Glossary M – P

| M | N | O | P |

M

Macroalgae

Macroalgae ('seaweeds') are an ancient class of large multicellular plants that resemble vascular plants but lack the complex array of tissues used for reproduction and water transport. More information

Macroinvertebrates

Benthic macroinvertebrates are organisms that live on the bottom of a water body (or in the sediment), have no backbone and are >50 cm in length.

Macrotidal

Coastal ocean or waterway with a high mean tidal range, e.g. greater than 4 metres.

Mangroves

Mangroves comprise several species of trees and shrubs that grow along sheltered intertidal shores, mainly in tropical & subtropical coastal waterways. More information

Marine pests

Marine pests are introduced species that threaten human health or environmental and economic values. More information

Marine Protected Areas

Marine Protected Areas are areas of sea that are dedicated to the protection and maintenance of biodiversity and natural and cultural resources. They are Commonwealth reserves under the EPBC Act. More information

Matters for target

Matters for target are broad themes within the National Monitoring and Evaluation Framework against which reports are made using a range of indicators and report cards. These broad themes include land salinity, soil condition, native vegetation communities' integrity, Inland aquatic ecosystems' integrity (rivers and other wetlands), estuarine, coastal and marine habitats' integrity, nutrients in aquatic environments, turbidity/suspended particulate matter in aquatic environments, surface water salinity in freshwater aquatic environments, significant native species and ecological communities, and ecologically significant invasive species. More information

Maturity Index

The "maturity index" of an estuary is the ratio of the present water surface area (Ap), to its palaeo-water area (Ao) referenced to around 6,500 years before present, when sea level achieved its present position. More information

Mesotidal

Coastal ocean or waterway with a moderate mean tidal range, e.g. between 2 and 4 metres.

Metal Adsorption

The adherence of one substance (atoms, ions or molecules) to the surface of a solid substance with which is has been brought in contact.

Metal contaminants

Metal contaminants comprise metals and metalloids found in concentrations that exceed national guidelines. More information

Micro community

An assemblage of species within a facies that depend on facies member species. Many landscape managers assume that conservation of the facies will generally safeguard the conservation of associated micro communities [1].

Butler, A., P. Harris, et al. (2001). An Interim Bioregionalisation for the continental slope and deeper waters of the South-East Marine Region of Australia., National Oceans Office.

Microinvertebrates

Microinvertebrates are microscopic invertebrates ( < 10 mincrons) that live on the bottom of a water body (or in the sediment) and have no backbone.

Microtidal

Coastal ocean or waterway with a low mean tidal range, e.g. less than 2 metres.

Monitoring

Monitoring is regular gathering of information, and the preliminary analysis of this information, in order for for day-to-day management or evaluation. More information

Mouth

The entrance of the coastal waterway, or the place where the sea meets or enters the coastal waterway.

Mud

Fine sedimentary material, typically comprising both inorganic (mineral) and organic material.

Multi(ple) Criteria Analyses

Multi(ple) Criteria Analyses are methods for weighting and aggregating data, and prioritising options and alternatives. More information

Multibeam Sonar or Swath Echosounders

A multibeam sonar is an echo sounder which transmits a wide acoustic pulse which extends to either side of the ship, in a manner similar to a sidescan sonar. The receive transducer array resolves the returning signal into numerous beams, recording two-way travel time, and angle of arrival for each beam. In this way, accurate depth soundings (or bathymetry) are achieved for the entire swath. The accuracy of a multibeam sonar is critically dependant on corrections applied for vessel motion (e.g. pitch, roll, yaw, heave), and spatial location, which is achieved by a highly accurate global positioning system (GPS). Consequently, multibeam sonars require real time integration with a number of other specialist sensor systems. Various multibeam sonars are appropriate for use in a range of water depths and environments. High resolution systems (over 400 kHz) can achieve < 1 cm vertical resolution, have over 200 very narrow beams (around 0.5°) and swath widths of approximately 3 - 4x water depth in shallow water (~50 m). Conversely, low-frequency systems are available that can be used in great depths (e.g. several km), however these have lower resolution and much larger beam 'footprints'. Multibeam sonar systems can also provide 'backscatter' information (e.g. reflected sound intensity) in a manner similar to a sidescan sonar, which is useful for determining seabed character.

N

National

An adjective describing something that is produced or agreed by jurisdictions at all levels including the Australian Government, State/NT Governments, NRM Regions and Local Governments.

