Sydney Harbour is slightly net heterotrophic with very low CO2 emissions compared to estuaries globally (see Chen et al., 2013). However, these high CO2 emission estimates are biased towards disturbed North American and highly engineered European systems with elevated loadings of organic matter and associated high respiration (Chen et al., 2013). In contrast, there was a small net uptake of -04 to -2.0 mmol m-2 d-1 of CO2 in three warm temperate east Australian estuaries driven by net autotrophic production (Maher and Eyre, 2012) and a hypersaline bay with restricted circulation in western Australia and a sub-tropical estuary in south east Queensland were weak emitters of CO2 (2.0 mmol m-2 d-1; Smith and
Atkinson, 1983 and 0.2 mmol m-2d-1; Adiyanti et al., 2016 respectively). A large emission of
CO2 (up to 252.1 mmol m-2 d-1) from the Australian river dominated Richmond River estuary reflects the influence of acidic wetland (Ruiz-Halpern, 2015) (Table 2b).
60
Table 2b. Comparison of area-weighted seasonal and annual air-water CO2 emission from Australian estuaries.
Area Weighted CO2 Emission (mmol m−2d−1) Annual CO2Emission
(mol m−2 y−1)
Estuary Sumer Autumn Winter Spring Dry Wet Annual Gas exchange
Coefficient Reference Sydney Harbour Estuary 1.1 4.0 5.0 0.6 2.9 3.8 0.8 2.7 4.2 2.4 6.0 6.8 0.6 2.9 3.8 -0.8 -1.7 -0.8 0.4 1.5 1.8 W92 RC01 J08 This Study Hastings
River 0.7 -5.4 3.3 -3.5 -0.4 RC01 Maher and Eyre
(2012) Camden
Haven -4.5 -3.6 -3.1 -8.4 -1.8 RC01 Maher and Eyre
(2012) Wallis Lake
-9.1 3.5 -5.3 -11.2 -2.0 RC01 Maher and Eyre
(2012) Richmond River 252.1 RC01 Ruiz-Halpern et al. (2015) Caboolture River Estuary 0.3 0.3 0.3 0.1 0.1 W92 Adiyanti et al. (2016)
Previous studies have shown that the estimates of gas transfer velocity can vary significantly depending on the parameterization used (Wanninkhof et al., 1992; Wanninkhof and McGillis,
1999; Wanninkhof et al., 2004; Ho et al., 2006; Weiss et al., 2007; Jaing et al., 2008). When
comparing emissions from different estuaries the same relationship should be used for consistency (personal communication R. Wanninkhof, 2016). Currently calculations of global emissions are based on a variety of piston velocities and lack comprehensive measurements over a range of environmental conditions so that confidence in the direct comparison between estuary emission rates is low. To provide a measure for comparing estuaries of vastly different length and drainage basin size to the Sydney Harbour estuary the rate of discharge per unit area was used (Table 3).
61
Table 3. Mean discharge per unit area for a range of estuaries with annual air-water CO2 emission calculated using the transfer velocity parameterizations of RC(2001), W(1992), Borges(2004), Jiang (2008) and a constant velocity (8 cm h-1).
