Ocean Science www.ocean-sci.net 1812-0784 1812-0792 5 4 2009 10.5194/os-5-523-2009 http://www.ocean-sci.net/5/523/2009/ http://www.ocean-sci.net/5/523/2009/os-5-523-2009.html http://www.ocean-sci.net/5/523/2009/os-5-523-2009.pdf 523 535 2009-11-04 Sensors for observing ecosystem status S. Kröger silke.kroeger@cefas.co.uk E. R. Parker J. D. Metcalfe N. Greenwood R. M. Forster D. B. Sivyer D. J. Pearce Centre for Environment, Fisheries and Aquaculture Science (Cefas), Pakefield Rd, Lowestoft, Suffolk NR33 0HT, UK This paper aims to review the availability and application of sensors for observing marine ecosystem status. It gives a broad overview of important ecosystem variables to be investigated, such as biogeochemical cycles, primary and secondary production, species distribution, animal movements, habitats and pollutants. Some relevant legislative drivers are listed, as they provide one context in which ecosystem studies are undertaken. In addition to literature cited within the text the paper contains some useful web links to assist the reader in making an informed instrument choice, as the authors feel that the topic is so broad, it is impossible to discuss all relevant systems or to provide appropriate detail for those discussed. It is therefore an introduction to how and why ecosystem status is currently observed, what variables are quantified, from what platforms, using remote sensing or in-situ measurements, and gives examples of useful sensor based tools. Starting with those presently available, to those under development and also highlighting sensors not yet realised but desirable for future studies. % vor jede Referenz Arnold, G. P. and Dewar, H.: Electronic tags in marine fisheries research: A 30 year perspective., in: Electronic tagging and tracking in marine fisheries, edited by: Nielsen, J. R. S. J. L., Kluwer Academic Press, Dordrecht, The Netherland, 7–64, 2001. Aylott, J. W., Richardson, D. J., and Russell, D. A.: Optical biosensing of nitrate ions uisng a sol-gel immobilized nitrate reductase, Analyst, 122, 77–80, 1997. Bargeron, C. P., Hydes, D. J., Woolf, D. K., Kelly-Gerreyn, B. A., and Qurban, M. A.: A regional analysis of new production on the northwest european shelf using oxygen fluxes and ship-of-opportunity, Estuar. Coas. Shelf S., 69, 478–490, 2006. Birchenough, S. N. R., Boyd, S. E., Coggan, R. A., Limpenny, D. S., Meadows, W. J., and Rees, H. L.: Lights, camera and acoustics: Assessing macrobenthic communities at a dredged material disposal site off the north east coast of the uk, J. Marine Syst., 62, 204–216, 2006. Campas, M. and Katakis, I.: DNA biochip arraying, detection and amplification strategies, TRAC Trends In Analytical Chemistry, 23, 49–62, 2004. Campàs, M., de la Iglesia, P., Le Berre, M., Kane, M., Diogène, J., and Marty, J.-L.: Enzymatic recycling-based amperometric immunosensor for the ultrasensitive detection of okadaic acid in shellfish, Biosens. Bioelectron., 24, 716–722, 2008. Carter, R. M., Poli, M. A., Pesavento, M., Sibley, D. E. T., Lubrano, G. J., and Guilbault, G. G.: Immunoelectrochemical biosensors for detection of saxitoxin and brevetoxin, ImmunoMethods, 3, 128–133, 1993. Chang, S. T., Lee, H. J., and Gu, M. B.: Enhancement in the sensitivity of an immobilized cell-based soil biosensor for monitoring pah toxicity, Sensors and Actuators B Chemical, 97, 272–276, 2004. Charrassin, J.-B., Hindell, M., Rintoul, S., Roquet, F., Sokolov, S., Biuw, M., Costa, D., Boehme, L., Lovell, P., Coleman, R., Timmermann, R., Meijers, A., Meredith, M., Park, Y.