National Action Plan for Salinity and Water Quality

The National Action Plan for Salinity and Water Quality (NAP) is a commitment by the Australian, state and territory governments to jointly fund actions tackling major NRM issues facing Australia's rural industries, regional communities and our unique environment. It supports practical remedies such as improvements to native vegetation, engineering works, the protection and rehabilitation of waterways and land and water use changes. More information

National Estuarine Environmental Condition Assessment Framework (NEECAF)

A framework for reporting on the broad ecological integrity of estuaries at a national level, developed and adopted by regions states/territories and the Australian Government.

National Intertidal/Subtidal Benthic Habitat Classification Scheme (NISB)

The National Intertidal/Subtidal Benthic Habitat Classification Scheme (NISB) was designed to support the production of maps for the purpose of representing areas of marine and coastal habitats at the national scale [1,2]. The scheme is hierarchical and initially divides habitats according to broad substrate type, and then according to whether they are spatially dominated by "structural macrobiota" (SMB) or by the substrate (i.e. largely "bare" of visible biota) [1,2].

National Intertidal/Subtidal Benthic Habitat Classification Scheme

Figure 1. National Intertidal/Subtidal Benthic Habitat Classification Scheme

References

Mount, R.E. and P.J. Bricher, 2008a. Estuarine, Coastal and Marine (ECM) National Habitat Mapping Project, Project Report, Version 1 February 2008. Spatial Science Group, School of Geography and Environmental Studies, University of Tasmania. Report to the Department of Climate Change and the National Land and Water Resources Audit, Canberra, ACT
Mount, R.E. and P.J. Bricher, 2008b. Estuarine, Coastal and Marine (ECM) National Habitat Map Series User Guide Version 1 February 2008. Spatial Science Group, School of Geography and Environmental Studies, University of Tasmania. Report to the Department of Climate Change and the National Land and Water Resources Audit, Canberra, ACT.

National Monitoring and Evaluation Framework (NM&EF), Australian

The National Monitoring and Evaluation Framework (NM&EF) was established in 2002 to assess the health of Australia's land, water and biological resources, and the performance of NHT/NAP (and other) government programs. More information

National outcomes, NRM

National outcomes are aspirational statements about a desired national natural resource result. More information

Native vegetation

Native vegetation is defined as vegetation that is indigenous to a given state, including trees, shrubs, understory plants and some specified grasslands. More information

Natural Heritage Trust

The Natural Heritage Trust (the Trust) was established by the Australian Government in 1997 to help restore and conserve Australia's environment and natural resources. More information

Nautical Mile

A nautical mile (M) is a unit of distance equal to 1,852 metres. More information

Neap Tide

Tide smaller than the mean tidal range. Occurs about every two weeks, during half-Moons.

Near-pristine estuaries

Near-pristine estuaries are coastal waterways that have not been significantly impacted upon by humans, and are considered to exist in an essentially natural state. As summarised in Table 1, near-pristine estuaries are not used for aquaculture, fishing is limited and sustainable and water movements through the estuaries and fringing wetlands have not been altered by roads or engineering structures (e.g. training walls, causeways and barrages). In addition, the catchments of near-pristine estuaries retain most of their natural vegetation cover.

Physical Characteristics	Condition
Catchment natural cover	>90%
Land use	Limited roads and disturbance to natural conditions and processes
Catchment hydrology	No dams or impoundments, virtually nil abstraction
Tidal regime	No impediments to tidal flow, changes from natural morphology (e.g. Training walls, barrages, bridges and causeways)
Floodplain	Wetlands intact in vegetation and hydrology, no alterations to flood pattern
Estuary use	Extractive activities limited to indigenous or limited and sustainable commercial and recreational fishing, no aquaculture
Pests and weeds	Minimal impact on estuary from catchment weeds and limited pests and weeds within estuary
Estuarine ecology	Ecological systems and processes intact (e.g. benthic flora and fauna)

Table 1. The criteria used during the first National Land and Water Resources Audit to define a near-pristine estuary (NLWRA, 2002 [1]).

NLWRA (2002) Australian Catchment, River and Estuary Assessment 2002, Vol 1. National Land and Water Resources Audit, Commonwealth Government, Canberra.

More information

NEECAF

Commonly used abbreviation for the National Estuarine Environmental Condition Assessment Framework.

Negative Estuary

An estuary in which evaporation exceeds freshwater inflow and therefore hypersaline conditions exist.