Estuary Classification Drainage Area
(x103 km2) Mean Discharge Rate (x103m3/s) Mean Discharge per unit area
(m3/s/km2) Annual CO2 Emission (mol C m−2 y−1) Gas exchange Coefficient Reference Australia Sydney Harbour Estuary
Drowned River Valley 0.5 0.007 (a) 0.014 (a) 0.4 1.5 1.8 W(1992) RC(2001) J(2008) This study USA Neusse River York River Hudson River Altamaha
Drowned River Valley Drowned River Valley Drowned River Valley Sound 16 6.9 1.8 36 0.15 (b) 0.071 (c) 0.460 (d) 0.585 (e) 0.009 0.010 0.014 0.0115 4.7 5.6 5.9 26.8 Jiang (2008) Clark et al. (1994) Clark et al. (1994) W(1992) Crosswell et al. 2012 Raymond et al. (2000) Jaing et al. (2008) Europe Scheldt Elbe River Rhine River Aveiro Engineered System Engineered System Engineered Tectonic Lagoon 22 148 160 2.6 0.12 (f) 0.87 (f) 2.0 (f) 0.025 (d) 0.005 0.006 0.014 0.010 94.1 65.7 21.9 12.4 Constant (8 cm h-1) “ “ Borges and Frankingnoulle (Unpublished) Frankingnoulle et al. (1998) “ “ Borges and Frankingnoulle (Unpublished) Vietnam
Mekong River Tectonic Delta 795 14.5 (e) 0.018 30.8 W(1992) Borges (unpublished) China
Yangtze River Tectonic Delta 1959 34 (f) 0.017 24.9 W(1992) Zhai et al. (2007) India
Godavari
River Tectonic Delta 313 3.5 (g) 0.011 29 W(1992) Sarma et al. (2001) Taiwan
Tan Shui Tectonic Estuary 26 0.025 (f) 0.010 49.8 W(1992) Sarma et al. (2001) Drainage area and mean discharge rate; (a) Modified from Lee and Birch (2011), (b) Cresswell
et al. (2012), (c) Nichols et al. (1991), (d) Choi and Wilkin (2007), (e) McCallum and Alhadeff (2004), (f) Fettweis et al. (2012), (d) Genio et al. (2008), (e) Gupta (2000), Mook et al. (2000), (g) Sarma (2012), (h) Lui (2001).
Of the 165 estuaries with CO2 emissions (Chen et al., 2013) the Hudson River and Yangtze River are the only other large temperate estuaries included that are located adjacent to megacities (New York and Shanghai respectively both host to a population of over 20 million). Compared to these and other large estuaries (Figure 7) CO2 emission (weighted m3 s-1 of discharge per km2 of estuary surface area) from Sydney Harbour (0.4 to 1.8 mol C m-2 y-1) were
62 an order of magnitude lower than large tectonic deltas of China, Vietnam, Taiwan and India (24.9 to 31 mol C m-2 y-1) the lagoon systems and highly engineered and polluted estuaries of Europe (63 to 94 mol C m-2 y-1). However, emissions in Sydney Harbour were lower but similar to other natural drowned river valleys in the USA including the York River, the Neuse and the Hudson River (4.7 to 5.9 mol C m-2 y-1). As such, discharge per unit area appears to be a good predictor of CO2 emissions for estuaries of a similar geomorphic class.
Figure 7. Comparison of air-water CO2 emissions in natural drowned river valley estuaries (round dots) to tectonic, sounds, lagoons and engineered estuary systems (triangles). Estuaries adjacent to megacities are marked with an (*). (References for the data are listed in Table 3).
Note: Comparisons with other estuaries incorporated studies with sites located in tropical or
temperate regions, where estuaries were of a similar large geomorphology and where CO2 emissions had been measured with adequate temporal and spatial resolution along the main channel. Out of the many estuaries that fit these criteria many had insufficient seasonal data to resolve meaningful annual values with others having been calculated using a variety of different models so the values were not specifically relatable to those calculated for the Sydney Harbour Estuary.
63
References
Abril, G., Etcheber, H., Borges, A.V., Frankingnoulle, M. (2000) Excess atmospheric carbon dioxide transported by rivers into the Scheldt estuary. Cr. Acad. Sci. ll A., 330, 761-768. Adiyanti, S., Eyre, B.D., Maher, D.T., Santos, I., Golsby-Smith, L., Mangion, P. and Hipsey, M.R., Stable isotopes reduce parameter uncertainty of an estuarine carbon cycling model.