-H., Bailleul, F., Goebel, M., Tremblay, Y., Bost, C.-A., McMahon, C., Field, I., Fedak, M., and Guinet, C.: Southern ocean frontal structure and sea-ice formation rates revealed by elephant seals, P. Natl. Acad. Sci., 105, 11634–11639, 2008. Cheun, B. S., Loughran, M., Hayashi, T., Nagashima, Y., and Watanabe, E.: Use of a channel biosensor for the assay of paralytic shellfish toxins, Toxicon, 36, 1371–1381, 1998. Chouteau, C., Dzyadevych, S., Chovelon, J. M., and Durrieu, C.: Development of novel conductometric biosensors based on immobilised whole cell chlorella vulgaris microalgae, Biosens. Bioelectron., 19, 1089–1096, 2004. Chouteau, C., Dzyadevych, S., Durrieu, C., and Chovelon, J.-M.: A bi-enzymatic whole cell conductometric biosensor for heavy metal ions and pesticides detection in water samples, Biosens. Bioelectron., $21$, 273–281, 2005. Dennis, A., Forster, R. M., Mills, D. K., and Greenwood, N.: The use of high-frequency observations in the calculation of primary production, Challenger conference, 2006. Dennis, A.: The calculation of primary production using high-frequency data from data-buoys in uk waters, NOC Southampton and Cefas, 2006. Devic, E., Li, D. H., Dauta, A., Henriksen, P., Codd, G. A., Marty, J. L., and Fournier, D.: Detection of anatoxin-a(s) in environmental samples of cyanobacteria by using a biosensor with engineered acetylcholinesterases, Appl. Environ. Microbiol., 68, 4102–4106, 2002. Devlin, M. J., Barry, J., Mills, D. K., Gowen, R. J., Foden, J., Sivyer, D., and Tett, P.: Relationships between suspended particulate material, light attenuation and secchi depth in uk marine waters, Estuar. Coast. Shelf S., 79, 429–439, 2008. Dickey, T. D.: Physical-optical-biological scales relevant to recruitment in large marine ecosystems., in: Large marine ecosystems: Patterns, processes, and yields, edited by: Sherman, K., Alexander, L. M., and Gold, B. D., Am. Assoc. Adv. Sci. Publ, 90, 82–98, 1990. Diercks, S., Metfies, K., and Medlin, L. K.: Development and adaptation of a multiprobe biosensor for the use in a semi-automated device for the detection of toxic algae, Biosens. Bioelectron., $23$, 1527–1533, 2008a. Diercks, S., Metfies, K., Schröder, F., Medlin, L. K., and Colijn, F.: Detection of phytoplankton with nucleic acid sensors NATO Security through Science Series, C: Environmental Security, 285–300, 2008b. Draisci, R., Volpe, G., Compagnone, D., Purificato, I., delli Quadri, F., and Palleschi, G.: Development of an electrochemical elisa for the screening of 17b-estradiol and application to bovine serum, Analyst, 125, 1419–1423, 2000. Drummond, T. G., Hill, M. G., and Barton, J. K.: Electrochemical DNA sensors, Nature Biotechnology, 21, 1192–1199, 2003. Eastwood, P. D., Souissi, S., Rogers, S. I., Coggan, R. A., and Brown, C. J.: Mapping seabed assemblages using comparative top-down and bottom-up classification approaches, Can. J. Fish. Aquat. Sci., 63, 1536–1548, 2006. Engblom, S. O.: The phosphate sensor, Biosens. Bioelectron., 13, 981–994, 1998. Epstein, J. R., Biran, I., and Walt, D. R.: Fluorescence-based nucleic acid detection and microarrays, Anal. Chim. Acta, 469, 3–36, 2002. Fa\" hnrich, K. A., Pravda, M., and Guilbault, G. G.: Disposable amperometric immunosensor for the detection of polycyclic aromatic hydrocarbons (pahs) using screen-printed electrodes, Biosens. Bioelectron., $18$, 73–82, 2003. Foden, J., Sivyer, D. B., Mills, D. K., and Devlin, M. J.: Spatial and temporal distribution of chromophoric dissolved organic