Marine Atlas: Maximizing Benefits for Kiribati

THE DOSE MAKES THE POISON: PHOSPHATE AND NITRATE CONCENTRATION While nutrients including phosphate and nitrate provide much-needed nutrients for the marine food chain, too much from agricultural run-off and other sources negatively affect Kiribati’s coastal ecosystems.

The mounds of garbage on some coasts pose clearly visible problems. Other types of pollution are less visible—but every bit as serious. TRASH IN THE SURF, POISON IN THE SEA POLLUTION The mounds of garbage on some coasts pose clearly visible problems. Other types of pollution are less visible—but every bit as serious. TRASH IN THE SURF, POISON IN THE SEA POLLUTION

welling. Within Kiribati’s waters, the nitrate concentration ranges from 0.6 to 3.2 mmol m-3, with the highest concentrations again in the eastern island groups, particularly along the equator, but the South-West Tropi- cal Pacific (SWTP) is generally considered a nitrogen-limited area. Although not shown on the map, local- ized concentrations of both phosphate and nitrate are often higher around dense populations due to land and coast-

al inputs, which can include inorganic fertilizers, wastewater treatment from municipal sources, soaps and detergents. This is where the dose makes the poison: while phosphate and nitrate are impor- tant nutrients, too much of them can be bad for marine and coastal ecosystems. In Kiribati’s waters, there is certainly no shortage of sun, and thus photosyntheti- cally available radiation, but there is a general limit of phosphate and nitrate. Once these nutrients are added from

On a global scale, Kiribati’s waters have a moderately low phosphate concentration, ranging from 0.28 to 0.51 umol/L. Higher concentrations are observed in the eastern island groups (Line and Phoenix), particular- ly along the equator. Generally, the highest phosphate concentrations are found in high latitudes and in areas of coastal upwelling. A similar pattern can be seen in global nitrate concentrations, which are generally low, with the highest concentrations found in high latitudes and some areas of coastal up-

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NITRATES AND PHOSPHATES CAUSES: Industrial agriculture like intensive animal husbandry and intensive crop cultivation. EFFECTS AND TRENDS: Since the 1950s and 1960s agriculture around the world has developed into a m ssive industry. Discharge of animal manure and artificial fertilizer reach rivers via groundwater and end up in the ocean, resulting in dead zones off the coasts. International agreements attempt to combat these effects by reducing discharges.

NITRATES AND PHOSPHATES CAUSES: Industrial agriculture like intensive animal husbandry and intensive crop cultivation. EFFECTS AND TRENDS: Since the 1950s and 1960s agriculture around the world has developed into a massive industry. Discharge of animal manure and artificial fertilizer reach rivers via groundwater and end up in the ocean, resulting in dead zones off the coasts. International agreements attempt to combat these effects by reducing discharges.

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PHOSPHATE CONCENTRATION (umol/L)

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Kiribati Provisional EEZ Boundary

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PLASTIC WASTE CAUSES: Only 20 percent of the plastic waste that ends up in the ocean actually comes from the ocean. The other 80 percent comes from dry land, mainly from countries where there is no, or very poor, waste management. EFFECTS AND TRENDS: Five large garbage patches are known. Most garbage, however, land on coastlines around the world and is thus a global problem. In 2015, for example, 100 cubic meters of plastic aste collected on the coast of Spitsbergen, a remote island halfway be- tween Norway and the North Pole. The mounds of trash grow larger each year.

Copyright © MACBIO Map produced by GRID-Arendal Sources : Becker et al, 2009; Claus et al, 2016; IHO-IOC GEBCO, 2017; Smith and Sandwell, 1997.

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CHEMICALS AND HEAVY METALS CAUSES: Industrial wastewater and waste gas, mining, burning heating oil. EFFECTS AND TRENDS: According to the OECD, there are around 100,000 different chemical substances in circulatio around the orld. They include heavy metals like lead and mer- cury but also persistent organic pollutants (POP). Many of these substances are highly problematic because they accumulate in the bodies of marine organisms, entering the food chain where they pose a risk to human health.

PLASTIC WASTE CAUSES: Only 20 percent of the plastic waste that ends up in the ocean actually comes from the ocean. The other 80 percent comes from dry land, mainly from countries where there is no, or very poor, waste management. EFFECTS AND TRENDS: Five large garbage patches are known. Most garbage, however, lands on coastlines around the world and is thus a global problem. In 2015, for example, 100 cubic meters of plastic waste collected on the coast of Spitsbergen, a remote island halfway be- tween Norway and the North Pole. The mounds of trash grow larger each year.

CHEMICALS AND HEAVY METALS CAUSES: Industrial wastewater and waste gas, mining, burning heating oil. EFFECTS AND TRENDS: According to the OECD, there are around 100,000 different chemical substances in circulation around the world. They include heavy metals like lead and mer- cury but also persistent organic pollutants (POP). Many of these substances are highly problematic because they accumulate in the bodies of marine organisms, entering the food chain where they pose a risk to human health.

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land-based activities such as farming and wastewater treatment, primary produc- tivity increases dramatically. The impact of too many nutrients (eutrophication) is especially significant in coastal waters, such as enclosed lagoons, where increased

nutrients can result in algal blooms. These blooms can affect coastal habitats such as coral reefs by smothering, in the case of macro-algae, or limiting light availability, which can lead to rapid declines in reef biodiversity (Fabricius, 2005).

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THREATS MAXIMIZING BENEFITS FOR KIRIBATI

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