Environmental Modelling & Software, 79, 2016, pp. 233-255,
http://dx.doi.org/10.1016/j.envsoft.2016.02.011
Bauer, J.E., Cai, W.J., Raymond, P.A., Bianchi, T.S., Hopkinson, C.S., Regnier, P.A.G. (2013) The changing carbon cycle of the coastal ocean. Nature, 504(7478): 61-70. doi: 10.1038/nature12857
Benson, B.B., Krause, Jr., D. (1984) The concentration and isotopic fractionation of oxygen dissolved in freshwater and seawater in equilibrium with the atmosphere. Limnology and
Oceanography, 29: 620-632.
Birch, G.F., Cruickshank, B., Davis, B. (2010). Modelling nutrient loads to Sydney estuary (Australia). Environmental Monitoring and Assessment, 167(1–4), 333–348. doi:10.1007/S10661-009-1053-Z
Borges, A.V., Vanderborght, J.-P., Schiettecatte, L.-S., Gazeau, F., Ferrón-Smith, S., Delille, B., Frankingnoulle M. (2004) Variability of the gas transfer velocity of CO2 in a macrotidal estuary (the Scheldt). Estuaries, 27, 593–603. doi:10.1007/Bf02907647
Borges, A.V. and Abril, G. (2011) Carbon Dioxide and Methane Dynamics in Estuaries, in: Treatise on Estuarine and Coastal Science, edited by: Eric, W. and Donald, M., Academic Press, Amsterdam, 119–161.
Borges, A.V. Delille, B, Frankingnoulle, M. (2005) Budgeting sinks and sources of CO2 in the coastal ocean: Diversity of ecosystems counts. Geophysical Research Letters, Vol. 32, L14601. doi: 10.1029/2005GL023053
Bouillon, S., Borges, A.V., Casteneda-Moya, E., Diele, K., Dittmar, T., Duke, N.C., Kristensen, E., Lee, S.Y., Marchand, C. Middelburg, J.J., Rivera-Monroy, V.H., Smith, T.J. III, Twilley, R.R. (2003) Mangrove production and carbon sinks: A revision of global budget estimates. Global Biogeochemical Cycles, Vol. 22. doi: 10.1029/2007GB00305
Bricker, S.B., Clement, C.G., Pirhalla, D.E., Orlando, S.P. and Farrow, D.R.G., 1999, National Estuarine Eutrophication Assessment: Effects of Nutrient Enrichment in the Nation’s Estuaries. NOAA, National Ocean Service, Special Projects Office and the National Centers for Coastal Ocean Science. Silver Spring, MD, 71 pp.
Cai, W.J. (2003) Riverine inorganic carbon flux and rate of biological uptake in the Mississippi River plume. Geophysical Research Letters, 30: 1032. doi: 10.1029/2002gl016312
64 Cai, W.J. (2011) Estuarine and coastal ocean carbon paradox: CO2 sinks or sites of terrestrial carbon incineration. Annual Review of Marine Science, Vol. 3, 123-145. doi: 10.1146/annurev- marine-120709-142723
Cerco, C.F. (1989) Estimating estuarine reaeration rates. Journal of Environmental Engineering, 115, 1066-1070.
Chen, C.-T.A, Huang, T.-H., Fu, Y.-H., Bai, Y. He, X. (2012) Strong sources of CO2 in upper estuaries become sinks of CO2 in large river plumes. Current Opinion in Environmental Sustainability, 4, 179-185.
Chen, C.-T.A, Huang, T.-H., Chen, Y.-C., Bai, Y. He, X., Kang,Y. (2013) Air-Sea exchanges of CO2 in the world’s coastal seas. Biogeosciences, 10, 6509-6544. doi: 10.5194/bg-10-6509- 2013
Choi, B-J, Winlin, J.L. (2007) The effect of wind on the dispersal of the Hudson River Plume. Journal of Physical Oceanography, V37(7), 1878-1897. doi: dx.doi.org/10.1175/JPO3081.1 Clarke, J.F., Wanninkhof, R. Schlosser, P., Simpson, H.J. (1994) Gas exchange rates in the tidal Hudson River using a dual tracer technique. Tellus, 46B, 274-285.