matter (cdom) fluorescence and its contribution to light attenuation in uk waterbodies, Estuar. Coast. Shelf S., 79, 707–717, 2008. Fones, G. R., Davison, W., Holby, O., Jorgensen, B. B., and Thamdrup, B.: High-resolution metal gradients measured by in situ dgt/det deployment in black sea sediments using an autonomous benthic lander, Limnol. Oceanogr., 46, 982–988, 2001. Glud, R. N., Ramsing, N. B., Gundersen, J. K., and Klimant, I.: Planar optrodes: A new tool for fine scale measurements of two-dimensional o sub(2) distribution in benthic communities, Mar. Ecol. Prog. Ser., 140, 1–3, 1996. Gobi, K. V., Sasaki, M., Shoyama, Y., and Miura, N.: Highly sensitive detection of polycyclic aromatic hydrocarbons (pahs) and association constants of the interaction between pahs and antibodies using surface plasmon resonance immunosensor, Sensors And Actuators B Chemical, 89, 137–143, 2003. Gohin, F., Druon, J. N., and Lampert, L.: A five channel chlorophyll concentration algorithm applied to sea wifs data processed by seadas in coastal waters, Int. J. Remote Sens., 23, 1639–1661, 2002. Gooding, J. J.: Electrochemical DNA hyhridization biosensors, Electroanalysis, 14, 1149–1156, 2002. Gregg, W. W. and Casey, N. W.: Global and regional evaluation of the seawifs chlorophyll data set, Remote Sens. Environ., 93, 463–479, 2004. Gunn, J. and Block, B.: Advances in acoustic, archival, and satellite tagging of tunas, in: Tuna: Physiology, ecology and evolution., edited by: Block, B. A. and Stevens, E. D, Academic Press, 167–219, 2001. Harashima, A., Kimoto, T., Wakabayashi, T., and Toshiyasu, T.: Verification of the silica deficiency hypothesis based on biogeochemical trends in the aquatic continuum of lake biwa-yodo river-seto inland sea, Japan, Ambio, 35, 36–42, 2006. Hill, R.: Theory of geolocation by light levels, in: Elephant seals: Population ecology, behavior, and physiology, edited by: Le Boeuf, B. J. and Laws, R. M., University of California Press, Berkeley, 227–236, 1994. Hiscock, K., Langmead, O., Warwick, R., et al.: Identification of seabed indicator species from time-series and other studies to support implementation of the eu habitats and water framework directives, Report to the Joint Nature Conservation Committee and the Environment Agency from the Marine Biological Association. Plymouth: Marine Biological Association, JNCC Contract F90-01-705, 109~pp., 2004. Homs, W. C. I.: DNA sensors, Anal. Lett., 35, 1875–1894, 2002. Horry, H., Charrier, T., Durand, M.-J., Vrignaud, B., Picart, P., Daniel, P., and Thouand, G.: Technological conception of an optical biosensor with a disposable card for use with bioluminescent bacteria Sensors and Actuators B, 122, 527–534, 2007. Hunter, E., Aldridge, J. N., Metcalfe, J. D., and Arnold, G. P.: Geolocation of free-ranging fish on the european continental shelf as determined from environmental variables. I. Tidal location method, Mar. Biol., 142, 601–609, 2003. Hunter, E., Buckley, A. A., Stewart, C., and Metcalfe, J. D.: Migratory behaviour of the thornback ray, raja clavata l in the southern north sea, J. Mar. Biol. Assoc., 85, 1095–1105, 2005. Hunter, E., Berry, F., Buckley, A. A., Stewart, C., and Metcalfe, J. D.: Seasonal migration of thornback rays and implications for closure management, J. Appl. Ecol., 43, 710–720, 2006. Ivask, A., Virta, M., and Kahru, A.: Construction and use of specific luminescent recombinant bacterial sensors for the assessment of bioavailable fraction of cadmium, zinc, mercury and chromium in the soil, Soil Biol. Biochem., 