Nephelometry

Nephelometry is a kind of turbidity measurement in which the intensity of light scattered by a sample is compared with the intensity of light scattered by a standard reference suspension under the same conditions. More information

N-Fixation

Conversion of N2 gas to a form that is available for use by organisms.

NISB

Abbreviation for National Intertidal/Subtidal Benthic Habitat Classification Scheme.

Nitrification

Nitrification or 'ammonium oxidation' is a two-step respiratory process occurring in sediment (benthic nitrification) or the water column (pelagic nitrification) in which bacteria oxidise ammonium (NH₄) to nitrite (NO₂) and nitrate (NO₃).

(Eq. 1) NH₄⁺ + 1.5O₂ = NO₂^- + H₂O + 2H⁺
(Eq. 2) NO₃^- + 0.5O₂ = NO₃^-

Nitosomonous spp. and Nitrobacter spp. are the main organisms responsible for steps (Eq. 1) and (Eq. 2) respectively. Nitrification exerts an important influence on marine primary productivity because:

it modifies the form of nitrogen released during the decomposition of organic matter);
it shunts nitrogen to denitrification pathways; and
it competes with heterotrophic bacteria for dissolved oxygen supplies [1]. Water temperature is the most important factor regulating benthic and pelagic nitrification rates in estuaries [2].

Henriksen, K, and Kemp, W.M. 1988. Nitrification in Estuarine and Coastal Marine Sediments, pp. 207-249 in T.H. Blackburn and J. Sorensen (eds.), Nitrification in Estuarine and Coastal Marine Sediments. Nitrogen Cycling in Coastal Marine Environments, John Wiley and Sons Ltd.
Berounsky, V.M. and Nixon, S.W. 1990. Temperature and the annual cycle of nitrification in waters of Narragansett Bay. Limnology and Oceanography 35, 1610-1617.

Nitrate

Nitrate is a dissolved (oxidised) nitrogen species with an empirical formula of NO3-. It consists of a central nitrogen atom surrounded by three identical oxygen atoms. More information

Nitrite

Nitrite is a dissolved (oxidised) nitrogen species with an empirical formula of NO2-. More information

Nitrogen fixation, biological

Biological nitrogen fixation is the reduction of dinitrogen (N₂) to ammonia (NH₃). The reaction can be represented as:

N₂ + 3H₂ = 2NH₃

The process is catalysed by the enzyme nitrogenase and is conducted by a large range of nitrogen-fixing bacteria such as Rhizobium and cyanobacteria. A broad range of environmental and biochemical factors can affect the nature and extent of nitrogen fixation within a particular environment or system. Light, water temperature, pH, salinity, dissolved oxygen, trace elements, inorganic nitrogen and organic substrate availability have all been shown to modulate nitrogenase activity in specific situations [2].

Postgate, J.R. 1998. Nitrogen Fixation. 3rd Edition. Canbridge University Press, London.
Capone, D.G. 1988. Benthic Nitrogen Fixation. In: Blackburn, T.H. and Sorensen, J. (eds.) Nitrogen Cycling in Coastal Marine Environments, pp. 85-123. Wiley & Sons, New York.

Non-point Sources

A source of sediment or nutrients that is not restricted to one discharge location.

NOX

NOX refers to the sum total concentration of oxidised forms of nitrogen in a sample. Those oxidised forms of nitrogen include nitrite (NO2-) and nitrate (NO3+). More information

NRM

NRM is a the commonly used abbreviation for Natural Resource Management

NRM regions

The Australian Government, in association with state and territory governments, identified 56 regions covering all of Australia in order to facilitate the integrated delivery of Natural Resource Management (NRM). NRM is delivered via the integrated implementation of the National Action Plan for Salinity and Water Quality and the Natural Heritage Trust, and relies on the cooperation of governments at all levels. More information

NRM toolbar

The NRM Toolbar comprises online tools and databases that simplify the process of finding and sharing NRM information. Once downloaded (http://www.nrmtoolbar.net.au/home), the NRM Toolbar provides a single point of access to the NRM Search Engine. It was designed by the Knowledge for Regional NRM programme at Land & Water Australia.

Nutrients

Nutrients are the essential building blocks for plant and animal growth. They comprise nitrogen (N) and phosphorus (P), as well as metals, such as copper, zinc and chromium, when present at low concentrations (micronutrients). More information

O

Ocean Acidification

Ocean acidification is the reduction of the pH of the world's oceans due to higher CO2 concentrations in the atmosphere. More information

Organic Material

Once-living material (typically with high carbon content), mostly of plant origin. More information.