Cole, J.J., Caraco, N.F. (2001) Carbon in catchments: connecting terrestrial carbon losses with aquatic metabolism. Marine and Freshwater Research, 52, 101-110.
Cotovicz Jr, L.C., Knoppers, B.A., Brandindi, N., Costa Santo, S.J., Abril, G. (2015) A strong CO2 sink enhanced by eutrophication in a tropical coastal embayment (Guanabara Bay, Rio de Janeiro, Brazil). Biogeosciences, 12, 6125-6146. doi: 10.5194/bg-12-6125-2015
Crosswell, J.R., Wetz, M.S., Hales, B., Paerl, H.W. (2012) Air-water CO2 fluxes in the microtidal Neuse River Estuary, North Carolina. Journal of Geophysical Research, 117, C08017. doi:10.1029/2012JC007925
Cui, L. and Shi, J. (2012) Urbanization and its environmental effects in Shanghai, China. Urban Climate, 2, 1-15. doi: 10.1016/j.uclim.2012.10.008
Cruickshank, B. (2006) Modelling nutrient load to the Port Jackson estuary, Australia. B.Sc. Honours Thesis (unpublished), School of Geosciences, University of Sydney.
Crump, B.C., Hopkinson, C.S., Sogin, M.L., Hobbie, J.E. (2004). Microbial biogeography along an estuarine salinity gradient: combined influences of bacterial growth and residence time. Applied and Environmental Microbiology, 70, 1494–1505. doi: 10.1128/AEM.70.3.1494-1505.2004
Das, P., Marchesiello, P., Middleton, J. (2000) Numerical modelling of tide-induced residual circulation in Sydney Harbour. Marine and Freshwater Research, 51, 97-112.
Day, J.W., Charles, A.S., Michael, K., Alejandro, Y.A. (1989) Estuarine Ecology. Wiley- Interscience; 1 edition, 576 pp. ISBN 0-10-0471062634.
65 Dinauer, A., Mucci, A. (2017) Spatial variability of surface-water pCO2 and gas exchange in the world’s largest semi-enclosed estuarine system: St Lawrence Estuary (Canada). Biogeosciences Discuss. doi: 10.5194/bg-2017-1
Eyre, B.D. (1994) Nutrient Biogeochemistry in the Tropical Moresby River-Estuary System North Queensland, Australia. Estuarine, Coastal and Shelf Science, 39, 15-31.
Eyre, B.D., 2000. A regional evaluation of nutrient transformation and phytoplankton growth in nine river dominated sub-tropical East Australian estuaries. Marine Ecology Progress Series, 205, 61-83.
Eyre, B.D., Ferguson, A.J.P., Webb, A., Maher, D., Oakes, J.M. (2011) Denitrification, N- fixation and nitrogen and phosphorus fluxes in different benthic habitats and their contribution to the nitrogen and phosphorus budgets of a shallow oligotrophic sub-tropical coastal system (southern Moreton Bay, Australia). Biogeochemistry 102, 111-133.
Feely, R. A., Alin, S. R., Newton, J., Sabine, C. L., Warner, M., Devol, A., Krembs, C., Maloy, C. (2010) The combined effects of ocean acidification, mixing, and respiration on pH and carbonate saturation in an urbanized estuary. Estuarine, Coastal and Shelf Science 88, 442– 449. doi:10.1016/J.ECSS.2010.05.004
Ferguson, A.J.P., Eyre, B.D., Gay, J. (2004a) Nutrient cycling in the sub-tropical Brunswick estuary, Australia. Estuaries, 27, 1-18.
Ferguson, A.J.P., Eyre, B.D., Gay, J. (2004b) Benthic nutrient fluxes in euphotic sediments along shallow sub-tropical estuaries, northern New South Wales, Australia. Aquatic Microbial Ecology, 37, 219-235.