34, 1439–1447, 2002. Kerman, K., Kobayashi, M., and Tamiya, E.: Recent trends in electrochemical DNA biosensor technology, Meas. Sci. Technol., 15, R1–R11, 2004. Kirkwood, D. S., Aminot, A., and Carlberg, S. R.: The 1994 quastimeme laboratory performance study: Nutrients in seawater and standard solutions, Mar. Pollut. Bull., $32$, 640–645, 1996. Kirstein, D., Kirstein, L., Scheller, F., Borcherding, H., Ronnenberg, J., Diekmann, S., and Steinrucke, P.: Amperometric nitrate biosensors on the basis of pseudomonas stutzeri nitrate reductase, J. Electroanal. Chemi., 474, 43–51, 1999. Kreuzer, M. P., Pravda, M., O'Sullivan, C. K., and Guilbault, G. G.: Novel electrochemical immunosensors for seafood toxin analysis, Toxicon, 40, 1267–1274, 2002. Kröger, S., Piletsky, S., and Turner, A. P. F.: Biosensors for marine pollution research, monitoring and control, Mar. Pollut. Bull., 45, 24–34, 2002. Kröger, S. and Law, R. J.: Sensing the sea, Trends Biotechnol., 23(5), 250–256, 2005. Kromkamp, J. C., Dijkman, N. A., Peene, J., Simis, S. G. H., and Gons, H. J.: Estimating phytoplankton primary production in lake ijsselmeer (the netherlands) using variable fluorescence (pam-frrf) and c-uptake techniques, Eur. J. Phycol., 43, 327–344, 2008. Kulagina, N. V., Mikulski, C. M., Gray, S., Ma, W., Doucette, G. J., Ramsdell, J. S., and Pancrazio, J. J.: Detection of marine toxins, brevetoxin-3 and saxitoxin, in seawater using neuronal networks, Environ. Sci. Technol., $40$, 578–583, 2006. Kwan, R. C. H., Leung, H. F., Hon, P. Y. T., Barford, J. P., and Renneberg, R.: A screen-printed biosensor using pyruvate oxidase for rapid determination of phosphate in synthetic wastewater, Appl. Microbiol. and Biotechnol., 66, 377–383 2005. Larsen, L. H., Kjaer, T., and Revsbech, N. P.: A microscale no3- biosensor for environmental applications, Anal. Chem., 69, 3527–3531, 1997. Leonard, P., Hearty, S., Brennan, J., Dunne, L., Quinn, J., Chakraborty, T., and O'Kennedy, R.: Advances in biosensors for detection of pathogens in food and water, Enzyme Microb. Tech., 32, 3–13, 2003. Lu, Y., Liu, J., Li, J., Bruesehoff, P. J., Pavot, C. M. B., and Brown, A. K.: New highly sensitive and selective catalytic DNA biosensors for metal ions, Biosens. Bioelectron., 18, 529–540, 2003. Mallat, E., Barzen, C., Abuknesha, R., Gauglitz, G., and Barceló, D.: Fast determination of paraquat residues in water by an optical immunosensor and validation using capillary electrophoresis-ultraviolet detection, Anal. Chim. Acta, 427, 165–171, 2001. Marquette, C. A., Coulet, P. R., and Blum, L. J.: Semi-automated membrane based chemiluminescent immunosensor for flow injection analysis of okadaic acid in mussels, Anal. Chim. Acta, 398, 173–182, 1999. Mbeunkui, F., Richaud, C., Etienne, A. L., Schmid, R. D., and Bachmann, T. T.: Bioavailable nitrate detection in water by an immobilized luminescent cyanobacterial reporter strain, Appl. Microbiol. Biotechnol., 60, 306–312, 2002. Metcalfe, J. D. and Arnold, G. P.: Tracking fish with electronic tags, Nature, 387, 665–666, 1997. Metcalfe, J. D.: Summary report of a workshop on daylight measurements for geolocation in animal telemetry, in: Electronic tagging and tracking in marine fisheries reviews: Methods and technologies in fish biology and fisheries, edited by: Sibert, J. and Nielsen, J., Kluwer Academic Press, Dordrecht, The Netherlands, 331–342, 2001. Metcalfe, J. D.: Fish population structuring in the north sea, J. Fish Biol., 69, 48–65, 2006. Metcalfe, J. D., Righton, D. A., Hunter, E., and