiancun, B. S. Wang
Effect Of Grazing Intensity On Photosynthesis And Soil Respiration Of Alpine Grassland In Tibet, Y. F. Wan, Q. Z. Gao, Y. Li, X. B. Qin, W. Z. Jiancun, B. S. Wang
IGC Proceedings (1997-2023)
No abstract provided.
Effect Of Gradually Water Stress And Recovery On Photosynthesis, Transpiration, And Stomatal Conductance In Two Plantago Species, A. Rahimi, H. R. Rahimian Mashhadi, M. R. Jahansoz
Effect Of Gradually Water Stress And Recovery On Photosynthesis, Transpiration, And Stomatal Conductance In Two Plantago Species, A. Rahimi, H. R. Rahimian Mashhadi, M. R. Jahansoz
IGC Proceedings (1997-2023)
No abstract provided.
Changes Of Residue Function And Signaling Regrowth After Forage Cutting, Huimin Yang, Linag Zhao, Yuying Shen, Xiaoyan Zhang
Changes Of Residue Function And Signaling Regrowth After Forage Cutting, Huimin Yang, Linag Zhao, Yuying Shen, Xiaoyan Zhang
IGC Proceedings (1997-2023)
No abstract provided.
Changes Of Cap Of Creeping Bentgrass As Affected By Light Intensity During Summer Stress, Zhiming Yang, Zhihua Li
Changes Of Cap Of Creeping Bentgrass As Affected By Light Intensity During Summer Stress, Zhiming Yang, Zhihua Li
IGC Proceedings (1997-2023)
No abstract provided.
Photosynthesis And Transpiration Of Chicory With Different Irrigation Treatments In Beijing, Lin Meng, Yingjun Zhang, Peichun Mao, Guofang Zhang
Photosynthesis And Transpiration Of Chicory With Different Irrigation Treatments In Beijing, Lin Meng, Yingjun Zhang, Peichun Mao, Guofang Zhang
IGC Proceedings (1997-2023)
No abstract provided.
Responses Of Photosynthetic Rate Of Lucerne And The Mechanisms Under Cutting At Different Water Availabilities, Shubin He, Huimin Yang, Guoli Liu, Zhilong Zhang
Responses Of Photosynthetic Rate Of Lucerne And The Mechanisms Under Cutting At Different Water Availabilities, Shubin He, Huimin Yang, Guoli Liu, Zhilong Zhang
IGC Proceedings (1997-2023)
No abstract provided.
The Study On The Photosynthetic Characteristics Of Three Melilotoides Ruthenica Strains, Lili Zhao, Zhaolan Wang, Qingfeng Li, Jiancai Du, Xiaotao Mao
The Study On The Photosynthetic Characteristics Of Three Melilotoides Ruthenica Strains, Lili Zhao, Zhaolan Wang, Qingfeng Li, Jiancai Du, Xiaotao Mao
IGC Proceedings (1997-2023)
No abstract provided.
Alteration Of Physiological Parameters Of Milkvetch (Astragalus Adsurgens) By The Pathogen Embellisia Astragali, Binhua Yu, Zhibiao Nan
Alteration Of Physiological Parameters Of Milkvetch (Astragalus Adsurgens) By The Pathogen Embellisia Astragali, Binhua Yu, Zhibiao Nan
IGC Proceedings (1997-2023)
Milkvetch (Astragalus adsurgens) is sown on > 1 M ha in China as a forage legume and to control soil and water erosion. It is drought-tolerant and has high herbage yield, wide adaptability and medium forage quality. However, fungal disease is a major factor affecting its persistence and productivity. Embellisia astragali is a highly virulent seed-borne pathogen which commonly causes stunt and root rot. The objective of this study was to characterize the impact of Embellisia astragali on the physiological status of milkvetch by monitoring changes through time in net photosynthesis, stomatal conductance and other parameters of milkvetch inoculated …
Physiological Efficiency Of Some Weeds Species Under Hill Farming Systems Of Subtropical Meghalaya, D. P. Patel, Anup Das, G. C. Munda
Physiological Efficiency Of Some Weeds Species Under Hill Farming Systems Of Subtropical Meghalaya, D. P. Patel, Anup Das, G. C. Munda
IGC Proceedings (1997-2023)
Weeds are integral part of any farming system. Weeds are more aggressive in their ability to utilize limited moisture and nutrients in the soil relative to cultivated crops. Weeds grow more profusely in high rainfall areas such as subtropical Meghalaya owing to favourable climatic conditions which favours the growth of weeds particularly in uplands and limits the crop yields due to increased crop-weed competition for nutrients and light. The weed species such as Ageratum conyzoides, Spilanthus acmella, Galinsoga parviflora, Bidens pilosa, Crassocephalum crepidioides, Polygonum capitatum, Alternanthera philoxeroides, Amaranthus spinosus and Mikania micrantha are very common in most of the cultivated …