Optically Stimulated Thermoluminescence Dating (OSL)

When quartz grains are buried, they begin to accumulate a trapped-charge population that increases in a measurable and predictable way in response to the ionising radiation to which the grains are exposed. Exposure to sunlight releases the light-sensitive trapped charge, thereby resetting the OSL signal: this process is commonly referred to as ‘bleaching'. The time elapsed since sediment grains were last exposed to sunlight can be determined by measuring the OSL signal from a sample of sediment, determining the De that this represents, and estimating the rate of exposure of the grains to ionising radiation since they were buried [1,2]. The latter parameter of interest is termed the dose rate (Dr) and the burial age of well-bleached grains may be obtained from the following equation:

Burial age (years) =

De (Gy)
Dr (Gy year^-1)

(Gy = gray, where 1 Gy = 1 J/kg)

When clean quartz grains are exposed directly to sunlight, the OSL signal is reduced to a negligible level within a few seconds [2,3]. However, incomplete or non-uniform bleaching is commonplace in many depositional environments [4], due to surface coating on grains and/or poor exposure to sunlight during sediment transport. This results in grains being deposited with a heterogeneous distribution of residual trapped charge and a correspondingly wide range of measured De values. For such sediments, Olley et al. [5,6] suggested that the population of grains with lowest measured De values provides the most accurate estimate of Db: the burial dose to which those grains that were well bleached at deposition have been exposed since the most recent transport event.

Huntley D.J., Godfrey-Smith D.I., Thewalt M.L.W., 1985. Optical dating of sediments. Nature 313, 105-107.
Aitken, M.J., 1998. An Introduction to Optical Dating: The Dating of Quaternary Sediments by the Use of Photon-stimulated Luminescence. Oxford University Press, Oxford.
Wintle, A.G., 1997. Luminescence dating: laboratory procedures and protocols. Radiation Measurements 27, 769-817.
Murray, A.S., Olley, J.M., 2002. Precision and accuracy in the optically stimulated luminescence dating of sedimentary quartz: a status review. Geochronometrica 21, 1-16
Olley, J.M., Caitcheon, G.G., Roberts, R.G., 1999. The origin of dose distributions in fluvial sediments, and the prospect of dating single grains of quartz from fluvial deposits using optically stimulated luminescence. Radiation Measurements 30, 207-217.
Olley, J.M., Pietsch, T., Roberts, R.G., 2003. Optical dating of Holocene sediments from a variety of geomorphic settings using single grains of quartz. Submitted to Geomorphology

Author

Jon Olley, CSIRO Land and Water

Oxidation-Reduction Reactions

Oxidation-reduction or 'redox reactions' involve a transfer of electrons, and cause changes in the oxidation state of both the reactants and the products. Oxidation is the loss of electrons and reduction is the gain of electrons. Redox reactions are important in marine systems because the chemical properties of many elements change depending on their oxidation state: for example sulphate (SO₄^2-) and hydrogen sulfide gas (H₂S) formed by sulfate reduction have very different physical, chemical and ecotoxological properties.The redox condition of a solution is usually expressed in terms of pE, which is dimensionless, or Eh which is measured in volts.

P

Particulate Nitrogen (PN)

Comprises nitrogen compounds associated with or a constituent of mineral particles and organic material. More information.

Particulate Organic Matter

Particulate organic matter (POM) is organic matter that is retained on a 0.45 µm sieve. It consists of living organisms (phytoplankton, bacteria and animals) and detritus (e.g. biogenic material in various stages of decomposition). POM may be coarse or fine in size: coarse particulate organic matter (CPOM) is larger than 1 mm; and fine particulate organic matter (FPOM) is smaller than 1 mm.

Partitioning

Partitioning refers to the transfer of solutes (including contaminants such as heavy metals) between different phases and biological components (benthos and plankton) in natural waters. Solid phases include bottom sediments and suspended sediments and soluble phases refer to dissolved species in the water column.