Eastwood, P.: Migration and habitat choice in marine fishes, in: Fish behaviour, edited by: Magnhagen, C., Braithwaite, V. A., Forsgren, E., and Kapoor, B. G., Science Publishers Inc., Enfield, USA,187–223, 2008. Metcalfe, J. D., Fulcher, M. C., Clarke, S. R., Challiss, M. J., and Heatherington, S.: An archival tag for monitoring key behaviours (feeding and spawning) in fish, in: Tagging and Tracking of Marine Animals with Electronic Devices, edited by: Nielsen, J. L., Arrizabalaga, H., Fragoso, N., Hobday, A., Lutcavage, M., and Sibert, J., Methods and Technologies in Fish Biology and Fisheries, 9, 243–254, 2009. Mills, H. J., Hunter, E., Humphrys, M., Kerkhof, L., McGuinness, L., Huettel, M., and Kostka, J. E.: Characterization of nitrifying, denitrifying, and overall bacterial communities in permeable marine sediments of the northeastern gulf of mexico, Appl. Environ. Microbiol., 74, 4440–4453, 2008. Mo, Z. H., Long, X., and Fu, W.: A new sandwich-type assay of estrogen using piezoelectric biosensor immobilized with estrogen response element, Anal. Commun., 36, 281–283, 1999. Moretto, L. M., Ugo, P., Zanata, M., Guerriero, P., and Martin, C. R.: Nitrate biosensor based on the ultrathin-film composite membrane concept, Anal. Chem., 70, 2163–2166, 1998. Nakamura, H., Hasegawa, M., Nomura, Y., Arikawa, Y., Matsukawa, R., Ikebukuro, K., and Karube, I.: Development of a highly sensitive chemiluminescence flow-injection analysis sensor for phosphate-ion detection using maltose phosphorylase, J. Biotechnol., 75, 127–133, 1999. Nielsen, M., Larsen, L. H., Jetten, M. S. M., and Revsbech, N. P.: Bacterium-based no2 - biosensor for environmental applications, Appl. Environ. Microbiol., 70 6551–6558, 2004. Palecek, E. and Jelen, F.: Electrochemistry of nucleic acids and development of DNA sensors, Critical Reviews In Analytical Chemistry, 32, 261–270, 2002. Parellada, J., Narvaez, A., Lopez, M. A., Dominguez, E., Fernandez, J. J., Pavlov, V., and Katakis, I.: Amperometric immunosensors and enzyme electrodes for environmental applications, Anal. Chim. Acta, 362, 47–57, 1998. Patolsky, F., Katz, E., Helegshabtai, V., and Willner, I.: A crosslinked microperoxidase-11 and nitrate reductase monolayer on a gold electrode - an integrated electrically contacted electrode for the bioelectrocatalyzed reduction of no3, Chemistry-A European Journal, 4, 1068–1073, 1998. Pearson, T. H. and Rosenberg, R.: Macrobenthic succession in relation to organic enrichment and pollution of the marine environment, Mar. Biol. Annu. Rev., 16, 229–311, 1978. Penalva, J., Gonzalez-Martinez, M., Puchades, R., Maquieira, A., Marco, M. P., and Barcelo, D.: Immunosensor for trace determination of irgarol in seawater using organic media, Anal. Chim. Acta, 387, 227–233, 1999. Pratscher, J., Stichternoth, C., Fichtl, K., Schleifer, K.-H., and Braker, G.: Application of recognition of individual genes-fluorescence in situ hybridization (ring-fish) to detect nitrite reductase genes (nirk) of denitrifiers in pure cultures and environmental samples, Appl. Environ. Microbiol., 75, 802–810, 2009. Prest, A. G., Winson, M. K., Hammond, J. R. M., and Stewart, G.: The construction and application of a lux-based nitrate biosensor, Lett. Appl. Microbiol., 24, 355–360, 1997. Ramsay, G. and Wolpert, S. M.: Utility of wiring nitrate reductase by alkylpyrroleviologen-based redox polymers for electrochemical biosensor and bioreactor applications, Anal. Chem., 71, 504–506, 1999. Rees, H. L., Boyd, S. E., Schratzberger, M., and Murray, L. A.: Benthic indicators of anthropogenic effects: Practical considerations in meeting regulatory needs., International Council for the Exploration of the Sea (CM Papers and Reports),CM 2003/J:04, 20, 2003. Revsbech, N. P.: Analysis of microbial communities with electrochemical microsensors and microscale biosensors, Methods in Enzymology, 397, 147–166, 2005. Rhoads, D. C. and Germano, J. D.: Characterization of organism-sediment relations using sediment profile imagining - an efficient Method of Remote Ecological Monitoring of the Seafloor (Remots TM System), Mar. Ecol. Prog. Ser., 8, 115–128, 1982. Rodriguez, B. B., Bolbot, J. A., and Tothill, I. E.: Development of urease and glutamic dehydrogenase amperometric assay for heavy metals screening in polluted samples, Biosens. Bioelectron., 19, 1157–1167, 2004. Rogers, S. I. and Greenaway, B.: A uk perspective on the development of marine ecosystem indicators, Mar. Pollut. Bull., 50, 9–19, 2005. Rynearson, T. A. and Armbrust, E. V.: Genetic differentiation among populations of the planktonic marine diatom \textitditylum brightwellii (bacillariophyceae), J. Phycol., 40, 34–43, 2004. Rynearson, T. A., Newton, J. A., and Armbrust, E. V.: Spring bloom development, genetic variation, and population succession in the planktonic diatom \textitditylum brightwellii, Limnol. Oceanogr., 51, 1249–1261, 2006. Sasaki, S., Karube, I., Hirota, N., Arikawa, Y., Nishiyama, M., Kukimoto, M., Horinouchi, S., and Beppu, T.: Application of nitrite reductase from alcaligenes faecalis s-6 for nitrite measurement, Biosens. Bioelectron., 13, 1–5, 1998. Scholin, C. A.: What are "ecogenomic sensors?" – a review and thoughts for the future, Ocean Sci. Discuss., 6, 191–213, 2009. Schratzberger, M., Forster, R. M., Goodsir, F., and Jennings, S.: Nematode community dynamics over an annual production cycle in the central north sea, Mar. Environ. Res., 66, 508–519, 2008. Schuster, U., Hannides, A., Mintrop, L., and Körtzinger, A.: Sensors and instruments for oceanic dissolved carbon measurements, Ocean Sci. Discuss., 6, 491–524, 2009. Shitanda, I., Takamatsu, S., Watanabe, K., and Itagaki, M.: Amperometric screen-printed algal biosensor with flow injection analysis system for detection of environmental toxic compounds, Electrochimica Acta, $54$, 4933–4936, 2009. Sims, D. W., Southall, E. J., Richardson, A. J., Reid, P. C., and Metcalfe, J. D.: Seasonal movements and behaviour of basking sharks from archival tagging no evidence of winter hibernation, Mar. Ecol. Prog. Ser., 248, 187–196, 2003. Smith, M. T. and Whelpdale, P.: Environmental variables and their influence on growth of the great scallop (pecten maximus) in the English Channel UK, ICES, CM G:08, 2007. Solan, M., Germano, J. D., Rhoads, D. C., Smith, C., Michaud, E., Parry, D., Wenzhöfer, F., Kennedy, B., Henriques, C., Battle, E., Carey, D., Iocco, L., Valente, R., Watson, J., and Rosenberg, R.: Towards a greater understanding of pattern, scale and process in marine benthic systems: A picture is worth a thousand worms, J. Exp. Mar. Biol. Ecol., 285–286, 313–338, 2003. Solan, M., Wigham, B. D., Hudson, I. R., Kennedy, R., Coulon, C. H., Norling, K., Nilsson, H. C., and Rosenberg, R.: In situ quantification of bioturbation using time-lapse fluorescent sediment profile imaging (f-spi), luminophore tracers and model simulation, Mar. Ecol. Prog. Ser., 271, 1–12, 2004. Solé, S., Merkoçi, A., and Alegret, S.: Determination of toxic substances based on enzyme inhibition. Part ii. Electrochemical biosensors for the