Improved Drought Stress Tolerance Of White Clover Through Hybridisation With Trifolium Uniflorum L., Shirley N. Nichols, Rainer W. Hofmann, Isabelle M. Verry
Improved Drought Stress Tolerance Of White Clover Through Hybridisation With Trifolium Uniflorum L., Shirley N. Nichols, Rainer W. Hofmann, Isabelle M. Verry
IGC Proceedings (1997-2023)
The objective of this study was to determine the effect of hybridisation with Trifolium uniflorum L. on drought resistance of Trifolium repens L. (white clover). Shoot dry weight of backcross 1 (BC1) hybrids was reduced less by water stress than for backcross 2 (BC2) hybrids and white clover, as were key morphological traits such as leaf area. Under water stress, important differences for the BC1 generation compared to white clover also included lower senescence, higher stolon density, increased root dry weight, and a higher maximum nodal root diameter. Drought decreased the net photosynthetic rate by up to 48% in BC2 …
Relative Salt Tolerance Of Seven Japanese Spirea Cultivars, Yuxiang Wang, Liqin Li, Youping Sun, Xin Dai
Relative Salt Tolerance Of Seven Japanese Spirea Cultivars, Yuxiang Wang, Liqin Li, Youping Sun, Xin Dai
Plants, Soils, and Climate Faculty Publications
Spirea (Spiraea sp.) plants are commonly used in landscapes in Utah and the intermountain western United States. The relative salt tolerance of seven japanese spirea (Spiraea japonica) cultivars (Galen, Minspi, NCSX1, NCSX2, SMNSJMFP, Tracy, and Yan) were evaluated in a greenhouse. Plants were irrigated with a nutrient solution with an electrical conductivity (EC) of 1.2 dSmL1 (control) or saline solutions with an EC of 3.0 or 6.0 dSmL1 once per week for 8 weeks. At 8 weeks after the initiation of treatment, all japanese spirea cultivars irrigated with saline solution with an EC of 3.0 dSmL1 still exhibited good or …
Single-Cell Growth Rates In Photoautotrophic Populations Measured By Stable Isotope Probing And Resonance Raman Microspectrometry, Gordon T. Taylor, Elizabeth A. Suter, Zhuo Q. Li, Stephanie Chow, Dallyce Stinton, Tatiana Zaliznyak, Steven R. Beaupre
Single-Cell Growth Rates In Photoautotrophic Populations Measured By Stable Isotope Probing And Resonance Raman Microspectrometry, Gordon T. Taylor, Elizabeth A. Suter, Zhuo Q. Li, Stephanie Chow, Dallyce Stinton, Tatiana Zaliznyak, Steven R. Beaupre
Faculty Works: Biology, Chemistry, and Environmental Studies
A newmethod tomeasure growth rates of individual photoautotrophic cells by combining stable isotope probing (SIP) and single-cell resonance Raman microspectrometry is introduced. This report explores optimal experimental design and the theoretical underpinnings for quantitative responses of Raman spectra to cellular isotopic composition. Resonance Raman spectra of isogenic cultures of the cyanobacterium, Synechococcus sp., grown in 13C-bicarbonate revealed linear covariance between wavenumber (cm−1) shifts in dominant carotenoid Raman peaks and a broad range of cellular 13C fractional isotopic abundance. Single-cell growth rates were calculated from spectra-derived isotopic content and empirical relationships. Growth rates among any 25 cells in a sample varied …
Influence And Interaction Of Iron And Cadmium On Photosynthesis And Antioxidative Enzymes In Two Rice Cultivars, Houjun Liu, Chengxin Zhang, Junmei Wang, Chongjun Zhou, Huan Feng, Manoj D. Mahajan, Xiaori Han
Influence And Interaction Of Iron And Cadmium On Photosynthesis And Antioxidative Enzymes In Two Rice Cultivars, Houjun Liu, Chengxin Zhang, Junmei Wang, Chongjun Zhou, Huan Feng, Manoj D. Mahajan, Xiaori Han
Department of Earth and Environmental Studies Faculty Scholarship and Creative Works