Fettweis, M., Monbaliu, J. Baeye, M., Nechad, B., Van den Eynde, D. (2012) Weather and climate induced spatial variability of surface suspended particulate matter concentration in the North Sea and the English Channel. Methods in Oceanography, Vol 3(4), 25-39.
Foran, B., Poldy, F. (CSIRO Resource Futures Working Paper 02.01. CSIRO Sustainable Ecosystems, Canberra, ACT, 337 p.
Fortunato C.S., Herfort L., Zuber P., Baptista A.M., Crump B.C. (2012). Spatial variability overwhelms seasonal patterns in bacterioplankton communities across a river to ocean gradient. ISME Journal, 6, 554–563. doi: 10.1038/ismej.2011.135
Frankingnoulle, M., Abril, G., Borges, A.V., Bourge, I., Canon, C., DeLille, B., Libert, E., Théate, J.M. (1998) Carbon dioxide emissions from European estuaries. Science, 282, 434- 436.
Garnaut, R. (2008) The Garnaut climate change review. Cambridge University Press, Melbourne, Vic, 616 p.
Genio, L., Sousa, A., Vaz, N, Dias, J.M., Barroso, C. (2008) Effect of low salinity on the survival of recently hatched beliger of Nassirius reticulatua (L.) in estuarine habitats: A case study of Ria de Aveiro. Journal of Sea Research, 59, 133-143.
66 Gillanders, B.M., Elsdon, T.S, Halliday, I.A., Jenkins, G.P., Robins, J.B., Valesini, F.J. (2011) Potential effects of climate change on Australian estuaries and fish utilising estuaries: a review. Marine and Freshwater Research, 62, 115-1131.
Gupta, A. (2007) Large rivers: geomorphology and management. Chichester, England, John Wiley.
Gypens, N., Borges, A.V., Lancelot, C. (2009) Effect of eutrophication on air-sea CO2 fluxes in the coastal Southern North Sea: a model study of the past 50 year. Global Change Biology, 15:1040-1056.
Harrison, D.P. (2012) Sydney Metropolitan Catchment Management Authority water quality sampling of Parramatta River, Methods and Sampling Protocol. Sydney Institute of Marine Science, Mosman, Australia.
Hedge, L.H., Johnston, E.L., Ayoung, S.T., Birch, G.F., Booth, D.J., Creese, R.G., Doblin, M.A., Figueira W.F., Gribben, P.E., Hutchings, P.A., Mayer Pinto, M, Marzinelli, E.M., Pritchard, T.R., Roughan, M., Steinberg, P.D. (2014), Sydney Harbour: A systematic review of the science. Sydney Institute of Marine Science, Sydney, Australia.
Ho, E.T., Law, C.S., Smith, M.J., Schlosser, P., Harvey, M., Hill, P. (2006) Measurements of air-sea gas exchange at high wind speeds in the Southern Ocean: Implications for global parameterizations. Geophysical Research Letters, 33, L16611. doi: 10.1029/2006GL026817 Hose, G.C., Gordon, G., McCullough, F.E., Pulver, N., Murray, B.R. (2006) Spatial and rainfall related patterns of bacterial contamination in Sydney Harbour estuary. Journal of Water and Health, 3(4), 349-358. doi: 10.2166/wh.2005.060
Hunt, C.W., Salisbury, J.E., Vandemark, D. (2014) CO2 input dynamics and air-sea exchange Jaing, L.Q., Cai, W.J., Wang, Y. (2008) A comparative study of carbon dioxide degassing in river- 834and marine-dominated estuaries. Limnology and Oceanography, 53(6), 2603–2615. Jeffries, T.C., Schmitz Fontes, M.L., Harrison, D.P., Van-Dongen-Vogels, V., Eyre, B.D., Ralph, P.J., Seymour, J.R. (2016) Bacterioplankton dynamics within a large anthropogenically impacted urban estuary. Frontiers in Microbiology, Vol. 6, 1438. doi: 10.3389/fmicb.2015.01438
Joesoef, A., Huang, W.J., Gao, Y., Cai, W.J. (2015) Air-water fluxes and sources of carbon dioxide in the Delaware Estuary: spatial and seasonal variability. Biogeosciences, 12, 6085- 6101.
