Joanie Kleypas | National Center for Atmospheric Research (NCAR) (original) (raw)

Papers by Joanie Kleypas

Research paper thumbnail of An intermediate complexity marine ecosystem model for the global domain

Deep-sea Research Part Ii-topical Studies in Oceanography, 2001

A new marine ecosystem model designed for the global domain is presented, and model output is com... more A new marine ecosystem model designed for the global domain is presented, and model output is compared with field data from nine different locations. Field data were collected as part of the international Joint Global Ocean Flux Study (JGOFS) program, and from historical time series stations. The field data include a wide variety of marine ecosystem types, including nitrogen-and iron-limited systems, and different physical environments from high latitudes to the mid-ocean gyres. Model output is generally in good agreement with field data from these diverse ecosystems. These results imply that the ecosystem model presented here can be reliably applied over the global domain.

Research paper thumbnail of Rhodolith Beds Are Major CaCO3 Bio-Factories in the Tropical South West Atlantic

PLOS One, 2012

Rhodoliths are nodules of non-geniculate coralline algae that occur in shallow waters (,150 m dep... more Rhodoliths are nodules of non-geniculate coralline algae that occur in shallow waters (,150 m depth) subjected to episodic disturbance. Rhodolith beds stand with kelp beds, seagrass meadows, and coralline algal reefs as one of the world's four largest macrophyte-dominated benthic communities. Geographic distribution of rhodolith beds is discontinuous, with large concentrations off Japan, Australia and the Gulf of California, as well as in the Mediterranean, North Atlantic, eastern Caribbean and Brazil. Although there are major gaps in terms of seabed habitat mapping, the largest rhodolith beds are purported to occur off Brazil, where these communities are recorded across a wide latitudinal range (2uN -27uS). To quantify their extent, we carried out an inter-reefal seabed habitat survey on the Abrolhos Shelf (16u509 -19u459S) off eastern Brazil, and confirmed the most expansive and contiguous rhodolith bed in the world, covering about 20,900 km 2 . Distribution, extent, composition and structure of this bed were assessed with side scan sonar, remotely operated vehicles, and SCUBA. The mean rate of CaCO 3 production was estimated from in situ growth assays at 1.07 kg m 22 yr 21 , with a total production rate of 0.025 Gt yr 21 , comparable to those of the world's largest biogenic CaCO 3 deposits. These gigantic rhodolith beds, of areal extent equivalent to the Great Barrier Reef, Australia, are a critical, yet poorly understood component of the tropical South Atlantic Ocean. Based on the relatively high vulnerability of coralline algae to ocean acidification, these beds are likely to experience a profound restructuring in the coming decades.

Research paper thumbnail of Impact of Anthropogenic CO2 on the CaCO3 System in the Oceans

Science, 2004

Rising atmospheric carbon dioxide (CO 2 ) concentrations over the past two centuries have led to ... more Rising atmospheric carbon dioxide (CO 2 ) concentrations over the past two centuries have led to greater CO 2 uptake by the oceans. This acidification process has changed the saturation state of the oceans with respect to calcium carbonate (CaCO 3 ) particles. Here we estimate the in situ CaCO 3 dissolution rates for the global oceans from total alkalinity and chlorofluorocarbon data, and we also discuss the future impacts of anthropogenic CO 2 on CaCO 3 shellforming species. CaCO 3 dissolution rates, ranging from 0.003 to 1.2 micromoles per kilogram per year, are observed beginning near the aragonite saturation horizon. The total water column CaCO 3 dissolution rate for the global oceans is approximately 0.5 Ϯ 0.2 petagrams of CaCO 3 -C per year, which is approximately 45 to 65% of the export production of CaCO 3 .

Research paper thumbnail of An intermediate complexity marine ecosystem model for the global domain

Deep-sea Research Part Ii-topical Studies in Oceanography, 2001

A new marine ecosystem model designed for the global domain is presented, and model output is com... more A new marine ecosystem model designed for the global domain is presented, and model output is compared with field data from nine different locations. Field data were collected as part of the international Joint Global Ocean Flux Study (JGOFS) program, and from historical time series stations. The field data include a wide variety of marine ecosystem types, including nitrogen-and iron-limited systems, and different physical environments from high latitudes to the mid-ocean gyres. Model output is generally in good agreement with field data from these diverse ecosystems. These results imply that the ecosystem model presented here can be reliably applied over the global domain.

Research paper thumbnail of Rhodolith Beds Are Major CaCO3 Bio-Factories in the Tropical South West Atlantic

PLOS One, 2012

Rhodoliths are nodules of non-geniculate coralline algae that occur in shallow waters (,150 m dep... more Rhodoliths are nodules of non-geniculate coralline algae that occur in shallow waters (,150 m depth) subjected to episodic disturbance. Rhodolith beds stand with kelp beds, seagrass meadows, and coralline algal reefs as one of the world's four largest macrophyte-dominated benthic communities. Geographic distribution of rhodolith beds is discontinuous, with large concentrations off Japan, Australia and the Gulf of California, as well as in the Mediterranean, North Atlantic, eastern Caribbean and Brazil. Although there are major gaps in terms of seabed habitat mapping, the largest rhodolith beds are purported to occur off Brazil, where these communities are recorded across a wide latitudinal range (2uN -27uS). To quantify their extent, we carried out an inter-reefal seabed habitat survey on the Abrolhos Shelf (16u509 -19u459S) off eastern Brazil, and confirmed the most expansive and contiguous rhodolith bed in the world, covering about 20,900 km 2 . Distribution, extent, composition and structure of this bed were assessed with side scan sonar, remotely operated vehicles, and SCUBA. The mean rate of CaCO 3 production was estimated from in situ growth assays at 1.07 kg m 22 yr 21 , with a total production rate of 0.025 Gt yr 21 , comparable to those of the world's largest biogenic CaCO 3 deposits. These gigantic rhodolith beds, of areal extent equivalent to the Great Barrier Reef, Australia, are a critical, yet poorly understood component of the tropical South Atlantic Ocean. Based on the relatively high vulnerability of coralline algae to ocean acidification, these beds are likely to experience a profound restructuring in the coming decades.

Research paper thumbnail of Impact of Anthropogenic CO2 on the CaCO3 System in the Oceans

Science, 2004

Rising atmospheric carbon dioxide (CO 2 ) concentrations over the past two centuries have led to ... more Rising atmospheric carbon dioxide (CO 2 ) concentrations over the past two centuries have led to greater CO 2 uptake by the oceans. This acidification process has changed the saturation state of the oceans with respect to calcium carbonate (CaCO 3 ) particles. Here we estimate the in situ CaCO 3 dissolution rates for the global oceans from total alkalinity and chlorofluorocarbon data, and we also discuss the future impacts of anthropogenic CO 2 on CaCO 3 shellforming species. CaCO 3 dissolution rates, ranging from 0.003 to 1.2 micromoles per kilogram per year, are observed beginning near the aragonite saturation horizon. The total water column CaCO 3 dissolution rate for the global oceans is approximately 0.5 Ϯ 0.2 petagrams of CaCO 3 -C per year, which is approximately 45 to 65% of the export production of CaCO 3 .