Particulate nitrogen

Particulate nitrogen consists of nitrogen in plants and animals, and their remains, as well as ammonium (NH4+) adsorbed onto mineral particles. More information

Particulate phosphorus

Particulate phosphorus consists of phosphorus in plants and animals, and their remains, phosphorus in minerals (e.g. fluorapatite) and phosphate adsorbed onto iron oxyhydroxides on mineral surfaces. More information

Pathogen

A pathogen is a causative agent of disease. Microbial pathogens are microscopic organisms including bacteria, viruses, protozoa and fungi. More information

Pelagic Fish

Pelagic fish are fish that live in the water column.

pH

pH is a measure of acidity or alkalinity of water on a log scale from 0 (extremely acidic) through 7 (neutral) to 14 (extremely alkaline). It is the negative base-10 log of the hydrogen ion (H+)activity in moles per litre. More information

Photosynthesis

Photosynthesis, primary production, carbon production or simply 'production' is the process whereby pigments such as chlorophyll a in plants and algae capture sunlight and covert it to organic matter and oxygen. Plankton generally has a Redfield molar proportion (e.g. C₁₀₆H₂₆₃O₁₁₀N₁₆P₁). Therefore photosynthesis by phytoplankton can be represented by the following reaction [1]:

106CO₂ + 16 NO₃^- + HPO₄^2- + 122H₂O + 18H⁺ + (solar energy, trace elements) = C₁₀₆H₂₆₃O₁₁₀N₁₆P₁ + 138O₂

A maximum photosynthetic rate (P-max) is attained when an increase in light level no longer causes an increase in production rate (Figure 1).

Pmax is the maximum photosynthetic rate. It is achieved at a certain light level for which any increase in light does not increase the production rate. However, a decrease may occur due to high light levels and is called photoinhibition (Contributed by Samantha Wellman, University of Newcastle).

Figure 1. Pmax is the maximum photosynthetic rate. It is achieved at a certain light level for which any increase in light does not increase the production rate. However, a decrease may occur due to high light levels and is called photoinhibition (Contributed by Samantha Wellman, University of Newcastle).

Drever, J.I. 1982. The Geochemistry of Natural Waters, Prentice-Hall, Inc., Englewoods Cliffs, N.J., pp. 388.

Phosphate

Phosphate is a dissolved inorganic species of phosphorus with an empirical formula of PO43-. It is often reported as filterable reactive phosphorus or FRP. More information

Phytoplankton

Microscopic, planktonic plants which exist within the water column.

Piscivorous Fish

Piscovorous fish are fish that feed on other fish.

Planktivorous Fish

Planktivorous fish are fish that feed on plankton.

Point Sources

A source of sediment or nutrients that is restricted to one discharge location.

Precipitation

A chemical reaction in which a previously dissolved substance forms an insoluble solid substance which drops out of solution (i.e. precipitates).

Pressures, causal pressures

In Natural Resource Management, causal pressures are the driving forces behind changes in waterways. Causal pressures often result from human activities and uses, although natural climate change and natural disasters can also constitute causal pressures or ecosystem forcing functions. More information

Prograde

The outward building of a sedimentary deposit, such as the seaward advance of a delta or shoreline.

Prograding Coastlines

Coastal regions in which water has withdrawn from parts of the land surface due to a fall in sea level relative to the land are called prograding coastlines.

Pyrite Oxidation

Pyrite (FeS₂) is an iron sulfide mineral that is formed through the process of sulfate reduction. Pyrite is stable under anoxic conditions. However, on exposure to air, a mole of pyrite oxidises to form 2 moles of sulfuric acid in a 3 step reaction [1]:

(Eq. 1) FeS₂ + 7/2O₂ + H₂O = Fe²⁺ + 2SO₄^2- + 2H⁺
(Eq. 2) Fe²⁺ + 1/4O₂ + 3/2H₂O = FeOOHppt + 2H⁺
(Eq. 3) FeS₂ + 15/4O₂ + 7/2H₂O = Fe(OH)₃ppt + 2SO₄^2- + 4H⁺

Aluminium and Iron Mobilisation

The sulfuric acid formed in sulfate reduction may then react with clay minerals to release silica and metals of which aluminum (Al³⁺), iron (Fe²⁺), potassium (K⁺), sodium (Na⁺) and magnesium (Mg²⁺) are most abundant [1]:

(Eq. 4) (K_0.5N_0.36Ca_0.05)(Al_1.5Fe_0.25Mg_0.3)(Al_0.45Si_3.46)O₁₀(OH)₂ + 7.41H⁺ + 2.59H₂O = 0.5K⁺+ 0.36Na⁺ + 0.05Ca²⁺+ 0.3Mg²⁺ + 0.25Fe(OH)₃ + 1.95Al³⁺ + 3.46H₄SiO₄

Manganese and metal contaminants may also be released in the process [1].

Sammut, J., White, I., Melvilles, M.D. 1996. Acidification of an estuarine tributary in eastern Australia due to drainage of acid sulphate soils, Marine and Freshwater Research 47, 669-684.