Laruelle, G.G., Durr, H.H., Lauerwald, R., Hartmann, J., Slomp, C.P., Goossens, N., Regnier, P.A.G. (2013) Global multi-scale segmentation of continental and coastal waters from the watersheds to the continental margins. Hydrology and Earth System Sciences, 17(5), 2029– 2051. doi:10.5194/hess-17-2029-2013
Laruelle, G.G., Lauerwald, R., Rotschi, J., Raymond, P.A., Hartmann, J., Regnier, P. (2014) Seasonal response of air-water CO2 exchange along the land-ocean aquatic continuum of the
67 northeaset North American coast. Biogeosciences, 12, 1447-1458. doi: 10.5194/bg-12-1447- 2015.
Lee, S.B., Birch, G.F., Lemckert, C.J. (2011) Field and modelling investigations of fresh-water plume behaviour in response to infrequent high-precipitation events, Sydney Estuary, Australia. Estuarine, Coastal and Shelf Science, 92, 389-402.
Liu, Y., Dong, Q., Shi, H. (2015) Distribution and population structure characteristics of microorganisms in urban sewage system. Applied Microbiology and Biotechnology, 99, 7723– 7734. doi: 10.1007/s00253-015-6661-7
Liu, W.C., Hsw, M.H., Kuo, A.Y. Kuo, J.T. (2001) The influence of river discharge on salinity intrusion in the Tanshui estuary, Taiwan. Journal of Coastal Research, 17(3), 544-529.
Macklin, P.A., Maher, D.T., Santos, I.R. (2014) Estuarine canal estate waters: hotspots of CO2 outgassing driven by enhanced groundwater discharge? Marine Chemistry, Vol. 167, 82-92. doi: 10.1016/jmarchem.2014.08.002
Maher, D.T., Eyre, B.D. (2012) Carbon budgets for three autotrophic Australian estuaries: Implications for global estimates of the coastal air-water CO2 flux. Global Biogeochemical Cycles, Vol. 26, GB1032. doi: 10.1029/2011GB004075
McCallum, B.E., Alhadeff, D.V. (2004) Water resources data – Georgia, 2004. Volume 1: Continuous water-level, streamflow, water-quality, and periodic water-quality data, Water Year 2004. USGS Water-Data Report GA-04-1.
McGillis, W.R., Edson, J.B., Hare, J.E., Fairall, C.W. (2001) Direct covariance air-sea CO2 Fluxes. Journal of Geophysical Research: Oceans, Vol. 106(C8), 16729-16745. doi: 10.1029/2000JC000506
McNeil, B.I. (2010) Diagnosing coastal ocean CO2 interannual variability from a 40 year hydrographic time series station off the east coast of Australia. Global Biogeochemical Cycles, Vol. 24, GB4034. doi: 10.1029/2010GB003870
Montoya, D. (2015), Pollution in Sydney Harbour: sewage, toxic chemicals and microplastics, NSW Parliamentary Research Service, viewed 09 February 2016, http://apo.org.au/node/53648.
Mook, W.G., Gat, J.R., Meijer, H.A. (2000) Environmental isotopes in the hydrological cycle: principles and applications. In: Mook W.G. (ed) Technical Documents in Hydrology, Vol 2, UNESCO, IAEA, Paris.
Nichols, M.M., Kim, S.C., Brouwer, C.M. (1991) Sediment characterisation of the Chesapeake Bay and its tributaries, Virginian Province. National estuarine inventory: supplement. NOAA Strategic Assessment Branch, 88p.
