Limnology and Oceanography
0024-3590
1939-5590
Mỹ
Cơ quản chủ quản: Wiley-Blackwell , WILEY
Lĩnh vực:
OceanographyAquatic Science
Phân tích ảnh hưởng
Thông tin về tạp chí
Limnology and Oceanography (L&O) publishes research articles, reviews, and comments about all aspects of the sciences of limnology and oceanography. The journal’s unifying theme is the understanding of aquatic systems. Submissions are judged on their originality and intellectual contribution to the fields of limnology and oceanography, whether physical, chemical, or biological in nature, empirical or theoretical in method, and from elemental to geological, ecological to evolutionary, species to ecosystem, or system to global in scale. Preference is given to papers that are based within the scientific philosophy of novel, hypothesis-driven or observational research that contributes significantly to a broader understanding of aquatic sciences.
Các bài báo tiêu biểu
Major flux of terrigenous dissolved organic matter through the Arctic Ocean High‐latitude rivers supply the Arctic Ocean with a disproportionately large share of global riverine discharge and terrigenous dissolved organic matter (DOM). We used the abundance of lignin, a macromolecule unique to vascular plants, and stable carbon isotope ratios (δ13 C) to trace the high molecular weight fraction of terrigenous DOM in major water masses of the Arctic Ocean. Lignin oxidation products in ultrafiltered DOM (UDOM; >1,000 Da) from Arctic rivers were depleted in syringyl relative to vanillyl phenols (S/V = 0.3–0.5) compared to UDOM in temperate and tropical rivers (S/V = 0.5–1.2), indicating that gymnosperm vegetation is a major source of terrigenous UDOM to the Arctic Ocean. High concentrations of lignin oxidation products (83–320 ng L−1 ) and a depletion of 13 C (δ13 C = −23.0 to −21.9) in UDOM throughout the surface Arctic Ocean indicate that terrigenous UDOM accounts for a much greater fraction of the UDOM in the surface Arctic (5–33%) than in the Pacific and Atlantic oceans (0.7–2.4%). In contrast, UDOM in deep water from the Arctic Ocean as well as waters from throughout the Greenland Gyre had relatively low concentrations of lignin oxidation products (24–45 ng L−1 ) and was enriched in 13 C (δ13 C = −21.0 to −20.8). Terrigenous UDOM has a relatively short residence (∼1–6 yr) in surface polar waters prior to export to the north Atlantic Ocean. Assuming that the bulk of Arctic‐derived DOM is compositionally similar to the UDOM fraction, we estimate that 12–41% of terrigenous DOM (2.9–10.3 Tg C yr−1 ) discharged by rivers to the Arctic Ocean is exported to the North Atlantic via surface waters of the East Greenland Current. It appears very little terrigenous DOM from the Arctic is incorporated into North Atlantic Deep Water and distributed globally via deep thermohaline circulation.
Tập 44 Số 8 - Trang 2017-2023 - 1999
Organic carbon partitioning during spring phytoplankton blooms in the Ross Sea polynya and the Sargasso Sea In this study we evaluate the partitioning of organic carbon between the particulate and dissolved pools during spring phytoplankton blooms in the Ross Sea, Antarctica, and the Sargasso Sea. As part of a multidisciplinary project in the Ross Sea polynya we investigated the dynamics of the dissolved organic carbon (DOC) pool and the role it played in the carbon cycle during the 1994 spring phytoplankton bloom. Phytoplankton biomass during the bloom was dominated by an Antarctic Phaeocystis sp. We determined primary productivity (PP; via H14 CO3 , incubations), particulate organic carbon (POC), bacterial productivity (BP; via [3 H]thymidine incorporation), and DOC during two occupations of 76°30′S from 175°W to 168°E. Results from this bloom are compared to blooms observed in the Sargasso Sea in the vicinity of the Bermuda Atlantic Time‐Series Study station (BATS). We present data that demonstrate clear differences in the production, biolability, and accumulation of DOC between the two ocean regions. Despite four‐ to fivefold greater PP in the Ross Sea, almost an order of magnitude less DOC (mmol m−2 ) accumulated during the Ross Sea bloom compared to the Sargasso Sea blooms. In the Ross Sea 89% (˜1 mol C m−2 ) of the total organic carbon (TOC) that accumulated during the bloom was partitioned as POC, with the remaining 11% (˜0.1 mol C m−2 ) partitioned as DOC. In contrast, a mean of 86% (0.7.5–1.0 mol m−2 ) of TOC accumulated as DOC during the 1992, 1993, and 1995 blooms in the Sargasso Sea, with as little as 14% (0.08–0.29 mol C m−2 ) accumulating as POC. Although a relatively small portion of the fixed carbon was produced as DOC in the Ross Sea, the bacterial carbon demand indicated that a qualitatively more labile carbon was produced in the Ross Sea compared to the Sargasso Sea. There are fundamental differences in organic carbon partitioning between the two systems that may be controlled by plankton community structure and food‐web dynamics.
