Respiration and its measurement in surface marine waters

Abstract

OutlineThis chapter reviews the current state of knowledge of the process and measurement of microplankton respiration in marine surface waters. The principal approaches are outlined and their potentials and limitations discussed. A global database, containing 1662 observations has been compiled and analyzed for the spatial and temporal distribution of surface water respiration. The database is tiny compared to that of photosynthesis and biased with respect to season, latitude, community structure, and depth. Measurements and models show that the major portions of respiration lies in that attributable to bacteria (12-59%) and to algae A global estimate of 13.5 Pmol O 2 a −1 is derived from the mean depth-integrated rate, which significantly exceeds contemporary estimates of ocean plankton production (2.3-4.3 Pmol O 2 a −1 ). This difference is at variance with the results of mass-balance calculations, which suggest a small difference (ca. 0.18) between oceanic production and respiration. The reasons for this are discussed. IntroductionThis chapter reviews our present understanding of the process of marine planktonic respiration, and the methodologies used for its determination. We collate the global database of measured respiration and use it to assess how far we can determine seasonal, regional, and latitudinal patterns of distribution. Measurements of respiration are not yet routine within national and international marine biogeochemical programs. A significant relationship between respiration and more routinely measured parameters would substantially progress our ability to determine its spatial and temporal variability. We investigate whether such a relationship exists. Linked to this is the importance of an appreciation of the distribution of respiration within the microbial food web, and so improved food web model parameterization and verification. When considered on comparable time and space scales, the balance between plankton respiration and photosynthesis indicates the potential amount of photosynthetically fixed carbon available for export from the upper mixed layer. We assume that the epipelagic zone of the open oceans approaches this ideal, and analyze the distributions of respiration and photosynthesis in order to assess the global balance between photosynthesis and respiration. Available approaches and their constraintsRates of planktonic respiration can be derived in a number of ways: (i) from the measurement of the rate of production/consumption of a product 147

Experimentally determined temperature thresholds for Arctic plankton community metabolism

“…Gross primary production (GPP) was calculated by solving the mass balance equation GPP = NCP + CR (Carpenter, 1965;Carritt and Carpenter, 1966). The mean analytical precision of oxygen determinations across both experiments was 0.9 % (median= 0.7 %), which is well above the analytical limit of the method determined to be 0.02 % (Robinson and Williams, 2005), but comparable to the error reported in other efforts to resolve metabolic rates in the Arctic (Cotrell et al 2006). The low precision is attributable to the small volume of the Winkler bottles (25-35 mL) used compared to standard volumes (100-250 mL) which were chosen to avoid depleting the microcosms of water.…”

“…This may be due to the fact that a majority of bacterial cells in marine plankton communities are metabolically inactive (Gasol et al, 1995) or may also be due to the inherent covariation of both bacterial abundance and production with chlorophyll a concentrations (Li et al, 2004;Lopez-Urrieta and Morán, 2007) that confounds the relationship of community respiration with temperature (Lopez-Urrieta and Morán, 2007). We argue that chlorophyll a is an appropriate parameter due to the fact that community respiration is constrained by the flow of organic matter from autotrophs, which is strongly correlated with chlorophyll a, and the previous relationships found between CR and chlorophyll a (Robinson and Williams 2005).…”

SISI: A New Device for In Situ Incubations at the Ocean Surface

“…Namely Most importantly for demonstrating the benefit of using the SISI, the absolute O 2 turnover rates in the Baltic Sea and Pacific Ocean were in a range comparable with those previously reported. Namely [18]. At all three stations, both in the Baltic Sea and the Pacific open ocean, SML samples showed the strongest respiration rates in dark incubations compared to underlying water depths; which is in line with previous observations on enhanced heterotrophic respiration within the SML [16,17].…”

“…The light/dark bottle incubation technique is the primary approach used to measure planktonic production and respiration in surface water [18]. For assessment of the plankton's metabolic potential, it is common practice to incubate sea water samples in closed containers on deck [19], although this method is less compatible with adequate temperature control, especially in tropical regions [20].…”

Major role of marine vegetation on the oceanic carbon cycle

“…As the total organic carbon burial rate in the coastal ocean is about 9% of the calculated NCP figure, it follows that the bulk (>91%, as some of the buried material is of terrestrial origin), of the benthic net ecosystem production (NEP) must either be exported to the open ocean or support respiration in the pelagic compartment. The pelagic compartment of coastal ecosystems is often heterotrophic (Smith and Hollibaugh, 1983;Duarte et al, 2004;Lucea et al, 2005), and a NEP range for the pelagic coastal ocean of −2304 Tg C y −1 to 104 Tg C y −1 has been proposed (Robinson and Williams, 2005). The excess benthic NEP that must be exported to support respiration in the global ocean can be calculated as,…”