In this study, a soil pot experiment was conducted to investigate the changes in photosynthesis and antioxidative enzymes in two rice varieties (Shendao 6 and Shennong 265) supplied with iron (Fe), cadmium (Cd), and Fe and Cd together. The concentrations of Fe and Cd in the soil were 0, 1.0 g Fe·kg−1and 0, 2.0 mg Cd·kg−1, respectively. Photosynthetic indices and antioxidative enzyme activities were recorded at different rice growth stages. At the early stage, Cd showed a transient stimulatory effect on the photosynthetic rate of Shennong 265. For Shendao 6, however, Cd showed a transient stimulatory effect on photosynthetic rate, …
Community Production Modulates Coral Reef Ph And The Sensitivity Of Ecosystem Calcification To Ocean Acidification, Thomas M. Decarlo, Anne L. Cohen, George T. F. Wong, Fuh-Kwo Shiah, Steven J. Lentz, Kristen A. Davis, Kathryn E. F. Shamberger, Pat Lohmann
Community Production Modulates Coral Reef Ph And The Sensitivity Of Ecosystem Calcification To Ocean Acidification, Thomas M. Decarlo, Anne L. Cohen, George T. F. Wong, Fuh-Kwo Shiah, Steven J. Lentz, Kristen A. Davis, Kathryn E. F. Shamberger, Pat Lohmann
OES Faculty Publications
Coral reefs are built of calcium carbonate (CaCO3) produced biogenically by a diversity of calcifying plants, animals, and microbes. As the ocean warms and acidifies, there is mounting concern that declining calcification rates could shift coral reef CaCO3 budgets from net accretion to net dissolution. We quantified net ecosystem calcification (NEC) and production (NEP) on Dongsha Atoll, northern South China Sea, over a 2 week period that included a transient bleaching event. Peak daytime pH on the wide, shallow reef flat during the nonbleaching period was ~8.5, significantly elevated above that of the surrounding open ocean (~8.0-8.1) as …
Productivity, Absorbed Photosynthetically Active Radiation, And Light Use Efficiency In Crops: Implications For Remote Sensing Of Crop Primary Production, Anatoly A. Gitelson, Yi Peng, Timothy J. Arkebauer, Andrew E. Suyker
Productivity, Absorbed Photosynthetically Active Radiation, And Light Use Efficiency In Crops: Implications For Remote Sensing Of Crop Primary Production, Anatoly A. Gitelson, Yi Peng, Timothy J. Arkebauer, Andrew E. Suyker
School of Natural Resources: Faculty Publications
Vegetation productivity metrics such as gross primary production (GPP) at the canopy scale are greatly affected by the efficiency of using absorbed radiation for photosynthesis, or light use efficiency (LUE). Thus, close investigation of the relationships between canopy GPP and photosynthetically active radiation absorbed by vegetation is the basis for quantification of LUE. We used multiyear observations over irrigated and rainfed contrasting C3 (soybean) and C4 (maize) crops having different physiology, leaf structure, and canopy architecture to establish the relationships between canopy GPP and radiation absorbed by vegetation and quantify LUE. Although multiple LUE definitions are reported in the literature, …
Divergent Responses Of Atlantic Coastal And Oceanic Synechococcus To Iron Limitation, Katherine R. M. Mackey, Anton F. Post, Matthew R. Mcilvin, Gregory A. Cutter, Seth G. John, Mak A. Saito
Divergent Responses Of Atlantic Coastal And Oceanic Synechococcus To Iron Limitation, Katherine R. M. Mackey, Anton F. Post, Matthew R. Mcilvin, Gregory A. Cutter, Seth G. John, Mak A. Saito
OES Faculty Publications
Marine Synechococcus are some of the most diverse and ubiquitous phytoplankton, and iron (Fe) is an essential micronutrient that limits productivity in many parts of the ocean. To investigate how coastal and oceanic Atlantic Synechococcus strains acclimate to Fe availability, we compared the growth, photophysiology, and quantitative proteomics of two Synechococcus strains from different Fe regimes. Synechococcus strain WH8102, from a region in the southern Sargasso Sea that receives substantial dust deposition, showed impaired growth and photophysiology as Fe declined, yet used few acclimation responses. Coastal WH8020, from the dynamic, seasonally variable New England shelf, displayed a multitiered, hierarchical cascade …