Tập 43 Số 3 - Trang 375-386 - 1998
Bacterial utilization of different size classes of dissolved organic matter Bacterial utilization of high‐molecular‐weight (HMW; > 1 kDa) and low‐molecular‐weight (LMW; <1 kDa) dissolved organic C (DOC) was investigated in freshwater and marine systems by measuring dissolved oxygen consumption, bacterial abundance, and bacterial production in size‐fractionated samples. Tangential‐flow ultrafiltration was used to separate HMW and LMW DOC. More than 80% of the DOC in Amazon River samples was recovered in the HMW fraction, whereas most marine DOC (up to 70%) was of LMW. Bacterial growth efficiencies were consistently higher in the LMW fractions (16‐66%) than in the HMW fractions (8‐39%), indicating compositional differences in the two size fractions. In all experiments, measured rates of bacterial growth and respiration in HMW incubations were higher than those in LMW incubations. Carbon‐normalized bacterial DOC utilization rates were 1.4–4‐fold greater in the HMW fractions than in the LMW fractions, and a greater proportion (0.7–22.5%) of HMW DOC was utilized per day than LMW DOC (0.5–6.6%). All bacterial growth and respiration measurements indicated that HMW DOC was utilized to a greater extent than LMW DOC in all environments investigated. The traditional model of DOM degradation, stating that LMW compounds are most bioreactive, does not appear to apply to the bulk of natural DOM. Rather, the data and results from independent studies suggest a new conceptual model whereby the bioreactivity of organic matter decreases along a continuum of size (from large to small) and diagenetic state (from fresh to old). This size‐reactivity continuum model suggests that the bulk of HMW DOM is more bioreactive and less diagenetically altered than the bulk of LMW DOM.
Tập 41 Số 1 - Trang 41-51 - 1996
SEASONAL VARIATIONS OF CADMIUM, COPPER, MANGANESE, LEAD, AND ZINC IN WATER AND PHYTOPLANKTON IN MONTEREY BAY, CALIFORNIA1 Surface water and mixed phytoplankton samples, collected over 1 year in Monterey Bay, California, were analyzed for Cd, Cu, Mn, Pb, and Zn. The phytoplankton appeared to have little effect on the concentrations of these elements in water with the exception of Cd, which decreased during peak periods of productivity. Generally, metal levels in nearshore surface waters appeared to be more dependent on hydrographical fluctuations than on biological factors. Surface water collected on a transect between Hawaii and Monterey was analyzed for these same trace metals, for inshore‐offshore comparisons. Levels of Cu, Mn, and Zn were usually higher inshore than offshore especially during periods of strong upwelling. Concentrations of Cd and Pb were almost always an order of magnitude higher inshore.
Tập 18 Số 4 - Trang 597-604 - 1973
SOME FACTORS AFFECTING THE FEEDING OF MARINE COPEPODS OF THE GENUS <i>CALANUS</i>1 The grazing rates of 4 species of Calanus were measured on several species of marine phytoplankton, both singly and in mixtures. Grazing rates varied inversely with phytoplankton concentration, the duration of the experiment, and the age of the phytoplankton cultures used. Calanus spp. generally removed large cells at higher rates than small when feeding on a mixture of two species of phytoplankton. Because of this selectivity and the difference in volume between large and small cells, the large cells contributed by far the greater fraction of the total volume of food ingested by the copepods, even when considerably less abundant than the smaller cells. Comparison of the grazing rates of the copepodite stage V and adult female animals of C. finmarchicus, C. glacialis, and C. hgperboreus on a mixture of 7 species of diatoms demonstrated further the importance of large cells. Marked quantitative differences in rate of food intake were found between the different developmental stages of each species and between the different species of copepods, and some qualitative differences in selective feeding were also indicated.
Tập 8 Số 2 - Trang 239-250 - 1963
Motile behavior and predation risk in planktonic copepods Abstract Predation is an important source of mortality in zooplankton but factors governing predation risk in marine food webs are still not well understood. Here, we examine the role of zooplankton behavior in determining predation risk. We first quantified motility of copepods with different feeding behaviors (ambush feeding, cruising, and feeding‐current feeding). Second, we estimated remote predator detection and escape characteristics of the studied copepods. Third, we proposed a simple behavior‐dependent encounter model to predict copepod predation risk from rheotactic predators. Finally, we compared our predictions with predation risk previously determined experimentally. For similar sized copepods, predicted predation risks were similar between feeding‐current feeders and cruising feeders, whereas predation was up to 8.5 times lower (range: 1.5–8.5) for ambush feeders. Predicted predation risks further differed between males and females depending on feeding behavior: in ambush feeders males actively search for non‐motile females and their predation risk was up to 6 times higher (range 1.2–6) than for females. In contrast, feeding current‐ and cruising feeders showed small differences in predation risk between genders. In all cases, predicted relative predation risks between particular behaviors were confirmed by empirical data from previous predation experiments. Our results demonstrate that prey behavior of zooplankton may lead to a predictable variation in predation risk from rheotactic predators of up to an order of magnitude, and therefore that individual behavior is an important factor in structuring zooplankton communities.