Nightingale, P.D., Malin, G., Law, C.S., Watson, A.J., Liss, P.S., Liddicoat, M.I., Boutin, J., Upstill-Goddard, R.C. (2000) In situ evaluation of air-sea gas exchange parameterizations using novel conservative and volatile tracers. Global Biogeochem Cycles, 14, 373-387.
68 Northern Territory Environmental Protection Authority (2014) A stormwater strategy for the Darwin Harbour Region. NTEPA Report, 23 p.
Parramatta City Council (2015) Water quality monitoring review. PCC calibration and Maintenance Report, 2015.
Paul, M.J. and Meyer, J.L. Streams in the Urban Landscape, Annual Review of Ecology and
Systematics, 32, 2001, 333-365. http://www.jstor.org/stable/2678644.
Pierrot, D., Neill, C. Sullivan, K., Castle, R., Wanninkhof, R., Lüger, H., Johannessen, T., Olsen, A. Feely, R.A., Cosca, C.E. (2009) Recommendations for the autonomous underway pCO2 measuring systems and data-reduction routines. Deep-Sea Research II, 56, 512-522. Pierrot, D., Lewis, E., Wallace, D.W.R. (2006) MS Excel program developed for CO2 system calculations: ORNL/ CDIAC-105a, Carbon Dioxide Information Analysis Center Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee.
Pinckney, J.L., Paerl, H.W., Tester, P., Richardson, T.L. (2001) The role of nutrient loading and eutrophication in estuarine ecology. Environmental Health Perspectives, 109(Suppl 5), 699.
Pritchard, D.W. (1967) What is an estuary: physical viewpoint. In: G.H. Lauf, (Ed.) Estuaries. American Association for the Advancement of Science, 83, Washington, D.C., pp. 3-5. Ran, L. Lu, X.X, Liu, S. (2016) Dynamics of riverine CO2 in the Yangtze River fluvial network and their implications for carbon evasion. Biogeosciences Discussions, Dec 2016. doi: 10.5194/bg-2016-507
Raymond, P.A, Bauer, J.E., Cole, J.J. (2000) Atmospheric CO2 evasion, dissolved inorganic carbon production, and net heterotrophy in the York River estuary. Limnology and Oceanography, 45(8), 1707-1717.
Raymond, P.A. and Cole, J.J. (2001) Gas exchange in rivers and estuaries: Choosing a gas transfer velocity. Estuaries, 24(2), 312-317.
Raymond, P.A., Caraco, N.F., Cole, J.J. (1997) Carbon dioxide concentration and atmospheric flux in the Hudson River. Estuaries, V. 20, 381-390.
Regnier, P. et al. (2013) Anthropogenic perturbation of the carbon fluxes from land to ocean. Nat. Geosci, 6, 597-607. doi: 10.1038/NGEO1830
Revelante, N. and Gilmartin M. (1978) Characteristics of the microplankton and nanoplankton communities of an Australian coastal plain estuary. Marine and Freshwater Research, 29(1), 9- 18.
Richardson, A.J. and Poloczanska, E.S. (2009) Australia’s Oceans. In A Marine Climate Change Impacts and Adaptation Report Card for Australia 2009 (Eds. E.S. Poloczanska, A.J. Hobday and A.J. Richardson), NCCARF Publication 05/09, ISBN 978-1-921609-03-9.
Roughan, M., Middleton, J.H. (2002) A comparison of observed upwelling mechanisms off the east coast of Australia. Continental Shelf Research, 22, 2551-2572.
69 Roy, P.S. (1984) New South Wales estuaries: their origin and evolution. In: B.G. Thom (Ed.) Coastal Geomorphology in Australia. Academic Press, Sydney, pp 99-121.
Ruiz-Halpern, S, Maher, D.T., Santos, I.R., Eyre, B.D. (2015) High CO2 evasion during floods