Spring Thaw Ionic Pulses Boost Nutrient Availability And Microbial Growth In Entombed Antarctic Dry Valley Cryoconite Holes, Jon Telling, Alexandre M. Anesio, Martyn Tranter, Andrew G. Fountain, Thomas H. Nylen, Jon Hawkings, Virendra B. Singh, Preeti Kaur, Michaela Musilova, Jemma L. Wadham
Spring Thaw Ionic Pulses Boost Nutrient Availability And Microbial Growth In Entombed Antarctic Dry Valley Cryoconite Holes, Jon Telling, Alexandre M. Anesio, Martyn Tranter, Andrew G. Fountain, Thomas H. Nylen, Jon Hawkings, Virendra B. Singh, Preeti Kaur, Michaela Musilova, Jemma L. Wadham
Geology Faculty Publications and Presentations
The seasonal melting of ice entombed cryoconite holes on McMurdo Dry Valley glaciers provides oases for life in the harsh environmental conditions of the polar desert where surface air temperatures only occasionally exceed 0°C during the Austral summer. Here we follow temporal changes in cryoconite hole biogeochemistry on Canada Glacier from fully frozen conditions through the initial stages of spring thaw toward fully melted holes. The cryoconite holes had a mean isolation age from the glacial drainage system of 3.4 years, with an increasing mass of aqueous nutrients (dissolved organic carbon, total nitrogen, total phosphorus) with longer isolation age. During …
Distributions Of Particulate Heme B In The Atlantic And Southern Oceans- Implications For Electron Transport In Phytoplankton, Martha Gledhill, Eric P. Achterberg, David J. Honey, Maria C. Nielsdottir, Micha J.A. Rijkenberg
Distributions Of Particulate Heme B In The Atlantic And Southern Oceans- Implications For Electron Transport In Phytoplankton, Martha Gledhill, Eric P. Achterberg, David J. Honey, Maria C. Nielsdottir, Micha J.A. Rijkenberg
OES Faculty Publications
Concentrations of heme b, the iron-containing component of b-type hemoproteins, ranged from b concentrations were enhanced in the photic zone and decreased with depth. Heme b concentrations correlated positively with chlorophyll a (chl a) in the TNA (r=0.41, pb did not correlate with chl a in the IB or SS. In the IB and SS, stations with high-chlorophyll and low-nutrient (Fe and/or Si) concentrations exhibited low heme bconcentrations relative to particulate organic carbon (< 0.1 μmolmol-1, and high chl a:heme b ratios (> 500). High chl a:heme b ratios resulted from relative decreases in …
Phosphorus Cycling In The Sargasso Sea: Investigation Using The Oxygen Isotopic Composition Of Phosphate, Enzyme-Labeled Fluorescence, And Turnover Times, Karen Mclaughlin, Jill A. Sohm, Gregory A. Cutter, Michael W. Lomas, Adina Paytan
Phosphorus Cycling In The Sargasso Sea: Investigation Using The Oxygen Isotopic Composition Of Phosphate, Enzyme-Labeled Fluorescence, And Turnover Times, Karen Mclaughlin, Jill A. Sohm, Gregory A. Cutter, Michael W. Lomas, Adina Paytan
OES Faculty Publications
Dissolved inorganic phosphorus (DIP) concentrations in surface water of vast areas of the ocean are extremely low (<10 nM) and phosphorus (P) availability could limit primary productivity in these regions. We explore the use of oxygen isotopic signature of dissolved phosphate (δ18OPO4) to investigate biogeochemical cycling of P in the Sargasso Sea, Atlantic Ocean. Additional techniques for studying P dynamics including 33P-based DIP turnover time estimates and percent of cells expressing alkaline phosphatase (AP) activity as measured by enzyme-labeling fluorescence are also used. In surface waters, δ18OPO4 values were lower than equilibrium by 3–6%, indicative of dissolved organic phosphorous (DOP) remineralization by extracellular enzymes. An isotope mass balance model using a variety of possible combinations of …