Tập 62 Số 5 - Trang 1810-1824 - 2017
Combat between predatory copepods and their prey: <i>Cyclops, Epischura</i>, and <i>Bosmina</i>1 Predatory copepods are not imprecise hunters: they are capable of sophisticated behavior. Pelagic species (Cyclops, Epischura ) usually sense approaching prey from a distance and must judge approach angle and prey speed, reorient during attack, and often vary their handling responses. Below certain crucial sizes that trigger avoidance responses in the predator, attack distances are related to prey size and speed. Cyclopoids and predatory calanoids (Epischura ) capture and handle prey differently, and the morphology of the first maxillae reflects these modes. Apparently, the coexistence of certain small‐bodied cladocerans (Bosmina, Chydorus ) with predatory copepods results more from the evolution of effective defenses in the prey than from the clumsiness of the predator.
Tập 23 Số 6 - Trang 1089-1102 - 1978
The concentration and isotopic fractionation of oxygen dissolved in freshwater and seawater in equilibrium with the atmosphere1 Previous work on the solubility of oxygen in freshwater has been extended to seawater. Measurements of the Henry coefficient in the ranges 0° < t < 45°C and 0< S < 50 fit the Setschenow relationship for the variation with salinity. The temperature dependence of the Setschenow coefficient for oxygen is found to be K =T + 2,565.68/T 2 . The equation for the Henry coefficient as a function of temperature and salinity is used to calculate values for unit standard atmospheric concentrations (USAC) in freshwater and seawater in equilibrium with air at a total pressure of 1 atmosphere. It is estimated that the possible error in the new USAC values is no greater than ±0.1% and probably less. Tables and equations are presented for obtaining accurate USAC values in the ranges 0° < t < 40°C and 0 < S < 40. Simple procedures are given for calculating standard atmospheric concentrations at pressures different from 1 atm. The presence of sea salt has a negligible effect on the fractionation of the oxygen isotopes during solution.
Tập 29 Số 3 - Trang 620-632 - 1984
A comparative study of carbon dioxide degassing in river‐ and marine‐dominated estuaries The partial pressure of carbon dioxide (p CO2 ), concentration of total dissolved inorganic carbon, and total alkalinity were measured at both high tide and low tide in the surface water of three Georgia estuaries from September 2002 to May 2004. Of the three estuaries, Sapelo and Doboy Sounds are marine‐dominated estuaries, while Altamaha Sound is a river‐dominated estuary. During all sampling months, the three estuaries were supersaturated in CO2 with respect to the atmosphere (39.5–342.5 Pa, or 390–3380 [atm) because of CO2 inputs from within the estuarine zone (mainly intertidal marshes) and the river. Overall, p CO2 in the river‐dominated estuary is much higher than that in the marine‐dominated estuaries. The calculated annual air‐water CO2 flux in Altamaha Sound (69.3 mmol m−2 d−1 ) is 2.4 times those of Sapelo and Doboy Sounds (28.7–29.4 mmol m−2 d−1 ). The higher CO2 degassing in the river‐dominated estuary is fueled largely by CO2 loading from the river. Because of the substantial differences between river‐ and marine‐dominated estuaries, current estimates of air‐water CO2 fluxes in global estuaries (which are based almost entirely on river‐dominated estuaries) could be overestimated.
Tập 53 Số 6 - Trang 2603-2615 - 2008
Atmospheric CO<sub>2</sub> evasion, dissolved inorganic carbon production, and net heterotrophy in the York River estuary Direct measurements of the partial pressure of CO2 (pCO2 ) and dissolved inorganic carbon (DIC) were made over a 2‐yr period in surface waters of the York River estuary in Virginia. The pCO2 in surface waters exceeded that in the overlying atmosphere, indicating that the estuary was a net source of CO2 to the atmosphere at most times and locations. Salinity‐based DIC mixing curves indicate there was also an internal source of both DIC and alkalinity, implying net alkalinity generation within the estuary. The DIC and alkalinity source displayed seasonal patterns similar to that of pCO2 and were reproducible over a 2‐yr study period. We propose that the source of inorganic carbon necessary for both the sustained CO2 evasion to the atmosphere and the advective export of DIC is respiration in excess of primary production (e.g., net heterotrophy). The rates of CO2 evasion and DIC export were estimated to provide an annual rate of net heterotrophy of ~100 g C m−2 yr−1 . Approximately 40% of this excess inorganic carbon production was exported as DIC to the coastal ocean, whereas 60% was lost as CO2 evasion to the atmosphere. The alkalinity generation needed to sustain the export of inorganic carbon, as HCO3 − , is most likely provided by net sulfate reduction in sediments. Accumulation of sulfide in the sediments of a representative site directly adjacent to the York River estuary is sufficient to account for the net export of alkalinity. The seasonality of net heterotrophy causes large variations in annual CO2 and DIC concentrations, and it stresses the need for comprehensive temporal data sets when reporting annual rates of CO2 evasion, DIC advection, and net heterotrophy.
Tập 45 Số 8 - Trang 1707-1717 - 2000