determination of pesticides using flow systems, Critical Rev. Anal. Chem., 33, 127–143, 2003a. Solé, S., Merkoçi, A., and Alegret, S.: Determination of toxic substances based on enzyme inhibition. Part i. Electrochemical biosensors for the determination of pesticides using batch procedures, Critical Rev. Anal. Chem., 33, 89–126, 2003b. Suri, C. R., Raje, M., and Varshney, G. C.: Immunosensors for pesticide analysis antibody production and sensor development, Critical Rev. Biotechnol., 22, 15–32, 2002. Takayama, K.: Biocatalyst electrode modified with whole-cells of p-denitrificans for the determination of nitrate, Bioelectroch. Bioener., 45, 67–72, 1998. Tang, A. X. J., Pravda, M., Guilbault, G. G., Piletsky, S., and Turner, A. P. F.: Immunosensor for okadaic acid using quartz crystal microbalance, Anal. Chim. Acta, 471, 33–40, 2002. Tengberg, A., Hovdenes, J., Andersson, J. H., Brocande, O., Diaz, R., Hebert, D., Arnerich, T., Huber, C., Koerzinger, A., Khripounoff, A., Rey, F., Roenning, C., Sommer, S., and Stangelmayer, A.: Evaluation of a life time based optode to measure oxygen in aquatic systems, Limnol. Oceanogr. Methods, 4, 7–17, 2006. Tett, P., Gowen, R., Mills, D., Fernandes, T., Gilpin, T., Huxham, M., Kennington, K., Read, P., Service, M., Wilkinson, M., and Malcolm, S.: Defining and detecting undesirable disturbance in the context of marine eutrophication, Mar. Pollut. Bull., 55, 282–297, 2007. Thouand, G., Horry, H., Durand, M. J., Picart, P., Bendriaa, L., Daniel, P., and DuBow, M. S.: Development of a biosensor for on-line detection of tributyltin with a recombinat escherischia coli strain, Appl. Microbial Biotechnol., 62, 218–225, 2003. Urban Jr., E R.,~Sundby, B.,~Malanotte-Rizzoli, P., and~Melillo, J M.: Watersheds, bays, and bounded seas, the science and management of semi-enclosed marine systems, Island Press, 288~pp., 2008. Vedrine, C., Leclerc, J. C., Durrieu, C., and Tran-Minh, C.: Optical whole-cell biosensor using chlorella vulgaris designed for monitoring herbicides, Biosens. Bioelectron., 18, 457–463, 2003. Vercoutere, W. and Akeson, M.: Biosensors for DNA sequence detection, Current Opinion In Chemical Biology, 6, 816–822, 2002. Volpe, G., Cotroneo, E., Moscone, D., Croci, L., Cozzi, L., Ciccaglioni, G., and Palleshi, G.: A bienzyme electrochemical probe for flow injection analysis of okadaic acid based on protein phosphatase-2a inhibition: An optimization study, Anal. Biochem., $385$, 50–56, 2009. Wang, J.: Electrochemical nucleic acid biosensors, Anal. Chim. Acta, 469, 63–71, 2002. Wilson, R., Ducamp, J.-J., Rees, W., Culik, B., and Niekamp, K.: Estimation of location: Global coverage using light intensity., in: Wildlife telemetry, edited by: Priede, I. G. and Swift, S., Ellis Horwood, New York, 131–134, 1992. Wilson, R. P., Steinfurth, A., Ropert-Coudert, Y., Kato, A., and Kurita, M.: Lip-reading in remote subjects an attempt to quantify and separate ingestion, breathing and vocalisation in free-living animals using penguins as a model, Mar. Biol., 140, 17–27, 2002. Zazoua, A., Hnaien, M., Cosnier, S., Jaffrezic-Renault, N., and Kherrat, R.: A new hrp/catalase biosensor based on microconductometric transduction for nitrite determination, Mater. Sci. Eng., $29$, 1919–1922, 2009. Zehr, J. P., Hewson, I., and Moisander, P.: Molecular biology techniques and applications for ocean sensing, Ocean Sci., 5, 101–113, 2009. Zhang, H. and Davison, W.: Diffusional characteristics of hydrogels used in dgt and det techniques, Anal. Chim. Acta, 398, 329–340, 1999.